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| Titel |
Pigment signatures of phytoplankton communities in the Beaufort Sea |
| VerfasserIn |
P. Coupel, A. Matsuoka, D. Ruiz-Pino, M. Gosselin, D. Marie, J.-É. Tremblay, M. Babin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 4 ; Nr. 12, no. 4 (2015-02-17), S.991-1006 |
| Datensatznummer |
250117820
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| Publikation (Nr.) |
 copernicus.org/bg-12-991-2015.pdf |
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| Zusammenfassung |
| Phytoplankton are expected to respond to recent environmental changes of the
Arctic Ocean. In terms of bottom-up control, modifying the phytoplankton
distribution will ultimately affect the entire food web and carbon export.
However, detecting and quantifying changes in phytoplankton communities in
the Arctic Ocean remains difficult because of the lack of data and the
inconsistent identification methods used. Based on pigment and microscopy
data sampled in the Beaufort Sea during summer 2009, we optimized the
chemotaxonomic tool CHEMTAX (CHEMical TAXonomy) for the assessment of
phytoplankton community composition in an Arctic setting. The geographical
distribution of the main phytoplankton groups was determined with clustering
methods. Four phytoplankton assemblages were determined and related to
bathymetry, nutrients and light availability. Surface waters across the whole
survey region were dominated by prasinophytes and chlorophytes, whereas the
subsurface chlorophyll maximum was dominated by the centric diatoms
Chaetoceros socialis on the shelf and by two populations of
nanoflagellates in the deep basin. Microscopic counts showed a high
contribution of the heterotrophic dinoflagellates Gymnodinium and
Gyrodinium spp. to total carbon biomass, suggesting high grazing
activity at this time of the year. However, CHEMTAX was unable to detect
these dinoflagellates because they lack peridinin. In heterotrophic
dinoflagellates, the inclusion of the pigments of their prey potentially
leads to incorrect group assignments and some misinterpretation of CHEMTAX.
Thanks to the high reproducibility of pigment analysis, our results can serve
as a baseline to assess change and spatial or temporal variability in several
phytoplankton populations that are not affected by these misinterpretations. |
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