BIOL150 Chapter Notes - Chapter 3: Limnetic Zone, Cyanobacteria, Oceanic Zone
14 Sep 2018
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Document Summary
Nutrient availability, water depth, and water movement are the 3 key physical factors affect the distribution and abundance or organisms. Nutrient levels limit growth rates in the photosynthetic organisms that provide food for other species. In still water, nutrient fall to the bottom and collect in the form of debris; in moving water, nutrient can be washed away. The 2 important events that affect nutrient availability in lakes and oceans: (1) ocean upwelling. Winter stratification: dense 4 degrees celsius water at the bottom is nutrient rich but lack of oxygen while colder water near surface becomes oxygenated. A gradient in temperature thermocline (heat slope), thermal stratification occurs. Spring turnover: surface water warms to 4 degrees celsius and sinks carrying oxygen down and driving nutrients up. Summer stratification: dense 4 degrees celsius water at the bottom becomes nutrient rich while warmer water near surface becomes oxygenated.
