Innovative techniques that use satellites to monitor ocean acidification are set to revolutionize the way that scientists study the Earth’s oceans. This new approach offers remote monitoring of large swathes of inaccessible ocean from satellites, including ESA’s Soil Moisture and Ocean Salinity (SMOS) mission.

More than a quarter of the carbon dioxide we release into the atmosphere every year is soaked up by the oceans. Initially, this may appear to be a good thing, tempering global warming, but there is a downside.

As more carbon dioxide dissolves into the oceans, the more acidic the seawater becomes – with extremely damaging effects.

Over the 21st century, ocean acidification has the potential to alter many marine ecosystems so that sea life is affected.

Carefully assessing changes in ocean acidity is essential, and particularly because these changes are not uniform around the world.

Until now, this information has only been available from measurements taken from research vessels and lab experiments.

Scientists from the University of Exeter, Plymouth Marine Laboratory, the French Institute of Research for the Exploitation of the Sea (Ifremer), and the European Space Agency, are developing new methods that allow them to monitor the acidity of the oceans from space.

“Satellites are likely to become increasingly important for the monitoring of ocean acidification, especially in remote and often dangerous waters like the Arctic,” said Dr Jamie Shutler of the University of Exeter, UK, who is a co-author of the paper reporting the first results in the journal Environmental  Science and Technology.

“It can be both difficult and expensive to take year-round direct measurements in such inaccessible locations. 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.”

Piecing together salinity data from ESA’s SMOS mission with satellite sea-surface temperature measurements and additional auxiliary data, it is possible to work out the pH of seawater and therefore provide accurate information to help address the growing problem of ocean acidification.

“In recent years, great advances have been made in the global provision of satellite and in situ data. It is now time to evaluate how to make the most of these new data sources to help us monitor ocean acidification, and to establish where satellite data can make the best contribution,” said Dr Peter Land of Plymouth Marine Laboratory, the lead author of the paper.

“By unifying various different efforts, for the first time we are now able to use satellites to systematically determine the pH of surface seawater. In particular, by capitalizing on salinity measurements from SMOS, we aim to routinely generate a novel value-added data product: a global surface ocean pH atlas,” added co-author Dr Roberto Sabia, Earth observation data engineer at ESA.


Peter E. Land et al. 2015. Salinity from Space Unlocks Satellite-Based Assessment of Ocean Acidification. Environ. Sci. Technol. 49 (4), pp. 1987–1994; doi: 10.1021/es504849s

Updated on : Jul 09, 2016   View : 202