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Microbial Biogeochemistry of Walker Lake, NV. Dr. Duane Moser, Dr. Jim Bruckner, and Dr. Jen Fisher 10/28/09. duane.moser@dri.edu. Walker Lake microbiology (justification) Fleeting opportunity to establish baseline trophic structure while lake is still viable for fisheries
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Microbial Biogeochemistry of Walker Lake, NV Dr. Duane Moser, Dr. Jim Bruckner, and Dr. Jen Fisher 10/28/09 duane.moser@dri.edu
Walker Lake microbiology (justification) • Fleeting opportunity to establish baseline trophic structure while lake is still viable for fisheries • Little known about microbial communities in alkaline habitats or terminus lakes
Walker Lake micro (justification cont.) • Almost nothing known about microbial community/function in this alkaline terminus lake • Insights for management (e.g. oxygen depletion, sulfide and ammonia production, nutrient dynamics, food web structure, trophic status)
Microbial Biogeochemistry Example: Internal N loading From Lake Task 6 Final Report
Heroes: Ron Hershey and Jeramie Memmott From Walker Basin Task 6 report Snapshot: Walker Lake (9/18/08)
DNA Molecular ecology 16S rRNA gene
Walker Lake Microbial Communities Neighbor-joining tree from four Walker Lake samples (16S rRNA gene). J.C. Bruckner
Epilimnion Metalimnion Hypolimnion Select Environmental Chemistry Variables Data provided by Ron Hershey.
Epilimnion Metalimnion Hypolimnion Sediment 1 1 3 5 10 10 0 0 0 0 10 10 5 4 1 1 3 4 10 10 10 0 0 0 10 10 10 10 4 4 2 1 2 1 1 3 7 10 10 10 10 10 10 10 10 10 17.5 4 5 3 1 2 2 1 4 5 10 10 10 10 10 10 10 10 10 18 4 5 3 1 2 3 2 4 6 10 10 10 10 10 10 10 10 10 19 4 5 4 2 4 4 5 4 4 10 10 10 10 10 10 10 10 10 22 6 5 4 3 4 3 4 4 6 10 10 10 10 10 10 10 10 10 SS Abundances of Major Microbial Physiotypes Cells per mL Iron FeNTA Reducer Iron Citrate Reducer Aerobes Depth (m) Nitrate Reducer Sulfate Reducer Sulfur Reducer Arsenate Reducer Arsenite Oxidizer Fermenter 5 10 0 5 5 4 4 4 4 5 5 5 10 10 10 10 10 10 10 10 10 SD
Epilimnion Metalimnion Hypolimnion Stable Isotopic Evidence for Sulfate Reduction Sort of Anna Szynkiewicz and Lisa Pratt, Indiana University
Permanganate assay for arsenite oxidation Sulfide/HCl assay for arsenate reduction Arsenic Biogeochemisty Jen Fisher
IC-ICP-MS data generated by Britta Planer-Friedrich at Universität Bayreuth, Germany
An Interesting Observation Flow cytometric cell counts (RBD-3000)
Snapshot: Walker Lake (9/18/08) Autofluoroescent cells Total cells Dissolved O2 Temp YSI data courtesy Jeramie Memmott and Chris Fritsen, DRI
Snapshot: Walker Lake (9/18/08) Chlorophyll a Phycobillins YSI data courtesy Jeramie Memmott and Chris Fritsen, DRI
Walker Lake Mystery Microbe. Epifluorescence microscopy: Zeiss AxioScop, rhodamine filter (L), phase contrast (R)
Cyanobacteria-like 16S rRNA Clones Neighbor-joining tree, 16S rRNA gene
Photosynthetic Electron Transport in Cyanobacteria SQR = sulfide quinone reductase. Wolf-Simon…Andrew Knoll, Iron, Sulfur, Oxygen, and Water: Geochemical implications of facultative anoxygenic photosynthesis in cyanobacteria and the slow rise of oxygen. AGU Poster 2008
Conclusions • Diverse and novel alkaliphilic microbial • community • Metal-driven redox cycling (As, Fe) appear to be • present (important?) • Microbial tipping point to Mono Lake-like • microbial communities may have already occurred • Historical sulfide accumulations in hypolimnion may • now be consumed by As reduction and facultatively • anaerobic cyanobacteria This project was funded through Congress by Public Law 109-103, Section 208 and awarded to the Nevada System of Higher Education under the administration of the Department of the Interior, U.S. Bureau of Reclamation with supplemental support to Jim Bruckner provided by the DRI/DEES postdoc program. Special thanks to Chris Fritsen and crew for help with lake access and Ron Hershey, Britta Planer-Friedrich, and Anna Szynkiewicz and Lisa Pratt for aquatic chemistry. Thanks to Jeremy Dodsworth and Brian Hedlund for assistance with sampling and dissolved gas analysis. Thanks also to Journet Wallace, Julius DeLeon, Susanna Blunt and other students from our lab who assisted with sample processing.
Aquatic Chemistry Summary Data from Ron Hershey.
Environmental Microbiology Lab Fluxes denoted as: a, anoxygenic photosynthesis; b, oxygenic photosynthesis; c, sulfide oxidation by disproportionation or phototrophic S-oxidizers; d, S0 respiration by cyanobacteria, e, sulfate reduction; f, S0-OM export/ballasting; g, pyrite formation; h, aerobic respiration; i, OM export and j, O2 export. Wolf-Simon…Andrew Knoll, Iron, Sulfur, Oxygen, and Water: Geochemical implications of facultative anoxygenic photosynthesis in cyanobacteria and the slow rise of oxygen. AGU Poster 2008
Arsenic speciation determined by IC-ICP-MS 22 m 9/18/09