Meeting Abstract

65.11  Jan. 7  Effect of high CO2 on the metabolism of jumbo squid Dosidicus gigas ROSA, R/A*; SEIBEL, B/A; University of Rhode Island; University of Rhode Island rrosa@etal.uri.edu

The absorption of atmospheric CO2 causes ocean acidification, i.e., decreasing pH. Since the effects of environmentally relevant pH reduction on the marine biota are still poorly understood, here we investigate the impact of short-term exposure (up to 24 hours) of juvenile squid, Dosidicus gigas , to elevated CO2 levels (0.1%). This species show diurnal migrations, spending the daytime in deep, cold and oxygen-depleted water (oxygen minimum layer; -10 �C at around 300 m) and migrates at night to shallow, warm (up to 30 �C) and aerated surface waters (where the specimen collection took place). Standard (SMR; between 4 and 21 &micromol h-1 g-1), routine (RMR, between 5 and 26 &micromol h-1 g-1) and active (AMR; between 7 and 38 &micromol h-1 g-1) metabolic rates showed a steady decrease of approximately 10-25% with high CO2 levels. The lowering of squid�s metabolism was also evident with the reduction of number of intervals of elevated activity per hour (n h-1), the scope for activity (RMR-SMR) and the % SMR of total RMR. Blood oxygen binding experiments in other ommastrephid squids also demonstrated lowered blood oxygen binding capacity caused by elevated CO2 and on-going enzymatic analysis of octopine production may show the eventual switch to anaerobic energy production under these conditions. Therefore, elevated environmental carbon dioxide and the consequent acidification seemed to significantly interfere with this squid�s respiratory physiology, which may have cascading and long-term impacts on its ecology.