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High abundance and dark CO2 fixation of chemolithoautotrophic prokaryotes in anoxic waters of the Baltic Sea.
- Source :
- Limnology & Oceanography; Jan2008, Vol. 53 Issue 1, p12-12, 1p
- Publication Year :
- 2008
-
Abstract
- We determined the abundance and distribution of chemolithoautotrophic prokaryotes in the redoxcline in two basins (Gotland Deep, Landsort Deep) of the central Baltic Sea by combining dark CO<subscript>2</subscript> fixation measurements with flow cytometric cell sorting. Maximum CO<subscript>2</subscript> fixation rates were recorded in sulfidic waters about 20 m below the chemocline. Flow cytometric analyses of deoxyribonucleic acid (DNA)-stained bacterioplankton revealed the existence of at least five different prokaryotic clusters in water samples collected below the chemocline. Dark CO<subscript>2</subscript> fixation in these clusters was determined by flow cytometric sorting after anoxic incubations with NaH<superscript>14</superscript>CO<subscript>3</subscript> tracer. Two clusters, representing about 30% of total prokaryotes, were responsible for 65% to 100% of the total dark fixation. Calculated cell-specific CO<subscript>2</subscript> fixation rates in the two basins ranged from 3.5 to 24.7 fg C cell<superscript>-1</superscript> d<superscript>-1</superscript> and suggested that these clusters are dominated by chemolithoautotrophic prokaryotes. Mean cell-specific fixation rates reached more than 10 fg C cell<superscript>-1</superscript> d<superscript>-1</superscript> in most cases, indicating relatively high growth rates (doubling times 1-2 d) of chemolithoautotrophic prokaryotes. Our results provide the first evidence of such high cell-specific CO<subscript>2</subscript> uptake and abundance of chemolithoautotrophic prokaryotes in a pelagic marine environment. However, the identity of the organisms as well as the mechanisms fueling CO<subscript>2</subscript> dark fixation in the anoxic zone remain unknown. [ABSTRACT FROM AUTHOR]
- Subjects :
- PROKARYOTES
FLOW cytometry
DNA
PLANKTON
MICROORGANISMS
Subjects
Details
- Language :
- English
- ISSN :
- 00243590
- Volume :
- 53
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Limnology & Oceanography
- Publication Type :
- Academic Journal
- Accession number :
- 31180217