MARPAH · Marine Micro-Algae as Global Reservoir of Polycyclic Aromatic Hydrocarbon Degraders

Polycyclic aromatic hydrocarbons (PAHs) are recognised as priority pollutants to the environment and human health because of their poor water solubility, recalcitrance, inherent toxicity and potential to bio-accumulate in higher organisms – EU Water Framework Directive (No. 2000/60/EC). To manage and mitigate the impacts of PAH pollution in the marine environment, it is necessary that we understand the mechanisms involved in their biodegradation. For this, the applicant has identified a previously unrecognised niche – i.e. the surfaces of marine phytoplankton – to which both specialist and generalist PAH-degrading bacteria (PAH-DB) are associated. This new finding is significant for three main reasons: (1) It defines for the first time a physical zone in our oceans that harbours PAH bio-catalytic activity; (2) It suggests that, based on the ubiquity of phytoplankton in our oceans, this pool of biocatalytic activity is widespread and likely to be concentrated within the euphotic zone; and (3) The association of this bacterial catabolic activity with phytoplankton could help government task forces improve on methods to mitigate marine oil and PAH pollution. The aims of this Outgoing International Fellowship are to utilise the expertise offered by the US host (University of North Carolina) in their exclusive use of a unique set of uniformly 13C-labeled PAH compounds coupled with molecular techniques (DNA-SIP, qPCR, DGGE) to identify and quantitatively assess PAH-DB that are specifically associated with phytoplankton species representing the major taxonomic groups. Together with the applicant’s extensive experience, and the skills and techniques (C14 PAH degradation, respirometry etc) offered by the return host (University of Lancaster), these objectives will be accomplished through the initiation of a trans-Atlantic collaboration between the European Union and the USA in a study that for the first time aims to define a link between PAH-DB and marine phytoplankton.