Ocean acidification can now be seen from space, highlighting an ongoing danger of climate change and revealing the regions most at risk.
Pioneering techniques that use satellites to monitor ocean acidification are set to revolutionize the way that marine biologists and climate scientists study the ocean.
This new approach offers remote monitoring of large swathes of inaccessible ocean from satellites that orbit the Earth some 700 km above our heads.
Seawater absorbs about a quarter of the carbon dioxide, a greenhouse gas that humans release into the atmosphere each year, mostly from the burning of fossil fuels, according to the National Oceanic and Atmospheric Administration (NOAA).
This process has slowed the warming of the globe, as all of that carbon is locked up in the ocean's "carbon sink" rather than floating freely in the atmosphere. But when seawater takes up carbon dioxide, it becomes more acidic. According to NOAA, the surface pH of the ocean has become 30 percent more acidic since the end of the Industrial Revolution.
Rising CO2 emissions, and the increasing acidity of seawater over the next century, has the potential to devastate some marine ecosystems. Careful monitoring of changes in ocean acidity is crucial.
That acidity is not necessarily evenly distributed, however, nor is it simple to measure. Most studies rely on physical measurements taken out in the open ocean from research vessels and buoys deployed from such vessels. These measurements are spotty and expensive to collect.
Researchers at the Plymouth Marine Laboratory, the University of Exeter, Institut Francais Recherche Pour L´Exploitation de la Mer (Ifremer), the European Space Agency (ESA) and a team of international collaborators are developing new methods that allow them to monitor the acidity of the oceans from space.
"We are pioneering these techniques so that we can monitor large areas of the Earth's oceans, allowing us to quickly and easily identify those areas most at risk from the increasing acidification," study leader Jamie Shutler, a senior lecturer in ocean science at the University of Exeter, said in a statement.