Basal ice microbiology at the margin of the Greenland ice sheet

TY - JOUR

T1 - Basal ice microbiology at the margin of the Greenland ice sheet

AU - Yde, Jacob C.

AU - Finster, Kai W.

AU - Raiswell, Rob

AU - Steffensen, Jørgen P.

AU - Heinemeier, Jan

AU - Olsen, Jesper

AU - Gunnlaugsson, Haraldur P.

AU - Nielsen, Ole B.

PY - 2010/12/1

Y1 - 2010/12/1

N2 - Basal ice at the margin of the Greenland ice sheet was studied with respect to its physical characteristics and microbiological community. The basal ice contained high concentrations of dissolved ferrous Fe and must therefore be anoxic. Oxygen consumption experiments indicate that 50% of the oxidation was due to biological activity while the rest could be attributed to chemical processes, most likely weathering reactions with ferrous Fe. At least six different Fe-containing mineral sources were detected in basal ice together with potential bioavailable Fe nanoparticles. An active denitrifier population was identified due to formation of 30N-dinitrogen gas after amendment of anoxic sediment slurries with 15N-NO3-. Sulfate reduction could not be detected. The solid ice faciès contained an abundant (∼108 cells cm-3) and complex microbial community that harbored representatives of at least eight major phyla within the domain Bacteria. The clone library was dominated by members of the ßsubdivision of proteobacteria of which the largest proportion was affiliated to the genus Rhodoferax that comprises facultative aerobic iron reducers. The second most abundant phylum was Bacteroidetes. The solid ice facies had many physical similarities with the overlying debris-rich banded ice faciès, indicating that they formed by similar subglacial processes and harbor similar microbial communities. This study extends our knowledge of life in subglacial environments such as beneath ice sheets. GenBank accession numbers: HM439882-HM439950; HQ144215-HQ144221.

AB - Basal ice at the margin of the Greenland ice sheet was studied with respect to its physical characteristics and microbiological community. The basal ice contained high concentrations of dissolved ferrous Fe and must therefore be anoxic. Oxygen consumption experiments indicate that 50% of the oxidation was due to biological activity while the rest could be attributed to chemical processes, most likely weathering reactions with ferrous Fe. At least six different Fe-containing mineral sources were detected in basal ice together with potential bioavailable Fe nanoparticles. An active denitrifier population was identified due to formation of 30N-dinitrogen gas after amendment of anoxic sediment slurries with 15N-NO3-. Sulfate reduction could not be detected. The solid ice faciès contained an abundant (∼108 cells cm-3) and complex microbial community that harbored representatives of at least eight major phyla within the domain Bacteria. The clone library was dominated by members of the ßsubdivision of proteobacteria of which the largest proportion was affiliated to the genus Rhodoferax that comprises facultative aerobic iron reducers. The second most abundant phylum was Bacteroidetes. The solid ice facies had many physical similarities with the overlying debris-rich banded ice faciès, indicating that they formed by similar subglacial processes and harbor similar microbial communities. This study extends our knowledge of life in subglacial environments such as beneath ice sheets. GenBank accession numbers: HM439882-HM439950; HQ144215-HQ144221.

UR - http://www.scopus.com/inward/record.url?scp=79960717446&partnerID=8YFLogxK

U2 - 10.3189/172756411795931976

DO - 10.3189/172756411795931976

M3 - Journal article

AN - SCOPUS:79960717446

SN - 0260-3055

VL - 51

SP - 71

EP - 79

JO - Annals of Glaciology

JF - Annals of Glaciology

IS - 56

ER -