Aquatic Ecosystems

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.