Elevated seawater pCO_2 affects reproduction and embryonic development in the pygmy squid, Idiosepius pygmaeus

摘要

The oceans are absorbing additional carbon dioxide (CO2) from the atmosphere and projected future CO2 levels and ocean acidification could have negative implications for many marine organisms, especially during early life stages. Cephalopods are ecologically important in marine ecosystems, yet the potential effects of increased partial pressure of CO2 (pCO(2)) in seawater on cephalopod reproduction and embryonic development are little studied. We allowed adult two-toned pygmy squid (Idiosepius pygmaeus) to breed in ambient control (similar to 445 mu atm; similar to 8.05 pH(T)) or elevated pCO(2) conditions (similar to 940 mu atm; similar to 7.78 pH(T)) and compared reproductive traits in adults and developmental characteristics of their eggs, which remained in control or elevated pCO(2) treatments until hatching. Breeding pairs at elevated pCO(2) produced clutches with 40% fewer eggs, vitelli that were 14% smaller directly after spawning, embryos that were 5% smaller upon hatching, and eggs with an 8% increase in late-stage egg swelling compared with pairs at control conditions. Elevated pCO(2) did not affect fertility, time to hatch, or hatching success. Eggs were laid 40% closer together in elevated pCO(2) compared with control conditions, indicating a possible effect of elevated pCO(2) on reproductive behaviour. These results show that elevated pCO(2) can adversely affect reproduction and embryonic development of the two-toned pygmy squid. As the potential for adaptation is influenced by reproductive success, testing the capacity for squid to adapt to future ocean conditions should be a priority for future research.