ENV234H1 Lecture Notes - Lecture 19: Dissolved Organic Carbon, Photic Zone, Aphotic Zone
28 Nov 2016
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Document Summary
11 basic structure of aquatic ecosystems cont. and microbes. Water absorbs mostly uv, red, infrared: blue wavelength makes it deepest in ocean. Coloured lake with dissolved organic carbon (doc: doc absorbs mostly uv and blue. Zonation in aquatic ecosystem is based on temperature and light. Light penetrates down to certain depth: light penetrates down to euphotic zone, photosynthesizers in this layer. Light does not reach past a certain depth: aphotic zone, no primary producers to photosynthesize, feeding organisms depend on zooplankton/phytoplankton draining down/dying or plants breaking down. Warm water: at the surface, where light is. Cold water: bottom, can dissolve more oxygen (no o2 input during stratification) Ice floats, so lakes and oceans do not freeze solid; allows life. Without microbes, cycle of nutrients and life of ecosystem halt. Involved in all key processes in the functioning of the biosphere: live in very wide range of habitats, evolve quickly (fast reproductive cycle)
