FACTORS REGULATING THE FLUX OF PHOSPHATE AT THE SEDIMENT-WATER INTERFACE OF A SUBTROPICAL CALCAREOUS LAKE - A SIMULATION STUDY WITH INTACT SEDIMENT CORES
W. Eckert et al., FACTORS REGULATING THE FLUX OF PHOSPHATE AT THE SEDIMENT-WATER INTERFACE OF A SUBTROPICAL CALCAREOUS LAKE - A SIMULATION STUDY WITH INTACT SEDIMENT CORES, Water, air and soil pollution, 99(1-4), 1997, pp. 401-409
Different factors which interactively control the flux of soluble reac
tive phosphorus (SRP) at the sediment-water interface (SWI) of Lake Ki
nneret were studied seasonally. The influence of pH, Eh and microbial
activity on SRP nux at the SWI was investigated by manipulating the co
nditions in the overlying water of intact sediment cores. The calculat
ed diffusive SRP flux out of the sediment was lower in cores sampled d
uring winter and spring than during the period of amixis. Potential SR
P release, as measured in the absence of microbial activity, was stron
gly enhanced upon the transition from oxic to anoxic conditions indica
ting P release from iron(III)-bound phosphorus. In spring and summer c
ores, an enhanced SRP flux from sediments at pH 7 in comparison to pH
8 indicated P release from carbonate-bound P which sedimented previous
ly as result of high pH values during the algal spring bloom. Microbia
l uptake at the SWI was the most important sink for SRP and no net-flu
x occured under oxic conditions. The higher net-flux of P under anoxic
conditions was linked to carbon limitation of the bacteria at the SWI
.