MICR 2420 Chapter Notes - Chapter 21.3: Biochemical Oxygen Demand, Aphotic Zone, Photic Zone
23 Oct 2014
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Document Summary
Bacteria and algae (water), algae produce biofuel 30x energy efficient than terrestrial biofuel plants (petroleum), marine (salt 3. 5%) na and cl ions (sulfate, iodine, bromide) e. coli is prevented but v. fisheri grows. Varying temperature, pressure, light penetration and concentration of organic matter, water column in open sea (pelagic zone) subdivided into regions: Neuston (10um): air water interface (thin but highest concentration of microbes) algae and protist hang from layer of surface tension. Euphotic zone (100-200um); upper part of water column receives light for phototrophs, open (extends down for couple hundred meters, coastal shelf less than 200 m to floor) more silt and organisms could decrease photic zone till 1m. Aphotic zone: below light only heterotrophs and lithotrophs can grow. Benthos: water column meets ocean floor and sediment below surface (thermal vent communities) benthic organisms. Thermocline (determine habitat) depth that temperature decreases steeply and water density increase (unmixed region) population of heterotroph peak eating organic matter from above.
