Increased soil moisture intensifies the impacts of forest-to-pasture conversion on methane emissions and methane-cycling communities in the Eastern Amazon

Author(s):Show less -

Venturini, Andressa M. ; Dias, Naissa M. S. ; Gontijo, Julia B. ; Yoshiura, Caio A. ; Paula, Fabiana S. ; Meyer, Kyle M. ; Nakamura, Fernanda M. ; da Franca, Aline G. ; Borges, Clovis D. ; Barlow, Jos ; Berenguer, Erika ; Nusslein, Klaus ; Rodrigues, Jorge L. M. ; Bohannan, Brendan J. M. ; Tsai, Siu M.

• Document type: Journal article
• Source: Environmental Research; v. 212, p. 13-pg., 2022-04-06.

Abstract

Climatic changes are altering precipitation patterns in the Amazon and may influence soil methane (CH4) fluxes due to the differential responses of methanogenic and methanotrophic microorganisms. However, it remains unclear if these climate feedbacks can amplify land-use-related impacts on the CH4 cycle. To better predict the responses of soil CH4-cycling microorganisms and emissions under altered moisture levels in the Eastern Brazilian Amazon, we performed a 30-day microcosm experiment manipulating the moisture content (original moisture; 60%, 80%, and 100% of field capacity - FC) of forest and pasture soils. Gas samples were collected periodically for gas chromatography analysis, and methanogenic archaeal and methanotrophic bacterial communities were assessed using quantitative PCR and metagenomics. Positive and negative daily CH4 fluxes were observed for forest and pasture, indicating that these soils can act as both CH4 sources and sinks. Cumulative emissions and the abundance of methanogenesis-related genes and taxonomic groups were affected by land use, moisture, and their interaction. Pasture soils at 100% FC had the highest abundance of methanogens and CH4 emissions, 22 times higher than forest soils under the same treatment. Higher ratios of methanogens to methanotrophs were found in pasture than in forest soils, even at field capacity conditions. Land use and moisture were significant factors influencing the composition of methanogenic and methanotrophic communities. The diversity and evenness of methanogens did not change throughout the experiment. In contrast, methanotrophs exhibited the highest diversity and evenness in pasture soils at 100% FC. Taken together, our results suggest that increased moisture exacerbates soil CH4 emissions and microbial responses driven by land-use change in the Amazon. This is the first report on the microbial CH4 cycle in Amazonian upland soils that combined one-month gas measurements with advanced molecular methods. (AU)

• FAPESP's process: 14/50320-4 - Dimensions US-BIOTA - São Paulo: collaborative research: integrating dimensions of microbial biodiversity across land use change in tropical forests
• Grantee: Tsai Siu Mui
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 15/13546-7 - Microbial community resilience capacity assessed by metagenomics and metatranscriptomics in Amazon forest and pasture soils
• Grantee: Andressa Monteiro Venturini
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/08564-6 - Molecular bioindicators of soil microbiome from corn crop under straw effect to N2O gas mitigation
• Grantee: Caio Augusto Yoshiura
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/25931-3 - Taxonomic and functional depiction of the microbial community involved in methane transformations in soils of the Brazilian Amazonia
• Grantee: Andressa Monteiro Venturini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/09616-5 - Revealing the soil microbial activity on the methane cycling with forest convertion throught isotopic labeling
• Grantee: Fernanda Mancini Nakamura
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/26138-0 - Taxonomic and functional evaluations of microbial community involved in methane cycling of Brazilian Amazon soils
• Grantee: Fabiana da Silva Paula
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/11268-2 - Uncovering microbial greenhouse gas flux mediators of the maize rhizosphere: how does Azospirillum brasiliense mitigate emissions?
• Grantee: Caio Augusto Yoshiura
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/09643-2 - Soil microbial communities in forest-to-pasture conversion: a multi-omics approach
• Grantee: Andressa Monteiro Venturini
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 17/09952-5 - Revealing the soil microbial activity on the methane cycling with forest conversion through isotopic labeling: part II
• Grantee: Fernanda Mancini Nakamura
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 15/12282-6 - MICROCOSMS AND THE ROLE OF ACTIVE MICROBIOTA ON METHANE CYCLE IN SOILS UNDER FORESTS AND PASTURE OF EASTERN AMAZON
• Grantee: Fernanda Mancini Nakamura
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/14974-0 - Dynamics of methane and sulfur microbial communities in Amazonian soils
• Grantee: Júlia Brandão Gontijo
• Support Opportunities: Scholarships in Brazil - Doctorate