EAR-Climate: Collaborative Research: Methane Dynamics Across Microbe-to-Landscape Scales in Coastal Wetlands

Collaborative Research: Methane Dynamics Across Microbe-to-Landscape Scales in Coastal Wetlands Partially to completely flooded soils in terrestrial sedimentary ecosystems, which include permafrost, floodplains, agricultural areas, and wetlands, are ubiquitous microbial habitats and important global carbon reservoirs. With prolonged inundation, redox conditions shift as oxygen is consumed in the soil, and enhanced release of greenhouse gases, such as methane (CH4), can occur from the microbial breakdown of modern and stored carbon. Although our knowledge of the potential taxonomic and functional diversity of microbes capable of CH4 production and consumption in different types of flooded soils is improving due to advances in ‘omics approaches, we lack a mechanistic understanding of the distribution and metabolic diversity of CH4 cycling among microbial groups in flooded wetland soils, and of the dynamic processes that could accelerate or reduce CH4 flux. Our work will apply a systems biology approach to uncover environmentally sensitive metabolic and regulatory dynamics for CH4 cycling from flooded wetland soils by answering key questions, (a) How does CH4 flux vary temporally and spatially in flooded wetland soils? (b) How do genomic potentials and expression levels of key and novel microbial players change during soil flooding by changing water types? (c) What are the predicted multiscale (i.e., local to basin-level) hydrodynamic and biogeochemical changes in net carbon flux that correspond to soil properties, vegetation types, and microbiomes? The results will inform multiscale hydrodynamic and biogeochemical models to predict net changes in CH4 emissions in response to different sea-level rise scenarios. Our proposed research will take advantage of the unique, long-term wetland monitoring program at the Louisiana Universities Marine Consortium (LUMCON) facility in Cocodrie, Louisiana. We will assess CH4 flux in the context of physicochemical and ecological conditions from naturally flooded soils and will use experimental mesocosms and “organs” at LUMCON to simulate press and pulse hydrologic stressors to quantify system CH4-mediated response to inundation that matches different sea-level rise scenarios. From natural and experiment soil samples, we will identify genes that contain information about proteins essential for functions within the CH4 cycle. We will also design novel data-loggers to provide unprecedented CH4 flux resolution from flooded soils. Our data will span multiple scales, and the environmental parameters, including soil and vegetation properties, inundation and salinity conditions, combined with soil microbiome data, will advance capabilities of existing coupled hydrodynamic and biogeochemical models, such as FVCOM-WASP, to forecast CH4 dynamics during sea-level rise.