Winter-to-summer changes in the composition and single-cell activity of near-surface Arctic prokaryotes
11 pages, 4, figures We collected surface samples in Franklin Bay (Western Arctic) from ice-covered to ice-free conditions, to determine seasonal changes in the identity and in situ activity of the prokaryotic assemblages. Catalysed reported fluorescence in situ hybridization was used to quantify th...
| Published in: | Environmental Microbiology |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Society for Applied Microbiology
2008
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10261/15909 https://doi.org/10.1111/j.1462-2920.2008.01674.x |
| Summary: | 11 pages, 4, figures We collected surface samples in Franklin Bay (Western Arctic) from ice-covered to ice-free conditions, to determine seasonal changes in the identity and in situ activity of the prokaryotic assemblages. Catalysed reported fluorescence in situ hybridization was used to quantify the abundance of different groups, and combined with microautoradiography to determine the fraction of active cells taking up three substrates: glucose, amino acids and ATP. In surface waters, Archaea accounted for 16% of the total cell count in winter, but decreased to almost undetectable levels in summer, when Bacteria made up 97% of the total cell count. Alphaproteobacteria were the most abundant group followed by Bacteroidetes (average of 34% and 14% of total cell counts respectively). Some bacterial groups appearing in low abundances (< 10% of total cell counts), such as Betaproteo- bacteria, Roseobacter and Gammaproteobacteria, showed a high percentage of active cells. By contrast, more abundant groups, such as SAR11 or Bacteroidetes, had a lower percentage of active cells in the uptake of the substrates tested. Archaea showed low heterotrophic activity throughout the year. In comparison with temperate oceans, the percentage of active Bacteria in the uptake of the substrates was relatively high, even during the winter season Financial support for this study was provided by grants from the Generalitat de Catalunya (DURSI 2003ACES00029/ANT), the Spanish Ministerio de Educación y Ciencia (REN2002-11565-E/ANT), and the Natural Sciences and Engineering Research Council of Canada through project CASES (Canadian Arctic Shelf Exchange Study) under the overall direction of L. Fortier. We sincerely thank our fellow scientists on board and the officers and crew of the CCGS Amundsen for their collaboration and support Peer reviewed |
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