1. Aquatic Ecosystems

2. Factors that affect which organisms live in which areas of the water:
Temperature
Sunlight
Oxygen
Nutrients
Salinity

3. Three groups of aquatic organisms based on location in the water:
Plankton – floaters found near the surface (phytoplankton & zooplankton)
Nekton – free-swimmers (fish, whales, turtles, etc.)
Benthos – bottom-dwellers & decomposers, some attach to hard surfaces

4. Section #1: Freshwater Ecosystems

5. Freshwater Lakes & Ponds (natural and man-made)
Littoral Zone
nutrient rich
found near shore
life is diverse & abundant
plants are rooted in mud underwater
Benthic Zone
bottom layer
little to no light
dead, decaying material
decomposers, insect larvae, clams

6. Littoral vs. Benthic Zones

7. Eutrophication of Lakes
runoff from land increases the amt. of nutrients (excess fertilizers, sewage, animal waste)
plants & algae grow quickly (& die)
increase in bacteria that feeds on decaying materials (use lots of O2)
other organisms needing O2 die from lack of available oxygen

8. This lake shows signs of eutrophication because of the large number of plants.

9. Freshwater Wetlands act as filters by removing pollutants from water
control flooding by absorbing extra water from overflowing streams & rivers
habitat for variety of wildlife, including many migratory birds
many fish use the area as spawning grounds
recreational use by humans

10. Location of the large freshwater wetlands in the U.S.

11. Freshwater Marshes found in areas with low, flat land
little water movement
mostly in southeastern parts of the US (Florida Everglades – largest)
non-woody plants are rooted in the nutrient-rich benthic layer in shallow waters
Examples = cattails, reeds, rushes
water can also be brackish or salty

12. Marshes contain mostly grass-like plants.

13. Freshwater Swamps
found near streams where the land is flat and poorly-drained
good habitat for amphibians, reptiles, & birds
dominated by woody plants like shrubs & water-loving trees
Examples = mangrove trees
water can also be brackish or salty

14. Alligators are found in both marshes & swamps

15. Human Impact on Wetlands
once considered wastelands – only good for breeding insects
were drained, filled, & cleared for farming or development
now protected by federal & state laws
some groups are working to restore natural wetlands

16. Rivers & Streams originate from snow melts in the mountains
at headwaters, water is cold, full of O2 & moves swiftly over a shallow riverbed
as elevation decreases, the river broadens, water slows, can hold less O2

17. Different Stages in a River

18. Life in Rivers & Streams
depends on location, current speed, amount of nutrients from runoff, amount of O2
plants in faster currents near the headwaters need to use special root systems called rhizoids to hold onto rocks
other plants near a river’s mouth can set roots into the bottom sediment

19. Life in Rivers & Streams
certain species like salmon & trout can only survive in the cold, fast-moving waters that hold lots of O2
fish such as catfish and carp live in the calmer, warmer waters
plankton cannot live in the strong currents and are also found in calmer, warmer waters

20. Rivers in Danger
people have used rivers as a way to dispose of waste material (garbage & sewage) for many years
industries have dumped hot water, toxins, and other waste materials into the water
pesticides, excess fertilizers, motor oil, & antifreeze are washed into rivers from the land

21. Section #2: Marine Ecosystems

22. Marine Ecosystems
while most freshwater ecosystems are self-contained & separate from other bodies of water like it, marine ecosystems are usually connected to others around the globe
located mostly in coastal areas and the open ocean
organisms must adapt to changes in salinity, tides, available nutrients

23. Coastal Wetlands
coastal land areas are covered by salt water for all or part of the time
includes:
estuaries
salt marshes
mangrove swamps
barrier islands

24. Estuaries
an area in which fresh water from a river mixes with salt water from the ocean
where the two mix, the denser salt water sinks carrying nutrients to the bottom
these nutrients are then used by the producers in shallow areas

25. Estuaries
very productive ecosystems because of the constant influx of nutrients
protected from harsh ocean waves by the surrounding land (peninsula)
sunlight reaches the bottom in most areas – lots of rooted plants & phytoplankton
good place for feeding & reproducing
organisms must adapt to constant changes in salinity (tides)

26. The Chesapeake Bay

27. Chesapeake Bay Watershed

28. Estuaries
6 out of 10 of the world’s largest urban areas were built on estuaries
problems with dumping waste & filling for development
estuaries in these densely populated areas cannot handle the large amounts of pollutants – certain species (like oysters) usually help filter the toxins out of the water, but they can only handle so much

29. Salt Marshes found along the Atlantic Coast & the Gulf of Mexico
develop in estuaries where rivers deposit their load of mineral-rich mud
considered a nursery to many species of shrimps, crabs, fishes – they are protected in the marsh when small, then migrate to the open ocean after reaching maturity

30. Mangrove Swamps
located in coastal areas of tropical & subtropical zones
dominated by mangrove trees
these trees grow partly submerged in the salt water – help cut down on erosion along shorelines & protect the land from storms
breeding & feeding grounds

31. Mangrove Trees

32. Rocky vs. Sandy Shores rocky shores have more plants than sandy shores
Why?
sandy shores dry out quickly when the tide goes out, plus not a good place for roots to anchor
rocks provide a place for creatures or roots to attach

33. Barrier Islands long, thin islands that run parallel to the coast
protect the mainland & the coastal wetlands from erosion & storms
in constant motion – trying to develop this land can lead to problems in the future

34. Barrier Island off the NY coast

35. Coral Reefs
made of limestone ridges secreted by tiny animals called coral polyps
accumulate slowly in tropical seas to form reefs
one of the most diverse ecosystems on Earth
corals can only survive in warm salt water with plenty of sunlight
as corals die, others build up on the skeletal remains

36. Coral Reefs of the World

37. Coral Reefs
corals cannot chase prey, so they use stinging tentacles to capture small organisms that come too close to the reef
provides a habitat for many sea creatures
to help restore reefs, some groups have tried to create artificial reefs by sinking old barges & ships (must make sure all hazardous materials are removed first)

38. Threats to Coral Reefs
fragile ecosystem – easily damaged – grows very slowly
Corals die when
water temp is changed ( or )
there’s too much freshwater
water is muddy or cloudy
nutrients cause algae to grow out of control & blocks sunlight
humans oil spills, dumping sewage
damage from ships, anchors, careless divers, people stealing pieces

39. Oceans average salinity = 35‰
sunlight reaches only the surface layer (to ~330 ft deep)
ocean life is concentrated in shallow coastal waters
plants can anchor to rocks & received nutrients from river inflow
phytoplankton live only where there’s enough nutrients
deep layer is always dark & very cold
food comes from creatures that die & sink to the ocean floor

40. Ocean Layers

41. Ocean Problems pollution & dumping algal blooms from excess nutrients
over-fishing
poor fishing practices
discarding fishing lines

42. Sea Lion Strangled by Fishing Line

43. Arctic & Antarctic Regions
depend on the ocean for almost all food
Arctic rich in nutrients from surrounding landmasses
plankton form the base of the food chain for all organisms (penguins, whales, seals, polar bears)