Physiological plasticity, long term resistance or acclimation to temperature, in the Antarctic bivalve, Laternula elliptica.
To further investigate the previously reported limited acclimation capacities of Antarctic marine stenotherms, the Antarctic mud clam, Laternula elliptica (King and Broderip, 1830-1831), was incubated at 3.0°C for 89days. The thermal windows of a suite of biochemical and physiological metrics that characterise tissue aerobic status, were then measured in response to acute temperature elevation (2-2.5°C increase per week). To test if acclimation had occurred at the higher temperature, results were compared with published data, from the preceding year, for L. elliptica which had been incubated at ambient temperature (0.0°C) and then subjected to the same acute temperature treatments. Incubation to 3.0°C led to a temperature induced increase of tissue aerobic status (reduced intracellular cCO(2) with increased O(2) consumption, PLA (phospho-L-arginine) and ATP). At the highest acute temperature (7.5°C) the increase in anaerobic pathways (summed acetate/succinate and propionate) was less after 3.0°C than 0.0°C incubation. No other metric shifted its reaction norm in response to acute temperature elevation and so whole animal acclimation had not occurred, even after 3months at 3.0°C. Combined with the constant mortality throughout the 3.0°C incubation period, these data suggest that the recorded physiological changes were either the early stages of acclimation or, more likely, time limited resistance mechanisms.
British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, UK. smor@bas.ac.uk
Simon A
SA
Morley
Timo
T
Hirse
Michael A S
MA
Thorne
Hans O
HO
Pörtner
Lloyd S
LS
Peck
D000064:Acclimatization; D000136:Acid-Base Equilibrium; D000227:Adenine Nucleotides / Q000378:metabolism; D000704:Analysis of Variance; D060105:Animal Shells / Q000033:anatomy & histology; D000818:Animals; D000864:Antarctic Regions; D001120:Arginine / Q000378:metabolism; D049872:Bivalvia / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology*; D001831:Body Temperature; D002245:Carbon Dioxide / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D003080:Cold Temperature; D006339:Heart Rate; D010101:Oxygen Consumption
D000227:Adenine Nucleotides; D002245:Carbon Dioxide; D001120:Arginine; D002950:Citrate (si)-Synthase