Limnology and Oceanography
A 3-yr study in Lake Michigan has shown a 27 mmol P m-2 increase in the mass of total P (TP) in the water during spring when the lake is mixed from surface to sediment. This value is an order of magnitude greater than the annual P input from external sources. TP changed in concert with increases in chlorophyll a and organic N and decreases in nitrate and soluble Si. The concentration of soluble reactive PO4-3 (SRP) remained relatively constant throughout the study. We hypothesize that the SRP concentration is maintained by a chemical equilibrium with calcium-phosphate species. The increased mass of TP arises from the sequestering of P by algae which displaces the chemical equilibrium and allows more P to be released to the water from the sediments. Solar irradiance and the duration of mixing determine the magnitude of the spring bloom and the demand for P that must be supplied through the flux of P from the sediments to the overlying water.
Original Publication Citation
Walsh, R.S., Cutter, G.A., Dunstan, W.M., Radford-Knoery, J., & Elder, J.T. (1994). Biogeochemical control of phosphorus cycling and primary production in Lake Michigan. Limnology and Oceanography, 39(4), 961-968. doi: 10.4319/lo.1994.39.4.0961
Walsh, R. S.; Cutter, Gregory A.; Dunstan, W. M.; Radford-Knoery, J.; and Elder, J. T., "Biogeochemical Control of Phosphorus Cycling and Primary Production in Lake Michigan" (1994). OEAS Faculty Publications. 52.