Savannah State University
Savannah State University
College of Sciences and Technology
Department of Natural Sciences and Mathematics
Marine Science Program
Syllabus Supplement
MSCI 1501K – Introduction to Marine Biology Fall 2011 Dr. M. Gilligan
Vocabulary:
Abyssopelagic Abiotic Adaptation Aerobic Ampulla Algae Amphineura Amphipoda Anaerobic Respiration Annelida Anoxic Anterior Aphotic Aposematic Aquaculture Aschelminthes Asexual Autotroph Baleen Barnacle Bathyal Bathypelagic Benthos Biochrome Biological clock Bioluminescence Biomass Biota Biotic community Brackish Bryozoa Byssal threads Calcareous Carapace Carnivore Cartilagenous Carotin Cephalopoda Cephalothorax Cerrata Cetacea Chaetae Chaetognatha Chela Chemosynthesis Chitin Chiton Chlorophyta Chromatophore Chrysophyta Cilium Ciguaterra Cirri Cirripedia Cnidoblast Coccolithophore Coelenterata Coelom Colonial animals Comb jelly Commensalism Community Compensation depth CaO3 Compensation depth Competition Copepoda Coral Crustacea Ctenophora Cypris Decapoda Decomposers Deep scattering layer Demersal Deposit feeder Dessication Detritus Diatom Diffusion Dinoflagellates Dolphin Dorsal Echolocation - Echinodermata Ecological efficiency Ecosystem Ectoderm Epifauna Epipelagic Estuary Euphotic zone Euryhaline Eurythermal Eutrophic Exoskeleton Fathom Fauna Fecal pellets Filter feeder Flagellum Flora Flotsam Food chain Food web Foraminafera Fouling Fringing reef Frustule Fucoxanthin Gastropoda Gill Habitat Hadal Herbivore Hermaphroditic Hermatypic coral Heterotroph Holdfast Holoplankton Homologous us. Hydrostatic skeleton Hydrothermal vent Hydrozoa Hypertonic Hypotonic Infauna In situ Intertidal Irridiophore Isohaline Isopoda Isotonic Isotope Jellyfish Key (Cay) Kelp Kelvin temperature scale (K) Knot(kt) Krill Larva Leeward Limpet Littoral Lophophore Mantle Mariculture Medusa Meroplankton Metazoans Mimicry Mollusca Molt Monera Mutualism Mycota Nanoplankton Natural selection Nauplius. Neap Tide Nektobenthos Nekton Neritic province Neritic sediment Neuston Niche Nitrogen Fixation Nudibranch Nutrientss. Obliterative counter-shading Oceanic Olfaction Offshore Omnivore Operculum Osmosis Osmotic pressure Otolith Parapodia Parasite Parasitism Pelagic Phaeoophyta Photophore Phytoplankton Piscivore Planktivore Plastron Polyp Population Porifera Port Predation Primary productivity Primary consumer Protista Protoplasm Protozoa Pseudopodia Pteropoda Pycnogonid Pyrrophyta Radial symmetry Radiata Radiolaria Ray Red tide Reef Respiration Rhodophyta Sabellid Salinity Salpa Salt marsh Saprophyte Sargasso Sea Sargassum Scaphopoda Scavenger Schematochome SCUBA Scyphozoant Sea anemone Sea cow Sessile Silaceous Siphon SONAR Species Spicule Spring tide Statocyst Stenohaline Stenothermal Starboard Stern Sublimination Sublittoral Substrate Supralittoral Surf zone Suspension feeder Swim bladder Symbiosis Taxon Taxonomy Tintinnid Tissue Trawl Trophic level Tube worms Tunicates Turbidity Ultraplankton Valve Veliger Ventral Vertebrata Water vascular Wrack Zonation Zooplankton Zooxanthellae
Taxa you must know: Metazoa Monera Protista Fungi Metaphyta Schizophyta Cyanophyta Chrysophyta Phaeophyta Chlorophyta Protozoa Rhodophyta Porifera Cnidaria (Coelenterata) Ctenophora Platyhelminthes Nemertea Nematoda Annelida Brachiopoda Bryozoa Mollusca Chordata Arthropoda Echinodermata Chaetognatha Hydrozoa Anthozoa Scyphozoa Polyplacophora(Amphineura) Gastropoda Bivalvia Cephalopoda Crustacea Asteroidea Ophiuroidea Echinoidea Holothuroidea Crinoidea Agnatha Chondrichthys Osteichthys Amphibia Reptilia Aves Mammalia Crustacea Cetacea Carnivora Sirenia Amphipoda Cirripedia Copepoda Decapoda Isopodqa Mysticeti Odontoceti
Mathematics Across the Curriculum (see problems after unit outlines below)
Provisional Lecture, Lab, Field Activity Schedule Spring 2009 (see attached)
* Exact dates are not given in advance because field/boat-based and field/boat-dependent exercises are scheduled when boats are available and when tides and weather permit and because some topics take more than one class period to complete.
Unit Learning Objectives, Outlines, Questions, Critical Thinking Essays, Doing the Math (from PINET Ch. 9,10,12,13,14,15)
Unit 1: Marine Ecology
Learning Objectives
1. Learn the major habitats and life styles of marine organisms and the controlling environmental factors of each.
2. Learn the basic classification of marine organisms.
3. Understand the various environmental factors that control the distribution and behavior of organisms.
9-1. Ocean Habitats
A. There are two major marine provinces: the benthonic (bottom) and the pelagic (water column).
1. The benthonic environment is divided by depth into the:
a. Intertidal zone - the area between the low and high tide.
- It is sometimes called the littoral zone.
b. Sublittoral zone - from the low tide mark to the shelf break, about 200 m deep.
- This area essentially coincides with the continental shelf.
c. Bathyal zone - from the shelf break to 2000 m.
- This area coincides with the continental slope and rise.
d. Abyssal zone - from 2000 to 6000 m.
- This includes the average depth of the deep ocean floor.
e. Hadal zone - sea floor deeper than 6000 m.
- This includes the trenches, the deepest part of the sea floor.
2. The pelagic environment is divided into the:
a. Neritic Zone - shallow water above the continental shelf.
- The neritic water column is generally illuminated throughout.
b. Oceanic Zone - deep water of the open ocean beyond the shelf break.
- The oceanic water column is usually subdivided by depth into the following zones:
1. Epipelagic zone - from the surface to 200 m, the maximum depth of light penetration.
2. Mesopelagic zone - between 200 and 1000 m.
3. Bathypelagic zone - between 1000 and 2000 m.
4. Abyssopelagic zone - between 2000 and 6000 m.
5. Hadalpelagic zone - any depth deeper than 6000 m.
B. The ocean can also be divided into zones based upon depth of light penetration.
1. The photic zone is the depth where light is sufficient for photosynthesis.
- It varies from about 20 m on the shelf to about 100 m in the open ocean, depending upon clarity of the water.
2. The dysphotic zone is where illumination is too weak for photosynthesis.
- It varies in depth from 100 to 200 m.
3. The aphotic zone receives no light from the surface because it is all absorbed by the water above.
9-2. Classification of Organisms
C. In 1735 Linnaeus developed the taxonomic classification used in zoology.
1. The categories are from largest to smallest: Kingdom, Phylum, Class, Order, Family, Genus, and Species.
2. The name of a species consists of the genus name combined with a trivial name.
- The genus name begins with a capital.
D. The five major kingdoms in the ocean are: Monera, Protista, Fungi, Metaphyta, and Metazoa.
1. Monera are the bacteria and blue-green algae.
a. Bacteria are important for decomposition and release of nutrients.
b. Blue-green algae are single cells which lack a nucleus and are important for converting ammonia and nitrogen into nitrates and nitrites.
2. Protista are single-celled organisms with a nucleus.
a. This kingdom includes plants and animals such as the foraminifera, coccoliths, diatoms, and radiolarians.
b. These groups are responsible for most deep sea oozes.
3. Fungi are abundant in the intertidal zone and are important in decomposition.
4. Metaphyta are the plants that grow attached to the sea floor.
a. This kingdom includes the red, brown, and green algae and the advanced plants of the salt marshes and coastal swamps.
b. They are only found in shallow areas where the bottom is in the photic zone.
5. Metazoa include all multicellular animals in the ocean.
9-3. Classification by Lifestyle
E. Marine organisms can also be classified by lifestyle.
1. Plankton are the organisms which float in the water and have no ability to propel themselves against a current.
a. Many forms undergo vertical migration in the water column.
b. They can be divided into phytoplankton (plants) and zooplankton (animals).
2. Nekton are active swimmers.
a. They include marine fish, reptiles, mammals, birds, and others.
b. The larger members of this group can swim against currents and have special adaptations for locomotion.
c. Their distribution is generally controlled by temperature and salinity.
3. Benthos are the organisms which live on the bottom (epifauna) or within the bottom sediments (infauna).
- Plants are restricted to the photic zone, but animals and bacteria survive at all depths.
4. Some organisms cross from one lifestyle to another during their life, being pelagic early in life and benthonic later.
9-4. Basic Ecology
F. Environmental factors in the marine environment include: temperature, salinity, pressure, nutrients, dissolved gases, currents, light, suspended sediments, substrate (bottom material), river inflow, tides, and waves.
1. Ecosystem is the total environment including the biota (all living organisms) and non-living physical and chemical aspects.
2. Temperature can control distribution, degree of activity, and reproduction of an organism.
a. Temperature controls the rate of chemical reactions within organisms and therefore controls their rate of growth and activity.
b. For every 10oC rise in temperature activity rates double.
- In polar waters animals grow more slowly, reproduce less frequently and live longer than do the same organisms in the tropics.
c. Tolerance to variation in temperature varies greatly between species and during an organism’s life span.
d. Temperature can indirectly control organisms by limiting their predators or restricting pathogens.
3. Salinity can control the distribution of organisms and force them to migrate in response to changes in salinity.
a. Availability of various dissolved chemicals can limit an organism’s ability to construct shells.
b. Epipelagic organisms tend to be more tolerant of changes in salinity because their environment is more subject to changes than in the deeper ocean.
c. Marine organisms’ body fluids are similar to that of sea water in the proportion of salts but not in salinity.
d. Diffusion is the physical process whereby molecules move from areas of higher concentration into areas of lower concentration.
e. Osmosis is the movement of water molecules through the cell membrane from where salinity is lower to where it is higher.
- Osmosis can result in the dehydration of the cell if the surrounding water is more saline or in the rupturing of the cell if it is more saline than the surrounding water.
f. Osmoregulation is the control of diffusion through the cell wall and the maintenance of sufficient body fluids.
1. Some marine organisms drink large amounts of water and have chloride cells which extract and dispose of excess salts, leaving the body with a ready supply of water to replace that lost by diffusion.
2. Freshwater organisms tend not to drink and have kidneys which produce large amounts of very dilute urine to dispose of excess water gained by diffusion.
4. Hydrostatic pressure is the pressure exerted by a column of water surrounding an organism.
a. Amount of hydrostatic pressure is determined by the height of the water column and the water’s density, which is a function of the temperature, salinity, and turbidity.
b. 10m of water exerts the pressure of 1 atmosphere or 14.7 lbs/in2.
c. Gases are highly compressible as pressure increases, but water is not.
1. Because the bodies of deep-ocean fishes lack an air bladder and are composed of mostly water, they are not sensitive to changes in pressure.
2. Fishes of the mesopelagic and shallower zones have a gas bladder and can be killed by a sudden change in hydrostatic pressure.
9-5. Selective Adaptive Strategies
G. More than 90% of marine plants are algae and most are unicellular and microscopic.
1. To photosynthesize (produce organic material from inorganic matter and sunlight) plants must remain within the photic zone.
a. Plants are more dense than water and have a tendency to sink, but have evolved various methods to retard sinking.
b. Increasing surface area retards sinking because of the frictional drag between the surface and water.
c. Because mass increases faster than surface area, small size produces a slower settling velocity because of less mass and greater frictional drag.
d. Plants also decrease mass by having very porous shells. They increase frictional drag by developing spines that increase the surface area.
e. Large plants anchor themselves in place with holdfasts, a root-like mass that functions only to hold the plant in place, not to absorb nutrients and water from the sediment as do roots.
2. Diatoms are single cells enclosed in a siliceous frustule (shell) that is shaped as a pillbox.
a. In reproducing, the frustule separates into the larger epitheca and smaller hypotheca.
b. Each part then secretes a new hypotheca.
- The original hypotheca now functions as an epitheca.
c. After numerous generations, one of the cell lines becomes progressively smaller until it reaches a critical size, abandons the hypotheca, reproduces sexually, grows larger as a naked cell and finally develops a frustule of the size of the original one in the sequence.
d. Diatoms thrive in cold nutrient-rich waters of the polar and subpolar regions and in the inshore water of the shelf in the mid-latitudes.
e. They can reproduce rapidly and produce plankton blooms when conditions are ideal.
3. Dinoflagellates are single cells with two whip-like tails (flagella).
a. Their shell, called a theca, if present, is composed of cellulose.
b. When the concentration of dissolved silica is low, dinoflagellates can out-number the diatoms.
H. Zooplankton include the copepods and foraminifera.
1. Copepods are small herbivores (plant-eating organisms) that filter diatoms from the water.
a. They molt (shed) their outer skeleton as they grow.
b. They display vertical seasonal migration.
2. Foraminifera are single-celled, microscopic organisms which build shells of calcium carbonate.
a. Benthonic forms greatly out number the pelagic.
b. Their shells are porous and protoplasm streams from inside the shell to engulf and digest food.
I. The morphology of fish has evolved to allow them to move through the water easily.
1.The fish’s body must overcome three types of drag (resistance).
a. Surface drag is the friction between the surface of the fish and the surrounding water.
1. This can be reduced by decreasing the surface area.
2. A sphere offers the least surface drag.
b. Form drag is a function of the volume of water that must be displaced for movement to occur.
1. Form drag increases as the cross sectional area of the body increases.
2. The ideal shape to reduce form drag is needle-shape or pencil-shape.
c. Turbulent drag is the turbulence created around the body as it moves through the water.
1. Turbulent drag can be decreased by having a blunt leading edge and tapering end.
2. The ideal shape is torpedo-shape.
2. Speed is dependent upon:
a. Body length.
b. Beat frequency - number of times the tail (caudal fin) sweeps back and forth in a unit of time.
c. Aspect ratio of the caudal fin.
3. Aspect ratio is the ratio of the square of the caudal fin height to caudal fin area.
AR = (Caudal Fin Height)2/Caudal Fin Area
a. A low aspect ratio means that the tail is broad and provides short, rapid acceleration and great maneuverability, but because of the large surface area, drag interferes with prolonged maintenance of high speed.
- Tail is designed for darting motion.
b. A high aspect ratio means the tail has little surface area to generate acceleration or assist in maneuverability, but because drag is reduced, it is ideal for maintenance of high speed.
4. There are three basic body forms, each adapted to a different life style.
a. The torpedo shape of the tuna is ideal for efficient, high speed cruising.
b. The more elongate pike is designed for sudden lunging motion.
c. The butterfly fish is designed for great maneuverability and delicate movements.
d. Most fish are generalists and combine aspects of the three body forms to suit their environment.
