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Aquatic Biomes and Food WebsWater surrounds us everywhere. Being the largest part of the biosphere, it covers nearly 75% of the Earth's surface. Aquatic areas house numerous species of animals, large and small, and plants. Today, without water, no life would be able to sustain itself and the earth would be a baron, desert-like place. The aquatic biome can be broken down into two basic areas, freshwater (i.e, ponds and rivers) and marine (i.e, oceans and estuaries). The only thing that links all the areas together is that there is water. Freshwater RegionsAs you might guess from the name, the water is fresh, meaning that there is a low salt concentration, usually less than 1%. Other characteristics of freshwater regions are that the plants and animals in the region are adjusted to the low salt content and would not be able to survive in areas of high salt concentration (i.e, ocean). There are different types of freshwater regions: ponds and lakes, streams and rivers, and wetlands. The following sections will talk about the different characteristics of each of these three freshwater zones.2743200147510500Ponds and LakesScattered throughout the earth, many of the first lakes evolved during the Pleistocene Ice Age. Many ponds are seasonal, just lasting a couple of months, such as sessile pools, while lakes last many years. There is not that much diversity in species since ponds and lakes are often isolated from one another and from other water sources like rivers and oceans. Lakes and ponds are divided into three different "zones" which are usually determined by depth and its distance from the shoreline. The top most zone near the shores of the lake or pond is the littoral zone. This shallow zone is the warmest since it is the area that light hits contains flora (plants) such as rooted and floating aquatic plants, and contains a very diverse community, which can include several species of algae (like diatoms), grazing snails, clams, insects, crustaceans, fishes, and amphibians. The fauna (animals) includes such species as turtles, snakes, and ducks feed on the vegetation and other animals in the littoral zone. Next to the littoral zone is the limnetic zone, which is basically the open water away from the shore. This zone like the littoral zone is also well-lighted, that is why it is dominated by plankton, such as phytoplankton and zooplankton. Plankton are small organisms that can feed and reproduce on their own and serve as food for small chains. Without plankton in the water, there would not be any living organisms in the world, including humans. A variety of freshwater fish also occupy this zone. The small plankton do not live for a long time. When they die, they fall into the deep-water part of the lake/pond, the profundal zone. This zone is much colder and denser than the other two zones. This zone is colder since not too much light penetrates all the way through the limnetic zone into the profundal zone. Streams and RiversThese regions are bodies of flowing water moving in one direction. They can be found everywhere, and their exact origin is not really known. They start off at headwaters, such as springs, snowmelt or even lakes, then travel all the way to a mouth, which is usually a channel or the ocean. The characteristics of a river or stream changes going from the source to the mouth. The temperature is cooler at the source than it is at the mouth. The water is also clearer, has high oxygen levels and freshwater fish such as trout along with heterotrophs can be found there. Towards the middle part of the stream/river, the width increases, and less shaded. Also the greatest species diversity along streams and rivers, including numerous aquatic green plants and algae, can be found around this area. Towards the mouth of the river/stream, the water becomes murky from all the sediments that it has collected from the upper parts, thus decreasing the amount of light that can penetrate through the water. Since there is less light, there is less diversity of flora, and because of the lower oxygen levels, fish that do not less as much oxygen, such as catfish and carp, can be found. WetlandsWetlands are areas covered with standing water that supports aquatic plants. Marshes, swamps, and bogs are all considered wetlands. Plants in a wetland include pond lillies, cattails, sedges, tamarack, and black spruce. Many species of amphibians, reptiles, birds, such as ducks and waders, and furbearers can be found in the wetlands. Not all wetlands are considered freshwater ecosystems. There are other wetlands, such as salt marshes, that have a high concentration of salt, and thus house different species of animals, such as shrimp and shellfish, and plants, such as grass. Wetlands are important because they help reduce erosion, filter pollutants, prevent floods by holding onto water from rivers and provide homes for a variety of organisms.Marine RegionsMarine regions include oceans, coral reefs, and estuaries. They covered about three-fourth of the Earth's surface. In terms of characteristics, algae that are found in the ocean supply much of the world's oxygen supply and takes in a huge amount of atmospheric carbon dioxide. The evaporation of the seawater provides rainwater for the