Nf. Caraco et al., SULFATE CONTROL OF PHOSPHORUS AVAILABILITY IN LAKES - A TEST AND REEVALUATION OF HASLER AND EINSELE MODEL, Hydrobiologia, 253(1-3), 1993, pp. 275-280
During summer stratification large amounts of phosphorus (P) accumulat
e in anoxic bottom waters of many lakes due to release of P from under
lying sediments. The availability to phytoplankton of this P is invers
ely related to the Fe:P ratio in bottom waters. Using data from 51 lak
es, we tested the hypothesis that sulfate concentration in lake water
may be critical in controlling the Fe:P ratio in anoxic bottom waters.
Results showed that Fe:P ratios in bottom waters of lakes were signif
icantly (p<0.001) related to surface water sulfate concentrations. The
higher Fe:P ratios in low sulfate systems is due not only to higher i
ron concentrations in anoxic bottom waters but also to lower P concent
rations in anoxic waters. Thus, our results suggest that anthropogenic
ally induced increases in sulfate concentrations of waters (e.g. from
fossil fuel burning) may have a double effect on P cycling in lakes. H
igher sulfate concentrations can both increase the magnitude of P rele
ase from sediments as well as increase the availability of P released
from sediments into anoxic bottom waters.