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Osmo-ionic regulation in the Brazilian ghost crab Ocypode quadrata (Fabricius, 1787) (Crustacea: Brachyura)
M.C.F. Santos, G.S. Moreira and R.O. Brotto

The effects of salinity on haemolymph osmotic, Ca2+, K+ Mg2+ and Na+ regulation in the Brazilian Ocypode quadrata were investigated. The species is a strong hyper-regulator in freshwater or low salinities, while at high salinities it is a hypo-regulator. The iso-osmotic and iso-ionic points are around 27 salinity, except for haemolymph lymph Mg2+, which is around 8 salinity There is a significant rise in the osmotic concentration during the exposure to freshwater, which coincides with a rise in the Ca2+, but not in the Na+ concentration. The haemolymph K+ and Mg2+ concentrations are well regulated in all experimental salinities. These results were compared with those reported early for the northern hemisphere Ocypode quadrata population, which seems to be more adapted to high salinity waters than is the Guaeca population.

Keywords: osmotic regulation, ionic regulation, ghost crab, salinity adaptation.
Contents of this volume Sci. Mar. 53(2-3) : 691-694 Back PDF
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