Climate Change May Destroy Global Food Chains, New Study Reveals

Disney's Pocahontas got it right when singing to John Smith that "every species is connected in a circle that never ends."What she didn't explain is what happens when a single plant, animal or organism is removed from this balanced system? But given the increasing amount of carbon build up, we may soon find out, a new study reveals.

Researchers from the University of Adelaide recently conducted a global analysis of marine responses to increasing carbon dioxide emissions, and their findings suggest fisheries and ocean ecosystems have a tough road ahead of them. Expected ocean acidification and warming will greatly reduce marine biodiversity and key species that support these ecosystems worldwide may be wiped out, according to the team's news release.

"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," said Ivan Nagelkerken, an associate professor from the University of Adelaide and a Australian Research Council (ARC) Future Fellow with the University's Environment Institute.

The university's recent report includes a wide range of marine ecosystems from tropical to arctic waters, including species living among coral reefs and kelp forests to open oceans. In total, their study included data from 632 published experiments, the release noted.

"This analysis combines the results of all these experiments to study the combined effects of multiple stressors on whole communities, including species interactions and different measures of responses to climate change," Seam Connell, co-author and a marine ecology professor from the University of Adelaide, said in a statement.

So what did this "meta-analysis" find that individual studies didn't? Researchers discovered that marine animals are limited as to how much they can acclimate themselves to warmer waters and acidification. Since many species will be unable to escape these environmental changes, researchers expect that diversity and abundance will be reducedwhile microorganisms will be able to increase and grow more diversity. Since not all marine life feeds off of these tiny organisms, larger predators will run out of food, ultimately leading to a species collapse from the top of the food chain down, researchers say.

"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," Nagelkerken explained in the release.

While individual populations of sea turtles or sea birds are affected by plastic pollution, warmer waters are bleaching coral reefs and marine bottom-dwellers are dying from oxygen dead zones, this study looks at those impacts as an integrated system, where any slight change could have a much broader impact on a wide range of species.  

Their study was recently published in the journal Proceedings of the National Academy of Sciences (PNAS).

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