Co-occurrence of denitrification and nitrogen fixation in a meromictic lake, Lake Cadagno (Switzerland) Export

@article{citeulike:5378638, abstract = {The nitrogen cycling of Lake Cadagno was investigated by using a combination of biogeochemical and molecular ecological techniques. In the upper oxic freshwater zone inorganic nitrogen concentrations were low (up to 223C3.4 03BCM nitrate at the base of the oxic zone), while in the lower anoxic zone there were high concentrations of ammonium (up to 40 03BCM). Between these zones, a narrow zone was characterized by no measurable inorganic nitrogen, but high microbial biomass (up to 4 נ107 cells ml22121). Incubation experiments with 15N-nitrite revealed nitrogen loss occurring in the chemocline through denitrification (223C3 nM N h22121). At the same depth, incubations experiments with 15N2- and 13CDIC-labelled bicarbonate, indicated substantial N2 fixation (31.7201342.1 pM h22121) and inorganic carbon assimilation (40201385 nM h22121). Catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and sequencing of 16S rRNA genes showed that the microbial community at the chemocline was dominated by the phototrophic green sulfur bacterium Chlorobium clathratiforme. Phylogenetic analyses of the nifH genes expressed as mRNA revealed a high diversity of N2 fixers, with the highest expression levels right at the chemocline. The majority of N2 fixers were related to Chlorobium tepidum/C. phaeobacteroides. By using Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH-SIMS), we could for the first time directly link Chlorobium to N2 fixation in the environment. Moreover, our results show that N2 fixation could partly compensate for the N loss and that both processes occur at the same locale at the same time as suggested for the ancient Ocean.}, address = {Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.; IFM-GEOMAR, Dsternbrooker Weg 20, 24105 Kiel, Germany.; Cantonal Institute of Microbiology and Alpine Biology Center Foundation Piora, 6500 Bellinzona, Switzerland.; Eawag, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland.; Max Planck Institute for Chemistry, JohannJoachimBecher Weg 27, 55128 Mainz, Germany.}, author = {Halm, Hannah and Musat, Niculina and Lam, Phyllis and Langlois, Rebecca and Musat, Florin and Peduzzi, Sandro and Lavik, Gaute and Schubert, Carsten J. and Singha, B\"{a}rbel and Laroche, Julie and Kuypers, Marcel M. M.}, citeulike-article-id = {5378638}, citeulike-linkout-0 = {http://dx.doi.org/10.1111/j.1462-2920.2009.01917.x}, citeulike-linkout-1 = {http://www.ingentaconnect.com/content/bsc/emi/2009/00000011/00000008/art00004}, citeulike-linkout-2 = {http://www3.interscience.wiley.com/cgi-bin/abstract/122314474/ABSTRACT}, doi = {10.1111/j.1462-2920.2009.01917.x}, issn = {1462-2920}, journal = {Environmental Microbiology}, keywords = {denitrification, ecology, geochemistry, n-fixation, ncycle}, number = {8}, pages = {1945--1958}, posted-at = {2009-08-11 20:48:24}, priority = {2}, publisher = {Blackwell Publishing}, title = {Co-occurrence of denitrification and nitrogen fixation in a meromictic lake, Lake Cadagno (Switzerland)}, url = {http://dx.doi.org/10.1111/j.1462-2920.2009.01917.x}, volume = {11}, year = {2009} }

TY - JOUR ID - citeulike:5378638 L3 - citeulike-article-id:5378638 N2 - The nitrogen cycling of Lake Cadagno was investigated by using a combination of biogeochemical and molecular ecological techniques. In the upper oxic freshwater zone inorganic nitrogen concentrations were low (up to 223C3.4 03BCM nitrate at the base of the oxic zone), while in the lower anoxic zone there were high concentrations of ammonium (up to 40 03BCM). Between these zones, a narrow zone was characterized by no measurable inorganic nitrogen, but high microbial biomass (up to 4 נ107 cells ml22121). Incubation experiments with 15N-nitrite revealed nitrogen loss occurring in the chemocline through denitrification (223C3 nM N h22121). At the same depth, incubations experiments with 15N2- and 13CDIC-labelled bicarbonate, indicated substantial N2 fixation (31.7201342.1 pM h22121) and inorganic carbon assimilation (40201385 nM h22121). Catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and sequencing of 16S rRNA genes showed that the microbial community at the chemocline was dominated by the phototrophic green sulfur bacterium Chlorobium clathratiforme. Phylogenetic analyses of the nifH genes expressed as mRNA revealed a high diversity of N2 fixers, with the highest expression levels right at the chemocline. The majority of N2 fixers were related to Chlorobium tepidum/C. phaeobacteroides. By using Halogen In Situ Hybridization-Secondary Ion Mass Spectroscopy (HISH-SIMS), we could for the first time directly link Chlorobium to N2 fixation in the environment. Moreover, our results show that N2 fixation could partly compensate for the N loss and that both processes occur at the same locale at the same time as suggested for the ancient Ocean. IS - 8 JF - Environmental Microbiology SN - 1462-2920 AD - Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.; IFM-GEOMAR, Dsternbrooker Weg 20, 24105 Kiel, Germany.; Cantonal Institute of Microbiology and Alpine Biology Center Foundation Piora, 6500 Bellinzona, Switzerland.; Eawag, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland.; Max Planck Institute for Chemistry, JohannJoachimBecher Weg 27, 55128 Mainz, Germany. EP - 1958 TI - Co-occurrence of denitrification and nitrogen fixation in a meromictic lake, Lake Cadagno (Switzerland) PB - Blackwell Publishing VL - 11 SP - 1945 KW - denitrification KW - ecology KW - geochemistry KW - n-fixation KW - ncycle AU - Halm, Hannah AU - Musat, Niculina AU - Lam, Phyllis AU - Langlois, Rebecca AU - Musat, Florin AU - Peduzzi, Sandro AU - Lavik, Gaute AU - Schubert, Carsten AU - Singha, Bärbel AU - Laroche, Julie AU - Kuypers, Marcel PY - 2009/// UR - http://dx.doi.org/10.1111/j.1462-2920.2009.01917.x ER -