land.OceansThe largest of all the ecosystems, oceans are very large body of water that dominants the earth's surface. Like ponds and lakes, the ocean regions are separated into separate zones: intertidal, pelagic, abyssal, and benthic. All four zones have a great diversity of species. Some say that the ocean contains the richest diversity of species even though it contains less species than there are on land. The intertidal zone is where the ocean meets the land, like the shore or rocky areas, thus it is submerged sometimes, and exposed at other times as waves come in and out of the area. Due to this, the communities are constantly changing.354330091440000On the highest part where only the highest tides reach, there are only a few species of algae and mollusks. In the part where it is usually submerged during high tide, there is more diverse array of algae and small animals, such as herbivorus snails, crabs, sea stars, and small fishes. The bottom of the intertidal zone, which is only exposed during the lowest tides, houses many invertebrates and fishes, along with a lot of seaweed. The pelagic zone is all the water that is not near the shore or land, basically the open ocean. The pelagic zone is generally cold and the flora in the pelagic zone include seaweed on the surface of the water. The fauna includes many species of fish and some mammals, such as whales and dolphins. They feed on the plankton that are found all over the water. Below the pelagic zone lies the abyssal zone. The water in this region is very cold (around 3 C), highly pressured, high in oxygen content, but low in nutritional content. The abyssal zone houses many species of invertebrates and fishes. Also in this zone are mid-ocean ridges, which contains hydrothermal vents. Since large amounts of hydrogen sulfide and other minerals are emitted from these ridges, chemosynthetic bacteria dominant the area in terms of plankton. These bacteria are thus the start of the food web as they are eaten by invertebrates and fishes. The benthic zone is the area below the pelagic zone, but not at the deepest parts of the ocean, as where the abyssal zone is located. The bottom of the zone consists of sand, slit, and/or dead organisms. The flora in this zone only consists of seaweed while the fauna, since it is very nutrient rich, includes all sorts of bacteria, fungi, sponges, sea anemones, worms, sea stars, and fishes. Coral ReefsCoral reefs are widely distributed in warm shallow waters. They can be found as barriers along continents (i.e., the Great Barrier Reef off Australia), fringing islands, and atolls. The dominating species in coral reefs is of course coral. Coral consists of both algae (zooanthellae) and tissues of animal polyp. Since the water in the area is generally nutritionally poor the coral obtains nutrients through the algae via photosynthesis and also by extending tentacles to obtain plankton from the water. Besides the coral, the fauna includes several species of microorganisms, invertebrates, fishes, sea urchins, octopuses, and sea stars. EstuariesEstuaries are areas where freshwater streams or rivers merge with the ocean. In this extent, these areas are unique in terms of their salt concentration due to the mixing of the two waters. Microflora, such as algae, and macroflora, such as seaweeds, marsh grasses, and mangrove trees (only in the tropics), can be found here. In terms of fauna, there are a variety of worms, oyster, crabs, waterfowls in and around estuaries. After reading the information on aquatic biomes answer the following questions:In the space provided, write the letter of the term or phrase that best matches the description.4686300156210a.wetlandb.benthic zonec.littoral zoned.salinitye.coral reefs f. abyssal zoneg.estuaryh. intertidal zone00a.wetlandb.benthic zonec.littoral zoned.salinitye.coral reefs f. abyssal zoneg.estuaryh. intertidal zone1.where ocean means land2.very cold, no sunlight, organisms perform chemosynthesis3.amount of dissolved salts in water4.swamps, marshes and bogs5.area where fresh water mixes with salt water6.limestone that consists of algae and tissues of animal polyp7.located near the bottom of a pond or lake10.aquatic zone found near the shoreIn the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.11.Estuaries are productive ecosystems because they constantly receive nutrients froma.rivers and oceans.b.coral reefs.c.lakes and ponds.d.photosynthesis.12.Which of the following is a factor that influences where an organism lives in an aquatic ecosystem?a.sunlightb.nutrient availabilityc.temperatured.all of the above13.In which of the following aquatic ecosystems are both littoral and benthic zones most likely found?a.open oceanb.coral reefc.laked.abyssal zone14.Estuariesa.are always saltwater ecosystems.b.are always freshwater ecosystems.c.are ecosystems where both fresh water and salt water are present.d.prevent the development of salt marshes.15.All of the following are examples of saltwater ecosystems excepta.swampb.coral reefs.c.salt marshes.d.intertidal zone16.One way in which wetlands control flooding is bya.filtering out water pollutants.b.absorbing water from rivers.c.providing habitats for migratory wildlife.d.reducing the amount of carbon dioxide released into the air.17. The three main categories