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| Titel |
Contribution of picoplankton to the total particulate organic carbon concentration in the eastern South Pacific |
| VerfasserIn |
C. Grob, O. Ulloa, H. Claustre, Y. Huot, G. Alarcón, D. Marie |
| 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 ; 4, no. 5 ; Nr. 4, no. 5 (2007-10-15), S.837-852 |
| Datensatznummer |
250001965
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| Publikation (Nr.) |
 copernicus.org/bg-4-837-2007.pdf |
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| Zusammenfassung |
| Prochlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to
the total particulate organic carbon concentration, derived from the total
particle beam attenuation coefficient (cp), were determined across the
eastern South Pacific between the Marquesas Islands and the coast of Chile.
All flow cytometrically derived abundances decreased towards the
hyper-oligotrophic centre of the gyre and were highest at the coast, except
for Prochlorococcus, which was not detected under eutrophic conditions. Temperature and
nutrient availability appeared important in modulating picophytoplankton
abundance, according to the prevailing trophic conditions. Although the
non-vegetal particles tended to dominate the cp signal everywhere along
the transect (50 to 83%), this dominance seemed to weaken from oligo- to
eutrophic conditions, the contributions by vegetal and non-vegetal particles
being about equal under mature upwelling conditions. Spatial variability in
the vegetal compartment was more important than the non-vegetal one in
shaping the water column particle beam attenuation coefficient. Spatial
variability in picophytoplankton biomass could be traced by changes in both
total chlorophyll a (i.e. mono + divinyl chlorophyll a) concentration and
cp. Finally, picophytoeukaryotes contributed ~38% on average to
the total integrated phytoplankton carbon biomass or vegetal attenuation
signal along the transect, as determined by size measurements (i.e.
equivalent spherical diameter) on cells sorted by flow cytometry and optical
theory. Although there are some uncertainties associated with these
estimates, the new approach used in this work further supports the idea that
picophytoeukaryotes play a dominant role in carbon cycling in the upper open
ocean, even under hyper-oligotrophic conditions. |
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