Effects of anoxia and sulphide on populations of Cletocamptus confluens (Copepoda, Harpacticoida)

The harpacticoid copepod Cletocamptus confluens (Schmeil 1894), which inhab its mud pools of sheltered shallow water bays, was studied to analyse its a bility to survive in anoxia and sulphidic anoxia, its normoxic oxygen consu mption, and its glycogen content. In addition, the impact of anoxia and sul phide on the viability of eggs and the time-scale of development of nauplii and copepodids was investigated. All measurements were carried out on labo ratory-reared specimens. The mean survival rate of non-gravid females did n ot drop below 96% after 96 h of exposure to both anoxia and sulphidic anoxi a. Males and egg sac bearing females showed lower survival rates. The weigh t-specific glycogen content of non-gravid females (891.8 +/- 51.0 pmol glyc osyl units g(-1) dw) was more than twice as high as that of males (404.3 +/ - 31.4 pmol glycosyl units g(-1) dw) and decreased to about 63% during 96 h exposure to anoxic and anoxic/sulphidic conditions. The weight-specific ox ygen consumption of males and non-gravid females amounted to 223.8 +/- 61.7 and 59.7 +/- 8.1 mu mol O-2 g(-1) dw h(-1), respectively. The viability of eggs was not affected during 96 h of anoxia and sulphidic anoxia, and hatc hing of nauplii was delayed for the period of exposure. The developmental t ime of nauplii and copepodids from eggs incubated in anoxic or anoxic/sulph idic conditions did not differ from that of the normoxic controls. Sex-spec ific responses to anoxia and possible consequences for population dynamics of C. confluens are discussed.