Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5747556 | Ecotoxicology and Environmental Safety | 2017 | 9 Pages |
Abstract
The effects of exposure to copper (Cu) on tissue Cu accumulation, on hemolymph osmotic, Na+ and Cl- regulation, and on gill Na+/K+-ATPase (NKA) and carbonic anhydrase (CA) activities were evaluated in the fiddler crab Minuca rapax. Waterborne copper was delivered to the crabs at one of three salinities (seawater at 25Ⱐsalinity [S] = isosmotic control; distilled water [<0.1ⰠS] = hypo-osmotic medium; or 60ⰠS = hyper-osmotic seawater) either for 5 days in a 0.5-cm water film containing 0, 50, 150, 250 or 500 µg Cu/L with free access to a dry surface, or in crabs fully submerged for 5 h at 0, 250 or 500 µg Cu/L. In the crabs with free access to a dry surface, the highest Cu concentrations were found in the hemolymph and hepatopancreas with some accumulation in the gills; accumulation in the hemolymph and gills was enhanced in low salinity but was salinity independent in the hepatopancreas. Osmotic regulation was unaffected by Cu exposure; however Na+ and Cl- hypo- regulation was impaired by Cu in 25 and 60ⰠS. Gill NKA activity was stimulated 2-fold at 50 µg Cu/L and markedly inhibited at 150 µg Cu/L and above in 0 and 25ⰠS. Gill CA was inhibited in <0.1ⰠS but stimulated in 25 and 60ⰠS; an inverse concentration-CA activity response was seen above 150 µg Cu/L for all salinities. In the submerged crabs, Cu accumulated in all tissues in 60ⰠS; however, there was no clear-cut Cu concentration-accumulation relationship evident in any tissue for either exposure regime, likely owing to the crabs' ability to regulate Cu. Copper exposure diminished osmotic, [Na+] and [Cl-] hypo-regulatory ability, especially in higher salinities. Gill NKA activity was markedly inhibited by Cu overall, and particularly above 250 µg Cu/L in <0.1ⰠS. Gill CA activity was inhibited in 25ⰠS but inconsistently affected in 0 and 60ⰠS. These findings show that Minuca rapax is affected both physiologically and biochemically by Cu contamination, although to different degrees, depending on the delivery regime, salinity, copper concentration and target tissue.
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Authors
Mariana V. Capparelli, John C. McNamara, Martin Grosell,