Low-cost sensor to detect long-term ocean acidity

The new technology, designed to measure pH levels in seawater, was developed by engineers from the National Oceanography Centre, in collaboration with oceanographers from University of Southampton Ocean and Earth Science, which is based at the centre.

The team tested the new device aboard the RRS Discovery, and presented their results in Anaytica Chimica Acta.

In its current form it can be used for on-board analysis of seawater samples, but the ultimate aim is to further develop the design so that it can be deployed for longer, in situ measurements.

Ocean acidification is occurring as a consequence of rising levels of atmospheric carbon dioxide (CO2), which is absorbed by the oceans. When it dissolves in seawater, CO2 forms a mild acid, which is decreasing ocean pH globally and has the potential to impact marine ecosystems.

‘We need to monitor seawater pH to a high level of precision and accuracy, and over long periods of time, in order to detect changes in the carbon system,’ said Dr Victoire Rérolle, lead author and researcher with NOC’s Sensors group.