Rainforest-to-pasture conversion stimulates soil methanogenesis across the Brazilian Amazon

Kroeger, M.E. and Meredith, L.K. and Meyer, K.M. and Webster, K.D. and de Camargo, P.B. and de Souza, L.F. and Tsai, S.M. and van Haren, J. and Saleska, S. and Bohannan, B.J.M. and Rodrigues, J.L.M. and Berenguer, E. and Barlow, J. and Nüsslein, K. (2020) Rainforest-to-pasture conversion stimulates soil methanogenesis across the Brazilian Amazon. ISME Journal. ISSN 1751-7362

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Abstract

The Amazon rainforest is a biodiversity hotspot and large terrestrial carbon sink threatened by agricultural conversion. Rainforest-to-pasture conversion stimulates the release of methane, a potent greenhouse gas. The biotic methane cycle is driven by microorganisms; therefore, this study focused on active methane-cycling microorganisms and their functions across land-use types. We collected intact soil cores from three land use types (primary rainforest, pasture, and secondary rainforest) of two geographically distinct areas of the Brazilian Amazon (Santarém, Pará and Ariquemes, Rondônia) and performed DNA stable-isotope probing coupled with metagenomics to identify the active methanotrophs and methanogens. At both locations, we observed a significant change in the composition of the isotope-labeled methane-cycling microbial community across land use types, specifically an increase in the abundance and diversity of active methanogens in pastures. We conclude that a significant increase in the abundance and activity of methanogens in pasture soils could drive increased soil methane emissions. Furthermore, we found that secondary rainforests had decreased methanogenic activity similar to primary rainforests, and thus a potential to recover as methane sinks, making it conceivable for forest restoration to offset greenhouse gas emissions in the tropics. These findings are critical for informing land management practices and global tropical rainforest conservation.

Item Type:
Journal Article
Journal or Publication Title:
ISME Journal
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1105
Subjects:
ID Code:
148660
Deposited By:
Deposited On:
03 Nov 2020 15:17
Refereed?:
Yes
Published?:
Published
Last Modified:
04 Nov 2020 07:54