5. There is a strong correlation between predation success and body form.
a. Tuna have a low success rate (15%) because of poor maneuverability, but because they travel over great distances they have many more encounters with prey than do sedentary fish.
b. Pike have a high success rate (85%), but spend most of their time waiting for prey to approach and have few encounters.
c. Generalists have a success rate somewhere between these two.
J. Intertidal benthonic communities generally display vertical zonation that parallels sea level.
1. Zonation reflects the amount of time the area is submerged and the ability of the organism to survive the stress of exposure.
a. The uppermost level is rarely wet and inhabited mainly by blue-green algae and snails.
b. The next lower level is occupied by barnacles near the top and muscles and brown algae at the base.
- Size of barnacles tends to increase downward because those living lower in the zone are submerged more often, for longer periods of time, and feed more frequently.
c. The lowest zone has a very diverse fauna and flora.
2. Benthonic communities also vary in response to substrate (bottom material).
a. Rocky substrate provides a stable and firm material for attachment but prevents burrowing.
b. Sandy substrate is mobile and abrasive but can be burrowed into.
c. Mud substrate provides little support but is easy to burrow through.
Box: Sampling Biota
K. There are various devices which can be employed for sampling planktonic and benthonic biota.
1. Plankton nets come in various mesh sizes depending upon the size of the biota to be sampled.
- Nets can be dragged behind the ship or water can be pumped onto the ship and passed through the net.
2. Trawling gear to catch nekton consists of a net with a pair of “otter boards” at the front of the net. They flare out as the net is towed so as to keep the net open and close the opening when trawling stops, preventing captured nekton from escaping.
3. A purse seine to collect nekton is a large net set out around an area and drawn in at the bottom to prevent organisms from escaping below the net.
4. An anchor dredge consists of a mesh net and metal frame which is dragged along the bottom and scoops up benthonic organisms.
5. A grab sampler consists of a pair of spring-loaded jaws that can scoop a sample of soft sediment, collecting both epifauna and infauna.
Box: Ecology of the Giant Kelp Community
L. A complex interaction between kelp, sea urchins, and sea otters controls the kelp community.
1. Macrocystis is a brown algae that grows up to 40 m long in extensive beds on North America’s Pacific coast continental shelf.
2. Sea urchins feeding on the kelp detach them from their holdfast and can devastate the kelp beds.
3. Sea otters feed on the sea urchins and serve as a control on their population.
a. Where sea otters abound, sea urchins are few, kelp beds thrive and sea otters feed mainly on fish.
b. Where sea otters are few, sea urchins abound and kelp beds are thin. Sea otters then mainly eat urchins.
Questions
Review of Basic Concepts
1. Compare the lifestyles of planktonic, nektonic, and benthic organisms. Cite several examples of each group.
2. What is a plankton bloom? What is its effect on the average size of a diatom population with the succeeding generations?
3. Explain why the benthos of an intertidal rocky coast commonly display vertical zonation.
4. Contrast how a fish and a razor clam attain rapid mobility.
5. Describe a direct and an indirect effect that temperature can have on marine organisms.
6. Why must most plants in the ocean be microscopic in size?
7. What principal role do bacteria play in the ocean?
Critical-Thinking Essays
1. How does the physical environment differ over a year for the neritic as distinguished from the abyssal sea bottom? Be specific and explain the differences.
2. Contrast the advantages and disadvantages associated with an epifaunal and an infaunal mode of existence.
3. Examine the drawing of the North Pacific pink salmon in the boxed feature entitled “Migrants” in the next chapter. Make some deductions about its swimming style, and defend your inferences.
4. Design a fish that would be reasonably adept at maneuvering through holes and crevices of a coral reef while also relying on a darting motion to catch prey. Explain your model.
5. Why are roots unnecessary for seaweeds but essential for trees?
Doing the Math
1. Given that the hydrostatic pressure increases at a rate of 1 atm per 10 meters of water depth, calculate the hydrostatic pressure for a sea bottom that lies at a depth of 1.5 kilometers. Is the hydrostatic pressure for a water depth of 3 kilometers simply twice the hydrostatic pressure for 1.5 kilometers? Why or why not?
2. Examine Figure 9–15. If you increase the diameter of an organism to 16 units, what will be the ratio of its area to volume?
3. Assume that a copepod that is 0.5 centimeters long processes 1 liter of water each day in order to feed. How much would a man 2 meters tall (average height) have to process for the volume to be proportional with that handled each day by the copepod?
4. Calculate the aspect ratio of a caudal fin that is 12 centimeters high and 36 centimeters square in area. For the same height, determine the area of the caudal fin that is necessary for a fish to be a fast cruiser.
5. Assume that phytoplankton are undergoing cell division once each day, meaning that the population is doubling its numbers every day. What will be the concentration of diatoms after a five-day-long bloom, if their initial concentration is 10 diatom cells per liter of seawater?
Unit 2 Biological Productivity in the Ocean
Learning Objectives
1. Understand the trophic dynamics among organisms in an ecosystem.
2. Explain the controls on productivity and how this determines the patterns of life observed in the ocean.
Unit Outline
10-1. Food Webs and Trophic Dynamics
A. An ecosystem is the totality of the environment encompassing all chemical, physical, geological, and biological parts.
1. Ecosystems function by the exchange of matter and energy.
2. Plants use chlorophyll in photosynthesis to convert inorganic material into organic compounds and to store energy for growth and reproduction.
- Plants are autotrophs and the primary producers in most ecosystems.
3. All other organisms are heterotrophs, the consumers and decomposers in ecosystems.
4. Herbivores eat plants and release the stored energy.
5. Material is constantly recycled in the ecosystem, but energy gradually dissipates as heat and is lost.
B. The word “trophic” refers to nutrition.
1. Trophic dynamics is the study of the nutritional interconnections among organisms within an ecosystem.
2. Trophic level is the position of an organism within the trophic dynamics.
a. Autotrophs form the first trophic level and provide the organic matter and energy for all other trophic levels.
b. Herbivores are the second trophic level.
c. Carnivores occupy the third and higher trophic levels.
d. Decomposers form the terminal level.
3. A food chain is the succession of organisms within an ecosystem based upon trophic dynamics. (Who is eaten by whom.)
a. Food chains are rarely simple because organisms tend to feed at several different levels.
b. Omnivores eat both plant and animal matter.
c. A food web is a series of interconnected food chains.
4. An energy pyramid is the graphic representation of a food chain in terms of the energy contained at each trophic level.
- The size of each successive level is controlled by the size of the level immediately below.
C. As the primary producers, plants require sunlight, nutrients, water, and carbon dioxide for photosynthesis.
1. Sunlight and nutrients are commonly the limiting factor.
2. The formula for photosynthesis is:
Sunlight + 6 CO2 + 6 H2O ( C6H12O6 (sugar) + 6 O2.
3. Phytoplankton blooms are the rapid expansion of a phytoplankton population because light and nutrients are abundant.
D. Animals must consume pre-existing organic material to survive.
1. Animals break down the organic compounds into their inorganic components to obtain the stored energy.
2. The chemical formula for respiration is:
C6H12O6 (sugar) + 6 O2 ( 6 CO2 + 6 H2O + Energy.
3. The recovered energy is used for movement, reproduction, and growth.
4. The food consumed by most organisms is proportional to their body size.
- Generally, smaller animals eat smaller food and larger animals eat larger food, although exceptions occur.
5. The basic feeding style of animals are:
a. Grazers - consume plant material.
b. Predators - hunt and kill prey.
c. Scavengers - consume dead organic matter.
d. Filter feeders - filter the water for suspended food.
e. Deposit feeders - selectively or non-selectively consume food that is mixed in the sediments.
6. Population size is dependent upon food supply.
- There is a lag between the maximum abundance of food and the maximum population size.
E. Bacteria are the decomposers; they break down organic material and release nutrients for recycling.
1. Few bacteria are capable of completely degrading organic material into its inorganic components.
-Most operate in succession with other bacteria to decompose material in a series of stages.
2. Bacteria also serve as food for other organisms either directly or indirectly.
3. Two basic types of bacteria are:
a. Aerobic bacteria - require free oxygen to respire and decompose dead matter.
b. Anaerobic bacteria - bacteria which live in an oxygen-free (anoxic) environment, but obtain oxygen for respiration from other sources, such as SO4-2 (sulfate ion) and release H2S (hydrogen sulfide gas) as a by-product of decay.
4. Most bacteria are heterotrophs, but two types are autotrophs:
a. Cyanobacteria (blue-green algae) photosynthesize.
b. Chemosynthetic bacteria use chemical energy released in the oxidation of inorganic compounds to produce food.
F. Food chains transfer energy from one trophic level to another.
1. Biomass is the quantity of living matter per volume of water.
2. With each higher trophic level, the size of organisms generally increases, but their number and the total biomass decrease.
- Rate of growth is inversely related to position in the food chain:
a. Low on the food chain, the individuals are small but reproduce rapidly.
b. High on the food chain, individuals are large but reproduce slowly.
3. The two major food chains in the ocean are:
a. Grazing food chain - herbivores consume autotrophs in the photic zone.
b. Detritus food chain - non-living wastes form the base of the food chain.
- Organic matter from the surface waters settles into the deep sea and enters into the deep-sea food chain when it is consumed by detritus feeders.
4. Only about 10-20% of energy is transferred between trophic levels which produces a rapid decline in biomass at each successive trophic level.
a. Most (80-90%) of the energy consumed by organisms is lost in movement or in growing non-nutritional structures, such as bone or shell.
b. The longer the food chain, the greater is the autotroph biomass that is needed to support it.
c. There must be a balance between the energy expended obtaining food and the energy obtained from the food.
- Not all potential food sources are practical for an organism to exploit.
10-2. General Marine Productivity
G. Primary production is the total amount of carbon (C) in grams converted into organic material per square meter of sea surface per year (gm C/m2/yr).
1. Factors that limit plant growth and reduce primary production include solar radiation and nutrients as major factors and upwelling, turbulence, grazing intensity, and turbidity as secondary factors.
2. Only 0.1 to 0.2% of the solar radiation is employed for photosynthesis and its energy stored in organic compounds.
a. The amount of light rapidly decreases with depth.
b. Net primary productivity is the amount of carbon converted into organic material above that required for the minimal survival of the autotroph.
- It is the amount of organic material available for growth and reproduction.
c. Compensation depth is the depth where net primary productivity equals zero.
- This is usually located where light intensity is about 1% of its surface value and typically occurs at a depth of about 110 m in clear ocean water.
d. Most of the light entering the ocean is converted into heat.
- Productivity is small below 0oC and above 40oC, but between these, productivity increases with temperature.
e. Despite decreasing solar radiation, productivity tends to increase poleward because of greater availability of nutrients away from the equator.
3. Nutrients are chemicals needed for survival, growth, and reproduction.
a. Macronutrients are elements or compounds required in large quantities and include phosphorus (P), nitrogen (N), and silicon (Si).
- Scarcity of macronutrients usually occurs over a broad region and limits growth on a regional scale.
b. Micronutrients are indispensable elements and compounds used in very small quantities.
- Because they are needed in small amounts, they rarely are scarce over a large region, but may limit growth locally.
c. Phytoplankton generally require phosphorus (P), nitrogen (N), and carbon (C) in the ratio of 116C:16N:1P.
1. Despite enormous demand for carbon, it is so abundant in sea water that carbon is never a limiting factor.
2. N and P are needed in much smaller amounts, but because of demand relative to their abundance, they can be a limiting factor.
3. Because decomposition releases nitrogen compounds more slowly than phosphorus and because much more nitrogen is required than phosphorus, nitrogen is usually the limiting nutrient.
4. Silicon can be a limiting factor for diatoms and silicaflagellates because they require it to construct their shells.
d. Dead organisms and waste material sink into the deeper water, removing the nutrients they contain from the productive surface zone.
- Decomposition eventually releases the nutrients into the deep water.
4. Upwelling and turbulence can return nutrients to the surface.
a. Upwelling is the slow persistent rising of nutrient-rich water toward the ocean surface.
- Upwelling occurs:
1. In the equatorial waters between the gyres, because Ekman transport pulls surface water to the north and south, inducing water from below to rise to the surface.
2. In coastal waters where persistent wind produces seaward Ekman transport of surface waters.
b. Near-shore turbulence from storms and strong tidal currents can mix nutrient-rich waters upwards.
- This is most pronounced if the sea floor is irregular and coastal currents are strong.
5. Over-grazing of autotrophs can deplete the population and lead to a decline in productivity.
6. Turbidity reduces the depth of light penetration and restricts productivity even if nutrients are abundant.
H. Productivity varies greatly in different parts of the ocean in response to the availability of nutrients and sunlight.
1. In the tropics and subtropics sunlight is abundant, but it generates a strong thermocline that restricts upwelling of nutrients and results in lower productivity.
- High productivity locally can occur in areas of coastal upwelling, in the tropical waters between the gyres and at coral reefs.
2. In temperate regions productivity is distinctly seasonal.
a. In winter, the water column is isothermal and mixes easily. Nutrients are abundant at the surface but limited sunlight restricts productivity.
b. In spring, sunlight becomes more abundant and there is a diatom bloom.
c. By summer, productivity declines as:
1. A thermocline develops and prevents vertical mixing and re-supply of nutrients.
2. Usage depletes the nutrients in the surface water.
3. Grazing by herbivores greatly reduces the population of phytoplankton.
d. In the fall, productivity initially increases as the water becomes isothermal and nutrients again become abundant, but then declines because the amount of sunlight decreases.
3. Polar waters are nutrient-rich all year but productivity is only high in the summer when light is abundant.
10-3. Global Patterns of Productivity
I. Primary productivity varies from 25 to 1250 gm C/m2/yr in the marine environment and is highest in estuaries and lowest in the open ocean.
1. In the open ocean productivity distribution resembles a “bull’s eye” pattern with lowest productivity in the center and highest at the edge of the basin.
- Water in the center of the ocean is a clear blue because it is an area of downwelling, above a strong thermocline and is almost devoid of biological activity.
2. Continental shelves display moderate productivity between 50 and 200 gm C/m2/yr because nutrients wash in from the land and tide- and wave- generated turbulence recycle nutrients from the bottom water.
3. Polar areas have high productivity because there is no pycnocline to inhibit mixing.
4. Equatorial waters have high productivity because of upwelling.
J. It is possible to estimate plant and fish productivity in the ocean.
1. The size of the plankton biomass is a good indicator of the biomass of the remainder of the food web.
2. Annual primary production (APP) is equal to primary production rate (PPR) times the area for which the rate is applicable.
APP = PPR x Area (to which applicable )
3. Transfer efficiency (TE) is a measure of the amount of carbon that is passed between trophic levels and is used for growth.
- Transfer efficiency varies from 10 to 20% in most food chains.
4. Potential production (PP) at any trophic level is equal to the annual primary production (APP) times the transfer efficiency (TE) for each step in the food chain to the trophic level of the organism under consideration.
PP = APP x TE (for each step)
5. Although rate of productivity is very low for the open ocean compared to areas of upwelling, the open ocean has the greatest biomass productivity because of its enormous size.
6. In the open ocean the food chains are longer and energy transfer is low, so fish populations are small.
- Most fish production is equally divided between area of upwelling and coastal waters.
7. Calculations suggest that the annual fish production is about 240 million tons/yr.
8. Over-fishing is removing fish from the ocean faster than they are replaced by reproduction and this can eventually lead to the collapse of the fish population.
