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Offspring learn how to cope with high CO2

Some fish species will be able to adapt to the predicted rising ocean temperatures and acidification associated with climate change, an Australian study shows.

The authors say the result is a "little bit of good news" and suggests a longer window for the world to bring carbon dioxide emissions under control.

In a paper, published today in Nature Climate Change , the authors show marine species have the ability to adjust to increasing carbon dioxide levels if their parents also experience high CO2 concentrations.

For 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, doctoral student Gabrielle Miller, of the ARC Centre of Excellence for Coral Reef Studies, says the study shows increased levels of CO2 have 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 says 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 writes.

She says this is the first time this effect has been studied in connection with ocean acidification.

Co-author Professor Philip Munday, also of the ARC Centre and James Cook University's School of Marine and Tropical Biology, says 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," he says.

"There seems to be an ability to acclimate when dealing with multiple generations."

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

Munday says 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.

But he adds the species in the study lives on coral reefs and would only be able to survive if its habitat - the corals - can adapt to the changes in ocean temperature as well.