Carbon fluxes in the Canadian Arctic: patterns and drivers of bacterial abundance, production and respiration on the Beaufort Sea margin

[摘要] During August 2009, measurements of bacterial abundance and nucleic acidcontent were made along with production and respiration in coastal waters ofthe Beaufort Sea (Arctic Ocean), an area influenced by the Mackenzie Riverinflow. The main purpose was to evaluate bacterial organic carbon processingwith respect to local sources, mainly primary production and river inputs.Bacterial production and abundance generally decreased from river tooffshore waters and from surface to deep waters. In contrast, the percentageof high nucleic acid bacteria was higher in deep waters rather than insurface or river waters. Statistical analyses indicated that bacterialproduction was primarily controlled by temperature and the availability oflabile organic matter, as indicated by total dissolved amino acidconcentrations. Direct comparisons of bacterial carbon demand and primaryproduction indicated net heterotrophy was common in shelf waters. Netautotrophy was observed at stations in the Mackenzie River plume, suggestingthat the carbon fixed in plume waters helped fuel net heterotrophy in theBeaufort Sea margin.

[学科分类] 地球化学与岩石