. Animal Ecology. Animal ecology. the (lc])tli to wliicli i>er cent i)t surface light pene- trates varies from in when tnrbidity is 5 ppm, to ni when turbidity is 115 ppm (Chandler 1942). Since phytopiankton rec|uire light for photosynthesis, abundance varies inversely with turbidity. Light penetration is also affected by the abundance of or- ganisms themselves, both phyto- and zooplankton. An appreciable amount of light jjasses through ice in the winter. This enables phyto])lankton photo- synthesis to continue. In eutrophic lakes many fish may suffocate when snow overlies surfa
. Animal Ecology. Animal ecology. the (lc])tli to wliicli i>er cent i)t surface light pene- trates varies from in when tnrbidity is 5 ppm, to ni when turbidity is 115 ppm (Chandler 1942). Since phytopiankton rec|uire light for photosynthesis, abundance varies inversely with turbidity. Light penetration is also affected by the abundance of or- ganisms themselves, both phyto- and zooplankton. An appreciable amount of light jjasses through ice in the winter. This enables phyto])lankton photo- synthesis to continue. In eutrophic lakes many fish may suffocate when snow overlies surface ice, pre- venting photosynthesis and, thus, the generation of oxygen (Greenbank 1945). The apparent color of water bodies may be the result variously of sky reflections, the color of the bottom, suspended materials, or of plants and animals. Hut apart from these extraneous factors, water often has an intrinsic color deriving from its chemical contents. The blue color of pure water is a result of blue light scattering by water molecules. Iron gives water a yellow hue. A green color is usually associ- ated with high concentrations of calcium carbonate. \\'ater from bogs or swamps contains humic ma- terials and is often dark brown. Many waters arc essentially colorless. In a Wisconsin lake showing practically no color, maximum photosynthesis of algae occurred at one meter depth on bright days: some photosynthesis occurred down as far as 15 meters. In a highly colored lake, maximum photo- svnthesis occurred at meter, none at 2 meters r'Schomer 1934). Photosynthesis releases oxygen into the water: respiration and decomposition absorb it. The upper layer of a lake, where photosynthesis predominates, is called the trophogcnic zone. Below this zone there may still be considerable photosynthesis, but oxygen absorption is greater than oxygen release. The deeper portion of a lake is called the tropholytic zone. The two zones are separated by a thin layer where the oxygen gains fro
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectanimalecology
