Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments

TY - JOUR

T1 - Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments

AU - Cameron, Karen A.

AU - Stibal, Marek

AU - Olsen, Nikoline S.

AU - Mikkelsen, Andreas B.

AU - Elberling, Bo

AU - Jacobsen, Carsten S.

N1 - CENPERMOA[2017]

PY - 2017/7/1

Y1 - 2017/7/1

N2 - The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2 enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g−1 d−1, which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments.

AB - The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2 enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g−1 d−1, which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments.

KW - Meltwater export

KW - Methane oxidation

KW - Methanogenesis

KW - River delta

KW - Subglacial environment

KW - Sulphate reduction

U2 - 10.1007/s00248-016-0926-2

DO - 10.1007/s00248-016-0926-2

M3 - Journal article

C2 - 28070677

AN - SCOPUS:85008698564

SN - 0095-3628

VL - 74

SP - 6

EP - 9

JO - Microbial Ecology

JF - Microbial Ecology

IS - 1

ER -