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| Sea lions swimming off the coast of Manly Beach. Picture: Nick Dawkins |
CLIMATE change will lead to a complete food chain collapse across the world’s oceans, an Adelaide university study has found.
Increased ocean acidification and warming is set to reduce numbers of and diversity in key species underpinning ecosystems across the world, University of Adelaide associate professor Ivan Nagelkerken says.
He also says the warmer water will boost the metabolic rates of animals, increasing competition for less food.
“There will be a species collapse from the top of the food chain down,” Prof Nagelkerken said on Tuesday.
He said this “simplification” of ocean ecosystems would have dire consequences for our way of life, particularly regions relying primarily on fishing.
The first-of-its-kind global analysis of marine responses to climate change forecasts a grim future for fish.
Marine ecologists from the University of Adelaide reviewed more than 600 published studies on coral reefs, kelp forests, open oceans, and tropical and Arctic waters.
Their meat-analysis, published in the October 12 edition of the US peer-reviewed journal Proceedings of the National Academy of Sciences, showed ocean acidification and warming would cut down on the diversity and numbers of various key species.
“This ‘simplification’ of our oceans will have profound consequences for our current way of life, particularly for coastal populations and those that rely on oceans for food and trade,” Nagelkerken said.
Very few organisms are expected to be able to adjust to warmer waters and acidification, with the exception of microorganisms, which are expected to increase in number and diversity.
But the increase in the smallest plankton is not expected to translate into more zooplankton and small fish, meaning bigger fish will struggle to find enough food to eat.
“With higher metabolic rates in the warmer water, and therefore a greater demand for food, there is a mismatch with less food available for carnivores — the bigger fish that fisheries industries are based around,” he said.
Oysters, mussels and corals are also expected to take a hit from global warming, which will further harm the environment for reef fish.