10-4. Biological Productivity of Upwelling Water
K. Upwelling of deep, nutrient-rich water supports large populations of phytoplankton and fish.
1. The waters off the coast of Peru normally are an area of upwelling, supporting one of the world’s largest fisheries.
2. Every three to seven years warm surface waters in the Pacific displace the cold, nutrient-rich water on Peru’s shelf in a phenomenon called El Niño.
3. El Niño results in a major change in fauna on the shelf and a great reduction in fishes.
- This can lead to mass starvation of organisms dependent upon the fish as their major food source.
Box: Large Sharks
L. There are over 300 species of sharks, each adapted to a particular habitat and life style.
1. Shark skeletons are composed of cartilage, not bone.
2. Sharks have well developed eyesight, sense of smell and hearing, and they can feel vibrations in the water.
3. Shark attack is uncommon in the U.S. and mainly occurs in areas where sharks primarily feed on marine mammals.
4. Although the great white shark is large and a man-eater, the largest of all sharks is the whale shark, which can reach 17 m in length and weigh 40,000 kg., but it is a filter feeder.
Box: Volcanic Vent Communities
M. The volcanic vent communities survive independent of the Sun and consist of bacteria, tube worms, mussels, and clams.
1. Sea water circulating through the rock of the sea floor near the oceanic ridges becomes super-heated and rich in dissolved minerals.
2. It is released from vents in the sea floor as underwater springs.
3. As the escaping water cools, metal sulfides precipitate and accumulate around the vents as tall chimney-like structures.
4. Anaerobic chemosynthetic bacteria thrive in the vents and are the autotrophs of the vent community.
5. Periodically, large masses of bacteria from within the vents are ripped free and swept into suspension, becoming food for filter feeders in the waters surrounding the vent.
6. When circulation of the hot water ceases, the vent community dies.
Box: Migrants
N. Some marine animals migrate across the ocean between the areas in which they live and where they breed.
1. Migrations are usually well established as to time of year and route taken.
2. Eels migrate to the Sargasso Sea from North America and Europe to breed and then die.
a. Eel eggs and larvae drift with the ocean currents for one to three years and metamorphose into an adult form as they near their coastal waters.
b. They migrate into fresh-water rivers and lakes where they live for the next decade before returning to the sea to reproduce.
3. Salmon live most of their lives in the sea, but return to the fresh-water streams and rivers in which they were hatched to reproduce and die.
Questions
Review of Basic Concepts
1. Describe how energy and matter flow through an ecosystem. Which of the two is recycled and which is not?
2. Why is nitrate rather than phosphate likely to limit plant production in the ocean?
3. Why is energy transfer between trophic levels such an inefficient process?
4. Contrast a detritus food chain with a grazing food chain. How are they linked?
5. What critical role(s) do bacteria play in the food cycle of the sea?
6. How and why does primary production vary with distance from land?
7. What is El Niño? What are the chemical and biological consequences of a strong El Niño occurrence offshore Peru?
Critical-Thinking Essays
1. Discuss how photosynthesis, respiration, nutrients, and sunlight are linked in ecosystems.
2. On a graph, plot the annual variation of solar radiation, water temperature, phosphate levels, plant biomass, and fish biomass that would characterize
a. A mid-latitude inner continental shelf
b. An Arctic shelf
c. A tropical shelf
d. The center of a large ocean
3. The Peruvian anchoveta must have survived many El Niño events in the recent geologic past. Speculate on the reasons that their numbers have not recovered from the effect of recent El Niño occurrences, notably those since 1972.
4. What are the chances of discovering large fish stocks in the center of the Indian Ocean, an area that has not been previously fished? Provide a solid argument for your assessment.
5. Why are seaweeds large in size and phytoplankton microscopic in size?
6. If you were in a submersible, how would you quickly establish whether a newly discovered hydrothermal vent was active? Explain your reasoning.
7. Examine Figure B10–6 in the boxed feature, “Satellite Oceanography.” Account for the time variations in plant productivity for the
a. Center of the North Atlantic circulation gyre (the Sargasso Sea)
b. North Atlantic waters off the east coast of Canada
c. Continental shelf waters off western Africa, near the Canary Islands ( hint: see Figure 10–11a)
Doing the math
1. Assume a three-step food chain (diatoms-copepods-small fish). If the transfer efficiency is 15 percent (0.15) between the plants and copepods and 10 percent (0.10) between the copepods and small fish, determine the quantity of fish that can be supported by 1,000 grams of diatoms.
2. If the diatoms in Question 1 are fixing carbon by photosynthesis at the rate of 50 gC/m2/day, estimate the daily primary production over an area of 100,000 square meters (105 m2). Now estimate the amount of carbon fixed by the diatoms over the total area for a year.
3. Given that a fishery harvests the small fish in the three-step food chain described in Questions 1 and 2, estimate the average daily (gC/day) fish production across the 105m2 area. If you need help, study Figure 10–13.
4. Assume that only 40 percent of the annual fish production can be harvested in the 105m2 area described in Question 3 if this fishery is to be sustainable from year to year. At what rate in gC/yr can fish be harvested from the region?
5. Assume that during one year the fishery in Question 4 is affected by an event like El Niño, which reduces diatom production to 10 gC/m2/day for that year. How many gC of fish can be caught for that year in order to maintain a sustainable harvest?
Unit 3: Coastal Habitats
Learning Objectives
1. Appreciate the various types of coastal environments.
2. Know the physical and biological differences between the various coastal environments.
Unit Outline
A. The term coast has a much broader meaning than shoreline and includes many other habitats and ecosystems associated with terrestrial and marine processes.
1. The six major coastal settings are:
a. Estuary - semi-enclosed body of water where fresh and marine waters mix.
b. Lagoon - semi-enclosed body of water receiving no appreciable inflow of fresh water.
c. Salt marsh - plant-covered intertidal zone.
d. Mangrove swamp - dense tree growth of the tropical and subtropical shoreline.
e. Coral reef - calcareous ridge constructed by corals and algae.
2. Shorelines are one of the most productive ecosystems and because they are shallow, they strongly respond to the effects of waves, tides, and weather.
12-1. Estuaries
B. Estuaries are semi-enclosed bodies of water where fresh water from the land mixes with sea water.
1. Estuaries originate as:
a. Drowned river valleys - With the rise in sea level, the lower portions of river valleys have flooded.
b. Fjords - As glaciers have retreated and sea level risen, the lower portions of glacial valleys have flooded.
1. Fjords typically are long, narrow, and deep with steep cliff-like sides.
2. The bottom of fjords frequently are partially blocked by glacial moraines (ridges of sediment deposited at the front of the glacier) which inhibit current flow and can produce hypoxic to anoxic conditions at the bottom.
c. Bar-built estuaries - Spits and sand bars may partially block the entrance to an embayment, thereby restricting tidal flow.
d. Tectonic estuaries - Uplift associated with plate tectonics can partially block the entrance to an embayment.
2. Salinity typically grades from normal marine salinity at the tidal inlet to fresh water at the mouth of the river.
a. In some estuaries the water is well stratified with a strong halocline separating the dense saline water below from the fresh water above.
b. Tidal flow provides the energy for mixing the fresh and salt water masses.
- If tidal flow is strong, stratification is weak.
C. Estuaries can be subdivided into three types based upon the relative importance of river inflow and tidal mixing.
1. Salt-wedge estuaries are dominated by the outflow from rivers.
a. The outflow from rivers is much greater than the inflow from the tides.
b. The water column is highly stratified with a well-defined, strong halocline that inhibits mixing.
c. Salt water forms a wedge that extends landward below the fresh water wedge that extends seaward.
d. Strong turbulent currents in the fresh water flow across the halocline and generate internal waves.
e. As the internal waves steepen and break, they mix salt water into the fresh, which is swept seaward.
f. The continual loss of salt water into the fresh water generates a slow current that flows in along the bottom and up along the underside of the fresh water wedge.
g. The bottom current is too weak to carry much sediment into the estuary from outside the tidal inlet.
h. Sediment distribution in the estuary consists of river sand at the landward edge of the saltwater wedge and mainly river clays and silts elsewhere.
2. Partially-mixed estuaries are dominated by neither river inflow nor tidal mixing.
a. Tidal currents promote greater mixing and both stratification and the halocline are greatly weakened.
b. As more saltwater mixes into the fresh, a stronger bottom current is generated.
c. The bottom current transports sediment into the estuary through the tidal inlet.
- The bottom of the seaward end of the estuary is covered with sediments from the shelf, whereas the landward end is dominated by river sediments.
d. Where currents are weak, suspended sediments sink onto the halocline and form a turbidity maximum in the water column.
1. Much suspended sediment is removed by filter-feeders, which concentrate it into fecal pellets and by flocculation, clay particles sticking together and forming larger aggregates which sink more rapidly.
2. Mud can accumulate where currents are weak and form mud shoals.
- Areas of deposition shift as tidal influence and river discharge vary.
3. In well-mixed estuaries tidal turbulence destroys the halocline and water stratification.
a. In wide estuaries, Coriolis deflects river outflow to one side and tidal inflow to the other.
b. A salinity gradient extends across the estuary but not vertically within the water column.
c. Sea water flows in and fresh water flows out on opposite sides of the tidal inlet at all depths.
d. Strong inflow of sea water transports abundant sediment into the estuary and marine sediments often dominate throughout the estuary.
4. Because river discharge and tidal flow vary, conditions within an estuary can also change, being well-mixed when river flow decreases relative to tidal mixing, to becoming a salt-wedge estuary at times of maximum river discharge.
D. The widely fluctuating environmental conditions in estuaries make life stressful for organisms.
1. Estuaries are extremely fertile because nutrients are brought in by rivers and recycled from the bottom because of the turbulence.
2. Stressful conditions and abundant nutrients result in low species diversity, but great abundance of the species present.
3. Despite abundance of nutrients, phytoplankton blooms are irregular and the base of the food chain is detritus washed in from adjacent salt marshes.
4. The benthonic fauna strongly reflects the nature of the substrate and most fishes are juvenile forms living within the estuary until they mature and migrate to the ocean.
12-2. Lagoons
E. Lagoons are isolated to semi-enclosed, shallow, coastal bodies of water that receive little if any fresh water inflow.
1. Lagoons can occur at any latitude and their salinities vary from brackish to hypersaline depending upon climate and local hydrology.
2. Bottom sediments are usually sand or mud eroded which was from the shoreline or swept in through the tidal inlet.
3. In the tropics, the water column is typically isothermal.
4. In the subtropics, salinity generally increases away from the inlet and the lagoon may display inverse flow.
a. Water flows in at the surface.
b. As it progresses across the lagoon, evaporation increases its salinity and density.
c. At the far end of the lagoon the water becomes so dense it sinks and flows across the bottom of the lagoon and out into the ocean through the bottom of the tidal inlet.
d. With inverse flow the direction of flow is the opposite of what is observed in estuaries.
12-3. Salt Marshes
F. Salt marshes are intertidal flats covered by grassy vegetation.
1. Marshes are most commonly found in protected areas with a moderate tidal range, such as the landward side of barrier islands.
2. Marshes flood daily at high tide and then drain through a series of channels with the ebb tide.
3. They are one of the most productive environments.
4. Marshes can be divided into two parts:
a. Low salt marshes - extend from the low tide mark to neap high tide.
1. Along the Atlantic and Gulf Coast these areas are dominated by Spartina alterniflora, a knee-high cordgrass that spreads underground through rhizomes, root-like stems.
2. Low marshes are the more productive area with productivity of 800 - 2600 gmC/m2/yr.
3. Nitrate is commonly the limiting nutrient.
4. Plants die in autumn, partially decompose and supply abundant detritus which becomes food for the detritivores or accumulates and eventually forms peat.
b. High salt marshes - extend from neap high tide to highest spring tide.
1. This area is flooded only at the highest spring tide or during a storm surge.
2. It is more terrestrial than marine in nature and has a more diverse fauna and flora.
5. Distribution and density of organisms in salt marshes strongly reflects availability of food, need for protection, and frequency of flooding.
12-4. Mangrove Swamps
G. Mangroves are large woody trees with a dense, complex root system that grows downward from the branches.
1. Mangroves are the dominant plant of the tropical and subtropical intertidal area.
2. Distribution of the trees is largely controlled by air temperature, exposure to wave and current attack, tidal range, substrate, and sea water chemistry.
3. Detritus from the mangrove forms the base of the food chain.
12-5. Coral Reefs
H. A coral reef is an organically constructed, wave-resistant, rock-like structure created by carbonate-secreting organisms.
1. Most of the reef is composed of loose to well-cemented organic debris of carbonate shells and skeletons.
2. The living part of the reef is just a thin veneer on the surface.
3. Corals belong to the Cnidara.
a. The animal is the coral polyp.
- The body of the polyp resembles a sac with the open end surrounded with tentacles.
b. The corallite is the exoskeleton formed by the polyp. Its interior is divided by septa, vertical partitions.
4. Corals share a mutualistic relationship (mutually beneficial) with the algae zooxanthallae which lives within the skin of the polyp and can comprise up to 75% of the polyp’s body weight.
a. The coral provides protection for the algae and supplies it with nutrients and carbon dioxide from the polyp’s metabolic wastes.
b. The algae supplies the coral with oxygen and food.
c. Recycling of nutrients between the polyp and algae allows the corals to thrive in the nutrient-poor tropical seas.
5. Corals can be either solitary or colonial.
a. Solitary corals, called ahermatypic corals, lack zooxanthallae and can live at any depth or temperature.
b. Colonial corals, called hermatypic corals, have zooxanthallae and therefore can only live in the photic zone where the temperature is above 18oC.
1. Ideal conditions for hermatypic corals are 20oC, normal marine salinity in clear water 30 m deep or shallower.
2. Because of temperature restrictions, coral reefs are more abundant on the west side of ocean basins where warm equatorial currents flow poleward.
6. Corals can not survive in fresh, brackish water or highly turbid water.
7. Corals do best in nutrient poor water because they are easily out-competed by benthonic filter feeders in nutrient-rich water where phytoplankton are abundant.
I. Coral reefs consist of several distinct parts developed in response to their exposure to waves.
1. The algal ridge occurs on the windward side of the reef and endures the pounding waves.
2. The buttress zone is the reef slope extending down from the algal ridge.
a. It consists of alternating coral-capped ridges, channels and furrows.
b. The irregular surface of the buttress zone disrupts the swell and dissipates wave energy.
3. The reef face extends downward from the buttress zone and usually is devoid of living colonial corals because insufficient light reaches this depth.
4. The reef terrace is landward of the algal ridge and lies at mean water level.
a. Much of the terrace is exposed at low tide.
b. Encrusting algae flourish here.
c. Islands may be present on the terrace.
d. The backside of the terrace grades into a shallow, usually less than 50 m deep, lagoon.
e. Numerous small organic knolls, called patch reefs, grow on the floor of the lagoon.
5. The shape of the colonial coral masses reflects the environment in which they live.
a. On the wave-pounded algal ridge, corals form thin encrusting sheets.
b. In the buttress zone corals form massive branching colonies or compact, durable mounds.
c. In deeper and quieter areas the colonies are delicately branching forms or thin wafer-like forms.
J. As a result of corals growing continuously upward towards the sunlight as sea level rises and/or land subsides, coral reefs pass through three stages of development.
