Concept 16 - Concept 50.3 Abiotic and biotic factors...

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Concept 50.3 Abiotic and biotic factors influence the structure and dynamics of aquatic biomes Varying combinations of biotic and abiotic factors determine the nature of the Earth’s  biomes,  major types of ecological associations that occupy broad geographic regions of land  or water. Aquatic biomes occupy the largest part of the biosphere. Ecologists distinguish between freshwater and marine biomes on the basis of physical and  chemical differences. Marine biomes generally have salt concentrations that average 3%, while freshwater biomes  have salt concentrations of less than 1%. Marine biomes cover approximately 75% of the earth’s surface and have an enormous effect  on the biosphere. The evaporation of water from the oceans provides most of the planet’s rainfall. Ocean temperatures have a major effect on world climate and wind patterns. Photosynthesis by marine algae and photosynthetic bacteria produce a substantial  proportion of the world’s oxygen. Respiration by these organisms consumes huge  amounts of atmospheric carbon dioxide. Freshwater biomes are closely linked to the soils and biotic components of the terrestrial  biomes through which they pass. The pattern and speed of water flow and the surrounding climate are also important. Most aquatic biomes are physically and chemically stratified. Light is absorbed by the water and by photosynthetic organisms, so light intensity decreases  rapidly with depth. There is sufficient light for photosynthesis in the upper  photic zone. Very little light penetrates to the lower 
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

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Concept 16 - Concept 50.3 Abiotic and biotic factors...

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