Surface water Hydrosphere
Learning Targets Compare streams and rivers and their importance Describe what ponds and lakes are, and why they are important Explain why wetlands are significant in the water cycle, and describe their biodiversity Describe the causes of floods and their effects
Surface Freshwater 3 categories: Moving water Non-moving water Wetlands
Moving water Flows downhill, constantly moving Streams – moving water confined by earthen banks Rivers – largest bodies of moving water Amazon river moves 220,000 m3/sec Source: where a stream begins Mouth: where a stream ends What is the largest body of moving water? River The point where a stream or river originates is called the source. What are examples of moving water? Rivers and streams
Non-moving Water Ponds – small body of freshwater Lakes – larger body of freshwater Most lakes are in the Northern Hemisphere Glacier melt from the last ice age Canada: 60% of worlds lakes The types of non-moving water are ponds and lakes.
Parts of a lake Littoral zone Photic zone (Limnetic) Along the shore Photic zone (Limnetic) Sunlight reaches this area Aphotic zone (profundal) Deep water; very little photosynthesis
Wetlands Wetland – land that holds a significant amount of water; can be fresh or saltwater Types of Wetlands Marsh – grasses; no trees Swamp – lush trees Low oxygen conditions – organisms must be adapted Estuary – place where river and ocean mix Brackish water What are the types of wetlands? Marsh, estuary, swamp
Marsh
Swamp
Estuary
Wetlands Ecological Importance Wetlands are very important Unique ecosystems – fragile and sensitive; many endangered species Very high biodiversity 5% of U.S. land area/30% of U.S. Plant species Wetlands naturally purify water Trap and remove fertilizers and pollutants Benefits of wetlands are wetlands are important regions of biodiversity and wetlands naturally purify water.
Floods Flood: overflow of water in one place All bodies of water flood; too much precipitation to be absorbed Lots of vegetation is the best way to limit flooding Wetlands minimize flooding; act as buffer between water and land Flooding moves and deposits nutrient rich sediments in floodplains Erosion The best way to prevent flooding is to have lots of vegetation in the area. What is a benefit of flooding? Floods deposit nutrient rich sediments in floodplains.