Physiological adaptations of Cyprideis torosa (Crustacea, Ostracoda) tohydrogen sulphide

Abstract

The ostracod Cyprideis torosa, Jones 1850 is one of the most abundantspecies of benthic fauna in the shallow water areas of the Baltic Sea, evenin sulphidic habitats. Investigations of the physiological basis of the highresistance to hypoxia and hydrogen sulphide show that the ostracod is indeedable to oxidize penetrating sulphide to non-toxic thiosulphate and sulphiteand to eliminate the oxidation products rather quickly. This detoxification,however, is not effective enough to prevent an increase of sulphide in theostracod's body. In spite of valve closure and consequently a low apparentdiffusion coefficient of about 8 x 10-7 cm2 s-1, sulphide concentrationin the tissues increases rapidly. Ambient sulphide concentration (1 mMsulphide) was reached within 2 h, due to the small size of the ostracod. Highsuccinate values in the tissues during sulphide exposure indicate that C.torosa is able to switch over to anaerobiosis, even under oxic conditions(70% air saturation). Obviously, C. torosa can resist long-term sulphidicconditions due to its high capacity for long-term anaerobiosis.