Aquatic Ecosystems Ch. 7

1. Aquatic Ecosystems Ch. 7

2. Bellringer

3. Objectives • Describe the factors that determine where an organism lives in an aquatic ecosystem. • Describe the littoral zone and the benthic zone that make up a lake or pond. • Describetwo environmental functions of wetlands. • Describe one threat against river ecosystems.

4. I. Freshwater Ecosystems • The types of organisms in an aquatic ecosystem are mainly determined by the water’s salinity – the amount of dissolved salts the water contains • Aquatic ecosystems are divided into freshwater and marine ecosystems

5. Freshwater – lakes, ponds, rivers, streams and wetlands – areas periodically underwater • Marine – coastal areas of marshes, swamps, coral reefs, ocean

6. A. Characteristics of Aquatic Ecosystems • Factors such as temperature, sunlight, oxygen, and nutrients determine which organisms live in which areas of the water • Aquatic ecosystems contain several types of organisms that are grouped by their location and adaptations

7. Aquatic Organisms • Plankton – organisms that float near the surface of the water -two types of plankton • phytoplankton – microscopic plants, and zooplankton – microscopic animals -phytoplankton produce most of the food for an aquatic ecosystem

8. Aquatic Organisms • Nekton – free-swimming organisms such as fish, turtles, and whales • Benthos – bottom-dwelling organisms such as mussels, worms, and barnacles -most live attached to hard surfaces

9. Aquatic Organisms • Decomposers – organisms that break down dead organisms are also part of aquatic ecosystems

10. B. Lakes and Ponds • Lakes, ponds, and wetlands can form naturally where groundwater reaches the Earth’s surface • Beavers can create ponds by damming up streams

11. B. Lakes and Ponds • Humans create artificial lakes by damming flowing rivers and streams to use them for power, irrigation, water storage, and recreation • Lakes and ponds can be structured into horizontal and vertical zones

13. Aquatic Zones • Horizontal Zones: • Littoral zone – near the shore, nutrient-rich, aquatic life is diverse and abundant • -plants such as cattails and reeds are rooted in the water and upper leaves and stems emerge from the water

14. Littoral zone • plants with floating leaves like pond lilies • -in the open water – plants, algae, and some bacteria perform photosynthesis • -Open water deep areas there is too little light for photosynthesis – bacterial decomposers live there -fish adapted to live in cool, dark areas

15. Limnetic Zone Open area of lake No rooted vegetation

16. Horizontal Zones: • Benthic zone – the bottom of a pond or lake -inhabited by decomposers, insect larvae, clams

17. Eutrophication • Eutrophication – an increase in plant nutrients in an aquatic ecosystem • -a lake that has a large amount of plant growth due to nutrients – eutrophic lake

18. Eutrophic Lake • -as the amount of plants and algae grows, the number of bacteria feeding on the decaying organisms also grows, these bacteria use the oxygen dissolved in the lake, the reduced amount of oxygen • -kills oxygen-loving organisms • -accelerated by runoff • -runoff is precipitation that carries sewage, fertilizers, or animals waste from land into bodies of water

19. A Lake Ecosystem

20. C. Freshwater Wetlands • Freshwater wetlands - areas of land that are covered with freshwater for at least part of the year

21. 2 main types Freshwater Wetlands • Marshes – contain nonwoody plants • Swamps – contain woody plants like trees and shrubs

22. Freshwater Wetlands • Wetlands performs several important environmental functions • -act as filters or sponges because they absorb and remove pollutants from water that flows through them • -controls flooding by absorbing extra water when rivers overflow which protects farms and urban and residential areas from damage • -used by fish for feeding and spawning “nurseries” • -home for native and migratory wildlife

23. Freshwater Wetlands • the vegetation traps carbon that would otherwise be released as carbon dioxide • -used to produce commercially important products like cranberries

24. Freshwater Wetlands

25. Location • Most freshwater wetlands in the US are in the southeast • -Florida Everglades is the largest freshwater wetland • -marshes tend to occur on low, flat lands that have little water movement • -in shallow waters, plant such as reeds, rushes and cattails root in sediment and stick out above the water year round

26. Zones • benthic zones of marshes are nutrient rich • -there are several kinds of marshes each which is characterized by its salinity • brackish marshes have slightly salty water • salt marshes contain saltier water