1. Fringe reefs form limestone shorelines around islands or along continents and are the earliest stage of reef development.
2. As the land is progressively submerged and the coral grows upward, an expanding shallow lagoon begins to separate the fringe reef from the shoreline and the reef is called a barrier reef.
3. In the final stage the land vanishes below the sea and the reef forms a ring of islands, called an atoll, around a shallow lagoon.
Box: Salt Marsh Evolution
K. Salt marshes pass through three stages of development.
1. Youthful salt marshes consist only of the low marsh zone.
a. Flood tides bring nutrients into the marsh and the growth of dense grasses slows the flow of water and encourage sediment deposition.
b. Grass roots bind the sediment in place, preventing erosion.
c. As more sediment accumulates, the marsh gradually builds upwards.
2. In the mature stage the marsh consists of almost equal amounts of low marsh and high marsh.
3. In the old marsh stage, most of the area is high marsh.
- Deposition by rivers and streams gradually raises the area above high tide range.
Box: Residence Time
L. Residence time is the average time that a material remains in a system.
1. Residence time calculations are only valid if input and output of material from the system are known.
2. If the system is in steady-state, the input equals the output.
3. Residence time = Material within the system/input or output for system.
Questions
Review of Basic Concepts
1. Contrast the composition of plants in low and high salt marshes. What ecological factors account for the differences between these two floral communities?
2. Why do estuaries have low species diversity?
3. What main factors control water circulation in estuaries?
4. How is a lagoon different from an estuary?
5. What are mangrove swamps, where do they occur, and what physical factors control their character?
6. What is a detritus food chain and what role does it play in salt marshes and mangrove forests?
7. What are zooxanthellae, and how do they interact with coral?
8. Identify the critical environmental factors that limit the growth of coral reefs.
9. Using diagrams, clearly distinguish among fringing reefs, barrier reefs, and atolls.
Critical-Thinking Essays
1. What general role do estuaries and salt marshes play in fish productivity?
2. Speculate about what might happen if you artificially fertilized (added essential nutrients) the water of a barrier reef.
3. Reread the section on the functional morphology of fishes in Chapter 9 (see Figures 9–20, 9–21, 9–22 in Chapter 9), and then deduce the likely swimming characteristics of the trigger fish and the butterfly fish in Figure 12–19.
4. Sketch a topographic profile of a barrier reef, and identify the algal ridge, the lagoon, the buttress zone, and the reef terrace. Specify in which of these environments you would likely find the following coral types, and give reasons.
a. Patch reefs
b. Encrusting coral
c. Fragile branching coral
d. Brain coral
5. How would the benthos and nekton of an estuary be affected if land reclamation for real-estate development eliminated all of the area’s salt marshes?
6. What factors promote and limit high biological production in the following?
a. Estuaries
b. Coral reefs
c. Salt marshes
Doing the math
1. Consult Figure B12–4. Calculate the elongation rate of the sand spit in kilometers and in meters per year. Has the rate varied with time?
2. Consult Figure B12–4d. Assume that at the core site, deposition began about 3,000 years ago in the low-marsh peat and about 2,400 years ago in the high-marsh peat. What is the depositional rate of each peat expressed as centimeters per year? Why is one rate so much higher than the other? Why is there an inverse relationship between the amount of sand and the amount of mud in the core?
3. Examine Figure B12–2c. Estimate the average yearly increase in the volume of anoxic water in Chesapeake Bay between the early 1950s and early 1980s. What simplifications did you make in order to calculate this average annual increase?
Unit 4: Ocean Habitats and Their Biota
Learning Objectives
1. Understand the difference in the environments and the biota of the continental shelf and the open ocean.
2. Explain the environmental factors that control the distribution of the marine organisms.
3. Discuss the unique adaptations evolved by organisms for dealing with the deep-sea environment.
Unit Outline
13-1. Biology of the Continental Shelf
A. The waters of the neritic zone are fertile and support a rich community of organisms.
1. The plankton are floaters and weak swimmers which are helplessly transported by ocean currents.
a. The major phytoplankton are the diatoms and dinoflagellates.
b. Seasonal variations in temperature, salinity and nutrients in the temperate and polar seas result in the proliferation of a succession of species.
c. The major zooplankton are the arthropods, especially the copepods.
d. Plankton distribution displays a patchiness with dense concentrations separated by large spaces where few individuals are found.
1. Dense populations typically occur in areas of downwelling.
2. Concentrated populations makes it possible for plankton to be used as a food source, otherwise consumers would expend more energy searching for food than the energy recovered from the food.
2. Nekton have the ability to swim against currents and actively search for a more hospitable environment.
3. Many fish display schooling, another form of patchiness.
a. Fish within a school are the same species and about the same size.
b. Schools swim as a single unit, smoothly performing complex maneuvers.
c. There are no designated leaders of a school and the fish maintain a uniform spacing.
d. School size can vary from hundreds to millions of individuals.
e. Advantages to schooling include:
1. To a predator a school may appear as a single large organism.
2. In a school, the likelihood of contact with a predator is less than if the fish were randomly scattered.
3. Hunting efficiency is low for predators when attacking a school because the numerous darting fish make it difficult for the predator to focus on a single prey.
B. Because the water column is shallow in the sublittoral zone, physical factors regulate the number, type and distribution of benthic organisms.
1. Bottom energy is a function of wave energy and tidal currents and these vary inversely with depth.
2. The sea floor can be divided into two areas based upon the energy of the environment:
a. High energy environments are near shore in relatively shallow water.
b. Low energy environments occur below wave base and in areas protected from currents and waves.
3. Bottom energy affects organisms by:
a. Moving sediment about and creating an unstable substrate.
1. This makes it difficult for epifauna to become established.
2. Strong currents can completely sweep away all sediment and leave rock exposed.
b. Controlling sediment size.
1. Mud collects in very placid environments such as below wave base and protected near shore areas.
2. Sand and gravel collect in high energy areas, especially the inner and middle shelf where it is too turbulent for mud to be deposited.
4. Bottom sediment strongly influences the feeding mode of benthic communities.
a. Areas with gravel and coarser sediment as the substrate are mainly inhabited by filter-feeders because the grain size is too large to ingest and the turbulent water required to prevent finer sediment from being deposited would also keep food in suspension.
b. Areas with fine sand and coarse silt as the substrate have a mixed fauna of detritus deposit feeders, infaunal filter-feeders, and a few epifaunal filter-feeders.
c. Areas with muddy substrates have almost exclusively deposit and detritus feeders because the sediment is rich in organics and the low energy conditions keep little material in suspension.
5. The two major benthic communities based upon substrate are:
a. Hard-bottom community - found in most high energy intertidal environments and characterized by a substrate of rock or gravel.
- Seaweed and a diverse benthic fauna are typically found in this community.
b. Soft-bottom community - substrate composed of unconsolidated sand and mud with a fauna largely controlled by grain size with one group typically dominating.
- In clean sands, filter-feeding bivalves dominate, but their numbers decrease and the numbers of worms and snails increase as the sediment becomes muddier.
13-2. Biology of the Open Ocean and the Deep Sea
C. The open ocean is the largest habitat on Earth, but life is sparse because of low nutrient concentration and great depth.
1. In the open ocean, diversity is high but the number of individual per species is low.
2. The only seaweed in the open ocean sea is sargassum gulfweed.
3. The major phytoplankton are diatoms, dinoflagellates, and coccolithophores; the major zooplankton are foraminifera and radiolaria.
- Diatoms dominate the shallow coasts, but decrease in abundance seaward.
4. Top predators are mackerel, squid, jellyfish, tuna, porpoise, shark, and man.
5. In the dysphotic zone, seasonal heating is minimal and conditions tend to be uniform most of the year.
a. The dysphotic fauna includes prawns, shrimp, copepods, amphipods, ostracods, squid, and fish.
b. Fish in this zone have special adaptations including:
1. Large light-sensitive eyes.
2. Photophores (light generating structures) which produce bioluminescence.
- Light is generated by bacteria and the photophores can be arranged on the body for species identification or employed to assist in capturing food.
c. Food in the dysphotic zone is scarce and some organisms display diurnal vertical migration.
- They migrate to the surface at night to feed and then return to the depths (700 - 900 m) during the day.
6. The aphotic zone is an area of permanent darkness and cold.
a. Most animals have red or black pigments.
b. Major organisms include copepods, ostracods, jellyfish, prawns, mysids, amphipods, and a variety of worms and fishes.
c. Characteristics of the mid-water fishes include:
1. Low abundance.
2. Small size, about 2 to 10 cm.
3. Large mouth with many sharp-pointed teeth.
4. A jaw that can be unhinged to accommodate large food.
5. An expandable stomach.
6. Bioluminescence to attract prey.
7. In some forms the male is parasitic upon female.
D. The biomass on the sea floor tends to decrease with depth faster than it does with distance from shore.
1. The benthic food chains largely depend upon food from the surface which reaches the bottom as:
a. Fine to coarse detritus that settles slowly through the water.
b. Large carcasses.
c. Organic material swept in by turbidity currents.
2. Characteristics of the benthic organisms include:
a. Year-round reproduction.
b. Smaller broods.
c. Slow growth.
d. Longer life.
3. Diversity of the benthos is greater than expected because the high predation rate prevents any group from dominating through competitive exclusion (when one group out-competes most others and drives them to extinction).
4. Four traits common to all abyssal depths are:
a. Perpetual darkness.
b. Low temperature.
c. High hydrostatic pressure.
d. Sparse food supply.
5. Rate of bacterial decay is greatly reduced under high hydrostatic pressure.
- This means that organic material that settles onto the sea floor remains for a long time before it decays and is thus more likely to be consumed.
Box: Penguins
E. Penguins are birds that have lost the ability to fly through the air, but have evolved for “flight” in water.
1. Evolutionary changes for life in the polar and subpolar seas include:
a. Larger and heavier bones.
b. Thick fatty deposits for insulation.
c. Greasy, water-proof feathers.
d. Streamed-lined body.
e. Small wings.
2. Some penguins remain at sea for months at a time, can dive to 250 m when feeding on squid, and remain submerged for 15 - 20 minutes.
3. Penguins are found only in the southern hemisphere.
4. Only two of the 18 species of penguins have rookeries in Antarctica.
Box: Sargassum Gulfweed
F. Sargassum gulfweed consist of eight species of planktonic brown algae which are mainly found drifting in the North Atlantic gyre, but are known from all oceans.
1. Most sargassum begins life as benthic seaweed in the Caribbean Sea, but becomes planktonic if dislodged by storms.
2. It is planktonic because its fronds have gas-filled floats.
3. Sargassum reproduces asexually by fragmentation when adrift.
4. As the plant ages, fewer floats are formed and eventually, the plant sinks out of the photic zone and dies.
5. Although not used as a food by herbivores, sargassum creates a unique and diverse habitat for other organisms, some of which mimic its appearance.
Box: Squids
G. Squids are large carnivorous nekton and one of the most advanced members of the Mollusca, class Cephalopoda.
1. The cephalopods have a well developed brain, acute eyesight, and chemosensors for “smelling.”
2. Members of the Cephalopoda include:
a. Nautilus - a rare form and the only one with an external shell.
b. Cuttlefish and octopus - mainly benthonic.
c. Squids - intelligent and fast swimming nekton.
3. Squids grow rapidly when young, reproduce sexually and are nocturnal hunters.
4. Architeuthis is the largest squid, up to 18 m long and weighing 4 tons.
a. Most of the length are the tentacles.
b. They live at depths between 300 and 600 m.
c. There is no evidence of them sinking ships, but they are known to have attacked people in the ocean.
Questions
Review of Basic Concepts
1. How does wave activity indirectly control the feeding behavior of the benthos on the floor of the continental shelf?
2. Describe diurnal vertical migration and explain its ecological significance.
3. Discuss the apparent reasons for the low biomass and high species diversity of the deep-sea benthos.
4. How exactly are rates of decomposition of organic matter affected by the high hydrostatic pressures associated with the deep-sea bottom?
5. Contrast the general feeding styles of benthos that occupy a mud substrate and a gravel substrate.
6. Describe how phytoplankton abundances and composition change with distance offshore and explain these changes.
7. What exactly is competitive exclusion and might this concept explain the unusual biodiversity of deep-sea bottom communities?
Critical-Thinking Essays
1. Biologists maintain that all food webs ultimately depend on primary production. How can this be true for communities on the deep-sea bottom where, because of perpetual darkness, there is no primary production?
2. Based on your understanding of fish morphology, which was covered in Chapter 9, design a “new” midwater fish that would be well adapted to life in the aphotic zone. Explain the reasons for your specific design features.
3. Schooling is a common behavior of fish that dwell in water of the photic zone. Speculate why midwater fish do not school.
4. Assume that California gray whales became extinct. What would be the geological and ecological consequences of this extinction for the Bering Sea? Argue logically for your deductions.
5. Using library and Web resources, contrast the predation styles of squid, shark, penguin, and porpoises.
Unit 5: The Ocean’s Resources
Learning Objectives
1. Learn the resources that are present in the sea and how ownership is determined.
2. Understand current technological limitations on exploiting the available resources.
3. Know the dangers of possible over-exploitation of the living resources.
Unit Outline
14-1. Law of the Sea
A. Several treaties regarding ownership and exploitation of the marine resources have been ratified in the last 50 years.
1. President Truman extended U.S. control of the marine resources from the shoreline to a depth of 100 fathoms (183 m).
2. The 1958 and 1960 Geneva Conventions on the Law of the Sea resulted in a treaty that placed the control of the sea bed, sea bed resources and water of the continental shelf under the country that owns the nearest land.
3. The 1982 United Nations’ Draft Convention on the Law of the Sea established:
a. Territorial waters that extend seaward for 12 nautical miles from the coast and are under the direct jurisdiction of the coastal nation.
b. An Exclusive Economic Zone (EEZ) that extends for 200 nautical miles offshore or to the edge of the continental shelf, if that is farther, giving coastal nations the right to regulate fishing, mineral resources, pollution, and research.
c. The right of vessels to free and innocent passage outside of the territorial waters and through international straits that lie within territorial waters.
d. That all private exploitation of mineral resources beyond the exclusive economic zones must be approved by the United Nation’s International Seabed Authority and that part of the revenue from the resources will be shared with the developing nations.
4. Exclusive economic zones contain about 40% of the ocean and the high seas represent the remaining 60%.
a. The U.S. has the world’s largest EEZ because of the large areas surrounding various island possessions and states.
b. The U.S.’s EEZ is 30% larger than the land area of the U.S.
14-2. Mineral Resources
B. Petroleum, oil, and gas are hydrocarbons derived from sedimentary rocks which were deposited in quiet, productive regions with anoxic bottom waters in which the remains of phytoplankton accumulated.
1. Deep burial resulting in high temperature and pressure converted the organic remains into hydrocarbons.
- Initially oil, but at higher temperatures and pressures, methane (CH4) natural gas was generated.
2. Pressure forced the oil and gas from the source rock into water-filled porous and permeable strata above.
3. Because oil and gas are less dense than water, they migrated upwards until their path was blocked by an impermeable layer.
4. Oil and gas accumulated, forming a large deposit within the pores of the rock, usually sandstone.
5. Location of possible accumulations of oil and gas can be determined using seismic reflection and refraction methods to determine the configuration of rock layers.
- These methods only indicate if the configuration of rock layers have the potential to trap oil and gas. They do not indicate if oil and gas are present.
