European sea bass, Dicentrarchus labrax, in a changing ocean

[摘要] Ocean acidification, caused by rising concentrations of carbon dioxide(CO₂), is widely considered to be a major global threat to marineecosystems. To investigate the potential effects of ocean acidification onthe early life stages of a commercially important fish species, European seabass (Dicentrarchus labrax), 12 000 larvae were incubatedfrom hatch through metamorphosis under a matrix of two temperatures (17 and19 °C) and two seawater pCO₂ levels (ambient and1,000 μatm) and sampled regularly for 42 days. Calculated dailymortality was significantly affected by both temperature and pCO₂,with both increased temperature and elevated pCO₂ associated withlower daily mortality and a significant interaction between these twofactors. There was no significant pCO₂ effect noted on larvalmorphology during this period but larvae raised at 19 °C possessedsignificantly larger eyes and lower carbon:nitrogen ratios at the end of thestudy compared to those raised under 17 °C. Similarly, when theincubation was continued to post-metamorphic (juvenile) animals (day 67–69),fish raised under a combination of 19 °C and 1000 μatmpCO₂ were significantly heavier. However, juvenile D. labraxraised under this combination of 19 °C and 1000 μatmpCO₂ also exhibited lower aerobic scopes than those incubated at19 °C and ambient pCO₂. Most studies investigating theeffects of near-future oceanic conditions on the early life stages of marinefish have used incubations of relatively short durations and suggested that theseanimals are resilient to ocean acidification. Whilst the increased survivaland growth observed in this study supports this view, we conclude that more workis required to investigate whether the differences in juvenile physiologyobserved in this study manifest as negative impacts in adult fish.

[学科分类] 地球化学与岩石