Ocean Acidification

The large mollusk known as the California mussel makes its home in the rocky shoreline along the Pacific Coast from Mexico to Alaska. Considered a “foundational” animal, Mytilus californianus provides homes for hundreds of other species and offers a rich food source for species ranging from spiny lobsters to humans.

As the waters off our coasts change due to human influences, scientists at the University of California San Diego are finding that the composition of California mussel shells is weakening as it becomes more tolerant of acidic conditions.

Scientists have known that rising levels of human-produced carbon dioxide that are increasingly absorbed into the world’s oceans will have an impact on sea life. But as ocean waters increasingly acidify, tracking impacts on specific species has been difficult to gauge over time. Most of what we know about species’ responses to acidifying waters comes from short-term experiments that suggest these increases in ocean acidity—causing a lowering of seawater pH and less availability of carbonate ions to make shells—can lead to less fortified shells and more vulnerable animals.

In the future, the Antarctic could become a greener place and be colonised by new species. At the same time, some species will likely disappear. 25 researchers recently presented these and many other findings in a major international project, in which they analysed hundreds of articles on the Antarctic published in the past ten years. By doing so, the team have provided an exceptionally comprehensive assessment of the status quo and future of Antarctica and the Southern Ocean that surrounds it.

Never before have researchers arrived at so many new findings on the biological and biochemical processes at work in the Antarctic than in the past ten years. Now 25 experts, led by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), have analysed and compiled these findings in the project “AnT-ERA.” Having ultimately processed several hundred articles on the Antarctic, the team have now distilled the content into ten core messages addressing a broad range of aspects, e. g. ocean acidification, biodiversity, and the significance of sea ice for various organisms. “If you look at the timeframe from 1970 to the present, roughly 80 percent of all academic publications on biology and biochemistry in the Antarctic were released between 2010 and 2020. That’s what moved us to condense this enormous amount of knowledge into a single article,” says marine biologist and project coordinator Julian Gutt from the AWI. The project outcomes have just been published in the journal Biological Reviews.