Anaerobic metabolism, hypoxia and hydrogen sulphide in the brackish water isopodSaduria entomon(L.)

Abstract

Abstract The Baltic brackish water isopod Saduria entomon was simultaneously exposed to hydrogen sulphide (150 µmol 1−1 ) and hypoxia (4.0-6.7 kPa) for up to 100 hours. In contrast to haemoglobin-carrying species, the haemocyanin of S. entomon functions as oxyhaemocyanin also in the presence of hydrogen sulphide. The synthesis of new haemocyanin is, however, prevented. The hydrogen sulphide is oxidised in the midgut gland to S2O3 2− and SO3 2− Both lactate and alanine accumulate in the presence of hydrogen sulphide. When exposed to hypoxia and hydrogen sulphide anaerobic end products start to accumulate already at a water oxygen tension of at least 4.0–6.7 kPa, this means that hydrogen sulphide is correlated with an anaerobic metabolism.