altered situaeon 1 of 3 note that contrary to common

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Unformatted text preview: weathering, tropical forest soils are generally depleted in nutrients Laterite Soils Fe, Al, Si –rich Residual composiEon (Mg,Fe)SiO4 CaAlSi2O8 IniEal composiEon soil profile oden 10s of meters thick! Forests shade soils from solar radiaEon. Deforested soil temperatures can be extremely high, making it difficult for seedlings and saplings to survive. Turkana Basin, Kenya: Not a forested region, but showing the potenEal for ground heaEng in the absence of shade. The take- home messages Temperate & boreal forests generally have high capacity for regrowth Some of the current carbon sink in the N.H. is related to regrowth of forests previously cleared by humans We can’t count on the same kind of regrowth in tropical forests due to low nutrient levels and thermal barriers to regrowth OK. So where is the other half of the ‘missing’ carbon going? 1a: 63 Gt/y 8: 8 Gt/y 7: 0.12 Gt/y land bioshpere (2200 Gt) 6: 0.4 Gt/y atmosphere (800 Gt) lithosphere (78,000,000 Gt) 1b: 4 5 Gt/ y 2b: 4 5.2 G t/y hydrosphere (38,400 Gt) LimiEng nutrients control the rate at which atmospheric CO2 can be introduced into the oceans P cycle, in moles (fluxes = moles/year) Most common form of P in rocks is the mineral apaEte: Ca5(PO4)3(OH,F) This could fairly well describe the Fe cycle, and that of other trace nutrients delivery of ‘goodies’ from the land to the sea Most common form of P in rocks is the mineral apaEte: Ca5(PO4)3(OH,F) Phosphate content of surface waters Note the vast regions of low nutrient content Eutroph...
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This document was uploaded on 03/26/2014 for the course GEC AS.270.103 at Johns Hopkins.

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