Physiological responses to salinity changes of the isopod Idotea chelipes from the Baltic brackish waters

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• 作者：Tomasz Ł ; apucki ; Monika Normant
• 关键词：Baltic Sea ; Heat dissipation ; Idotea chelipes ; Isothermal calorimetry ; Metabolic rate ; Osmoregulation ; Salinity
• 刊名：Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
• 出版年：2008
• 出版时间：March 2008
• 年：2008
• 卷：149
• 期：3
• 页码：299-305
• 全文大小：335 K

文摘

Survival, haemolymph osmolality and the specific metabolic rate of the isopod Idotea chelipes from the brackish waters of the southern Baltic Sea (salinity 7 psu) were investigated after acclimation to different salinities in the range of 3–30 psu keeping other parameters constant (T = 15 °C, full air saturation). Haemolymph osmolality of I. chelipes increased from 379 ± 33 mmol kg^{− 1} at 3 psu to 935 ± 12 mmol kg^{− 1} at 30 psu. In the salinity range of 3–11 psu I. chelipes exhibited a hyperosmotic pattern of haemolymph regulation, whereas from 14 to 25 it behaved like an osmoconformer. Isoosmosis occurred at 28.5 psu (920 mmol kg^{− 1}). The specific metabolic rate of I. chelipes was significantly (P < 0.05) related to salinity, with maximum (2.4 ± 0.8 J g^{− 1} wm h^{− 1}) and minimum values (0.6 ± 0.3 J g^{− 1} wm h^{− 1}) at 7 and 20 psu, respectively. The changes in the specific metabolic rate and in the difference between the osmolality of haemolymph and external medium were significantly correlated for I. chelipes (P < 0.05). Rates of change per salinity unit were, however, unequal varying according to salinity transition. These differences indicate that osmotic adjustment may be a more or less costly in terms of energy according to salinity.