Freshwater Ecosystems * Prepare yourself, there are 35 slides!
Freshwater Ecosystems Only covers 3% of Earth’s surface
What makes them different?
Abiotic Factors Water Speed / flow Depth Temperature Chemistry (salinity)
Organisms Grouped by location & adaptations 3 groups
1 - Plankton Float near the surface Phytoplankton – single celled algae; produce most of the food for an aquatic ecosystem Zooplankton – microscopic animals
2 - Nekton Free swimming Ex. fish & turtles
3 - Benthos Bottom dwelling Most live attached to hard surfaces Ex. mussels, worms & barnacles
Lakes – 5 Types!
1- Glacial lake: formed by depressions in the surface 2- Barrier lakes: formed from landslides 3- Crater lakes: volcanoes 4- Tectonic lakes: formed from rift valleys 5- Artificial lakes: humans (dams) & beavers
Ponds
Zones
Littoral Zone Shore Nutrient rich Diverse & abundant life
Benthic Zone No light Decomposers, insect larvae & clams
Animal Adaptations Water beetles – hair to trap air Catfish – whiskers to sense Amphibians – burrow in the cold
Eutrophication Increase in the amount of plant growth due to nutrients ↑algae = ↑bacteria = ↓oxygen Occurs naturally over long time Accelerated by run-off
Wetlands Covered with fresh water for part of year Traps & filters pollutants (keeping them out of cycle) Reduces chances of flood Prevents erosion
Provides spawning ground & habitats Provides recreational areas 2 types
Marsh Treeless Low, flat lands
Characterized by salinity Brackish Marsh – slight NaCl Salt Marsh – more NaCl
Swamp Has Trees Flat, poorly drained land Near streams Mangrove – near ocean
Human Impact on the Wetlands Drained, filled, cleared Farms, residential & commercial development Florida Everglades – from 8 million to 2 million acres
Stream
Rivers
Many originate from snow capped mountains Flows, broadens to become slower, warmer & wider Mosses anchor in the flow
River problems Industrial pollution Kills organisms Makes fish inedible Carries pollution in the run-off Dams alter ecosystems
Brainpop: Rivers