Phosphorus excretion by some zoobenthos in a eutrophic freshwater lake and its temperature dependency.

Abstract

The phosphorus excretion rate and its temperature dependency were investigated experimentally in four dominant species of zoobenthos in eutrophic freshwater lakes in Japan. The rates for the fourth instar larvae of Chironomus plumosus, Tokunaga-yusurika akamusi and Chaoborus flavicans and for Limnodrilus spp. were 1.44, 0.73, 5.82 and 0.49 ( 10 -1 gP Emgd Ew-1 Ed-1), respectively, at 15. The Q10 values of the excretion rate for Chironomus plumosus, Chaoborus flavicans and Limnodrilus spp. were 2.19, 1.66 and 2.00 below 30, respectively. The larvae of T. akamusi showed the lowest Q10 value of 1.20 below 15. Inorganic phosphorus accounted for more than 55% of the excreted total phosphorus for C. plumosus and 85% for Limnodrilus spp. The contribution of phosphate excretion by zoobenthos to the phosphate release from lake sediment was discussed.