Belowground changes to community structure alter methane-cycling dynamics in Amazonia

Kyle M Meyer; Andrew H Morris; Kevin Webster; Ann M Klein; Marie E Kroeger; Laura K Meredith; Andreas Brændholt; Fernanda Nakamura; Andressa Venturini; Leandro Fonseca de Souza; Katherine L Shek; Rachel Danielson; Joost van Haren; Plinio Barbosa de Camargo; Siu Mui Tsai; Fernando Dini-Andreote; José M S de Mauro; Jos Barlow; Erika Berenguer; Klaus Nüsslein; Scott Saleska; Jorge L M Rodrigues; Brendan J M Bohannan

doi:10.1016/j.envint.2020.106131

Belowground changes to community structure alter methane-cycling dynamics in Amazonia

Environ Int. 2020 Dec:145:106131. doi: 10.1016/j.envint.2020.106131. Epub 2020 Sep 24.

Authors

Kyle M Meyer¹, Andrew H Morris², Kevin Webster³, Ann M Klein⁴, Marie E Kroeger⁵, Laura K Meredith⁶, Andreas Brændholt⁷, Fernanda Nakamura⁸, Andressa Venturini⁸, Leandro Fonseca de Souza⁸, Katherine L Shek², Rachel Danielson⁹, Joost van Haren¹⁰, Plinio Barbosa de Camargo⁸, Siu Mui Tsai⁸, Fernando Dini-Andreote¹¹, José M S de Mauro¹², Jos Barlow¹³, Erika Berenguer¹⁴, Klaus Nüsslein⁵, Scott Saleska⁷, Jorge L M Rodrigues⁹, Brendan J M Bohannan²

Affiliations

¹ Department of Integrative Biology, University of California - Berkeley, Berkeley, CA, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA. Electronic address: kmmeyer@berkeley.edu.
² Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA.
³ Planetary Science Institute, Tucson, AZ, USA.
⁴ Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA; College of the Siskiyous, Weed, CA, USA.
⁵ Department of Microbiology, University of Massachusetts Amherst, MA, USA.
⁶ School of Natural Resources and the Environment, Tucson, AZ, USA; Biosphere 2, University of Arizona, Tucson, AZ, USA.
⁷ Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.
⁸ Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, São Paulo, Brazil.
⁹ Department of Land, Air, and Water Resources, University of California - Davis, Davis, CA, USA.
¹⁰ Biosphere 2, University of Arizona, Tucson, AZ, USA; Honors College, University of Arizona, Tucson, AZ, USA.
¹¹ Department of Soil Science, 'Luiz de Queiroz' College of Agriculture, University of São Paulo, Piracicaba, São Paulo, Brazil.
¹² Universidade Federal do Oeste do Pará, Santarém-Tapajós, Pará, Brazil.
¹³ Lancaster Environmental Centre, Lancaster University, Lancaster, UK.
¹⁴ Lancaster Environmental Centre, Lancaster University, Lancaster, UK; Environmental Change Institute, University of Oxford, Oxford, UK.

PMID: 32979812
DOI: 10.1016/j.envint.2020.106131

Abstract

Amazonian rainforest is undergoing increasing rates of deforestation, driven primarily by cattle pasture expansion. Forest-to-pasture conversion has been associated with increases in soil methane (CH₄) emission. To better understand the drivers of this change, we measured soil CH₄ flux, environmental conditions, and belowground microbial community structure across primary forests, cattle pastures, and secondary forests in two Amazonian regions. We show that pasture soils emit high levels of CH₄ (mean: 3454.6 ± 9482.3 μg CH₄ m^-2 d^-1), consistent with previous reports, while forest soils on average emit CH₄ at modest rates (mean: 9.8 ± 120.5 μg CH₄ m^-2 d^-1), but often act as CH₄ sinks. We report that secondary forest soils tend to consume CH₄ (mean: -10.2 ± 35.7 μg CH₄ m^-2 d^-1), demonstrating that pasture CH₄ emissions can be reversed. We apply a novel computational approach to identify microbial community attributes associated with flux independent of soil chemistry. While this revealed taxa known to produce or consume CH₄ directly (i.e. methanogens and methanotrophs, respectively), the vast majority of identified taxa are not known to cycle CH₄. Each land use type had a unique subset of taxa associated with CH₄ flux, suggesting that land use change alters CH₄ cycling through shifts in microbial community composition. Taken together, we show that microbial composition is crucial for understanding the observed CH₄ dynamics and that microorganisms provide explanatory power that cannot be captured by environmental variables.

Keywords: Amazon basin; Biodiversity-ecosystem function; Land use change; Methane; Methanogen; Methanotroph; Microbial ecology.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Brazil
Cattle
Forests
Methane*
Soil Microbiology
Soil*

Substances

Soil
Methane