Phytoplankton carbon fixation, chlorophyll-biomass and diagnostic pigments in the Atlantic Ocean

Poulton, A.J.; Holligan, P.M.; Hickman, A.; Kim, Y.N.; Adey, T.R.; Stinchcombe, M.C.; Holeton, C.; Root, S.; Woodward, E.M.S.. 2006 Phytoplankton carbon fixation, chlorophyll-biomass and diagnostic pigments in the Atlantic Ocean. Deep-Sea Research II, 53 (14-16). 1593-1610. https://doi.org/10.1016/j.dsr2.2006.05.007

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Official URL: http://dx.doi.org/10.1016/j.dsr2.2006.05.007

Abstract/Summary

We have made daily measurements of phytoplankton pigments, size-fractionated (<2 and >2-μm) carbon fixation and chlorophyll-a concentration during four Atlantic Meridional Transect (AMT) cruises in 2003–04. Surface rates of carbon fixation ranged from <0.2-mmol C m−3 d−1 in the subtropical gyres to 0.2–0.5-mmol C m−3 d−1 in the tropical equatorial Atlantic. Significant intercruise variability was restricted to the subtropical gyres, with higher chlorophyll-a concentrations and carbon fixation in the subsurface chlorophyll maximum during spring in either hemisphere. In surface waters, although picoplankton (<2-μm) represented the dominant fraction in terms of both carbon fixation (50–70%) and chlorophyll-a (80–90%), nanoplankton (>2-μm) contributions to total carbon fixation (30–50%) were higher than to total chlorophyll-a (10–20%). However, in the subsurface chlorophyll maximum picoplankton dominated both carbon fixation (70–90%) and chlorophyll-a (70–90%). Thus, in surface waters chlorophyll-normalised carbon fixation was 2–3 times higher for nanoplankton and differences in picoplankton and nanoplankton carbon to chlorophyll-a ratios may lead to either higher or similar growth rates. These low chlorophyll-normalised carbon fixation rates for picoplankton may also reflect losses of fixed carbon (cell leakage or respiration), decreases in photosynthetic efficiency, grazing losses during the incubations, or some combination of all these. Comparison of nitrate concentrations in the subsurface chlorophyll maximum with estimates of those required to support the observed rates of carbon fixation (assuming Redfield stoichiometry) indicate that primary production in the chlorophyll maximum may be light rather than nutrient limited.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.dsr2.2006.05.007
ISSN:	0967-0645
Additional Keywords:	phytoplankton; carbon fixation; picoplankton; nanoplankton; chlorophyll-a; Atlantic Meridional Transect
Date made live:	06 Feb 2007 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/143985

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.dsr2.2006.05.007

ISSN:

0967-0645

Additional Keywords:

phytoplankton; carbon fixation; picoplankton; nanoplankton; chlorophyll-a; Atlantic Meridional Transect

Date made live:

06 Feb 2007 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/143985