C. Gas Hydrates refer to the unusual hydrocarbon deposits that consist of frozen water molecules entrapping a single molecule of methane (natural gas).
1. Gas hydrates occur in polar sediments and in deposits of the continental slope between the depths of 300 and 500 m where cold water is in contact with the sea floor.
2. These deposits contain incredibly large amounts of gas, but currently there is no economical method for its recovery.
D. Sand and gravel are natural aggregates of unconsolidated sediment with grain size greater than 0.0625 mm in diameter.
1. Sand and gravel accumulate in high energy environments where strong currents and/or waves currently prevail and occur as relict sediments across the continental shelf from when sea level was lower.
2. These materials are used for construction of roads and buildings and to replenish beaches which are undergoing erosion.
3. Mining sand and gravel deposits from the shelf threatens both the benthic and pelagic communities and introduces large amounts of material into suspension.
E. Manganese nodules are composed of about 20-30% manganese, 10-20% iron oxide, 1.5% nickel, and less than 1% cobalt, copper, zinc, and lead.
1. Locally, the nodules can be very abundant, as on the subtropical sea floor of the Pacific Ocean, where billions of kilograms occur.
2. Currently, there is no economical method of recovering the nodules from the deep sea.
F. The sides of many seamounts and islands are enriched in cobalt between the depths of 1 and 2.5 km.
- Cobalt is a strategic metal used in making jet engines, and the U.S. cannot produce sufficient cobalt to meet its needs.
G. Phosphorus is required for growth by all organisms.
1. Phosphate deposits generally form on submarine terraces where coastal upwelling generates high productivity.
2. Organic wastes and remains accumulate in the sediment, and as they decay, they releases phosphorus compounds which precipitate as phosphate nodules.
3. Nodules grow at the rate of about 1 - 10mm/1000 years.
4. World consumption of phosphate is about 150 million tons per year and known supplies should last until 2050.
14-3. Living Resources
H. Marine finfish can be divided into the pelagic fish which live in the water column and groundfish which live on the sea floor.
1. Most of the ocean is sparsely populated because of low nutrient availability.
2. Areas of major fish production are the coastal waters and regions of upwelling.
3. Because they are economic to capture, major commercial fishes are those which form large schools.
4. The fishing industry uses sonar, scouting vessels, airplanes, and satellites to locate schools and then deploy the fishing fleets to those areas.
5. Drift nets are controversial because they capture everything too large to pass through the mesh of the net and needlessly kill many organisms.
- The 1989 United Nations’ Convention for the Prohibition of Long Drift Nets prohibited drift nets longer than 2.5 km, but compliance is largely voluntary and impossible to enforce on the open sea.
6. World ocean fish production appears to have leveled at between 80 and 90 million tons annually.
7. Currently, the expense incurred in fishing exceeds the profit from the sale of the fish and fishing industries only survive through government subsidy.
I. Mariculture is marine agriculture or fish farming of finfish, shell fish, and algae.
1. Mariculture requires raising the organisms under favorable conditions until they are large enough to be harvested for food.
2. Currently, about one out of every four fish consumed spent part of its life in mariculture and for some organisms the percentage supplied by mariculture is even larger.
3. For mariculture to be economically viable the species must be:
a. Marketable.
b. Inexpensive to grow.
c. Trophically efficient.
d. At marketable size within 1 to 2 years.
e. Disease resistant.
Box: Offshore Oil and Gas in the Gulf of Mexico
J. The continental shelf between Louisiana and Texas has a highly irregular surface reflecting the upward migration of deep salt deposits through the layers of sediment.
1. The salt warps and pierces the layers of sediment as it migrates upwards and forms traps in which oil and gas accumulate.
2. Current technology will allow the exploitation of deposits in water to a depth of about 790 meters.
Box: Modern Whaling
K. Since the 1970s, the whale catch has drastically declined because of over-fishing.
1. Established in 1946, the International Whaling Commission works to conserve the stock of whales and perpetuate whaling. The commission did little to prevent overfishing and the decimation of whale populations.
2. In 1985 the Commission proposed a complete ban on whaling to allow species to recover.
3. Since then, only a few species have shown a marked increase in numbers.
Box: Antarctic Krill
L. Krill are shrimp-like crustaceans that are one of the most abundant organisms in the ocean.
1. There are 85 species of krill from the tropics to the polar seas; each species is adapted to a specific water temperature.
2. The Antarctic kill is Euphasia superba and is widely distributed in the waters around Antarctica.
3. The Antarctic krill reaches about 6 cm long and weighs about one gram.
4. Adults form dense swarms and many species display diurnal vertical migration.
5. As herbivores, krill are a keystone species, the important link between the autotrophs and the rest of the food chain.
6. Krill first began being harvested in the 1960s, and the catch has varied considerably over the years.
7. As a food source, krill must be processed within three hours or enzymes in its body will foul the meat and make it inedible. Because the shell contains fluoride, it must be removed.
8. The United Nations 1981 Convention on the Conservation of Antarctic Marine Living Resources was designed to protect the Antarctic ecosystem.
- Limits set on the amount of krill that can be removed annually have been criticized because too little is known about krill stocks and environmental controls on their populations.
9. Mismanagement of krill could cause a collapse of the Antarctic ecosystem.
Questions
Review of Basic Concepts
1. What is the difference between a territorial sea and an Exclusive Economic Zone?
2. How are oil and natural gas formed?
3. What is the difference between a gas hydrate deposit and a natural gas deposit?
4. What problems are associated with mining sand and gravel from the sea bed?
5. What economically important metals are contained in manganese nodules?
6. What is the difference between pelagic fish and groundfish?
7. What are drift nets and why do regulatory agencies wish to have them banned outright?
8. What is mariculture and why will fish protein produced in this way not help feed the world’s poor?
CRITICAL THINKING ESSAYS
1. Who should benefit from the exploitation of resources that lie seaward of Exclusive Economic Zones? Argue compellingly for your choice.
2. Argue for and against the proposal that landlocked countries should benefit economically from the exploitation of marine resources.
3. Assume that there is a long-standing groundfish fishery on a continental shelf that borders a coast where responsible and necessary house construction is underway. Although the annual groundfish harvest has fluctuated markedly for the past decade, the catch on the average has declined systematically despite more intense fishing and a larger fishing fleet. The sand of the shelf bottom in the fishery area is desperately needed for the development plans of the local communities. What should or can be done? Develop arguments for your resolution of this conflict.
4. Using your knowledge of biological oceanography, speculate on the possibility that the extensive harvesting of krill in the Southern Ocean could potentially damage Antarctica’s marine ecosystem.
5. Assume that you have decided to invest a substantial amount of money in a mariculture project. What sort of organism would you consider and what sort would you not? Specify the reasons for each case.
Minke whales have recovered well during the global ban on whaling. Should they now be hunted responsibly and sustainably? Why or why not?
Unit 6: The Human Presence in the Ocean
Learning Objectives
1. Understand what constitutes pollution and how various forms of pollution impact the marine environment, especially its living resources.
2. Learn the causes of overfishing and the problems of preventing it from occurring.
3. Appreciate the potential danger inherent in climate change.
Unit Outline
15-1. Pollution: What is it?
A. Pollution is the introduction by man, directly or indirectly, of substances or energy into the environment, resulting in deleterious effects such as harm to living resources, hazards to human health, hindrance of marine activities, including fishing, impairing quality for use of sea water, and reduction of amenities.
1. In studying pollution it is important to have a baseline from which to measure man’s impact upon the environment because some of what is considered to be pollution may be occurring naturally and not caused by man.
2. Pollution tends to be concentrated in three parts of the ocean environment:
a. Sea floor - accumulation on the bottom either by the settling out of particles or being chemically attached to sediment.
- This mainly affects the benthos.
b. Pycnocline - some pollution accumulates along the pycnocline because it is too light to sink through the dense bottom water.
- This is very common in estuaries.
c. Neuston layer - accumulation of pollution on the air-water interface.
- This mainly affects the plankton.
3. Pollutants are eventually broken down by various oceanographic and biological processes.
15-2. Hydrocarbons in the Sea
B. Petroleum is a complex mixture of hydrocarbons, combinations of hydrogen and carbon with various amounts of nitrogen and metals.
1. Oil as it comes from the ground is called crude oil or petroleum.
a. The composition of the petroleum varies greatly depending upon the geologic history of the material.
b. The smaller the size of the hydrocarbon molecule, the lighter (less dense) the oil is.
c. Oil can be separated into various densities by distillation because oils of different densities evaporate at different temperatures.
2. Only a small fraction of the oil in the sea comes from major oil tanker accidents.
a. About 33% of the oil in the sea comes from contaminated rivers.
b. Another 33% of the oil is released by tankers as they pump out their bilges and from the incomplete burning of fuel in their engines.
c. 13% of the oil enters the sea as leakage from coastal refineries.
d. 21% of the oil is from natural oil seeps, atmospheric fallout, and from general ship traffic.
3. Once in the environment, an oil spill begins to be altered.
a. The oil slick naturally spreads outward and is additionally distributed by waves and currents.
- This greatly increases the surface area of the spill.
b. The light fraction of the oil evaporates, the soluble portion dissolves into the water and the heavy insoluble fraction emulsifies (mixing of one fluid into another without dissolving) and is vertically mixed in the water column.
- Emulsified oil forms globules which eventually become floating tar balls that finally sink to the bottom or wash ashore where they weather or are buried.
c. Microbes begin to degrade the petroleum into CO2.
d. Larger organisms ingest and metabolize some of the oil.
4. The rate at which the oil is dispersed and dissipated depends upon the weather, composition of the crude, and the waves and currents.
5. All oil is toxic at all levels of the food chain, but the degree of damage depends upon the type of petroleum and upon the specific habitat and ecosystem.
a. In a coastal environment an oil spill kills benthic, pelagic, and nektonic organisms by poisoning or smothering.
b. On a muddy intertidal flat a spill will decimate the benthos, both plants and animal.
c. On the open sea a spill does less damage because the volume of water into which it mixes is much greater and the bottom is so deep it may be unaffected.
6. There are several methods employed in attempting to clean a spill.
a. Floating booms are barriers placed around the spill to try and prevent it from dispersing so that it can be removed more easily.
- This is not effective if waves are large or winds and currents are strong.
b. Chemical dispersants disperse the oil into the water.
- Dispersants do not actually remove the oil and frequently are as damaging or even more damaging to the environment than the oil.
c. Burning the oil at the surface.
- Oil is difficult to ignite and to keep burning. Additionally this method creates air pollution which later settles onto the sea.
d. Skimming involves removing the surface water and recovering the oil.
e. Bioremediation involves stimulating the growth of microbes that feed on the oil so that they decompose it.
f. If oil reaches the shore, it should be removed without disturbing the substrate.
15-3. Municipal and Industrial Effluents
C. Each year humans produce over 20 billion tons of wastes, much of which is disposed of in the ocean.
1. Most of the wastes come from farmland, cities, and industrial areas and enter the sea by way of rivers.
2. Wastes tend to be concentrated in harbors, bays, and estuaries.
3. All bodies of water have a natural capacity to clean themselves of a certain amount of pollution, but dense populations can produce so much pollution that the self-cleaning capacity is exceeded.
4. As pollution enters the sea, it can be greatly diluted depending upon the waves and currents.
5. Various pollutants behave differently depending upon their temperature, density and solubility.
6. As effluents are released, they form a contaminant plume which increases in size with distance as the pollutant is diluted by surrounding water.
a. Particulate matter will settle out at greater distances from the source as particle size decreases.
b. Some of the material will be concentrated on the pycnocline.
c. Outward from the point of entry, the influence of the pollution decreases and a series of gradational changes can be seen in the bottom fauna.
1. At the source the bottom will consist of a sludge and there will be almost no infauna.
2. Farther from the source the fauna will consist of dwarfed individuals.
3. At a still greater distance the fauna will be unusually abundant and form dense masses.
4. At a great distance the fauna will be unaffected by the pollution and occur in normal density of normal size individuals.
d. In estuaries, because of the reversing flow with the ebb and flood tides, pollutants can be concentrated in the area where released and not dispersed evenly.
D. Municipal and industrial wastes in the ocean can be divided into three general categories: sewage, metals and artificial biocides.
1. Sewage consists of a messy sludge or organic and inorganic chemicals.
a. Human wastes are a major component of sewage and consist of organic matter, inorganic nutrients (mainly nitrates and phosphates), and pathogens (disease-causing organisms such as bacteria, viruses and parasites).
b. If sufficient nutrients are released into the waters, it can promote a phytoplankton bloom.
- As dead phytoplankton sink to the bottom and decompose, this creates an excessive biological oxygen demand (BOD) that results in the water becoming hypoxic or anoxic in a process called eutrophication.
c. The resulting low oxygen content will kill most organisms on the bottom and in the affected water column.
d. As the herbivores are killed, there is less grazing.
- More phytoplankton survive to reproduce and generate additional organic matter that will create an even greater BOD.
e. Eventually the entire food web can be decimated.
f. Eutrophication has been observed in lakes, embayments, and even on sections of the continental shelf.
2. Heavy metal is a term loosely applied to a collection of elements such as lead, mercury, cadmium, arsenic, and copper that normally occur in trace amounts in the ocean but become toxic in larger dosages.
a. Heavy metals are normally added to the sea in small amounts through weathering and volcanic activity.
b. Manufacturing and industrial processes can greatly increase the amount of heavy metals released into the environment.
c. Mercury, especially in the form of methyl mercury, is highly poisonous because it is not biodegradable. It is stored in the fatty tissue of an organism and damages the central nervous system.
3. Artificial biocides are man-made toxic chemical compounds that do not occur naturally.
a. Halogenated hydrocarbons or organochlorines are common biocides and of these DDT (dichloro-diphenyl-trichloro-ethane) and PCB (polychlorinated biphenyls) are the most widely distributed in the ocean.
b. These chemical compounds are not biodegradable and remain in the environment for a long time.
c. They are adsorbed on the surface of silt grains, ingested by deposit feeders and filter-feeders and stored in fatty tissue.
d. DDT is a highly toxic pesticide that is now banned in most of the western world, but its use continues to increase in underdeveloped countries.
1. Sprayed on crops and soil, much of it washes into rivers.
- Some remains airborne, contaminating rain and snow or settling out directly onto the ocean surface.
2. It has been detected in the muds of the deep ocean and in the ice of Antarctica.
e. PCB is used in electrical equipment, paints, and adhesives and is released into the environment by incineration and unregulated disposal.
- PCBs have been found throughout the ocean environment.
4. Bioaccumulation is the process whereby organisms retain and concentrate a toxic material within their body.
5. Biomagnification is the process whereby a toxic material increases in concentration with each trophic level of a food chain.
- It results from bioaccumulation at each trophic level.
15-4. Ocean Dredging and Mining
E. Dredging accounts for 80 to 90% of the material dumped at sea each year.
1. If the dredged material is clean, it presents no long-term environmental problem.
a. If the material is dumped slowly enough, many benthonic organisms can work their way to the surface through the new layer of sediment, but if too rapid, they are buried and killed.
b. If the dumped material is not the same as the original substrate, a different group of organisms may colonize the area.
c. Clean dredgings can be used to replenish beaches that are eroding.
