Climate Change: Can Ocean Predators Help Reverse It?

First Posted: Oct 02, 2015 04:36 PM EDT

A loss of ocean predators may have a severe impact on climate change strategies and large fish populations that should be kept intact for carbon capture and long-term storage, according to a recent study.

Large fish populations are essential to the accumulation of carbon along with the long-term storage in coastal habitats like mangroves, salt marshes and sea grass vegetation, according to co-author of the study, Professor Rod Connolly, a marine scientist from Griffith University's Australian Rivers Institute.

The over-harvesting of larger fish populations will affect how people look at climate change as a whole, the researchers said. Connolly also warned that the loss of major ocean predators through over-culling and over-fishing can have major environmental impacts. Furthermore, the research also sparks the necessity for further investigations regarding the influence of predators on carbon cycling and in improving policy and management regarding blue carbon reserves.

"These predators have a cascading effect on the food web and the ecosystem generally that ultimately changes the amount of carbon captured and locked up in the seabed," Connolly said, in a news release.

This research has had a major effect in Australia, specifically due to the recent occurrences of shark attacks. Some have even been fatal, resulting in intense public debates about shark culling in Australia. These predators have long-term effects on the food web and the ecosystem and instantaneously change the amount of carbon captured and locked up in the seabed, according to Connolly. Coastal wetlands also play a vital role in the process as they extract carbon from the atmosphere, burying it within the mud for hundreds and thousands of years.

"When we change the abundance of higher order predators, this affects the number of smaller animals living in the mud, and that has flow-on effects for carbon storage in coastal wetlands," Connolly said. Coastal wetlands are essential environmental pluses, taking a quarter of a trillion kilograms of carbon out of the atmosphere every year.

"Predators play an important and potentially irreplaceable role in carbon cycling. The effect of the disproportionate loss of species high in the food chain cannot be underestimated," Connolly added.

More information regarding the paper "Predators help protect carbon stocks in blue carbon ecosystems," can be found in the journal Nature Climate.

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