Effect of Ocean Acidification on Organic and Inorganic Speciation of Trace Metals

Anthony Stockdale, Edward Tipping, Stephen Lofts, Robert J. G. Mortimer
  • Environmental Science & Technology, February 2016, American Chemical Society (ACS)
  • DOI: 10.1021/acs.est.5b05624

Ocean acidification - the effect on biological availability of metal nutrients

What is it about?

Rising concentrations of atmospheric carbon dioxide are causing acidification of the oceans. This results in changes to the concentrations of key chemical species such as hydroxide, carbonate and bicarbonate ions. These changes will affect the distribution of different forms of trace metals. We used a chemical model to predict changes in the distribution of different forms of trace metals.

Why is it important?

Under a scenario where emissions peak after the year 2100 we predicted that free ion concentrations (the simplest form of a metal ion in water) of aluminium, iron, copper and lead increase by up to a factors of 21. Concentrations of organically complexed metal (which may more accurately reflect an organisms availability to access essential elements) typically have a lower sensitivity to ocean acidification induced changes. Although modest, these changes may have significance for the biological availability of metals given the close adaptation of marine microorganisms to their environment.


Anthony Stockdale

Whilst we are predicting relatively modest changes to metal forms, we have based our work on the assumption that there will be no parallel change in oceanic metal inputs (from either freshwater sources or the atmosphere via pollution or dusts). It important to state that ocean acidification is already having severe impacts that are a result of factors not assessed here, more are likely to be identified as atmospheric carbon dioxide concentrations increase further.

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The following have contributed to this page: Anthony Stockdale