'Fishes may be able to cope with rising CO2 levels'



`Fishes may be able to cope with rising CO2 levels` Melbourne: As the Earth copes with rising carbon dioxide levels, some marine species are likely to be able to adapt to the predicted rising ocean temperatures and acidification associated with climate change, a new study has found.

A paper published in Nature Climate Change magazine today said that marine species would adjust to rising carbon dioxide levels if their parents also experience high CO2 concentrations, according to an ABC report.

During the study, breeding pairs of cinnamon anemonefish (Amphiprion melanopus) were exposed to three different levels of carbon dioxide to reflect various climate change scenarios - current levels, moderate levels expected by mid-century and high levels of CO2 predicted for the end of the century.

Water temperature rises were also reflected from the current levels to a 1.5 C to 3 C rise by the end of the century.

The hatchlings of the breeding pairs were either raised in similar conditions to their parents or transferred to warmer and more CO2-dense waters.

Co-author Gabrielle Miller of ARC Centre of Excellence for Coral Reef Studies said the study showed increased levels of CO2 had a major impact on growth rate and survival of juvenile fish.

However, those hatchlings who were raised in the same water temperatures and CO2 levels experienced by their parents showed no adverse impacts.

Miller said this suggests the parents are somehow able to pass on some non-genetic information that helps prepare juvenile fish to cope with the environmental stress.

"The conditions experienced by adults can have significant carry-over effects on the performance of their offspring, often leading to improved capacity to cope with environmental stress," Miller said, adding this was the first time this effect has been studied in connection with ocean acidification.

Philip Munday of ARC Centre and James Cook University's School of Marine and Tropical Biology, said most studies on the impact of ocean acidification are short term and "almost none" consider more than one generation.

"(But) you do get a different perspective if you do research for a couple of generations. There seems to be an ability to acclimate when dealing with multiple generations".

He said further research is needed to understand exactly what "information" is passed between the generations and whether it has a molecular or nutritional basis.

Munday said the finding is a "little bit of good news" and suggests there might be some capacity for marine species to cope with climate change over the longer term.

PTI