Journal
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
Volume 53, Issue 10, Pages 1616-1634Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.dsr.2006.07.008
Keywords
phytoplankton; biomass; primary production; growth; Atlantic subtropical gyres; AMT
Categories
Funding
- Natural Environment Research Council [NER/O/S/2001/00680] Funding Source: researchfish
Ask authors/readers for more resources
Ninety-four stations were sampled in the Atlantic subtropical gyres during 10 cruises carried out between 1995 and 2001, mainly in boreal spring and autumn. Chlorophyll a (Chl-a) and primary production were measured during all cruises, and phytoplankton biomass was estimated in part of them. Picoplankton (< 2 mu m) represented > 60% of total Chl-a concentration measured at the surface, and their contribution to this variable increased with depth. Phytoplankton carbon concentrations were higher in the upper metres of the water column, whereas Chl-a showed a deep maximum (DCM). At each station, the water column was divided into the upper mixed layer (ML) and the DCM layer (DCML). The boundary between the two layers was calculated as the depth where Chl-a concentration was 50% of the maximum Chl-a concentration. On average DCML extends from 67 to 126 in depth. Carbon to Chl-a (C:Chl-a) ratios were used to estimate phytoplankton carbon content from Chl-a in order to obtain a large phytoplankton carbon dataset. Total C:Chl-a ratios averaged (+/- s.e.) 103 +/- 7 (n = 22) in the ML and 24 +/- 4 (n = 12) in the DCML and were higher in larger cells than in picoplankton. Using these ratios and primary production measurements, we derived mean specific growth rates of 0.17 +/- 0.01 d(-1) (n = 173) in the ML and 0.20 +/- 0.01 d(-1) (n = 165) in the DCML although the differences were not significant (t-test, p > 0.05). Our results suggest a moderate contribution of the DCML (43%) to both phytoplankton biomass and primary production in the Atlantic subtropical gyres. (c) 2006 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available