Large winter bacterioplankton metabolic diversity under the Coastal Arctic Ocean

SALA, M. M.; TERRADOS, R.; LOVEJOY, C.; UNREIN, F.; PEDRÓS-ALIÓ, C.

ENVIRONMENTAL MICROBIOLOGY

Wiley Blackwell

Año: 2008 vol. 10 p. 942 - 949

1462-2912

Metabolic diversity of heterotrophic bacterioplanktonwas tracked from early winter through spring withBiolog Ecoplates under the seasonally ice coveredarctic shelf in the Canadian Arctic (Franklin Bay,Beaufort Sea). Samples were taken every 6 days fromDecember 2003 to May 2004 at the surface, the haloclinewhere a temperature inversion occurs, and at200 m, close to the bottom. Despite the low nutrientlevels and low chlorophyll a, suggesting oligotrophyin the winter surface waters, the number of substratesused (NSU) was greater than in spring, when chlorophylla concentrations increased. Denaturing gradientgel electrophorisis analysis also indicated that thewinter and spring bacterial communities were phylogeneticallydistinct, with several new bands appearingin spring. In spring, the bacterial communitywould have access to the freshly produced organiccarbon from the early phytoplankton bloom and thegrowth of rapidly growing specialist phenotypeswould be favoured. In contrast, in winter bacterioplanktonconsumed more complex organic matteroriginated during the previous year’s phytoplanktonproduction. At the other depths we tested the NSUwas similar to that for the winter surface, with noseasonal pattern. Instead, bacterioplankton metabolismseemed to be influenced by resuspension, advection, and sedimentation events that contributed organic matter that enhanced bacterial metabolism.