High abundance and dark CO2 fixation of chemolithoautotrophic prokaryotes in anoxic waters of the Baltic Sea

2008/01/01 by Günter Jost, Jost GÜnter, Mikhail V. Zubkov +5 · 6 citations
Environmental Science · Earth and Planetary Sciences · #Microbial Community Ecology and Physiology #Methane Hydrates and Related Phenomena #Marine and coastal ecosystems

paper · pdf · doi:10.4319/lo.2008.53.1.0014

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 2 fixation measurements with flow cytometric cell sorting. Maximum CO 2 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 2 fixation in these clusters was determined by flow cytometric sorting after anoxic incubations with NaH 14 CO 3 tracer. Two clusters, representing about 30% of total prokaryotes, were responsible for 65% to 100% of the total dark fixation. Calculated cell‐specific CO 2 fixation rates in the two basins ranged from 3.5 to 24.7 fg C cell −1 d −1 and suggested that these clusters are dominated by chemolithoautotrophic prokaryotes. Mean cell‐specific fixation rates reached more than 10 fg C cell −1 d −1 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 2 uptake and abundance of chemolithoautotrophic prokaryotes in a pelagic marine environment. However, the identity of the organisms as well as the mechanisms fueling CO 2 dark fixation in the anoxic zone remain unknown.

Cited by

• Energy Transfer Through Food Webs at Hydrothermal Vents: Linking the Lithosphere to the Biosphere
• The relationship between anaerobic oxidation of methane and dark carbon fixation in methane seep sediments
• Sulfurimonas gotlandica sp. nov., a chemoautotrophic and psychrotolerant epsilonproteobacterium isolated from a pelagic redoxcline, and an emended description of the genus Sulfurimonas. [europepmc]
• Sulfurimonas subgroup GD17 cells accumulate polyphosphate under fluctuating redox conditions in the Baltic Sea: possible implications for their ecology. [europepmc]
• Comamonadaceae OTU as a Remnant of an Ancient Microbial Community in Sulfidic Waters. [europepmc]
• Dams Determine the Composition and Activity of Microbial Communities in Semiclosed Marine Basins of the White and Barents Seas, Russia. [europepmc]

Related

• Microbial oceanography of the dark ocean's pelagic realm
• Major contribution of anaplerosis to inorganic carbon fixation in the dark ocean
• Dense sub-ice bloom of dinoflagellates in the Baltic Sea, potentially limited by high pH
• Minor contribution of ammonia oxidizers to inorganic carbon fixation in the ocean
• Sea ice as habitat for microalgae, bacteria, virus, fungi, meio- and macrofauna: A review of an extreme environment