SYDNEY: A global marine food chain collapse due to greenhouse gas emissions could hit many popular eating fish, an Australian study has found.
Warmer waters, coupled with ocean acidification, mean that the higher a fish is up the food chain, the more imperilled it would be.
“They will need more food, but less food will be available – and these are the fish that we like to eat,” said University of Adelaide marine ecologist Ivan Nagelkerken.
“There will be a species collapse from the top of the food chain down.”
The oceans have taken up about one third of all the world’s increased carbon dioxide emissions since 1750, according to the Intergovernmental Panel on Climate Change.
In the upper 75 metres of the ocean, the global average temperature has warmed by 0.11 degree celsius per decade over the past 40 years, the IPCC says.
Meanwhile the World Meteorological Organisation says carbon dioxide input is increasing ocean acidity at a rate unprecedented in 300 million years – amounting to four kilograms of carbon dioxide per day, per person.
Associate Professor Nagelkerken’s analysis, published on Tuesday in the Proceedings of the National Academy of Science, draws together the results of 632 experiments on the direction and magnitude of ecological change forced by greenhouse gases.
The work, with fellow University of Adelaide marine ecologist Sean Connell, is aimed at filling a knowledge gap on how climate change will more broadly affect the marine environment.
Associate Professor Nagelkerken found that only the smallest plankton was likely to benefit from warmer waters.