2. Contaminated sediment represents an initial and long-term source of pollution.
a. Dredging the contaminated sediment reintroduces pollution into the water at the site of dredging.
b. Dumping the sediment releases pollution at the dumping site.
c. As the dumped sediment compacts, contaminated pore water escapes and contaminates the water column.
d. Storms and currents which disturb the sediment will also re-introduce pollution.
e. So as to minimize reintroduction of the pollutants, contaminated sediment is frequently covered by layers of clean sediment.
F. Mining of deep ocean deposits will most likely be accomplished with a hydraulic pumping system that will vacuum water, sediment, and organisms from the sea floor and bring them to the surface.
1. The majority of the organisms drawn into the system will be killed.
2. Large areas of the sea floor each day will be disrupted and stripped of life.
3. Sediment released at the surface will create a massive sediment plume as it sinks to the bottom.
a. If the plume sinks quickly, it will have little impact on photosynthesis, but if remains suspended at the surface it could inhibit productivity.
b. Rapidly subsiding sediment could bury organisms on the sea floor and smother them.
c. Pollutants in the deep water could be introduced into the surface water and contaminate the food chain.
15-5. Overfishing
G. Overfishing is removing a living resource from the sea faster than it can replace itself, and if continued sufficiently long, the resource will collapse.
1. Overfishing is possible today because:
a. Technology has made it easier to locate large schools of fish and direct fishing fleets to those locations.
b. Mismanagement of policies related to sustaining fish production.
c. Fishermen resist quotas and misreport catches.
2. Maximum sustainable yield is the theoretical maximum amount of fish that can be removed from a population without significantly interfering with the population’s ability to renew itself.
a. The maximum sustainable yield is based upon biological factors such as population dynamics, food webs and spawning success, and the fishing effort required to produce a given catch.
b. Problems with determining a maximum sustainable yield include:
1. Under-reporting the amount of fish caught.
2. Natural fluctuations of populations due to predation and food supply.
3. The inherent difficulty in determining the size of fish populations.
4. The unknown impact of discard fish (those returned to the sea because they are too small or of poor quality) on the population.
c. Politics frequently result in altering the scientifically determined maximum sustainable yields to meet a political end.
3. It has been suggested that the concept of the maximum sustainable yield be replaced by the “precautionary principle,” which is to avoid anything that may damage or negatively impact a fishery.
15-6. Climate Change
H. All Earth systems: geologic, atmospheric, and hydrospheric, are interconnected and alteration of one will impact the others.
1. Oceans store heat and transfer it poleward in the ocean gyres.
- Currents and upwelling can have a direct impact on local and regional climate.
2. Carbon dioxide (CO2) in the atmosphere allows light to pass, but traps heat.
3. Burning fossil fuel is increasing the amount of CO2 in the atmosphere and together with deforestation is causing the greenhouse effect or global warming.
a. In the last 150 years the amount of CO2 gas in the atmosphere has increased 44%.
b. The actual amount of gas released was greater, but the oceans have absorbed between 30-50% of the CO2 released each year.
c. Computer models suggest that in the next 50 to100 years the world’s average temperature will increase 2oC.
- The increase will be greater at the poles, about 6 to 10oC, and less at the equator.
4. Possible consequences of global warming include:
a. Melting of glaciers in Greenland and Antarctica.
b. Rising sea level and flooding of most coastal cities.
c. Smaller temperature differences between the equatorial and polar regions resulting in changes in wind and rain patterns.
15-7. The Ocean’s Future
I. Based upon a study by the U.N., the current state of the marine environment is:
1. Most of the water of the open ocean is clean, except for heavily traveled shipping lanes.
2. Coastal waters and shelf waters are contaminated to varying degrees everywhere; the amount of contamination depends upon population density, degree of urbanization, agricultural practices, and shipping activity.
3. Coastal habitats are being severely affected and destroyed at an increasing rate.
4. Major pollutants in the ocean should be the immediate concern, but the long-term presence of minor pollutants is uncertain.
5. Too little is being done to reduce human activity on land that impacts the ocean.
Box: Bioremediation
J. Bioremediation is the use of micro-organisms to degrade a contaminant in the environment.
- For petroleum spills there are two approaches to bioremediation:
a. Fertilizing contaminated water encourages the growth and reproduction of micro-organisms already in the environment, including those which degrade petroleum.
- This has been successfully used on beaches with less negative impact than other means of clean-up.
b. Seeding contaminated water with the micro-organisms that degrade petroleum either with or without fertilization.
- A possible advance in this technology would be to use bioengineered micro-organisms that are more efficient in degrading petroleum, but this has several inherent risks and has not yet been attempted.
Box: Red Tides
K. Some dinoflagellates produce toxins that are an irritant when ingested or inhaled.
1. Normally these species of dinoflagellates are present in the ocean in small numbers, but occasionally they experience a bloom, called a harmful algal bloom (HAB).
2. A pigment in the cell gives it a red color and when the concentration of these species is sufficiently high, they will impart a reddish hue to the water, hence the name red tide.
3. The toxin can bioaccumulate in seafood, especially shellfish, to such an extent that consuming them can be fatal.
4. If the dinoflagellate cells burst in turbulent water, an aerosol rich in the toxins can form and affect breathing.
5. Small HAB are not serious, but large ones can cause massive fish kills as well as kill many other forms of marine life.
6. The number of HABs has been increasing recently and they are occurring in areas where they were previously unknown.
Questions
Review of Basic Concepts
1. What is the definition of pollution?
2. What exactly is crude oil?
3. To reduce significantly the oil pollution of the ocean, where should we concentrate our effort and funds? Explain your reasons.
4. What processes affect an oil spill in the open ocean? Which of these are most important in the first few days of the spill? Which are most significant several weeks after the spill? Explain.
5. What is eutrophication? How is it caused and how can it be prevented?
6. By what biological process can even low-level concentrations of metals and artificial biocides dissolved in water affect an ecosystem? Describe the process.
7. What specific environmental impacts are associated with mining the floor of the deep sea?
8. What is bioremediation, and what are its advantages and disadvantages for the clean-up of oil spills?
9. What combination of factors have caused fisheries to collapse?
10. What is the greenhouse effect and how does it connect to a rise in sea level?
Critical-Thinking Essays
1. The standing water in a pond of a remote and isolated salt marsh is naturally hypoxic most of the time. Is this pollution? Why or why not?
2. How can deepening of a tidal channel in an estuary by dredging be considered a form of pollution? Be specific.
3. What are the short- and long-term consequences of a large oil spill along a coastline? of discharging heavy metals in an estuary? of discharging raw sewage in a bay?
4. Why are dredge spoils usually not suitable for the sand nourishment of a badly eroding beach? Be specific.
5. Speculate about the long-term consequences of using genetically engineered microbes for bioremediation of a shoreline.
6. If you were in charge of sustaining the George’s Bank fishery, what would you do? What kinds of information would you need to decide on a management policy?
7. How are even the most remote parts of the ocean—the polar seas and the deep-sea floor—being affected by pollution?
8. Should municipalities and states start planning for the expected global rise in sea level? Or is it more prudent to wait and see whether a rapid rise of sea level will occur sometime in the twenty-first century?
Doing the math
1. Assume that a metal dissolved in the water of a bay occurs in a concentration of 0.000005 ppm (parts per million). The concentration of this same metal in the tissue of ospreys that hunt fish in the area is 50 ppm. How many times has the metal been biomagnified?
2. Examine Figure 15–12b. How many orders of magnitude is DDT magnified in ospreys in comparison to DDT levels in the water?
3. If a machine that collects nodules processes on the average about 5,000 tons of sediment per day, how many tons of nodules are mined each day if the nodule-to-sediment ratio by weight is 4 to 1?
4. Examine Figure B15–2. Calculate the average rate of drift of the oil spill in centimeters per second and in knots (see Appendix II) between March 18 and 24.
5. Given the rate of drift calculated for the preceding question, estimate the average wind speed, assuming the spill was drifting at about 3 percent of wind speed.
Lab 1: Open and Closed Sea water Systems: Theory and Practice
I. Equipment and materials
A. Tanks
B. Filtration 1. Mechanical
2. Biological
C. Substrate - pH regulation
D. Water 1. sea salt mix
2. natural
E. Temperature and light
II. Setting up and conditioning
A. Tank placement
B. Assembly
C. Conditioning
III. Animals and plants
A. How many?
B. What kinds? - Fish, crabs, shrimp, barnacles, oysters, sea shells, anemones, gorgonians, starfish, urchins, worms, sand dollars, algae (sea weeds). Avoid: sea cucumbers, sponges, and large fish.
IV. Maintenance
A. Evaporation and water changes
B. Cleaning
C. Feeding
D. Problems and tips
1. Cloudy water and mortalities
2. Diseases and copper
3. Water color
VI. Collecting your own specimens
A. Collecting
B. Handling and transporting
Plankton
A. Terminology: sizes
B. Collection techniques: nets, mesh sizes, towing schemed, preserving
1. Describe the terms used to characterize plankton by sizes, taxonomy, function, life histories
2. Describe and demonstrate the correct use of: plankton nets of appropriate sizes and mesh sizes, net towing schemes, plankton preservation
mero-, holo-, phyto-, zoo-, micro-, nano-, macro-plankton, mesh sizes, towing schemes, quantitative sampling, plankton splitter
Trawling and dredging
A. Otter trawl
B. Bottom sampling
C. Quantitative sampling
1. Describe the parts and correct working arrangements of parts of the otter trail
2. Describe the type of bottom sampler best suited for different bottom types
3. Describe how dredges, trawls, and grab samplers can be used for quantitative sampling otter trawl and its parts, dredge, grab sampler, Peterson grab.
Preserving Marine Organisms
A. Preservatives and their preparation
B. Fixatives and stains
C. Special procedures
Natural Resources of the University by the Sea:
Habitats and Ecosystems of Savannah State University
First published by the Savannah State College Archives, Volume 1, number 2 winter 1994.
Revised 1/21/99
For more than 100 years the beauty of Savannah State University's campus has provided an inspirational setting for intellectual and spiritual growth at "The University by the Sea." The beauty is more than skin deep. Containing elements of two biologically diverse and important coastal ecosystems, the maritime live oak forest and the salt marsh estuary, the 165-acre campus is ecologically unique among the 34 instructional units of the University System of Georgia. These natural habitats and ecosystems provide natural laboratories for instruction and research in the School of Science and Technology where they are closely linked to abundant "hands-on" exposure and experiences, particularly in the Bachelor of Science degree programs in Marine Biology and Environmental Studies.
Savannah State University, formerly Georgia State Industrial College for Colored Youth, was founded as a result of the Land Grant Act of 1890 which forced the Georgia General Assembly to establish a land grant college for Blacks in Georgia or risk losing federal funds. Higher education for Blacks at Atlanta University resulting from the 1862 Land Grant Act became unsuccessful when legislators withdrew the funds from the institution, arguing that since white students were being taught, the laws of segregation of races in public education in Georgia were being violated (Hall 1991). A community effort was begun on March 6, 1891, at the First African Baptist Church to secure the college for Savannah. The group convinced a commission of five persons appointed by the governor to locate the college in Savannah, and the first 76 acres of land upon which the current 165-acre campus resides was deeded to the Trustees of the University of in 1891 in two tracts: 10 acres donated by George Parsons of New York City and 66 acres were purchased from Sara B. Postell for $6,000. Bordering the predominantly white town of Thunderbolt and Southeast coastal salt marsh, the land was, at one time, part of the Placentia Plantation, later known as Warren Place and contained two large homes which became Parson's Hall, located at the site of the current swimming pool, and Boggs Hall, located in front of Camilla-Hubert Hall (Hall 1991).
Construction of buildings on the campus began near these structures on the sandy bluff overlooking the salt marsh in the area now known as Felix J. Alexis Circle. This high ground represents barrier island beach dunes that were formed during the Pleistocene epoch 35,000 to 40,000 years ago. At that time the coastline was adjacent to the current campus because the sea level was higher as the result of globally warmer temperatures and more water in the oceans from melted polar ice. Small changes in sea level coupled to tidal and wave scouring can result in significant landscape rearrangement along broad, gently-sloping, sandy, barrier island coastlines. Even without sea level changes, the action of wind, wave, and tides, especially during storms, annually re-configure barrier island coastlines. Certain places on Wassaw Island, a favorite field trip spot for SSC Marine Biology classes, have undergone changes from dune, to beach, to tide pool, to salt marsh, back to dune over a period as short as 14 years.
The campus is located in the low country, an area bordered by the Atlantic Ocean to the east, sand hills to the west, and extending from Georgetown, South Carolina, to St. Marys, Georgia. The diverse ecological communities of the low country and campus result from the considerable influence of fresh water, salty ocean water, and the tidal mixing of them resulting in the biologically productive shallow aquatic habitats called estuaries. The low country represents one of the most extensive salt marsh estuary systems in the United States. The magnitude of the system results from the broad gently sloping sandy coast and continental shelf of the Southeast U.S. coupled with one of the highest tide ranges along the east coast of North America. Each day, two high and two low tides averaging 6 to 8 feet in range inundate a vast area of the coastal zone, maintaining a system of creeks, channels, and rivers. Since tides are principally the result of the gravitational pull of the moon and the sun on the earth, the timing and range of the tides depend upon their relative positions. Tidal range is greater than average when the sun and moon are aligned with the earth during new and full moons and are called spring tides. Tidal range is smaller than average when they are not aligned during the other moon phases and are called neap tides.
Besides an average annual rainfall of over 50 inches per year, an enormous volume of freshwater enters the coastal zone from rivers. The fresh water that drains into the tidal zone is mixed with sea water and creating brackish conditions and one of the earth's most productive ecosystem. Energy captured by plants from sunlight flows from prey to predator throughout a complex estuarine food web in which nutrients are absorbed, redistributed, and recycled. Due to the abundance of early life stages of both coastal marine and oceanic species in the system, estuaries are called the "nurseries of the sea." The eggs and larvae of both estuarine and marine species are carried into a system where they find both resources and refuge. Estuarine habitats are subdivided into salt marsh shrub zone, salt marsh flats, needle rush marsh, smooth cord grass marsh, marsh edge zone, intertidal creek banks, bars and flats, and tidal pools, creeks, and rivers.
The saline influence of the ocean in coastal environments is significant. Sea water is salty because it contains 7 major ions (elements forming salts when not separated by water in a solution), 5 minor elements, and 11 trace elements. The salinity or saltiness of oceanic sea water is about 36 parts per thousand (3.6%) dissolved inorganic ions and elements. The salinity of the brackish water in the tidal creek and adjacent coastal waters can range from less than 5 to over 30 parts per thousand during the year. The plants and animals that inhabit this changing environment are generally well-adapted to it.
The major elements of the salt marsh ecosystem can be seen from the University dock adjacent to the Marine Biology building. Smooth cord grass is the dominant tall green grass found in the lower part of the marsh where the ground stays wet and very muddy as a result of the tides flooding the area twice daily. In late spring through late fall when most of the salt marsh is lush green, darker dead-looking sections of marsh grass can be seen. This dead-looking marsh grass has long, tubular stems and sharp brown- pointed tips and is called the needle rush. These two grasses are replaced toward higher ground by the sea oxeye, which has a succulent leaf with a yellow aster flower in June and the similar, but taller, marsh elder, a shrub that encroaches on part of the wooden walkway leading to the dock. None of these salt tolerant plants, called halophytes, is found beyond the influence of the brackish tidal water.
