12 1 Freshwater Environments Scientists classify freshwater environments
- Slides: 4
12. 1 Freshwater Environments • Scientists classify freshwater environments by how the water moves. w {rivers (fast moving) lakes/ponds marshes/wetlands (slow moving)}. • The variety and productivity of organisms found in freshwater environments depends on certain factors. w How deep sunlight reaches, the nutrient content of the water, the depth of the water, the speed the water is moving, and the oxygen level in the water. w Some organisms need very specific conditions, and others (like stickleback) can adapt to many different environments. Stickleback fish http: //en. wikipedia. org/wiki/Image: Gasterosteus_aculeatus. jpg See page 440 (c) Mc. Graw Hill Ryerson 2007
Life in Lakes and Ponds • Life in lakes and ponds is often found near the shallow shore, where there are nutrients for plants and animals • Plankton can live in the deeper, sunlit water w Phytoplankton are plants that produce food by photosynthesis (energy from the sun). w Zooplankton are tiny animals that eat other plankton for food. • Plankton are the beginning of many food chains. • Lakes and ponds store run-off as a part of the water cycle, provide habitat for plants and animals, and allow rooted plants to grow and filter water through natural processes. See page 441 (c) Mc. Graw Hill Ryerson 2007
Wetlands • Wetlands are found alongside other bodies of water. • One quarter of all wetlands in the world in in Canada. • Many wetlands have been destroyed because it was thought they only harboured pests. • Wetlands are very important: w w The vegetation removes pollutants from the water They act as a reservoir to prevent flooding. Many fish and animals live there. Thick vegetation helps stabilize surrounding soils. w Many endangered species live parts of their lives there. See page 442 (c) Mc. Graw Hill Ryerson 2007
Rivers, Streams and Estuaries • There are many plants and animals living in these moving waters. • What can live in these moving waters depends on: w The temperature of the water w The speed the water is moving w The turbidity of the water • Changes in variety or productivity of species in waterways can reveal potential problems. • Estuaries are nutrient-rich, brackish water. w In BC, 80% of all coastal wildlife use estuaries, which make up only 3% of the total coastal area. See pages 442 -443 Take the Section 12. 1 - 12. 3 Quiz (c) Mc. Graw Hill Ryerson 2007
