MSC 316 Lecture Notes - Lecture 19: Photic Zone, Upwelling, Benthos
23 Nov 2016
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Document Summary
Magnitude of regional primary production: historic background. John h. ryther published in science 166: 72-76. Open ocean, costal zone, and upwelling areas. Total productivity of ocean was estimated to be 20gigatons, but in reality it is more like 45gigatons. Was accurate as far as breakdown of each area. Trophic steps and transfer efficiency: review. 100kg grass 10kg cow 1kg human. Amount of biomass in successive trophic levels that can be sustained indefinitely: magnitude of plant biomass. Amount of standing biomass counted by chlorophyll a. Ocean less productive over given area than land. What drives productivity in water column is balance between light from above and nutrients from below: nutrient cycles. When there is a coastline and the wind blows parallel to it, the blows surface waters offshore, and brings lower layers upward. This brings up cold, nutrient rich water. Elevated primary production: upwelling food chains. Large plant cells grazed by large zooplankton. Occur on the western size of continents.
