AQUATIC BIOMES<br />The biosphere is that portion of Earth inhabited by life and represents the sum of all communities and ecosystems.<br />A biome is a broad, regional type of ecosystem characterized by distinctive climate and soil conditions and a distinctive kind of biological community adapted to those conditions. <br />
Aquatic Biomes account for the largest part of the biosphere in terms of area, and all types are found in the globe.<br />Ecologists distinguish between freshwater biomes and marine biomes on the basis of their physical and chemical differences.<br /><ul><li>Marine biomes generally have salt concentrations that average 3%, whereas freshwater biomes only have less than 1%.
Marine Biomes</li></li></ul><li>Many aquatic biomes are physically and chemically stratified for both a lake and marine environment. <br />Vertical Stratification<br /> based on physical and chemical variables, such as<br />light<br />temperature<br /><ul><li>Light</li></ul> is absorbed by organisms and the water<br /> intensity decreases rapidly with dept<br /><ul><li>Temperature</li></ul> light-penetrated layer<br />warmed by heat energy from sunlight2<br />deep waters<br /> beyond penetration of light<br />are uniformly cold<br />
The surface waters are warmer and the deeper ocean is colder. Between them is the thermocline which is a thin zone where temperature decreases rapidly with depth. <br />
PRIMARY PRODUCTIVITY<br />In Marine Ecosystems is limited by:<br />Light <br />is first variable to control primary production in oceans<br />since solar radiation can only penetrate to a certain depth (photic zone)<br />more than 50% of solar radiation is absorbed in first meter of water<br />even in "clear" water, only 5-10% of radiation reaches depth of 20m<br />Nutrients<br />nitrogen and phosphorus<br />most often limit marine production<br />are examples of limiting nutrients (nutrients that must be added for production to increase)<br />concentrations are low in photic zone where photosynthesis could occur<br />often more available in deep waters where its too dark for photosynthesis<br />
PRIMARY PRODUCTIVITY<br />In Freshwater Ecosystems is limited by:<br />Solar radiation and Temperature<br />Nutrient limitations also common<br />phosphorus is usually limiting nutrient (rather than nitrogen as in oceans), hence, shift in late 1970’s to phosphate-free detergents<br />Cultural eutrophication<br />Eutrophication of lakes as a result of input of nutrients from sewage and fertilizer pollution<br />
THE FRESHWATER BIOMES<br /> 1. Standing (Lentic) Bodies of Water<br />Lakes and Ponds<br />Wetlands<br /> 2. Moving (Lotic) Bodies of Water<br />Rivers and Streams<br />
THE MARINE BIOMES<br />Marine biomes include three categories: <br /> 1) Oceans 2) Coral reefs3) Estuaries <br />
THE DISTRIBUTION OF MAJOR AQUATIC BIOMES<br />
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