Linking Dissolved Organic Matter to CO₂ and CH₄ Concentrations in Canadian and Chilean Peatland Pools

Abstract

Peatland open‐water pools can be net carbon (C) emitters within heterogeneous peatland ecosystems that are generally net C sinks. However, the intra‐ and inter‐regional patterns and drivers of CO2 and CH4 production, as well as their link with dissolved organic matter (DOM) quality and quantity, remain poorly understood. We analyzed a range of optical characteristics and chemical variables controlling DOM and CO2 and CH4 concentrations in peatland pools across two regions with contrasting geographical properties (i.e., climate, topography, morphometry, and vegetation cover) of eastern Canada and Chilean Patagonia. We found inter‐regional patterns in CO2, CH4 and DOM concentrations and composition that were coherent with patterns in mean annual temperature and precipitation, and vegetation cover. Cross‐regional patterns of CO2 and CH4 were driven by morphometry, vegetation cover, and protein‐like DOM composition, a proxy of high biological activity, whereas temporal variations of CO2 and CH4 concentrations were further influenced by seasonal changes in humic‐like DOM composition, dissolved organic carbon and nutrients (i.e., total phosphorus and total nitrogen) concentrations, as well as pH and oxygen levels. Our results suggest that geophysical constraints associated with local peat and pool characteristics as well as climate patterns are major drivers of DOM and greenhouse gases concentrations and the links between them in broadly distributed peatland pools.

Activated Carbon Application Simultaneously Alleviates Paddy Soil Arsenic Mobilization and Carbon Emission by Decreasing Porewater Dissolved Organic Matter

“…Dissolved organic matter (DOM) is a representative electron shuttle for microbial Fe­(III) reduction. , Besides, DOM biodegradable components can serve as a microbial carbon source for anaerobic respiration . Multiple studies have reported that the biodegradable DOM links to As mobility in geogenic As-contaminated groundwater, , governing CH 4 emission in rivers and lakes. − However, the function of DOM as an electron shuttle in fueling As release and CH 4 emission has been only proposed but not investigated experimentally. , Therefore, the critical electron shuttling function of DOM in controlling soil Fe­(III) reduction and potentially regulating As fate and GHG emission needs to be systematically explored.…”

Mollisol Erosion-Driven Efflux of Energetic Organic Carbon and Microflora Increases Greenhouse Gas Emissions from Cold-Region Rivers

“…16−18 Resulting greenhouse gas fluxes are closely related to the quality (biodegradability) of aquatic DOM. 19,20 At low DOM concentrations, CO 2 emission rate can be restricted by the availability of organic C and physiological stress to microbial cells. 21,22 At high soil-to-water ratios approaching soil slurries (e.g., during the dry season), DOM biomineralization via microbial respiration can be limited by the supply of oxygen, for instance, to soil aggregates.…”

Peatland pools are tightly coupled to the contemporary carbon cycle

“…Ranging from <1 to 1000 m 2 in size and up to ~1 m in depth, pools can be hotspots of terrestrial C decomposition and CO 2 and CH 4 emissions, and provide a direct and rapid pathway for the release of C to the atmosphere (Downing, 2010; Holgerson & Raymond, 2016; Peacock et al., 2021; Rosentreter et al., 2021; Turner et al., 2016). Peatland pools are sensitive to both climate and land use change and could potentially serve as sentinels for shifts in patterns of peatland C cycling (Arsenault et al., 2023; Hassan et al., 2023).…”

“…Pools, or ponds, are small shallow standing water bodies that are commonly found in peatlands worldwide (Arsenault et al., 2022; Hassan et al., 2023). Ranging from <1 to 1000 m 2 in size and up to ~1 m in depth, pools can be hotspots of terrestrial C decomposition and CO 2 and CH 4 emissions, and provide a direct and rapid pathway for the release of C to the atmosphere (Downing, 2010; Holgerson & Raymond, 2016; Peacock et al., 2021; Rosentreter et al., 2021; Turner et al., 2016).…”