Marine bacterioplankton community structure in the vicinity of Antarctic icebergs
We studied marine bacterioplankton in the Scotia Sea in June 2008 and in the northwest Weddell Sea in March to mid April 2009 in waters proximal to three free-drifting icebergs (SS-1, A-43k, and C-18a), in a region with a high density of smaller icebergs (iceberg alley), and at stations that were upstream of the iceberg trajectories designated as far-field reference sites that were between 16-75 km away. Hydrographic parameters were used to define water masses in which comparisons between bacterioplankton-associated characteristics within and between water masses could be made. Influences of the icebergs on early winter Scotia Sea bacterioplankton were minimal, if not deleterious, as we found lower levels of heterotrophic production near A-43k in comparison to stations > 16 km away. Small but significant differences in bacterioplankton community structure were observed between two icebergs studied in early winter Scotia Sea. These icebergs differed greatly in size and the findings suggest that the larger iceberg had a greater effect. In the NW Weddell Sea in March–mid April there were some significant differences in community structure in the winter water and underlying upper circumpolar deep water masses between stations occupied close to C-18a and at stations 18 km away (i.e. Polaribacter and Pelagibacter-related 16S rRNA gene fragments were at low levels at the 18 km stations), though higher resolution, high throughput profiling tools will be needed to pinpoint specific organisms and ecological types. Likewise, a better understanding of local to regional scale structure of bacterioplankton communities is necessary. Overall, the results show that bacterioplankton, dominated by Rhodobacteracae Pelagibacter, and uncultivated Gammaproteobacteria groups were minimally influenced by icebergs in the regions and seasons studied here – at least directly – though further work addressing different scales, sizes of icebergs, and seasons is needed to better understand bacterioplankton-associated ecological processes and carbon cycling in regions of high iceberg production.
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Researchers should cite this work as follows:
Murray, AE, V Peng, C Tyler, P Wagh. 2011. Marine bacterioplankton biomass, activity and community structure in the vicinity of Antarctic icebergs. Deep Sea Research, II. 58: 1407-1421.
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The publisher and rights holder of this work is SCAR - Microbial Antarctic Resource System. This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.
Bacterioplankton; marine bacteria; 16S rRNA; LHPCR; Southern Ocean; icebergs; productivity; aminopeptidase activity; Weddell Sea; Heterotrophy; Other
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|Iceberg Project Website||http://iceberg.dri.edu/ UTF-8 text|
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This study occurred over two cruises in 2008 in the Scotia Sea, and in 2009 in the NW Weddell Sea, thus the bounding box encompasses the coverage in both cruises.
|Bounding Coordinates||South West [-62, -51], North East [-57, -42]|
Plankton surveys of community structure were conducted on bacteria passing through a 3.0 micron membrane filter.
|Start Date / End Date||2008-06-07 / 2008-06-23|
|Start Date / End Date||2014-03-10 / 2014-04-07|
No Description available
|Title||Marine bacterioplankton community structure in the vicinity of Antarctic icebergs|
|Funding||This research was supported by NSF award ANT-0636543.|
|Study Area Description||Hydrological casts of the water column were collected to 500 m using a Conductivity-Temperature-Depth (CTD) rosette in areas surrounding three icebergs, SS-1, and A-43k in the Scotia Sea north of the South Shetland Islands, and C-18a during March to mid April 2009 in the Powell Basin region in the NW Weddell Sea.|
The personnel involved in the project:
Samples were collected at 8 depths between 10-500 m with a CTD rosette and Niskin bottles and a tow fish for selected surface samples. Seawater for molecular analyses was filtered first through an in-line 3.0 micron filter and the < 3.0 micron fraction was collected onto a 0.2 micron filter.
|Study Extent||See Geographic Coverage|
|Quality Control||Sanger sequence data was assembled and manually curated using Sequencher and chimera checked using Mallard.|
Method step description:
- Three bacterial 16S rRNA gene clone libraries were prepared for this data set. A MICROBIAL_SEQUENCE_SET Description file describing 3 data sets was uploaded to the IPT. MIMARKS data for these three samples were uploaded to the IPT.
|Collection Name||Bacterioplankton around Antarctic Icebergs|
|Collection Identifier||IB02 and IB03|
|Parent Collection Identifier||Not applicable|
|Specimen preservation methods||Deep frozen|
- Vernet, M., KL Smith Jr., AO Cefarelli, JJ Helly, RS Kaufmann, H Lin, DG Long, AE Murray, BH Robison, HA Ruhl, TJ Shaw, AD Sherman, J Sprintall, GR Stephenson Jr., KM Stuart, BS Twining. 2012. Islands of ice: Influence of free-drifting Antarctic icebergs on pelagic marine ecosystems. Oceangr. 25(3): 38-39. http://dx.doi.org/10.5670/oceanog.2012.72
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