PPT Slide
Human impact on global P cycle
- enhanced availability of P by mining phosphate rocks for fertilizer
Human impact on local scale
- eutrophication of lakes and streams
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Linking global cycles of C, N, P
- N and P content of leaves is strongly correlated to photosynthetic rate (limiting nutrients)
- in oceans, primary productivity is easily predicted by C:N:P
- on land, the amount of available P is correlated to the accumulation of organic C in the soils
- imbalances in the supply of N and P can reduce forest growth
- free-living bacteria that fix N have a high demand for P
- in lakes, C:N:P determines PP, species composition of phytoplankton, abundance and size of zooplankton
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Elser et al. 1996. Organism size, life history, and N:P stoichiometry. Bioscience 46:674-684