Filtration and Oxygen Consumption Rates of Corbicula Species under Low Water Temperature Condition.

Abstract

Cyanobacterial bloom has been considered as the issue in summer season because high water temperature is preferable for cyanobacteria. However, the occurrence of cyano bacterial bloom under low water temperature has been reported, indicating to control cyanobacterial biomass in low water temperature are also required to improve water quality. Here, we estimated the filtration rate and oxygen consumption rate of two bivalve species, Corbicula japonica and C. sandai. Experiments were conducted with natural lake water from Lake Hachiro under low water temperature condition. The filtration rates of C. japonica and C. sandai were estimated as 21.1 and 16.9 L kg^－1 h^－1, respectively, under 6.7～11.3℃. Oxygen consumption rates of C. japonica and C. sandai were 0.014 and 0.032 mgO₂ g^－1 h^－1, respectively, under 5.4～11.4℃. Energy demand of both bivalves were also calculated based on the oxygen consumption rates to estimate the amount of dietary requirement during low water temperature season. C. japonica and C. sandai need to consume 0.032 and 0.073 m g^－1 h^－1 of algal dietary sources to meet their energy demand, respectively. These findings indicate that both bivalves can exert filtration and assimilation of suspended solids even low water temperature conditions.