of freshwater ecosystems are ______________________, __________________________ and ______________________.18. Flora refers to the ________________ of an ecosystems while fauna describes the ______________19. With out the small organisms called ___________________ in the water life on earth would not existOrganisms in Freshwater EcosystemsRead the passage below and answer the questions that follow.Aquatic organisms are grouped by location and by their adaptations. There are three groups of aquatic organisms. Plankton are organisms that cannot swim against currents, so they are drifters. Drifting algae, called phytoplankton, are the food base for most aquatic ecosystems. Most phytoplankton are microscopic. Drifting animals, which may be microscopic or as large as a jellyfish, are called zooplankton. Nekton are free-swimming organisms, such as fish and whales. Benthos are bottom-dwellers, such as mussels, worms, and barnacles. Many benthic organisms live attached to hard surfaces or burrow into softer sediments. Decomposers, which break down dead organisms, also live in aquatic ecosystems.In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.1.How are organisms in an aquatic ecosystem grouped?a.by size and shapeb.by the food they eatc.by how they reproduced.by location and adaptations2.Where do many benthic organisms live?a.attached to hard surfacesb.in open waterc.near the surface of the waterd.attached to benthos3.How many groups of aquatic organisms are discussed in this passage?a.2c.5b.3d.44.Which groups of aquatic organisms are discussed?a.phytoplankton and zooplanktonb.plankton, nekton, and benthosc.plankton, nekton, benthos, and decomposersd.plankton, phytoplankton, zooplankton, nekton, and benthos5.The food base of most aquatic ecosystems area.worms.b.phytoplankton.c.zooplankton.d.fish.5257800113030a.phytoplanktonb.planktonc.nektond.benthose.decomposersf.zooplankton00a.phytoplanktonb.planktonc.nektond.benthose.decomposersf.zooplanktonIn the space provided, write the letter of the term that best matches the description.6.aquatic organisms that float near the surface of the water7.aquatic organisms that break down dead organisms8.drifting algae9.drifting animals10.aquatic organisms that dwell at the bottom of the water11.aquatic organisms that are free-swimmingWrite “P” on the line in front of each example of plankton, “N” on the line in front of each example of nekton, and “B” on the line in front of each example of benthos.12.turtles13.worms14.zooplankton15.fish16.mussels17.barnacles18.phytoplankton19.whalesCompare and Contrast freshwater and marine ecosystems using the Venn diagram. Use the following terms/phrases:EstuaryWetlandsLess than 1% salinity Coral ReefsSupports large and small animalsVery large bodies of waterLakes, ponds, riversPhytoplanktonAlgaeLittoral, limnetic, profundal zonesTypes of organisms depend on temperature, depth and movement of water-36893560960 FreshwaterMarine 00 FreshwaterMarine 11430011430000Use the figure below, which shows the food web of an aquatic ecosystem, to complete the following questionsWhich organism is the only producer in this food chain? _______________________2. In the food web above, there are eight food chains that include krill. Identify FOUR of the eight food chains that INCLUDE krill. Make sure to use arrows appropriately:Chain 1: _________________________________________________________________________________________________________Chain 2: _________________________________________________________________________________________________________Chain 3: _________________________________________________________________________________________________________Chain 4: _________________________________________________________________________________________________________What organisms do cod eat?List all the organisms that eat squidWhat percentage of energy does the killer whale receive? Which organisms are omnivores?______ 7. The krill in the food web is considered adecomposerautotrophproducerherbivore457200-22860000The Falkland Islands are located in the South Atlantic Ocean, not too far from the southern tip of South America. Millions of penguins breed on the islands. Sea lions, seals, dolphins, and many birds are also native to the area. The map shows where these organisms are found.Use the map above to answer the questions below.Which species are apart of a marine ecosystem? (circle all that apply)Dolphin Duck Falcon Sea Lions Seagulls Seals Sparrows WhalesWhich species are apart of a freshwater ecosystem? (circle all that apply)Dolphin Duck Falcon Sea Lions Seagulls Seals Sparrows Whales3.Which species has the largest population? __________________________4. Ocean acidification is when the ocean absorbs carbon from the atmosphere and, once mixed with water, decreases the pH (makes the water more acidic). This would DIRECTLY effect which organism found on The Falkland Islands (refer to your Cycles Notes) ______________________Label the trophic level below using the following words:primary consumer, tertiary consumer, producer, secondary consumer, 235 kcals, 23.5 kcals, 2.35 kcals , 0.235 kcals, autotroph, heterotroph297180080835532004001962152743200143129028575001937385182880010858500 ................
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