Effects of temperature-induced sea breezes on phosphorus dynamics in a shallow eutrophic lake

Abstract

Wind gusts often contribute to the internal loading of nutrients in standing waters, but the linkage between the meteorological factors inducing wind gusts and phosphorus (P) dynamics in lakes is unclear. We tested the hypothesis that when atmospheric temperature-induced sea breezes occur, the total P (TP) concentration in a shallow eutrophic lake will be significantly greater than when there were no sea breezes. TP concentrations on days with sea breezes were significantly greater than on breezeless days, indicating that strong sea breezes increase sediment resuspension and that sediment P is supplied to surface water. In this case, water temperature also increased with increasing air temperature, which was significantly higher than on the days with no breezes. The high chlorophyll a and pH values alter the sequentially extracted algal available P fractions of suspended particles, which contained high levels of labile- and residual-P and low levels of NaOH-P. The NaOH-P concentration was lower on the days with sea breezes, indicating that P is released from this fraction. Our study illustrates how rising air temperature induces wind gusts, which are an important mechanism for P dynamics in shallow lakes.