AQUATIC ECOSYSTEMS

Vocabulary  Salinity – the amount of salt dissolved in water  Wetland – aquatic ecosystems that have a thin layer of water covering soil that is wet most of the time  Estuary – regions along coastlines where streams or rivers flow into a body of salt water  Intertidal Zone – the ocean shore between the lowest low tide and the highest high tide  Coral Reef– an underwater structure made from outside skeletons of tiny, soft-bodied animals called coral

Introduction to Aquatic Ecosystems  There are four major types of water, or aquatic, ecosystems  Freshwater Rivers and Streams Lakes and Ponds  Wetland (varied)  Estuary (brackish)  Ocean (salt water) Open ocean Coastal ocean Coral Reefs

Introduction to Aquatic Ecosystems  Abiotic factors include  Temperature  Sunlight  Dissolved oxygen  Salinity  Each ecosystem has a unique variety of organisms in and out of the water  Aquatic species have adaptations that enable them to use oxygen underwater  Fish use gills  Mangrove plants take in oxygen through small pores in their leaves and roots

Mangroves

Streams...  form from underground sources of water, such as springs or from runoff from rain and melting snow  have water that is often clear.  Soil particles are quickly washed downstream  have high oxygen levels because air mixes into the water as it splashes over rocks

Rivers...  form when streams flow together  have muddy water from the soil that washes into it from streams or nearby land  Soil adds nutrients, such as nitrogen, into rivers  that are slow-moving have higher levels or nutrients and lower levels of dissolved oxygen compared to fast- moving water (obviously!)

Stream & River Biodiversity  Willows and cottonwood trees are water-loving and grow along streams and on river banks  Trout, salmon, crayfish, and many insects are adapted to fast-moving water  Snails and catfish are adapted to slow-moving water.

Freshwater: Ponds and Lakes  Ponds and lakes contain freshwater that is not flowing downhill  Ponds  Shallow and warm  Sunlight can reach the bottom  Lakes  Larger and deeper  Sunlight penetrates into the top few feet.  Deeper water is dark and cold

Pond & Lake Biodiversity  Plants surround ponds and lake shores  Surface water contains plants, algae, and microscopic organisms that rely on photosynthesis  Cattails, reeds, insects, crayfish, frogs, fish and turtles live in shallow water near shorelines  Fewer organisms live in deeper, colder water of lakes where there is little sunlight  Lake fish include perch, trout, bass, and walleye

Human Impact  Freshwater sources are over-used for drinking, laundry, bathing, crop irrigation, and industrial purposes  Hydroelectric plants use the energy of flowing water to create electricity.  Dams stop the water’s flow and impede those fish species returning upstream to spawn  Runoff from cities, industries, and farms is a source of pollution  Excess nutrients can lead to Eutrophication

Wetlands  Wetlands are aquatic ecosystems that have a thin layer of water covering soil that is wet most of the time (not necessarily all the time)  Wetlands can be freshwater, saltwater, or both  They are among Earth’s most fertile ecosystems  High nutrient levels  High biodiversity  Wetlands trap sediment and purify water  Plants and microscope organisms filter out pollution and waste materials

Wetlands Biodiversity  Water-tolerate plants include grasses and cattails  Few trees live in saltwater wetlands  Willows, cottonwoods, and swamp oaks are trees found in freshwater wetlands  Insects are abundant  Dragonflies, and butterflies  More than one-third of North American bird species, including ducks, geese, herons, loons, warblers, and egrets, use wetlands for nesting and feeding  Alligators, frogs, turtles, and beavers depends on wetlands for food and breaking grounds.

Estuaries  Estuaries are regions along coastlines where streams or rivers flow into a body of salt water  Most estuaries form along coastlines, where freshwater in rivers meets salt water in oceans.  They have varying degrees of salinity

Estuaries  Estuaries help protect coastal land from flooding and erosion.  Like wetlands, estuaries purify water and filter out pollution  Nutrient levels and biodiversity are high

Estuary Biodiversity  Plants that grow in salt water include mangroves, pickleweeds, and seagrasses  Animals include worms and snails  They also have oysters, shrimp, crabs, and clams (yummmm)  Striped bass, salmon, flounder, and many other ocean fish lay their eggs in estuaries  Many species of birds depend on estuaries for breeding, nesting, and feeding

Human Impact  In the past, many people considered wetlands as unimportant. Water was drained away to build homes and roads and to raise crops.  Today, many wetlands are being preserved and drained wetlands are being restored  Large portions of estuaries have been filled with soil to make land for roads and buildings  Destruction of estuaries reduces habitat for estuary species and exposes the coastline to flooding & storm damage

Ocean: Open Oceans  Most of Earth’s surface is covered by ocean water with high salinity  Oceans have many different types of ecosystems  The open ocean extends from the steep edges of continental shelves to the deepest parts of the ocean  The amount of light depends on the depth  Photosynthesis takes place only in the uppermost, or sunlit, zone.  Very little sunlight reaches the twilight zone.  None reaches the deepest water, known as the dark zone.  Decaying matter &nutrients float down from the sunlit zone, through the twilight and dark zones, to the seafloor

Ocean Biodiversity  The sunlit (photic) zone is home to microscopic algae and other producers. They form the base of the food chain  Jellies, tuna, mackerel, and dolphins also live here.  Many species of fish stay in the twilight zone during the day and swim to the sunlit zone at night to feed.

Biodiversity  Sea cucumbers, brittle stars, and other bottom-dwelling organisms feed on decaying matter that drifts down from above  Many organisms in the dark zone live near cracks in the seafloor where lava erupts and new seafloor forms

Human Impact  Over fishing  Trash discarded from ocean vessels or washed into oceans from land is a source of pollution.

Ocean: Coastal Oceans  Coastal oceans include several types of ecosystems, including continental shelves and intertidal zones  The intertidal zone is the ocean shore between the lowest low tide and the highest high tide  Sunlight reaches the bottom of shallow coastal oceans  Nutrients washed in from rivers and streams contribute to high biodiversity

Intertidal Biodiversity  It is home to mussels, fish, crabs, sea stars, dolphins, and whales  Intertidal species have adaptations for surviving exposure to air during low tides and to heavy waves during high tides

Ocean: Coral Reefs  A coral reef is an underwater structure made from outside skeletons of tiny, soft-bodied animals called coral  High biodiversity  Form in shallow tropical oceans  Protect coastlines from storm damage and erosion

Biodiversity  Coral reefs provide food and shelter for many animals, including parrotfish, groupers, angelfish, eels, shrimp, crabs, scallops, clams, worms, and snails

Human Impact  Pollution, overfishing, and harvesting of coral threaten coral reefs  Coral structures extremely sensitive to acidification caused by increased absorption of CO 2, a greenhouse gas