Abstract
Mechanisms that can influence the tolerance of hypoxia in brackish waters were studied in resting and fed crabs, Carcinus maenas, at 15 °C. Mortality, blood oxygenation, acid-base status and lactate concentration were analysed in fed crabs held in full-strength normoxic seawater (32.5‰ S) and then transferred for 24 h to a partial pressure of oxygen (Po2) of 3 kPa (1.4 mg l−1) and various salinities (17, 12.5, 10, 8‰ S). At salinity levels >10‰, fed crabs tolerated Po2 values as low as 3 kPa in the ambient water and 0.5 kPa in their arterial blood for 24 h without switching to anaerobic metabolism. Only below 10‰ S did their blood-lactate content rise, leading to their death despite the fact that their blood O2-content was twice the control value measured in full-strength normoxic seawater and their blood Po2 did not decrease below values recorded at higher salinity levels. Addition of CO2 to 8‰ S water (CO2 partial pressure increasing from 0.1 to 0.3 kPa) decreased blood-lactate production and mortality, suggesting that at 10‰ S impairment of the O2 supply is limited by an excessive blood O2-affinity. The results are discussed in terms of the distribution (?10‰ S) of C. maenas along salinity gradients in estuaries and bays.
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Received: 30 October 1998 / Accepted: 15 October 1999
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Legeay, A., Massabuau, JC. Effect of salinity on hypoxia tolerance of resting green crabs, Carcinus maenas, after feeding. Marine Biology 136, 387–396 (2000). https://doi.org/10.1007/s002270050698
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DOI: https://doi.org/10.1007/s002270050698