Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise)
Predicting heterotrophic bacteria and phytoplankton specific growth rates (μ ) is of great scientific interest. Many methods have been developed in order to assess bacterial or phytoplankton μ. One widely used method is to estimate μ from data obtained on biomass or cell abunda...
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2007-11-01
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doaj-d8274f90d4b14781b8fe3f79a19a143f2020-11-24T23:53:10ZengCopernicus PublicationsBiogeosciences1726-41701726-41892007-11-0146941956Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise)S. DuhamelT. MoutinF. Van WambekeB. Van MooyP. RimmelinP. RaimbaultH. ClaustrePredicting heterotrophic bacteria and phytoplankton specific growth rates (&mu; ) is of great scientific interest. Many methods have been developed in order to assess bacterial or phytoplankton &mu;. One widely used method is to estimate μ from data obtained on biomass or cell abundance and rates of biomass or cell production. According to Kirchman (2002), the most appropriate approach for estimating μ is simply to divide the production rate by the biomass or cell abundance estimate. Most methods using this approach to estimate μ are based on carbon (C) incorporation rates and C biomass measurements. Nevertheless it is also possible to estimate μ using phosphate (P) data. We showed that particulate phosphate (PartP) can be used to estimate biomass and that the P uptake rate to PartP ratio can be employed to assess μ. Contrary to other methods using C, this estimator does not need conversion factors and provides an evaluation of &mu; for both autotrophic and heterotrophic organisms. We report values of P-based &mu; in three size fractions (0.2&ndash;0.6; 0.6&ndash;2 and &gt;2 μm) along a Southeast Pacific transect, over a wide range of P-replete trophic status. P-based &mu; values were higher in the 0.6&ndash;2 &mu;m fraction than in the &gt;2 &mu;m fraction, suggesting that picoplankton-sized cells grew faster than the larger cells, whatever the trophic regime encountered. Picoplankton-sized cells grew significantly faster in the deep chlorophyll maximum layer than in the upper part of the photic zone in the oligotrophic gyre area, suggesting that picoplankton might outcompete &gt;2 &mu;m cells in this particular high-nutrient, low-light environment. P-based μ attributed to free-living bacteria (0.2-0.6 μm) and picoplankton (0.6&ndash;2 μm) size-fractions were relatively low (0.11&plusmn;0.07 d<sup>&minus;1</sup> and 0.14&plusmn;0.04 d<sup>&minus;1</sup>, respectively) in the Southeast Pacific gyre, suggesting that the microbial community turns over very slowly. http://www.biogeosciences.net/4/941/2007/bg-4-941-2007.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
S. Duhamel T. Moutin F. Van Wambeke B. Van Mooy P. Rimmelin P. Raimbault H. Claustre |
spellingShingle |
S. Duhamel T. Moutin F. Van Wambeke B. Van Mooy P. Rimmelin P. Raimbault H. Claustre Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise) Biogeosciences |
author_facet |
S. Duhamel T. Moutin F. Van Wambeke B. Van Mooy P. Rimmelin P. Raimbault H. Claustre |
author_sort |
S. Duhamel |
title |
Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise) |
title_short |
Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise) |
title_full |
Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise) |
title_fullStr |
Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise) |
title_full_unstemmed |
Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise) |
title_sort |
growth and specific p-uptake rates of bacterial and phytoplanktonic communities in the southeast pacific (biosope cruise) |
publisher |
Copernicus Publications |
series |
Biogeosciences |
issn |
1726-4170 1726-4189 |
publishDate |
2007-11-01 |
description |
Predicting heterotrophic bacteria and phytoplankton specific growth rates (&mu; ) is of great scientific interest. Many methods have been developed in order to assess bacterial or phytoplankton &mu;. One widely used method is to estimate μ from data obtained on biomass or cell abundance and rates of biomass or cell production. According to Kirchman (2002), the most appropriate approach for estimating μ is simply to divide the production rate by the biomass or cell abundance estimate. Most methods using this approach to estimate μ are based on carbon (C) incorporation rates and C biomass measurements. Nevertheless it is also possible to estimate μ using phosphate (P) data. We showed that particulate phosphate (PartP) can be used to estimate biomass and that the P uptake rate to PartP ratio can be employed to assess μ. Contrary to other methods using C, this estimator does not need conversion factors and provides an evaluation of &mu; for both autotrophic and heterotrophic organisms. We report values of P-based &mu; in three size fractions (0.2&ndash;0.6; 0.6&ndash;2 and &gt;2 μm) along a Southeast Pacific transect, over a wide range of P-replete trophic status. P-based &mu; values were higher in the 0.6&ndash;2 &mu;m fraction than in the &gt;2 &mu;m fraction, suggesting that picoplankton-sized cells grew faster than the larger cells, whatever the trophic regime encountered. Picoplankton-sized cells grew significantly faster in the deep chlorophyll maximum layer than in the upper part of the photic zone in the oligotrophic gyre area, suggesting that picoplankton might outcompete &gt;2 &mu;m cells in this particular high-nutrient, low-light environment. P-based μ attributed to free-living bacteria (0.2-0.6 μm) and picoplankton (0.6&ndash;2 μm) size-fractions were relatively low (0.11&plusmn;0.07 d<sup>&minus;1</sup> and 0.14&plusmn;0.04 d<sup>&minus;1</sup>, respectively) in the Southeast Pacific gyre, suggesting that the microbial community turns over very slowly. |
url |
http://www.biogeosciences.net/4/941/2007/bg-4-941-2007.pdf |
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