1. Aquatic Ecosystems
Chapter 7

2. Water Biomes Types of organisms present depends on salinity
Divided into freshwater and marine
Freshwater includes lakes, ponds, rivers, streams, and wetlands
Marine ecosystems include marshes, swamps, coral reefs, and oceans

3. Characteristics of Aquatic Ecosystems
Temperature, sunlight, oxygen, and nutrients determine which organisms live in the water
Organisms are divided into three broad categories depending on their location and adaptations
These categories are plankton, nekton, and benthos.

4. Plankton Organisms that cannot swim against currents
Drifting plants, called phytoplankton, are the base for most aquatic ecosystems
Most are microscopic
Drifting animals are called zooplankton

5. Nekton
Free swimming organisms like turtles, fish, and whales

6. Benthos
Bottom dwelling organisms such as mussels, worms, and barnacles
Many attach to hard surfaces

7. Lakes and Ponds
Lakes and ponds form naturally where groundwater reaches Earth's surface
Humans and other animals can also create them
Lakes and ponds are structured into vertical and horizontal zones

8. Littoral Zone A nutrient rich zone near the shore
Rooted plants, such as cattails and pond lilies, live near the shore
Phytoplankton make their own food using photosynthesis

9. Benthic Zone Some areas are too deep for photosynthesis
Decomposes live on dead plants and animals that drift down from the top
Fish adapted to cooler water live here too

10. How Nutrients Affect Lakes
Eutrophication is an increase in the amount of nutrients in an aquatic ecosystem
This also causes an increase in the amount of bacteria
This eventually reduces the amount of available oxygen which begins to kill fish and other oxygen loving organisms
Runoff accelerates eutrophication

11. Freshwater Wetlands
Areas of land covered with freshwater for at least part of the year
Mainly swamps and marshes
Marshes contain non-woody plants
Swamps contain woody plants
Wetlands act as filters or sponges by absorbing and removing pollutants
Wetlands help control flooding

12. Environmental Functions of Wetlands
Trapping and filtering sediments, nutrients, and pollutants
Reducing the likelihood of floods
Buffering shorelines against erosion
Providing spawning grounds and habitat for fish and shellfish
Providing habitat for rare, threatened, and endangered species
Providing recreational areas

13. Marshes Most freshwater wetlands sin the US are in the southeast
The Florida Everglades is the largest
Most occur on low, flat land and have little water
Salinity in marshes varies

14. Swamps Occur on flat, poorly drained land, often near streams
Plant species depend on level of salinity
Freshwater swamps are ideal for amphibians

15. Human Impact on Wetlands
Wetlands used to be viewed as wastelands and breeding grounds for insects
Many have been drained, filled, and cleared for farming and housing
The Everglades used to cover over 8 million acres, now it barely covers 2 million acres
Laws now prevent the destruction of many wetlands

16. Rivers Many rivers originate from snow melt in the mountains
Headwaters (beginning of the river) water is usually cold and runs swiftly
As it flows down the mountain, it becomes wider and warmer
Runoff washes into the river affecting its health

17. Copy now, answer later
List two factors that determine where an organism lives in an aquatic ecosystem.
Compare the littoral zone with the benthic zone of a lake.
List two environmental functions that wetlands provide. How do these functions affect you?
Describe one threat against river ecosystems.
Write a short paragraph that explains how fertilizing your yard and applying pesticides can affect the health of a river ecosystem.