MEPS 175:121-128 (1998)  -  doi:10.3354/meps175121

ABSTRACT: The harpacticoid copepod Cletocamptus confluens (Schmeil 1894), which inhabits mud pools of sheltered shallow water bays, was studied to analyse its ability to survive in anoxia and sulphidic anoxia, its normoxic oxygen consumption, and its glycogen content. In addition, the impact of anoxia and sulphide on the viability of eggs and the time-scale of development of nauplii and copepodids was investigated. All measurements were carried out on laboratory-reared specimens. The mean survival rate of non-gravid females did not drop below 96% after 96 h of exposure to both anoxia and sulphidic anoxia. Males and egg sac bearing females showed lower survival rates. The weight-specific glycogen content of non-gravid females (891.8 ± 51.0 µmol glycosyl units g^-1 dw) was more than twice as high as that of males (404.3 ± 31.4 µmol glycosyl units g^-1 dw) and decreased to about 63% during 96 h exposure to anoxic and anoxic/sulphidic conditions. The weight-specific oxygen consumption of males and non-gravid females amounted to 223.8 ± 61.7 and 59.7 ± 8.1 µmol O₂ g^-1 dw h^-1, respectively. The viability of eggs was not affected during 96 h of anoxia and sulphidic anoxia, and hatching of nauplii was delayed for the period of exposure. The developmental time of nauplii and copepodids from eggs incubated in anoxic or anoxic/sulphidic conditions did not differ from that of the normoxic controls. Sex-specific responses to anoxia and possible consequences for population dynamics of C. confluens are discussed.

KEY WORDS: Meiofauna · Copepoda · Harpacticoida · Cletocamptus confluens · Glycogen · Respiration · Reproduction · Development · Sulphide · Brackish water