Coastal Antarctic study identifies large acidic change
A unique comparison of coastal water monitoring near Australia's Davis Station in East Antarctica has shown significant changes in ocean chemistry over the past 16 years.
The study, published this week in The Journal of Marine Chemistry, shows a marked and somewhat unexpected increase in the acidity of the seawater in the region.
The study reveals that the ocean's natural variability in seawater pH has exacerbated the change observed. However part of the change is consistent with that expected from increased carbon emissions resulting from human activities.
Lead author of the study, Nick Roden, an Institute for Marine and Antarctic Studies (UTAS) and CSIRO PhD candidate, spent 2010 in Antarctica collecting the seawater samples, work that continued an observational program initiated by Dr John Gibson in 1994.
The seawater samples were collected for analysis by drilling through 1.5 metres of sea-ice, often in temperatures as low as -30°C.
'The surprise was that the change in acidity was so large, indicating that natural and human induced changes have combined to amplify ocean acidity in this region,' said Mr Roden.
As the ocean absorbs atmospheric CO2 it lowers the pH of the waters, a process known as ocean acidification. Scientists are monitoring coastal waters globally to understand the interplay between natural and anthropogenic changes.
'Because this ecosystem is particularly vulnerable to ocean acidification, the combination of such changes are concerning, as it may accelerate the impacts that ocean acidification will have on this environment.'
'That's why it is necessary to understand how future change will influence ocean chemistry in this area,' Mr Roden said.
The study can be viewed at: www.sciencedirect.com/science/ … ii/S0304420313001370