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Metabolic limitations reduce tolerance to combined cadmium and temperature stress in oysters, Crassostrea virginica
Author(s) -
Sokolova Inna M.,
Cherkasov Anton S.,
Lannig Gisela
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1141-d
Subject(s) - crassostrea , ectotherm , cadmium , oyster , biology , hypoxia (environmental) , oxygen , environmental chemistry , ecology , chemistry , organic chemistry
In light of global warming and increasing anthropogenic impact on marine habitats, temperature effects in combination with other stressors like pollution have become of worldwide importance. Based on the concept of oxygen‐limited thermal tolerance in aquatic ectotherms (Pörtner Naturwissenschaften 2001), we show that a persistent pollutant, cadmium, can have detrimental effects on oyster populations by reducing thermal tolerance due to impaired energy metabolism and elevated costs of basal maintenance. Oysters ( Crassostrea virginica ) were acclimated to 20, 24 and 28°C and exposed to sublethal cadmium concentration (50 μg L −1 ). At 20 and 24°C but not at 28°C standard metabolic rate (SMR) of Cd‐exposed oysters increased compared to the respective controls indicating higher costs of basal maintenance. The absence of a cadmium‐induced increase in SMR and high mortality at 28°C suggests that the metabolic machinery has reached its maximum capacity. Cd‐exposed oysters had lower blood oxygen levels during acute temperature rise from 20°C to 24° and 28°C compared to their control counterparts indicating that oxygen delivery systems cannot provide enough oxygen to cover elevated metabolic demands. Heart rates were similar in control and Cd‐exposed oysters at all studied temperatures suggesting that oxygen uptake rather than circulation may be the limiting factor. Supported by NSF IBN‐0347238 and Alexander von Humboldt Foundation.