AME 45:107-113 (2006)  -  doi:10.3354/ame045107

SAR11 dominance among metabolically active low nucleic acid bacterioplankton in surface waters along an Atlantic meridional transect

I. Mary1, J. L. Heywood1, B. M. Fuchs2, R. Amann2, G. A. Tarran3, P. H. Burkill1, M. V. Zubkov1,*

1National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK
2Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany
3Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK
*Corresponding author. Email:

ABSTRACT: Low nucleic acid (LNA) bacterioplankton (sorted by flow cytometry) were characterised in surface water samples along a meridional transect from 48°N to 40°S across the Atlantic Ocean. The LNA bacterioplankton abundance and metabolic activity, assessed by their 35S-methionine uptake rate, were similar along the transect, representing 36 ± 6 and 36 ± 11% of total bacterioplankton, respectively. Fluorescence in situ hybridisation analysis of the flow-sorted cells revealed that the LNA bacterioplankton population was dominated (59 ± 4%) by and contained virtually all the identifiable SAR11 clade cells throughout the Atlantic Ocean. Therefore, the present study provides ecological characterisation of this flow-sorted group and suggests both phylogenetic and functional constancy of the LNA bacterioplankton at the basin-scale.

KEY WORDS: Flow cytometry sorting · Cell metabolic activity · SAR11 clade · CARD-FISH · Radioactive tracer labelling · Atlantic Ocean

Full text in pdf format