The first step in developing a cost-effective micro sensor for long-term monitoring of ocean acidification has been achieved by a team of scientists and engineers.
The new technology, that will measure pH levels in seawater, was developed by engineers from the National Oceanography Centre, in close collaboration with oceanographers from University of Southampton Ocean and Earth Science, which is based at the centre.
The team successfully tested the new device aboard the old RRS Discovery, and presented their results recently in the scientific journal 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 long periods of time in the ocean, taking 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 could 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," says Dr Victoire Rrolle, lead author and researcher with NOC's Sensors group.
As well as monitoring global change, the sensors can be used to measure more localised human impact. The micro sensors could be deployed to detect leakages from carbon capture and storage sites whereby CO2 is artificially removed from the atmosphere and stored in subsea reservoirs by measuring any proximal fluctuations in pH. The oil industry is also interested in this technology for monitoring seawater acidity around drilling sites.
The sensor works on the same principles as litmus paper that many people may have used in chemistry lessons at school, whereby the colour changes depending on the acidity of the solution.<
|Contact: Catherine Beswick|
National Oceanography Centre, Southampton (UK)