Underwater volcanic vents preview future ocean habitats

An underwater study of fish in their natural environment, first of its kind, by University of Adelaide marine ecologists, shows how anticipated ocean acidification may devastate temperate marine habitats and biodiversity.

Oceans have already absorbed a large volume of carbon dioxide from the air which is an alarming thing as it is having a great impact on the habitat of fish in the oceans. Though previously scientists though it was good for our planet as some carbon dioxide was actually removed from the air, currently they are warning against it’s harmful consequences.

Published on August 11, 2015 in the journal Nature Climate Change, the researchers used natural CO₂ underwater seeps to study how entire ecosystems have been impacted by the resulting acidification of the water. They studied underwater volcanic vents in temperate waters in both the Northern and Southern hemispheres with adjacent ecosystems that have sites releasing CO₂ in the water at concentrations predicted for the end of the century.

Previously it was found that water acidification results in a reduction of escape response of fish from predators, and the new study has confirmed those findings. As the fish were near their natural habitat, such impact of acidification seemed to disappear. This dramatic change in the behavior and physiology of fish has drawn the attention of the researchers.

“We also found that some species were more abundant in the acidified waters. But these were common or generalist species such as gobie and triplefin fishes which doubled or even tripled in number to the detriment of other species,” said project leader Ivan Nagelkerken.

“Ecosystems represent complex interactions between different species, and between species and their environment. Our research has given us a greater understanding of increasing CO₂ emissions as a driver of ecological change and what this might mean for future marine biodiversity and fisheries production,” says co-author Professor Sean Connell.

“As you swim from one area to the other you see a dramatic difference,” Connell adds. “One minute you’re in a kelp forest with one meter high kelp and lots of different fish. Then you move into the vent area where everything is barren with short turf algae, just a few centimeters high and devoid of the life and color of the other areas."

“Ecosystems represent complex interactions between different species, and between species and their environment. Our research has given us a greater understanding of increasing CO₂ emissions as a driver of ecological change and what this might mean for future marine biodiversity and fisheries production.”

Source: University of Adelaide

Featured image: A healthy kelp forest in the present-day CO2 levels. Credit: Ivan Nagalkerken, University of Adelaide.