Ocean Acidification May Change Ecosystems by the End of the Century

As our climate changes, our oceans are becoming more acidic. Gas dissolves in seawater, leading to environment that may have some major impacts on marine life in the near future. Now, scientists have discovered that ocean acidification could change oceanic ecosystems by the end of this century.

Ocean acidification occurs when our world's seas accumulate carbon dioxide. Our oceans actually absorb more than a quarter of anthropogenic carbon dioxide, forming a natural storage unit. Yet absorbing this gas takes its toll. The water becomes more and more acidic depending on how much gas is dissolved within it. Since different species react to this acidification process differently, scientists decided to take a closer look at how ocean acidity might impact ecosystems in the future.

The scientists surveyed all studies conducted so far that dealt with the consequences of ocean acidification for marine species from five animal taxa: corals, crustaceans, molluscs, vertebrates and echinoderms. In the end, the researchers compiled 167 studies with data from over 150 different species. Then, they used emission scenarios for carbon dioxide in order to classify these results.

"Our study showed that all animal groups we considered are affected negatively by higher carbon dioxide concentrations," said Astrid Wittmann, one of the researchers, in a news release. "Corals, echinoderms and molluscs above all react very sensitively to a decline in the pH value."

In fact, the scientists found that some echinoderms, such as brittle stars, have lower prospects of survival in carbon dioxide values predicted for the year 2100. Yet other species, such as the Atlantic spider crab, won't be affected until concentrations become higher.

"We compared our results with the widespread deaths of species around 250 and 55 million years ago when CO2 concentrations were also elevated," said Hans-Otto Portner, one of the researchers, in a news release. "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."

The findings reveal a little bit more about how ocean acidification could impact species in the future. In addition, it allows the scientists to assess which species need the most protection and is important for understanding how climate change might alter the world we live in.

The findings are published in the journal Nature Climate Change.