Trace Metal Availability Affects Greenhouse Gas Emissions and Microbial Functional Group Abundance in Freshwater Wetland Sediments.

Autor: Giannopoulos G; Department of Biology, Virginia Commonwealth University, Richmond, VA, United States., Hartop KR; Department of Biology, Virginia Commonwealth University, Richmond, VA, United States., Brown BL; Department of Biological Sciences, University of New Hampshire, Durham, NH, United States., Song B; Department of Biological Sciences, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA, United States., Elsgaard L; Department of Agroecology, Aarhus University, Tjele, Denmark., Franklin RB; Department of Biology, Virginia Commonwealth University, Richmond, VA, United States.
Jazyk: angličtina
Zdroj: Frontiers in microbiology [Front Microbiol] 2020 Sep 30; Vol. 11, pp. 560861. Date of Electronic Publication: 2020 Sep 30 (Print Publication: 2020).
DOI: 10.3389/fmicb.2020.560861
Abstrakt: We investigated the effects of trace metal additions on microbial nitrogen (N) and carbon (C) cycling using freshwater wetland sediment microcosms amended with micromolar concentrations of copper (Cu), molybdenum (Mo), iron (Fe), and all combinations thereof. In addition to monitoring inorganic N transformations (NO 3 - , NO 2 - , N 2 O, NH 4 + ) and carbon mineralization (CO 2 , CH 4 ), we tracked changes in functional gene abundance associated with denitrification ( nirS , nirK , nosZ ), dissimilatory nitrate reduction to ammonium (DNRA; nrfA ), and methanogenesis ( mcrA ). With regards to N cycling, greater availability of Cu led to more complete denitrification (i.e., less N 2 O accumulation) and a higher abundance of the nirK and nosZ genes, which encode for Cu-dependent reductases. In contrast, we found sparse biochemical evidence of DNRA activity and no consistent effect of the trace metal additions on nrfA gene abundance. With regards to C mineralization, CO 2 production was unaffected, but the amendments stimulated net CH 4 production and Mo additions led to increased mcrA gene abundance. These findings demonstrate that trace metal effects on sediment microbial physiology can impact community-level function. We observed direct and indirect effects on both N and C biogeochemistry that resulted in increased production of greenhouse gasses, which may have been mediated through the documented changes in microbial community composition and shifts in functional group abundance. Overall, this work supports a more nuanced consideration of metal effects on environmental microbial communities that recognizes the key role that metal limitation plays in microbial physiology.
(Copyright © 2020 Giannopoulos, Hartop, Brown, Song, Elsgaard and Franklin.)
Databáze: MEDLINE
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