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.
Describe two 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 Explain why an estuary is a very productive ecosystem.
Compare salt marshes and mangrove swamps.
Describe two 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

51. Disappearing coral reefs
-productive but fragile ecosystems
-27% are in danger of destruction from human activities
-if the water is too hot or too cold or if fresh water drains into the water surrounding the reef, the corals may die

52. Disappearing coral reefs
-if the water is too muddy, polluted, or too high in nutrients the algae that live within the coral will
die or grow out of control killing the corals
oil spills, sewage, pesticide, and silt runoff have been linked to coral reef destruction

53. Disappearing coral reefs
overfishing can decimate the fish populations and upset the balance of a reef’s ecosystem
-because coral reefs grow slowly a reef may not be able to repair itself after chunks of coral are destroyed by divers, fisheries, shipwrecks, ships dropping anchor, or people breaking off pieces of it

54. C. Oceans
Much of the ocean’s life is concentrated in the top 100m or 330 ft because that is how far sunlight can penetrate
most life is in the shallow coastal waters
Plants and animals of the ocean

55. Oceans
in the open ocean phytoplankton grows where there is enough light and nutrients
-the open ocean is one of the least productive of all ecosystems
-zooplankton feed on phytoplankton, these include jellyfish, tiny shrimp, larvae of fish and bottom-dwelling organisms such as oysters and lobsters

56. Plants and Animals of Oceans

57. Oceans fish feed on the plankton as to marine mammals like whales
-depths of the ocean are perpetually dark so most food consists of dead organisms that fall from the surface
-decomposers, filter-feeders, and the organisms that eat them live in these deep areas

58. Threats to the ocean
-Most ocean pollution arises from activities on land
-plant nutrients runoff the land’s fertilized fields may cause algal blooms some of which are poisonous

59. -industrial waste and sewage discharged into rivers is the biggest source of coastal pollution
-overfishing and certain fishing methods are also destroying some fish populations
trawl nets can entangle organisms that are larger than net holes such as dolphins and sea
turtles who need to breathe air can drown in the nets
discarded fishing lines in the ocean can strangle and kill fish and seals

60. Arctic and Antarctic Ecosystems
arctic ecosystems depend on marine ecosystems because nearly all the food comes from the ocean

61. Arctic Ocean
Arctic Ocean is rich in nutrients from the surrounding land masses and it supports large populations of
plankton which feeds a rich diversity of fish in the open water and under the ice
fish are food for ocean birds, whales, and seals
fish and seals also provide food for polar bears and people on land

62. Antarctic Antarctic is the only continent never colonized by humans
governed by an international commission and is used mainly for research
No Polar Bears

63. Antarctic
during the summer a few plants grow at the rocky edges of the continent
-plankton form the basis of this food web too which nourishes large numbers of fish, whales and birds such as penguins