27. Swamps • -occur on flat, poorly drained land often near streams • -dominated by woody shrubs or water-loving trees • -ideal habitat for many amphibians such as frogs or salamanders, and reptiles like the American alligator • Wetlands were previously considered to be wastelands that provided breeding grounds for insects and so • many have been drained, filled, and cleared for farms or development

28. Importance • -the important role of wetlands as purifiers of wastewater and flood prevention is now recognized • -they are vitally important for wildlife habitats • -law and the federal government protect many wetlands and most states now prohibit destruction of certain wetlands

29. Environmental Functions of Wetlands

30. D. Rivers • Many rivers originate from snow melt in the mountains • -At the headwaters, a river is usually cold and full of oxygen, and runs swiftly through a shallow riverbed • -As the river flows down a mountain, it may become warmer, wider, and slower and decrease in oxygen • -Change with the land and climate through which it flows • -Runoff may wash nutrients and sediment from the surrounding land and can affect the growth and health of the organisms in the river

31. Life in a river • Near the churning headwaters, mosses anchor themselves to rocks • Plankton do not live in the headwaters because the current is too strong for them to float • Trout and minnows are adapted to the cold, oxygen-rich headwaters -powerful swimmers

32. Life in a river • Downstream plankton can float in the warmer, calmer waters • -other plants can set roots in the plant’s sediment • -catfish and carp also live in the calmer waters

33. Rivers in danger • -industries use river water in manufacturing processes and as receptacles for waste • -runoff from the land puts pesticides and other poisons into rivers and coats riverbeds with toxic sediments • -dams also alter the ecosystems in and around a river

34. II. Marine Ecosystems • Located in coastal areas and in the open ocean • A. Coastal Wetlands • Coastal wetlands – land areas that are covered by salt water for all or part of the time -provide habitat and nesting areas for many fish and wildlife

35. Coastal Wetlands • -absorbs excess rain which protects areas from flooding • -filters out pollutants and sediments • -provide recreational areas for boating , fishing, and hunting

36. Estuary • Estuary – an area in which fresh water from a river mixes with salt water from the ocean -traps nutrients • -very productive ecosystems because they are constantly receiving fresh nutrients • Support many marine organisms because they have lots of nutrients and receive lots of sunlight

37. Threats to estuaries • -in populated areas estuaries were used to dump wastes • -used as building sites • -sewage, industrial waste containing toxic chemicals, agricultural runoff containing pesticides and fertilizers

38. Estuaries

39. Salt marshes • Salt marshes – develop in estuaries where rivers deposit a load of mineral-rich sediments • -support clams, fish, and aquatic birds • -acts as a nursery in which many species of shrimp, crabs, and fishes find protection when they are small • -absorb pollutants and protect inland areas

40. Quick LAB

41. Mangrove swamps • Mangrove swamps – located along coastal areas of tropical and subtropical zones dominated by mangrove trees • -protect coastline from erosion and reduce the damage from storms • -breeding ground for about 2000 animals species

42. Mangrove swamps • -filled with waste and destroyed in many parts of the world • Rocky shores have more plants and animals than sandy shores do • -rocks provide anchorage for seaweed and the many animals that live on them like sea anemones, mussels, sponges • Sandy shores dry out when the tide goes out

43. Barrier islands • Barrier islands – run parallel to the shore, and the long thin islands help protect the mainland and the coastal wetlands

44. Math Practice

45. Bellringer

46. Objectives • Explainwhy an estuary is a very productive ecosystem. • Compare salt marshes and mangrove swamps. • Describetwo threats to coral reefs. • Describe two threats to ocean organisms.

47. Coral Reefs • Corals live only in clear, warm salt water where there is enough light for photosynthesis.

48. B. Coral Reefs • Coral reefs – limestone ridges built by tiny coral animals called coral polyps. • -Coral polyps secrete skeletons of limestone (calcium carbonate) which slowly accumulates to form coral reefs.

49. Coral Reefs • -thousands of plant and animal species live in the cracks and crevices of the coral reefs • Coral reefs are among the most diverse ecosystems on Earth • Corals live only in clear and warm salt water where there is enough light for photosynthesis -found in shallow tropical seas

50. Coral Reefs • -only the outer layer or a reef contains living corals which build their rock homes with the help of photosynthetic algae • Corals use tentacles to capture their prey