Gill ATPase Activities and Microstructures of Juvenile Chinese Mitten Crab, Eriocheir sinensis, Exposed to Ambient Mercury

Experiments were carried out to investigate the effects of ambient mercury (Hg2+) on gill Na+-K+-ATPase, Ca2+-Mg2+-ATPase activities, and gill microstructure of juvenile Chinese mitten crab, Eriocheir sinensis. Crabs were exposed to ambient 0.00, 0.01, 0.05, 0.10, 0.20 and 0.30 mg/l Hg2+, and sampled on the days of 1, 7, 14 and 30 respectively. The results showed that both ambient Hg2+ concentrations and exposure time had significant effects on both gill Na+-K+-ATPase and Ca2+-Mg2+-ATPase activities of E. sinensis, which showed the tendency to decrease with ambient mercury concentration increasing and exposure time prolonging. While for crabs exposed to 0.01 mg/l Hg2+, no significant difference was observed when compared with the control. Significant interaction between ambient Hg2+ and exposure time on these two ATPases activities was also observed with the lowest values found in crabs exposed to 0.30 mg/l Hg2+ for 30 days. The anterior gill microstructure analysis of E. sinensis exposed to different ambient Hg2+ for 30 days showed that mercury could alter the gill microstructures of E. sinensis. However, there was no significantly structure change appeared in crabs exposed to 0.01 mg/l Hg2+. Combined, these results indicated that though ambient Hg2+ could lead to significant decrease of both gill Na+-K+-ATPase and Ca2+-Mg2+-ATPase activities, and could destroy the gill microstructures, the crab of E. sinensis could acclimate to low Hg2+ contamination less than 0.01mg/l.