Abstract
Increased Cd toxicity at low salinity has been attributed to increased free Cd2+ ion concentration ([Cd2+]sw), but transfer to dilute seawater also stimulates physiological ionic regulation in crabs. In this study, Cd accumulation and Ca homeostasis in the shore crab (Carcinus maenas) were explored at fixed [Cd2+]sw to reveal the physiological events during sublethal Cd exposure. Crabs were exposed to 3.4 or 34 microg/L [Cd2+], in both 100% seawater (SW) and 33% SW for up to 10 d and sampled for hemolymph composition as well as gill and hepatopancreas Ca, Cd, and Ca-ATPase activity. Cadmium exposure ameliorated the expected fall in hemolymph osmotic pressure and NaCl at low salinity and generally protected tissue Ca from decline. Cadmium exposure alone (within salinity) inhibited Ca-ATPase, but this was offset by stimulation of Ca-ATPase at low salinity. The Ca-ATPase activity in the anterior and posterior gills showed different responses to Cd/low salinity stress. Crabs were more sensitive to a 10-fold increase in [Cd2+]sw at low salinity. Overall, we conclude that exposure to a fixed sublethal [Cd2+]sw reveals a compensatory physiological response that is driven primarily by salinity rather than Cd2+ free ion concentration. Physiological responses are therefore important during low-level Cd exposure in dilute seawater.
Submitted Version
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
