Consumption of methane and CO$_2$ by methanotrophic microbial mats from gas seeps of the anoxic Black Sea TeX Export

@article{Treude07, abstract = {The deep anoxic shelf of the northwestern Black Sea has numerous gas seeps, which are populated by methanotrophic microbial mats in and above the seafloor. Above the seafloor, the mats can form tall reef-like structures composed of porous carbonate and microbial biomass. Here, we investigated the spatial patterns of CH4 and CO2 assimilation in relation to the distribution of ANME groups and their associated bacteria in mat samples obtained from the surface of a large reef structure. A combination of different methods, including radiotracer incubation, beta microimaging, secondary ion mass spectrometry, and catalyzed reporter deposition fluorescence in situ hybridization, was applied to sections of mat obtained from the large reef structure to locate hot spots of methanotrophy and to identify the responsible microbial consortia. In addition, CO2 reduction to methane was investigated in the presence or absence of methane, sulfate, and hydrogen. The mat had an average ?13C carbon isotopic signature of -67.1?, indicating that methane was the main carbon source. Eegions dominated by ANME-1 had isotope signatures that were significantly heavier (-66.4? ± 3.9 ? [mean ± standard deviation; n = 7]) than those of the more central regions dominated by ANME-2 (-72.9? ± 2.2? n = 7). Incorporation of 14C from radiolabeled CH4 or CO2 revealed one hot spot for methanotrophy and CO2 fixation close to the surface of the mat and a low assimilation efficiency (1 to 2\% of methane oxidized). Replicate incubations of the mat with 14CH4 or 14CO2 revealed that there was interconversion of CH4 and CO2. The level of CO 2 reduction was about 10\% of the level of anaerobic oxidation of methane. However, since considerable methane formation was observed only in the presence of methane and sulfate, the process appeared to be a rereaction of anaerobic oxidation of methane rather than net methanogenesis. Copyright {\copyright} 2007, American Society for Microbiology. All Rights Reserved.}, address = {Department of Marine Environmental Biology, University of Southern California, AHF 335, 3616 Trousdale Pkwy., Los Angeles, CA 90089-0371, United States}, author = {Treude, T. and Orphan, V. and Knittel, K. and Gieseke, A. and House, C. H. and Boetius, A.}, citeulike-article-id = {1572716}, citeulike-linkout-0 = {http://dx.doi.org/10.1128/AEM.02685-06}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/17277205}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=17277205}, citeulike-linkout-3 = {http://www.scopus.com/record/display.url?view=extended&origin=resultslist&eid=2-s2.0-34247465976}, doi = {10.1128/AEM.02685-06}, journal = {Applied Environmental Microbiology}, keywords = {sims}, number = {7}, pages = {2271--2283}, posted-at = {2007-08-17 17:49:33}, priority = {2}, title = {Consumption of methane and {CO}\$\_{2}\$ by methanotrophic microbial mats from gas seeps of the anoxic {Black Sea}}, url = {http://dx.doi.org/10.1128/AEM.02685-06}, volume = {73}, year = {2007} }

TY - JOUR ID - Treude07 L3 - citeulike-article-id:1572716 N2 - The deep anoxic shelf of the northwestern Black Sea has numerous gas seeps, which are populated by methanotrophic microbial mats in and above the seafloor. Above the seafloor, the mats can form tall reef-like structures composed of porous carbonate and microbial biomass. Here, we investigated the spatial patterns of CH4 and CO2 assimilation in relation to the distribution of ANME groups and their associated bacteria in mat samples obtained from the surface of a large reef structure. A combination of different methods, including radiotracer incubation, beta microimaging, secondary ion mass spectrometry, and catalyzed reporter deposition fluorescence in situ hybridization, was applied to sections of mat obtained from the large reef structure to locate hot spots of methanotrophy and to identify the responsible microbial consortia. In addition, CO2 reduction to methane was investigated in the presence or absence of methane, sulfate, and hydrogen. The mat had an average ?13C carbon isotopic signature of -67.1?, indicating that methane was the main carbon source. Eegions dominated by ANME-1 had isotope signatures that were significantly heavier (-66.4? ± 3.9 ? [mean ± standard deviation; n = 7]) than those of the more central regions dominated by ANME-2 (-72.9? ± 2.2? n = 7). Incorporation of 14C from radiolabeled CH4 or CO2 revealed one hot spot for methanotrophy and CO2 fixation close to the surface of the mat and a low assimilation efficiency (1 to 2% of methane oxidized). Replicate incubations of the mat with 14CH4 or 14CO2 revealed that there was interconversion of CH4 and CO2. The level of CO 2 reduction was about 10% of the level of anaerobic oxidation of methane. However, since considerable methane formation was observed only in the presence of methane and sulfate, the process appeared to be a rereaction of anaerobic oxidation of methane rather than net methanogenesis. Copyright © 2007, American Society for Microbiology. All Rights Reserved. IS - 7 JF - Applied Environmental Microbiology AD - Department of Marine Environmental Biology, University of Southern California, AHF 335, 3616 Trousdale Pkwy., Los Angeles, CA 90089-0371, United States EP - 2283 TI - Consumption of methane and {CO}$_{2}$ by methanotrophic microbial mats from gas seeps of the anoxic {Black Sea} VL - 73 SP - 2271 KW - sims AU - Treude, T AU - Orphan, V AU - Knittel, K AU - Gieseke, A AU - House, CH AU - Boetius, A PY - 2007/// UR - http://dx.doi.org/10.1128/AEM.02685-06 ER -