In the world’s first global analysis that details marine responses to the impact of rising CO2 emissions, marine ecologists from the University of Adelaide are saying that ocean warming and acidification will likely result in a decrease in the diversity of marine species.
Speaking with the Australian Broadcasting Association, Associate Professor Ivan Nagelkerken said, “Our large-scale analysis suggests that many species will show a decrease in abundance, as well as diversity. We looked at how climate change might affect marine ecosystems and species in the near future.”
Professor Nagelkerken, along with Professor Sean Connell, also of the University of Adelaide jointly conducted the meta-analysis that included tropical oceans, arctic waters, and a range of ecosystems from coral reefs, through kelp forests to open oceans.
Using data from 632 published experiments, researchers quantified not only the direction of ecological change, but also the magnitude of that change resulting from acidification and warming to get a broad picture of the overall changes to the marine ecosystem, as well as the changes in different species communities.
The researchers didn’t do the analysis using only single stressors, as many studies have relied on, but instead, used the different studies to look at the combined effects of multiple stressors on whole communities that included species interactions and their different responses to climate change.
Studies done over the past several years have already shown that marine life has been affected by pollution, sewage dumping and overfishing. The researchers say climate change would only add to the woes in the coming years. “Very few species will be able to cope with such conditions,” Professor Nagelkerken warned.
An interesting finding is that predators higher up in the marine food chain are going to be more affected than those species at the bottom. We are actually seeing some of this occurring now. “Some species might benefit a bit — primary producers like plankton and algae — but the bigger fishery species probably will not,” Nagelkerken adds.
Another important finding by the research team was that continued acidification will lead to a decline in dimethylsufide gas production by ocean plankton. dimethylsulfide is a climate gas that contributes to cloud production and control of the Earth’s heat exchange. The study found that about the only organisms that would acclimate to warming and acidification of the oceans would be bacteria.
The bottom line is grim. “There will be a species collapse from the top of the food chain down,” the study’s authors warned.
This very interesting study was published in the journal Proceedings of the National Academy of Sciences (PNAS), on October 12, 2015, and entitled: “Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions“
