Molecular Insights on Dissolved Organic Matter Transformation by Supraglacial Microbial Communities.
Snow overlays the majority of Antarctica and is an important repository of dissolved organic matter (DOM). DOM transformations by supraglacial microbes are not well understood. We use ultrahigh resolution mass spectrometry to elucidate molecular changes in snowpack DOM by in situ microbial processes (up to 55 days) in a coastal Antarctic site. Both autochthonous and allochthonous DOM is highly bioavailable and is transformed by resident microbial communities through parallel processes of degradation and synthesis. DOM thought to be of a more refractory nature, such as dissolved black carbon and carboxylic-rich alicyclic molecules, was also rapidly and extensively reworked. Microbially reworked DOM exhibits an increase in the number and magnitude of N-, S-, and P-containing formulas, is less oxygenated, and more aromatic when compared to the initial DOM. Shifts in the heteroatom composition suggest that microbial processes may be important in the cycling of not only C, but other elements such as N, S, and P. Microbial reworking also produces photoreactive compounds, with potential implications for DOM photochemistry. Refined measurements of supraglacial DOM and their cycling by microbes is critical for improving our understanding of supraglacial DOM cycling and the biogeochemical and ecological impacts of DOM export to downstream environments.
National Centre for Antarctic and Ocean Research, Headland Sada, Vasco-Da-Gama, Goa 403 804, India.
Runa
0000-0003-4829-4207
R
Antony
Old Dominion University , Department of Chemistry and Biochemistry, Norfolk, Virginia 23529, United States.
Amanda S
AS
Willoughby
Villanova University , Department of Chemistry, Villanova, Pennsylvania 19085, United States.
Amanda M
AM
Grannas
Villanova University , Department of Chemistry, Villanova, Pennsylvania 19085, United States.
Victoria
V
Catanzano
Old Dominion University , Department of Chemistry and Biochemistry, Norfolk, Virginia 23529, United States.|FBSciences, Inc. (Research and Development), Norfolk, Virginia 23508, United States.
Rachel L
RL
Sleighter
National Centre for Antarctic and Ocean Research, Headland Sada, Vasco-Da-Gama, Goa 403 804, India.
Meloth
M
Thamban
Old Dominion University , Department of Chemistry and Biochemistry, Norfolk, Virginia 23529, United States.
Patrick G
PG
Hatcher
National Institute of Oceanography, Dona Paula, Goa 403 004, India.
Shanta
S
Nair
D000864:Antarctic Regions; D013058:Mass Spectrometry; D012914:Snow