AME 43:33-41 (2006)  -  doi:10.3354/ame043033

Enhanced bacterioplankton activity after the ‘Prestige’ oil spill off Galicia, NW Spain

Antonio Bode*, Nicolás González, Jorge Lorenzo, Joaquin Valencia, Marta M. Varela, Manuel Varela

Instituto Español de Oceanografía, Centro Oceanográfico de A Coruña, Apdo. 130, 15080 A Coruña, Spain

ABSTRACT: The response of coastal bacterioplankton communities to the ‘Prestige’ oil spill in November 2002 was investigated off A Coruña (NW Spain). Abundance and activity (leucine uptake) of bacterioplankton communities were analysed in relation to total soluble hydrocarbon concentrations (THC) measured monthly for 1 yr after the spill. Temperature, chlorophyll a, total and particulate organic carbon (TOC and POC, respectively), along with oxygen concentrations were also measured. The highest THC values (140 µg l–1) were found near the coast shortly after the spill, decreasing thereafter, although peak concentrations of 75 µg l–1 were detected in summer. Besides those peaks, THC was much lower and was not correlated with TOC or with bacterial abundance or activity. In contrast, bacterial variables were significantly correlated with water temperature, chlorophyll a and TOC concentrations. Compared to data obtained before the spill, bacterial abundance did not change but bacterial activity was significantly enhanced, especially during winter and summer. Potential hydrocarbon degradation by bacteria was indicated by elevated production rates and an increase in the apparent oxygen utilisation during winter. The estimated degradation rates could account for the observed decrease in THC after the initial spill. Changes in hydrocarbons after the winter, however, could not be related to bacterial production, as the latter was more related to changes in phytoplankton biomass and TOC.

KEY WORDS: Bacterioplankton · Oil spill · Growth · Natural populations · Marine waters · Phytoplankton

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