AQUATIC ECOSYSTEMS What are the basic needs of aquatic biota (organisms)? CO2 O2 Sunlight Nutrients- food & minerals Types of Aquatic Ecosystems Freshwater Ecosystems Standing Water- lakes & ponds Moving Water- rivers & streams Transitional Communities
Estuaries Wetlands- bogs/fens, swamps, marshes Marine Ecosystems Shorelines Barrier Islands Coral Reefs Open Ocean Freshwater Ecosystems Usually 0.005% salt Some exceptions:
Great Salt Lakes- 5-27% salt Dead Sea- 30% salt Moving water- high elevations; cold; high O2; trout; streamlined plants Standing water- lower elevations; warmer; less O2; bass, amphibians; cattails, rushes Why would there be less oxygen in standing water? Plankton Plankton is a general term for
the tiny, free-floating organisms that live in both freshwater and saltwater environments. Unicellular algae, or phytoplankton, are supported by nutrients in the water and form the base of many aquatic food webs. Planktonic animals, or zooplankton, feed on the phytoplankton.
Transitional Communities ESTUARIES Where freshwater dumps into ocean Brackish water (less salty than seawater) Has rich sediments that often form deltas Productive & biodiverse Organisms adapted to varying levels of salinity as tide ebbs & flows Nursery for larval forms of many aquatic species of commercial fish & shellfish Delta
Transitional Communities WETLANDS Land saturated at least part of the year Swamps- have trees like bald cypress; high productivity Marshes- no trees; tall grasses; high productivity Bogs/Fens- may or may not have trees; waterlogged soil with lots of peat; low
productivity Swamp Marsh Fens- fed by groundwater & surface runoff Bogs- fed by precipitation Bog Fen Importance of Wetlands Highly productive- get lots of sunlight, plants = animals
Nesting, breeding ground for migratory birds Slows flooding by absorbing runoff Silt settles, making water clearer & nutrient rich Trap & filter water, Bacteria in soil break down contaminants = Natures Septic Tank Natural chemical rxns neutralize and detoxify pollutants Gives H2O time to percolate (filter thru soil) & replenish underground aquifers Threats- artificial eutrophication (see slide 13), draining, sedimentation via construction
Marine Ecosystems Benthic zone lowest level. Organisms living in this zone are called benthos. Photic Zone well-lit upper layer of the oceans. Aphotic Zone permanently dark layer of the oceans below the photic zone MARINE ECOSYSTEMS CORAL REEFS
Clear, warm shallow seas Made up of accumulated calcareous (made of calcium) skeletons of coral animals Formation of reefs depends on light penetration. Corals have a symbiotic relationship with algae (which are photosynthetic) . Very diverse, abundant (Rainforests of Sea) Threats- destructive fishing (cyanide & dynamite to stun fish), pet trade; about 75% of coral reefs have been destroyed What factors can alter aquatic ecosystems?
Natural Successionnormal cycle of pond becoming forest Artificial Successionhumans add Nitrogen & Phosphate to water via fertilizer & sewage causing succession to happen faster = EUTROPHICATION What factors can alter aquatic ecosystems? Humans! Find food
Recreation Waste disposal Cooling of power plants Transportation Dams, canals
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