Ocean acidification bad news for future fish, worse for coral; what will the ocean look like in 2100?

In 100 years we may be looking at a much different ocean species-wise.

A new study worked to predict the impact of ocean acidification on various species, and found they responded in their own specific ways, an Alfred Wegener Institute press release reported.

The study team analyzed previously collected data on the impact of ocean acidification regarding: “corals, crustaceans, mollusks, vertebrates such as fishes and echinoderms (animals such as starfish and sea urchins).”

The researchers analyzed data from 167 studies including 150 species. They used emission scenarios to predict the extent of acidification in the far future.

About a quarter of the world’s carbon emissions are absorbed into the vast ocean and stored, the scenario has protected the terrestrial environment from even more drastic warming than it has already seen. This phenomenon is not as kind to the oceans themselves, dissolved carbon dioxide causes  the pH value of oceans to drop, which is bad news for marine life.

“Our study showed that all animal groups we considered are affected negatively by higher carbon dioxide concentrations. Corals, echinoderms and mollusks above all react very sensitively to a decline in the pH value,” Dr. Astrid Wittmann, of the Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research (AWI), said.

A number of echinoderms have a low chance of survival in acidification levels predicted to appear in the year 2100. It would take a higher carbon level to threaten species such as the edible crab.

The team also considered “metabolism, growth, calcification or behavior change in high carbon dioxide concentrations,” Dr. Hans-Otto Pörtner, also of AWI, said.

They used physiological features to determine how certain species’ fitness would be affected in the changing waters.

Fish are able to adapt to different pH levels better than other species, such as coral. Since coral tends to spend its entire life on one spot, it is not adapted to deal with changes in environment.

“We compared our results with the widespread deaths of species around 250 and 55 million years ago when CO2 concentrations were also elevated. Despite the relatively rough statements we were able to make with the assistance of sediment samples from the past, we discovered similar sensitivities in the same animal taxa.” Pörtner said.

About 55 million years ago the coral populations declined dramatically, while fish were able to adjust to the environmental changes.

The findings surprised scientists as past studies have concluded fish larvae are ultra-sensitive to changing pH levels.

Rebekah Marcarelli, HNGN, 26 August 2013. Article.


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