The tidal creek supports much more marine life during the summer than during the winter. In summer, the warmer temperatures and greater sunlight increases the overall productivity of the salt marsh while in winter the colder temperatures and less sunlight decreases the productivity. While the water in the tidal creek is never crystal clear because the tides constantly stir up the mud, it is significantly clearer in the winter because there are fewer microscopic organisms such as algal cells suspended in it.
At low tide, the surface of the mud banks along the campus' tidal creek is highlighted by the golden hue of millions of algal cells called diatoms. Mud snails aggregate by the thousands on the mud zone. Mullet, Atlantic menhaden, killifishes, blue crabs, mud crabs, white shrimp, and brown shrimp are most responsible for activity at the surface of the water in the creek. Because of the significant tidal flushing, pollution does not accumulate in the creek; blue crabs and shrimp harvested here are safe to eat.
Attached to the dock and its pilings are barnacles, oysters, seaweeds and a variety of encrusting marine life known as hydrazoans, anthozoans, and ascidians. Because they strain microscopic particles from the water, including harmful microorganisms associated with animal waste, oysters from the creek by the campus and many other tidal creeks and rivers near human and animal habitation cannot safely be consumed. Attached and clinging to the stalks of the salt marsh grasses are ribbed mussels and periwinkle snails. In higher marsh sandy zones, fiddler crabs dig burrows, feed, and interact. The one enlarged chela (claw) of the male is useful for defense and communication but it is not effective for food gathering. As a result, males must spend twice as much time feeding as the females, which have two small chelae.
A non-natural, but common element of the salt marsh is marine debris: plastic containers, Styrofoam, cans, and other material of human origin, which ends up along coastal shorelines. These materials come from commercial and recreational boats and ships, marinas and docks where trash containers are absent or overflowing, construction sites and vehicles on roadways near the water, and from deliberate littering. Debris is constantly being redistributed on coastal shores by the action of tides, winds, and waves. Based upon a 1992 study of the rates of accumulation at four sites in Chatham County, over 40,800 kg or 40.8 metric tons of marine debris wash up on coastal shorelines in Chatham County annually (Gilligan et al).
The maritime influence on the campus climate and vegetation is significant. In the spring when it is somewhat hot and humid inland, the campus has cool breezes from the still-cold tidal waters, a form of natural air conditioning. In winter, the relatively warmer tidal waters can prevent vegetation from freezing. For example, cabbage palms, a distinctive tropical element of the low country, only grow naturally close to salt marshes.
Most of the natural and developed parts of the campus contain major elements of the maritime live oak forests, which characterizes the low country and its barrier islands. Well over 100 species of trees, shrubs, vines, and grasses can be found on or near the campus. The most notable and distinctive vegetative elements of the campus are the size and number of canopy trees (live oak, cabbage palm, loblolly pine, southern magnolia) and the large number of oak tree species.
Between the Marine Biology Building and dock are a weeping willow and red mulberry. A larger red mulberry is located directly behind the Kennedy Fine Arts Building. Adjacent to the Marine Biology Building along the marsh is an eastern red cedar, which is characterized by its dark, green, scaly leaves and light brown, fibrous bark and some very tall and old cabbage palms. The smaller variety of palm found in low-lying wooded areas is the saw palmetto because it has saw tooth edges at the base of the frond stems. Near the entrance to the Marine Biology Building are two sweet gum or gum-ball trees. Their star-shaped leaves are fragrant when crushed, and their fruit are round and prickly. Directly in front of the building are live oaks, so-called because they do not lose their leaves and look "dead" in winter. Hanging from them is Spanish moss which is neither Spanish nor a moss since it produces small green flowers. It is a bromeliad (air plant) obtaining its nutrients from debris on the branches. It does not harm the host tree but can reduce nut production in pecan trees.
Along the marsh directly behind Camilla-Hubert Hall are several laurel oaks between the parking lot and marsh. The leaves are elliptic, black and deeply furrowed. Bordering the east entrance to the building is a yucca or Spanish bayonet, a desert plant with succulent leaves with a sharp point, wax myrtle, a shrub with small gray, aromatic leaves and white berries, azaleas, and a hickory tree.
Across the street on Felix J. Alexis Circle is a southern magnolia which has very thick, shiny, oval, evergreen 5 to 10 inch-long 2 to 3 inch-wide leaves. The fruit is reddish brown with a fragrant smell. The circle is dominated by large live oaks, many of which have resurrection fern growing on the limbs. Under dry conditions the fronds curl up and turn brown but uncurl and turn green when wet. Scattered on the north half of the circle are some near record size loblolly pines which have pale blue needles bundled into threes and reddish-brown bark.
There is a high diversity of both indigenous and planted tree species on campus including pignut hickory (behind Herty Hall); tallow tree, sugarberry (between Hubert and Kennedy Halls); pecan (next to Kennedy Hall); slash pine (grove next to Griffith Drew Hall); long leaf pine, swamp chestnut oak (grove next to Whiting Hall); water oak, willow oak, Darlington oak, red oak (by Gardner Hall); black tupelo or black gum sweet bay (between NROTC and the Orsot Apartments); Virginia pine (behind Jordan Hall); Shumard oak, Carolina laurel (across from Plant Operations); Bradford pear, red maple, silver maple, dogwoods, lagustrum, mimosa, and many others.
Through the diversity and abundance of insects in the low country is fascinating to a biologist, they are generally regarded as pests, and in some cases, genuine nuisances. The prominent species in the later regard is the small biting midge, affectionately known as sand gnats or "no-see ums" which are occasionally abundant in early spring and late fall near the salt marshes where they breed. Fortunately, their populations are naturally regulated to unnoticeable levels during most of the year.
Mosquitoes, including a saltwater species, would be a significant problem on campus if it were not for the diligent and efficient efforts of the Chatham County Mosquito Control Commission which monitors populations and employs a variety of control methods. In the mid 1980's, the Asian tiger mosquito arrived in Savannah and has spread throughout the county. It is a container breeder and need only a small amount of standing water in which to lay its eggs, even water trapped in folded magnolia leaves. It is not only difficult to reduce its breeding habitat but also more difficult to control adult populations because it is active during the day, and pesticide spraying is only effective during the night.
The two major aquatic habitats on campus are the Placentia Canal, a county-maintained, fresh water drainage system which runs through the campus and drains into the Wilmington River, and the salt marsh estuary. Though they contain the same ecological components (producers, consumers and decomposers), fresh water and marine habitats are distinctly different in terms of their component species. Many amphibians (frogs and a large ell-like amphibian called the two-toed amphiuma) make their home in the canal, but no amphibians are found in marine habitats. Over 100 coastal marine and estuarine fishes have been collected from the salt marsh and nearly two dozen from the canal, but only a few species are at home in both habitats.
The reptilian inhabitants and visitors to the campus include a variety of non-poisonous snakes, lizards, geckos, and turtles. American alligators, though fairly abundant in some parts of the low country, are rare on or near the campus due to the lack of adequate fresh water habitats that they prefer. Natural resource personnel remove small alligators from the area to more suitable locations. The diamond back terrapin, an attractive turtle, lay its eggs on high ground in the salt marsh and several other turtle species are found on campus. Over 250 species of birds inhabit or visit the low country; however, fewer than 30 are seen daily on the campus. From the upland habitat of campus to salt marsh to sounds and beaches, the most commonly observed birds here are the common grackles, boat-tailed grackles, mockingbirds, common crows, fish crows, turkey vultures (buzzards), mourning dove, ground doves, swallows, red-winged blackbirds, cormorants, brown pelicans, five species of herons, three species of egrets, laughing gulls, ospreys, bald eagles, royal terns, least terns, and black skimmers. Winter migratory residents of the campus tidal creek include hooded mergansers and loons.
Fifty of nearly 100 species of coastal mammals recorded from the low country sea islands have been reported in Chatham County. They include both terrestrial species and marine species (whales, dolphins, and porpoises). The largest mammal encountered near the campus is the Atlantic bottlenose dolphin. Individuals and small pods have been observed from the University dock swimming up the tidal creek to feed on the abundant mullet. Pods exhibit a remarkable behavior here and in other tidal creeks of the low country: they chase schools of mullet onto the mud banks and emerge completely from the water onto the bank to feed on them.
Large river otters and mink are occasionally seen swimming or running along the mud banks and disappearing into the marsh grass along the tidal creek. Raccoons would probably be more abundant on campus were it not for the large populations of feral house cats that live and forage near the marsh and dormitory trash bins. Several undeveloped areas remain on the campus which contains natural understory vegetation of the maritime forest. These acres are principally located along the north margin of the campus bordered by the Placentia Canal, North Tompkins Road and Drew-Griffith Hall. Another small, but diverse section remains between the NROTC building and the Orsot Apartments.
No other instructional unit of the University System of Georgia can boast such a rich endowment of coastal habitats and ecosystems. On a calm cool evening in the early spring and late fall, the view through the oaks, pines, palms, cedars, and magnolias to the salt marsh grasses illuminated by the setting sun is a unique and enchanting experience of singular beauty, inspiration, and wonder.
The natural environments of its campus have enhanced the rich educational history and legacy of Savannah State University. This spiritually uplifting place lives in the memories of all those who have been touched by it and will continue to offer its unique qualities and experiences in higher education to all.
The 165-acre campus of Savannah State University contains elements of two biologically diverse coastal ecosystems: The maritime live oak forest and the salt marsh estuary. The variety of plants and animals found in these habitats provide a natural laboratory for instruction and research.
Acknowledgements
We wish to thank the following individuals for sharing information about the campus vegetation: Mr. Elias Golden, Head, Grounds and Maintenance, Dr. Margaret C. Robinson, Dean, School of Sciences and Technology, Mr. Risher Willard, Forester, Georgia Forestry Commission, for assistance with tree identification, and Dr. Louise Golden, Associate Professor of Humanities for editing. A 1993-1994 Title III Grant sponsored this faculty and student research publication. Dr. Charles J. Elmore, Director; Dr. John T. Wolfe, President
Authors
Matthew R. Gilligan, Ph.D., is a professor of Marine Sciences at Savannah State University where he has served since 1980. Kelvin Austin who assisted with the project was a student in the Marine Biology degree program at Savannah State University. His research included library research, interviews, and field trips with University and community experts.
Marine Mammals (Compiled by Gilligan and Caldwell 2003)
Classification
Kingdom Metazoa (Animalia)
Phylum Chordata
Subphylum Vertebrata
Class Mammalia
Order Cetacea
Suborder Mysticeti (baleen whales)
Family Balaenidae - Right whales (4 spp)
Family Neobalaenidae - Pigmy right whale (1 sp)
Family Balaenopteridae - Rorqual whales (8 spp)
Family Eschrichtiidae - Gray whale (1 sp)
Suborder Odontoceti (toothed whales).
Family Phyesteridae - Sperm whale (1 sp)
Family Kogiidae - Pigmy sperm whales (2 spp)
Family Ziphiidae - Beaked whales (4 spp)
Family Platanisidae – South Asian River Dolphin, Platanista gangetica, Common names: Ganges, Indus, Susu, Bhulan
Family Iniidae – Amazon River Dolphin, Innia geoffrensis, Common name: Boto
Family Lipotidae – Chinese River Dolphin, Lipotes vexillifer, Common names: Baiji, Yangtze dolphin
Family Pontoporiidae – La Plata Dolphin, Pontoporia blainvillei, Common names: Franciscana
Family Monodontidae (2 spp) - Beluga (white whale) and Narwhal
Family Delphinidae - Dolphins (35 spp)
Family Phocoenidae - Porpoises (6 spp)
Order Sirenia
Family Dugongidae - dugong
Dugong dugon
Family Trichechidae - manatees
Trichechus manatus (Caribbean species)
Trichechus senegalensis (West African species)
Trichechus inunguis (Amazonean species)
Order Carnivora
Suborder Pinnipedia Some scientists classify the pinnipeds as an order
Family -- Odobenidae. Walruses, monotypic family
Subfamily Odobeninae (living walruses)
Subfamily Dusignathinae (fossil walruses).
Family Phocidae - seals (19 spp)
Family Otariidae - sea lions and relatives (fur seals) (16 spp)
Family Ursidae (Bears)
Ursus maritimus Polar Bear (
Family Mustelidae (Weasels and otters)
Enhydra lutris Sea otter
In three living orders: Cetacea, Sirenia, and Carnivora (suborder Pinnipedia, Ursidae, & Mustelidae)
Order Cetacea relationship to ungulates (i.e. horses, cows, camels) accepted but closest living relative hotly debated
The order Cetacea includes about 84 living species of mammals that evolved from carnivorous ungulates 70 million years ago. Apparently are a monophyletic group. Characterized by being aquatic (mostly marine), streamlined with a flattened tail (fluke), no pelvic appendages externally (vestiges internal in some), no fur (bristles in young.
The two suborders include the mysticetes (baleen whales) and odontocetes (toothed whales). Mysticetes are larger, have two blowholes and baleen (keratin plates lining the rim of the upper palate to filter water for food). A 90-ton blue whale can hold 80 tons of water in its mouth (pleated folds in lower jaw). Gray whale only bottom feeder. Minke most abundant 300.000-400,000 individuals.
Odontocetes have monomorphic teeth (i.e. all one shape, e.g. conical in delphinids, spade shaped in phocoenids and ziphids) and more of them than any other mammal group. Hypothesized to have Evolved sophisticated echolocation probably allowing them to adaptively radiate into all ocean basins and some freshwater rivers. Echolocation abilities only tested in small dolphins that can be kept in captivity. Echolocation abilities hypothesized for most toothed whales.
Smaller varieties of toothed whales may be called dolphins or porpoises though scientists don't agree what taxonomic groups they may distinguish. The term dolphin is from the greek delphinus or delphys for 'womb' and porpoise is from the roman porcis for 'pig' and piscis for 'fish'. The dolphin fish also called 'mahi-mahi' or 'dorado' is a bony fish not a cetacean.
Dolphins can dive to over 300 m and the sperm whale to 2275 m.= 1.5 mi. for 80-90 min. 65-70% body weight is blood, blubber and spermaceti. Though they dive with full lungs they avoid squeezes and the bends by having collapsable rib cages and lungs (within 30-100 m., residual air in trachea), and a system of blood vessels that trap escaping dissolved gasses. Our incomplete knowledge of their physiology is partly a result of the Marine Mammal Protection Act which makes permits to study their physiology by invasive methods difficult.
The reason for their large brain is unclear. It is most probably related to home range, foraging in 3-D space and social relationships. Since a practical definition of intelligence does not exist, questions of intelligence in cetaceans are inappropriate. Mysticetes produce sounds from 10 to 5,000 Hz which may communicate over distances of several Kilometers, possibly more. Odontocetes produce clicks, pulsed clicks and unpulsed frequency modulated whistles of up to 200,000 Hz, 10 times the upper range of human hearing. sound focused by a variable shape (muscualr control) fatty/oily melon on head. Four beams - four targets? Spermaceti oil is 22-25% of body weight in sperm whale, largest of the odontocoetes. The spermaceti organ in the sperm whale is not homologous to the melon of odonocetes. Some evidence exists that the intensity of such sounds is sufficient to disrupt the sensory system of fish prey but no evidence exists for stunning prey. Also, no evidence exists of a language-like syntactical structure to the sequence of sounds though dialects develop in isolated populations. Dolphins, therefore appear to be no more communicatory than many social terrestrial animals (e.g. birds, carnivors, non-human primates).
