Osmotic and ionic regulation in the fiddler crab Uca rapax acclimated to dilute and hypersaline seawater |
| |
Authors: | I P Zanders W E Rojas |
| |
Institution: | (1) Laboratorio Ecofisiología Animal, Instituto Venezolano de Investigaciones Cientificas, Centro de Biofísica y Bioquímica, Apartado Postal 21827, 1020A Caracas, Venezuela |
| |
Abstract: | Adult male Uca rapax, collected from the central coast of Venezuela in early 1994 were gradually acclimated to salinities ranging from 1.7 to 139S. The hemolymph osmolality (791±15 mOsmol in crabs from 26S) changed less than three-fold over the entire range of concentrations tested. The urine was isosmotic with the hemolymph in crabs exposed to dilutions <26S, and significantly hyperosmotic in those exposed to media >34.8S. The hemolymph levels of Na+, Cl–, K+, Ca2+ and Mg2+ (320±13, 405±17, 7.8±0.7, 7.2±0.1 and 31±2.2 mmol l–1, respectively, in crabs acclimated to 26S) were maintained fairly constant over the range from 8.7 to 99S, decreasing by 15% in the more dilute media or increasing sharply to about twice those values in crabs from 139S. The excretory organs contributed to the osmoionic regulation of the hemolymph in crabs exposed to <3.5 or to >34.8S, by means of the partial reabsorption or excretion, respectively, of salts from or into the urine. The results described place U. rapax among the most powerful hypo/hyper-regulating crustaceans known. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|