1. Miss Napolitano & Mrs. Rodriguez Environmental Science
Aquatic Ecosystems
Miss Napolitano & Mrs. Rodriguez
Environmental Science

2. Aquatic Ecosystems 2 types: freshwater & marine (saltwater)
Determined by salinity, or amount of dissolved salts in water
Freshwater includes:
Lakes
Ponds
Rivers & streams
Wetlands
Marine includes:
Marshes
Swamps
Coral reefs
Oceans

3. Organisms of Aquatic Ecosystems
Plankton: cannot swim against current (drifters)
Phytoplankton: producers
Zooplankton: animals (consumers)
Nekton: free-swimming organisms
Ex: fish, turtles, whales
Benthos: bottom-dwellers
Ex: Mussels, worms, barnacles

4. Freshwater Ecosystems

5. Freshwater Ecosystems
Calm lakes and ponds
Moving rivers and streams
Wetlands – land that is periodically underwater
Organisms are affected by temperature, sunlight, dissolved oxygen, and available nutrients

6. Lakes & Ponds Can be divided into zones
Littoral zone: near the shore, diverse & abundant life
Benthic zone: bottom, contain decomposers
Organisms have specific adaptations
Water beetles – hairs under bodies trap air to help breathe when diving
Catfish – whiskers help sense food in dark lake bottoms
Amphibians – burrow in mud to avoid freezing temperatures

7. Nutrients in Lakes
Eutrophication: increase in the amount of nutrients in an aquatic ecosystem
Eutrophication causes overgrowth of algae since extra nutrients available
More algae = more bacteria = less dissolved oxygen = less oxygen-consuming organisms
Eutrophication can be accelerated by runoff
Runoff contains fertilizers, sewage, or animal wastes

8. Freshwater Wetlands
Wetlands: areas of land that are covered with fresh water for at least part of the year
2 different types:
Marshes – contain non-woody plants (cattails)
Swamps – contain woody plants (trees, shrubs)
Environmental functions of wetlands:
Absorb/remove pollutants from water
Control flooding by absorbing extra water when rivers overflow
Used for feeding & spawning
Home for migratory wildlife

9. Marshes Most located in Southeast US Largest = Florida Everglades
Low, flat, & little water movement
Plants such as cattails root themselves in bottom sediment & stick above surface year-round
Benthic zones are nutrient-rich & contain decomposers, scavengers, & plants
Salinity varies

10. Swamps Flat, poorly drained land Located near streams
Plant life depends on climate & salinity of water
Usually contain many amphibians & birds

11. Human Impact on Wetlands
Originally thought to be breeding grounds for disease- carrying insects, so drained or cleared for farms or industry
Now recognized to be important for purifying water & flood prevention, so being preserved

12. Rivers Many originate from snow melt in mountains
Start cold & full of oxygen
Becomes warmer, wider, & slower as it flows down a mountain with more vegetation & less oxygen
Affected by surrounding communities & industries
Water is drawn to use in homes & manufacturing
People dispose of sewage or garbage in rivers, causing pollution
Runoff causes toxicity

13. Marine Ecosystems

14. Marine Ecosystems Marine ecosystems: contain salt water
Found in & around oceans
Open water: amount of sunlight & nutrients vary from different parts of an ocean
Coastal areas: water level & salinity changes during the day

15. Coastal Wetlands
Coastal wetlands: covered by salt water for all or part of the time
Habitat & nesting areas for wildlife
Absorb excess rain & prevent flooding
Filter pollutants & sediments
Recreational areas for boating, fishing, & hunting

16. Estuaries
Estuary: where freshwater (river) mixes with saltwater (ocean)
Currents cause nutrients to fall to the bottom
Become available to producers
Productive because constantly receiving fresh nutrients
Surrounding land protects estuaries from harsh waves

17. Organisms & Threats of Estuaries
Support many marine organisms
Lots of light for photosynthesis
Lots of nutrients for plants & animals
Organisms can tolerate varying salinity
Provide protective harbors, access to oceans, & connections to rivers, so used as harbors
Once used as landfills, so habitat was destroyed
Sewage & runoff damages ecosystems

18. Salt Marshes, Mangrove Swamps, & Shores
Salt marshes – estuaries where rivers deposit mineral-rich mud
Many clams, fish, & aquatic birds
Protect young organisms
Absorb pollutants & protect inland areas
Mangrove swamps – dense growth of mangrove trees
Mangroves: special species of small trees adapted for shallow salt water
Found in tropical & sub-tropical zones
Protect the coastline from erosion & reduce storm impacts
Provides habitat to many species
Rocky & sandy shores
Rocks anchor organisms, so rocky shores have more biodiversity
Animals adapted to drying & low-tide exposure

19. Salt Marshes, Mangrove Swamps, & Shores
Rocky Shore

20. Coral Reefs
Coral reefs: limestone ridges built by tiny coral animals (coral polyps) & algae
House thousands of plant & animal species
One of the most diverse ecosystems on Earth
Found in shallow, clear, tropical waters
Must have enough light for photosynthesis
Living corals are only found in outer layer of reefs
Need help of photosynthetic algae to build homes
Corals – predators that sting & capture small animals as they pass
Corals are animals, not plants!

21. Coral Reefs in Danger
Sensitive to temperature, pollutant, or nutrient changes
Algae dies & causes coral bleaching, which eventually causes coral to die
Global warming, oil spills, & pollution runoff linked to coral reef destruction

22. Oceans Sunlight can only penetrate 100m (330 ft) below ocean surface
Most life is in shallow, coastal waters
Phytoplankton & zooplankton float near the surface
Fed on by fish & whales
Deep ocean contains mostly dead organisms that fall from the surface

23. Threats to the Ocean Oceans are becoming polluted slowly
Fertilizer runoff causes algal blooms
Overfishing kills wildlife
Fishing nets trap unintended marine animals & can drown ocean mammals that must move to breathe

24. Arctic & Antarctic Ecosystems
Arctic Ocean (North) is rich in nutrients
Supports large populations of plankton
Fish are food for ocean birds, whales, & seals, which are food for polar bears
Antarctic (South) – only continent never colonized by humans
Only few plants grow, even in the summer
Plankton is the basis of the food web, nourish large numbers of fish, whales, & birds (especially penguins)