(New section on sounds to be added/Cornell Program)
Most odontocetes depend upon social structure for foraging efficiency, predator detection, confusion and avoidance. Such pods maybe socially cohesive groups that may persist for weeks, years or even decades. (As such, occasional mass strandings are probably related to their inability to readjust to the loss or confusion of a social leader.) Where did you find this? I’ve nver heard of this before
Most cetaceans are polygynous rather than monogamous tending toward promiscuity. Females often mate with several males during periods of sexual activity. Non-reproductive sexual activity and homosexual activity is common in both captivity and in the wild and may be important in social bonding and reinforcing heirarchical social structures.
Migrations in mysticetes may be up to 10,000 km one-way (8000 km gray whale, Mexico to Chuckchi Sea). Mechanisms proposed to account for accurate long distance navigation in cetaceans include: sun orientation, cueing onto underwater topography by passive listening, echolocation of bottom topography, detection of thermal structure, chemoreception of water masses and ocean currents, magnetoreception.
Given adequate funding, science is on the verge of an explosion of information and knowledge about cetacean biology resulting directly from biotechnology (DNA fingerprinting applied to population biology and ecology), electronic technology (digital computer analysis of sound, satellite telemetry of movement and physiology.
Order Sirenia
Closest relatives elephants and hiraxes. All aqautic, sluggish swimmers, herbivores, five spp. one now extinct - Stellar sea cow killed by man in 1700s (1768).
Order Sirenia
Family Dugongidae - dugong
Dugong dugon
Family Trichechidae - manatees
Trichechus manatus (Caribbean species)
Trichechus senegalensis (West African species)
Trichechus inunguis (Amazonean species)
Dugongs inhabit warm shallow waters along the shores of the Indian Ocean and Western Pacific. They can reach up to 12 ft in length and weigh more than 600 pounds. Male dugongs have a single pair of upper incisor teeth that are modified into tusks. A single young is born after a gestation period of about 11 months. Due to the downturn of their mouths, Dugongs are obligate bottom feeders—dive deeper than manatees.
Manatees inhabit freshwater lakes and lagoons, wide sluggish rivers, and sheltered marine bays in tropical and subtropical Atlantic Ocean areas. They are known to reach lengths of 15 ft. and weights of up to 1,500 pounds. An adult normally needs 55 to 65 pounds of food daily. They can stay submerged for 12 to 15 min. at a time. Females reach maturity at 5 yr. and one offspring is born every 2 to 3 yr., gestation lasts about 12 to 14 mo. and the calf is dependent on the mother for 2 yr., first for milk and later to learn transmigrational routes and good areas for feeding. Manatees are primarily nocturnal and moderately social. However, when they cavort together they embrace each other with their flippers and even press their thick lips together in a "kiss." Horny plates are present in the front of their mouths in place of incisors and behind the plates they have enlarged molar-like teeth (conveyer teeth like elephants). Their flippers are used to clean their teeth and rub their sides which they love to do and get apparent pleasure from. Manatees cannot survive water colder than 46F (8C) and can live as long as 50 to 60 years.
Both dugongs and manatees have a heavy skeleton (a condition called pachyostosis) which probably helps them to remain submerged. The forelimbs of are modified into flippers, hind limbs are absent, and their broad tail is their primary source of propulsion. They are the only marine mammal herbivores feeding on marine grasses and algae. They are hunted for their fat and meat. In Florida, manatees perform a valuable service by consuming quantities of water hyacinth, which chokes many waterways.
Causes for diminishing manatee populations.
Sudden cold spells have been known to account for some annual mortality, but an enormous number of deaths are attributed to human related causes. For example, being struck by motor boats, being crushed in navigation locks and flood gates, and being entangled in fishing lines and traps, and diminishing habitat. Some natural causes of death for manatees other than old age include parasitism, disease, and occasional outbreaks of red tide. Unfortunately, there have been cases in which manatees have been injured intentionally. They are shot with arrows, have initials carved on their backs, are hooked with fishing lines, and are intentionally struck with power boats.
Order Carnivora
Sub-Order Pinnipedia
Pinnipeds are seals, sea lions, and walruses. Some scientists classify the pinnipeds as an order and some as a suborder of the order Carnivora.
Family -- Odobenidae. Walruses monotypic family
While the odobenids share some characteristics with the other two pinniped families, behaviorally they more closely resemble the Otariidae (the eared seals). Some researchers divide the Odobenidae into two subfamilies: the Odobeninae (living walruses) and the Dusignathinae (fossil walruses). Genus, species -- Odobenus rosmarus. Most scientists recognize two subspecies of walruses: Odobenus rosmarus rosmarus (Atlantic) and Odobenus rosmarus divergens (Pacific). Odobenus comes from the Greek "tooth walker," and refers to the walruses' method of pulling themselves up onto the ice with their long tusks. These two subspecies are physically and reproductively isolated: O. r. divergens lives in the Pacific Ocean and O. r. rosmarus lives in the Atlantic Ocean. The Pacific walrus is larger, with longer tusks and a wider skull. A third subspecies, Odobenus rosmarus laptevi, has been suggested based on specimens from the Laptev Sea in the Pacific Ocean. O. r. laptevi has skull characteristics similar to the Pacific walrus. Its size is intermediate to the Atlantic and Pacific subspecies.
The common name, walrus, originated with the Danish word hvalros, meaning "sea horse" or "sea cow." The Russian word for walrus is morzh. Eskimos call the walruses aivik (Inuit) or aivuk (Yu'pik).
The earliest of the odobenid fossils date back to the middle Miocene, about 14 million years ago.
The Dusignathinae, or fossil walruses, were abundant in the North Pacific 11 to 14 million years ago. Unlike the modern walrus with its elongated upper canines (tusks), the upper and lower canine teeth of these fossil walruses were about the same size. Ancestors of the Odobeninae, or modern walrus, probably made their way from the northern Pacific Ocean to the Atlantic during the late Miocene, 6.5 million years ago, by way of a Central American seaway. Within the last one million years, walruses re-entered the Pacific via the Arctic. The modern Pacific walrus originated from this Atlantic stock.
Family Phocidae - seals, lack external ear, hind limbs do not rotate under body, small, furredpectoral appendages with claws,. (to much of a generalization, many are circumpolar, some North Altantic (east and west coasts) South Atlantic and Pacific (all coasts, north and south, east and west).
Family Otariidae - sea lions and relatives (fur seals), sexually dimorphic/polygynous, external ears, hind limbs rotate under body, no fur on flippers, no claws, mostly Pacific, although two spp do live on the east coast of South America.
Northern elephant seal reduce to ca. 20 (10-30 Bartholomew and Hubbs 1960, Mammalia, 24:313-324) individuals on Guadalupe Island. One male may have done all the breeding for 10 years. Now over 200,000. When diving (200-400 m. 700 m. max.) do it constantly (< 10% time at surface), record dive male in Alut. Is. 77 min. to 1547 m.
Weddell seal physiology - diving 'response'. It is not. Individuals consiously control body regulatory mechanisms. These include:
- cessation of breathing
- variable brachycardia depending on duration
- variable central and peripheral vasoconstriction
- reduced aerobic respiration in most organs
- rapid O2 depletion in most muscles
- lactic acid accumulation after 20 min.
- variable blood chemistry changes (PO2, PCO2, pH, lactate) during and following dives.
- variable reduction in core temperature
key to deep diving is blood volume, myoglobin rich blood.
Marine Mammal Lecure References
Leatherwood, S., D.K. Caldwell and H.E. Winn. 1976. Whales, Dolphins and Porpoises of the Western North Atlantic. NOAA Technical Report NMFS CIRC-396. 176 pp.
Martin, A.R. and R.R. Reeves 2002. Diversity and Zoogeography. In R.A. Hoelzel (ed.) Marine Mammal Biology: An Evolutionary Approach. pp 1-37. Blackwell Publishing
Sea World, Inc. 1994 WWW page.
Sumich, J. Lecture NSF Oceanography Short Course, San Diego, CA July 6, 1990, Grossmont College.
Wursig, B. 1989. Cetaceans. Science 244(1550-1557)
Whither the Whales. (Spring) 1989. Oceanus. 23(1) 1-144.
Course References
Bartlett, J., ed., 1977. The Ocean Environment. H.W. Wilson, New York. 221p.
Borror D.J.1988. Dictionary of Word Roots and Combining Forms Mayfield Pub. Co., Palo Alto, CA 134 pp.
Cailliet, G.M., M.S. Love and A.W. Ebeling. 1986. Fishes: A Field and Laboratory Manual on their Structure, Identification, and Natural History. Wadsworth Pub. Co. Belmont, CA. 194 pp.
Castro, J.I. 1983. The Sharks of North American Waters. Texas A & M University Press. 180 pp.
Chaplin, C.C.G. and P. Scott. 1972. Fishwatchers Guide to West Atlantic Coral Reefs. Harrowood Books. 64pp.
Collins, H.H. Jr. 1981. Complete Field Guide to North American Wildlife. Harper an Row, New York. 714 pp.
Dahlberg, M.D. 1975. Guide to the Coastal Fishes of Georgia and Nearby States. University of Georgia Press. 187 pp.
Georgia Consevancy. A guide to the Georgia coast. 711 Sandtown Rd., Savannah, GA 31410. 199 pp.
Gilligan, M.R. 1989. An Illustrated Field Guide to the Fishes of Gray's Reef National Marine Sanctuary. NOAA Technical Memorandum, NOS MEMD 25. Marine and Estuarine Management Division, OOCRM, NOS, NOAA, U.S. Department of Commerce, Washington, D.C. February 1989. 77 p.
Gilligan, M.R., T. Kozel and J.P. Richardson. 1991. Environmental Science Laboratory: A Manual of Lab and Field Exercises. Halfmoon Pub. Savannah, GA, 156 pp.
Gilligan, M.R. 1994. Natural Resources of the College by the Sea: Natural Habitats and Ecosystems of Savannah State College. Savannah State College Archives. 1(2) Winter 1994.
Goodson, G. 1976. The Many-splendored Fishes of the Atlantic Coast Including the Fishes of the Gulf of Mexico, Florida, Bermuda, the Bahamas, and Caribbean. Marquest Colorguide Books. 202 pp.
** Gosner, K.L. 1978. A Field Guide to the Atlantic Seashore. Peterson Field Guide Series. Houghton Mifflin, Boston. 329 pp.
Greenberg, I. and J. Greenberg. 1977. Waterproof Guide to the Corals and Fishes of Florida, the Bahamas and the Caribbean. Seahawk Press. 64pp.
Grice, G.D. and M.R. Reeve, ed., 1982. Marine Mesocosms: Biological and Chemical Research in Experimental Ecosystems. Springer-Verlag, New York. xiii, 430p.
Heard, R.W. 1982. Guide to the Common Tide Marsh Invertebrates of the Northeastern Gulf of Mexico. Mississippi Alabama Sea Grant Consortium MASGP-79-004. 82pp.
James, D.E. 1975. Carolina Marine Aquaria, Carolina BiologicalSupply Co. #45-1780. 24 pp. $1.00.
Kaplan, E.K. 1982. A Field Guide to Coral Reefs. Peterson Field Guide Series. Houghton Mifflin, Boston. 289 pp.
Kaplan, E.K. 1988. A Field Guide to Southeasterm and Caribbean Seashores. Peterson Field Guide Series. Houghton Mifflin, Boston. 425 pp.
Leatherwood, S., D.K. Caldwell and H.E. Winn. 1976. Whales, Dolphins and Porpoises of the Western North Atlantic. NOAA Technical Report NMFS CIRC-396. 176 pp.
Littler, D.S., M.M. Littler, K.E. Bucher and J.N. Norris. 1989. Marine Plants of the Caribbean. Smithsonian Institution Press, Washington, D.C. 263 pp.
Manooch, C.S. 1984. Fisherman's Guide to the Fishes of the Southeastern United States. North Carolina State Museum of Natural History. Raleigh, North Carolina 362 pp.
Morris P.A. 1975. A Field Guide to the Shells of the Atlantic and Gulf Coasts and the West Indies. Peterson Field Guide Series. Houghton Mifflin, Boston. 330 pp.
Peterson R.T. 1980. A Field Guide to the Birds East of the Rockies. Peterson Field Guide Series. Houghton Mifflin, Boston. 384 pp.
* Pinet, P.R. 2009 Fifth Edition. Invitation to Oceanography. Jones and Bartlett. Subury, MA 594 pp.
This is also the current text for MSCI 3101 Marine Science I.
Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1980. A List of Common and Scientific Names of Fishes from the United States and Canada. American Fisheries Society Special Publication No. 12. 174pp.
**Robins, C.R., G.C. Ray and J. Douglass. 1986. A Field Guide to the Atlantic Coast Fishes of North America. Houghton Mifflin Co. 354p.
**Ruppert, E. and R. Fox. 1988. Seashore animals of the Southeast: A guide to the common shallow-water invertebrates of the southeastern Atlantic Coast University of South Carolina Press. 429p.
Schwartz, F.J. 1984. Sharks, Sawfish, Skates and Rays of the Carolinas. Special Publication. Institute of Marine Sciences. Morehead City, North Carolina 28557.
Shoettle, T. (no date) A Field Guide to Jekyll Island. Georgia Sea Grant College Program. Univ. of Georgia, Athens, GA.
Smith, D.L. A Guide to Marine Coastal Plankton and Marine Invertebrate Larvae. Kendall Hunt, Dubuque. 161 pp.
Spotte, S. 1979. Seawater Aquariums: The captive Environment. John Wiley and Sons. 413p.
Spotte, S. 1979. Fish and Invertebrate culture: Water management in a closed system. John Wiley and Sons. 179p.
Stokes, F.J. 1980. Handguide to the Coral Reef Fishes of the Caribbean. Lippincott and Crowell. 160pp.
Whither the Whales. (Spring) 1989. Oceanus. 23(1) 1-144.
Wursig, B. 1989. Cetaceans. Science 244(1550-1557)
Other References (Writing):
Blake, G and R.W. Bly, 1993. Elements of Technical Writing. Macmillan USA. 173 pp.
Borror D.J. 1988. Dictionary of Word Roots and Combining Forms. Mayfield Pub. Co., Palo Alto, CA 134 pp.
DeGeorge, J., G.A. Olson and R. Ray. 1984. Style and Readability in Technical Writing. 185 pp.
Gilligan, M.R. 1995. Improving Your Technical Writing. Fisheries 20(5):36
McMillian, V.E. 1997. Writing Papers in the Biological Sciences. St. Martin's Press. 197.
Pechenik, J.A. 1993. A Shout Guide to Writing About Biology., 2nd ed. Harper Collins Publishers, NY.
Strunk, W. Jr. and E. B. White. 1979. The Elements of Style. Macmillan. 85 pp.
Williams, Joseph. 1995. Style: Toward Clarity and Grace (Chicago Guides to Writing, Editing, and
Publishing) Univ. of Chicago Press. 208 p.
* course text
** strongly recommended
Dr. M. Gilligan
Marine Sciences Program
Department of Natural Sciences and Mathematics
School of Sciences and Technology
Savannah State University
Savannah, Georgia 31404
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