Collaborative Research:  Oxygen Isotope Tracers of Bacterial Manganese Oxidation
{'Code': '06030101', 'Directorate': {'Abbreviation': 'GEO', 'LongName': 'Directorate For Geosciences'}, 'Division': {'Abbreviation': 'EAR', 'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'John A. Maccini', 'PO_EMAI': None, 'PO_PHON': None}
The reactions leading to the formation of geological metal                 ore deposits are complex, and the potential role of microorganisms              in the formation of some low-temperature ore deposits, while                    recognized, has not been fully assessed.  In the past 9 months the              investigators developed techniques for measuring the 18O of                     manganese oxides and are using these measurements to compare                    microbial and nonbiological manganese oxidation mechanisms.  They               hypothesize that measurements of the oxygen isotopic composition                of Mn oxides can be used as geologic tracers for the microbial                  origin of Mn deposits or as a paleoindicator of the dissolved                   oxygen content, and there fore Eh conditions, of the water from                 which the deposit was formed.  Progress has been made in                        establishing the technical feasibility of this approach.  They                  will continue using oxygen isotopes to examine mechanisms of                    chemical and biological Mn(II) oxidation and determine if the                   isotopic signature of Mn oxides persist under environmental                     conditions.  First, they will assess the stability of the oxygen                tracer in the manganese oxide by a series of exchange experiments               with different Mn oxide minerals precipitated biologically and                  chemically.  Second, they will determine if bacteria fractionate                oxygen isotopes during Mn(II) oxidation by measuring the 18O of                 the initial and residual reactant (O2) as well as the Mn oxide                  product.  Third, the diversity of microbial mechanisms will be                  investigated by culturing a variety of Mn(ii) oxidizing bacteria                and measuring the 18O of their oxides.  Last, the relationship                  between dissolved oxygen concentration and the 18O of the                       manganese oxides will be tested in the field in anoxic water                    columns beginning with initial studies in the Black Sea and                     culminating in two cruises to an anoxic marine fjord.  This                     research has significant implications for paleoenvironmental                    studies.
{'FirstName': 'Bradley', 'LastName': 'Tebo', 'PI_MID_INIT': 'M', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Bradley M Tebo', 'EmailAddress': 'tebob@ohsu.edu', 'NSF_ID': '000397720', 'StartDate': '09/15/1988', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of California-San Diego Scripps Inst of Oceanography', 'CityName': 'LA JOLLA', 'ZipCode': '920931500', 'PhoneNumber': '8585341293', 'StreetAddress': '8622 DISCOVERY WAY # 116', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'California', 'StateCode': 'CA', 'CONGRESSDISTRICT': '50', 'CONGRESS_DISTRICT_ORG': 'CA50', 'ORG_UEI_NUM': 'QJ8HMDK7MRM3', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF CALIFORNIA SAN DIEGO', 'ORG_PRNT_UEI_NUM': 'QJ8HMDK7MRM3'}
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{'Code': '157100', 'Text': 'SCEC'}
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