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lecture_4_study_guide - Aquatic Ecosystems- 71% of the...

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Unformatted text preview: Aquatic Ecosystems- 71% of the Earths surface is water, 69 % saltwater- The oceans distribute heat, feed the hydrologic cycle, and are critical to the worlds biogeochemical cycles- About 250,000 species of plants and animals- Other resources: Oil Gas Marine Ecosystems- Coastal Zone high tide mark to the edge of the continental Shelf- Occupies less than 10% are a, but it h as > 90% of all plant and animal sp ecies, fisheri- Coastal wetlands occur in many shallow areas - Estuaries have reduces salinity and high nutrient levels- Productive nurseries, access route for anadromous species- Barrier breaches and barrier island important Development- Som e coastal zones support coral reefs (tropical rainforests of the ocean) Tremendous biodiversity 1. Open Ocean oceanic habitats differ primarily in salinity, light levels, nutrient concentrations, and depth Neritic zone- to the edge of the continental slope Oceanic zone - from the continental slope on out Top layer of water is euphotic zone Bathyl below the euphotic zone, much darker Compensation Depth separates the Euphotic and Bathyl zones Abyssal Zone Dark, no light, black, cold, about 4 degrees Celsius Upwelling - deep water with nutrients Aquatic Pollution mining operations- Desired compounds often < 3 0% of mined m at erial- Disposal of tailings problematic Aquatic Pollution-Sewage- Nutrient enrich m ent- Diseas e proble ms Aquatic Pollution Industrial Outflows- Point source pollution- Most proble m atic is non point source pollution- Lower Mississippi a nd Atchafalaya Rivers Wetlands- Transitional ecosyste m- Betwe en open water ecosyste m a nd up ground dry ecosyste m- Completely different plant life than both ecosyste m s around it- Water table shallow- FWS d efined in 1979: 1. Hydrophytes plants that can grow under water 2. Hydric soil- poorly oxygenated grey goo 3. Saturated non-soil- 7 categories of wetlands 1. Tidal Salt Marshes a) low diversity vegetation Spartina sp. b) Tidal flooding and dewatering c) Physiologically stressful 2. Tidal Freshwater Marshes a) No salinity: water level fluctuations from tidal damming b) Much higher diversity of salt-intolerant plants c) Important bird and fish habitats 3. Mangrove Wetlands a) Tropical and subtropical climates, common in Texas, Louisiana, and Florida b) Important nursery and rookery habitats c) Soil stabilization, nutrient cycling 4. Freshwater Marshes a) Shallow, emergent vegetation, grasses, sedges, bulrushes, cattails b) Found throughout the U.S. c) Huge losses to agriculture 5. Northern Peatlands a) Peat deposits in northern biomes b) Thick peat layers in old lake basins c) Partially decomposed plant material d) Waterlogged soil, acidic, low nutrients e) CH 4 emissions vs. CO 2 fixation 6. Southern Deepwater Swamps a) Standing water for most of the year b) Taxodium distichum, nyssa aquatic c) Often tied to large river systems d) Nutrient rich, productive e)...
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This note was uploaded on 10/02/2011 for the course RNR 1001 taught by Professor W.kelso during the Fall '08 term at LSU.

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lecture_4_study_guide - Aquatic Ecosystems- 71% of the...

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