Coupled abiotic-biotic cycling of nitrous oxide in tropical peatlands

Abstract

Atmospheric nitrous oxide (N2O) is a potent greenhouse gas thought to be mainly derived from microbial metabolism as part of the denitrification pathway. Here, we report that in unexplored peat soils of Central and South America, N2O production can be driven by abiotic reactions (≤ 98 %) highly competitive to their enzymatic counterparts. Extracted soil iron positively correlated with in-situ abiotic N2O production determined by isotopic tracers.Moreover, we found that microbial N2O reduction accompanied abiotic production, essentially closing a coupled abiotic-biotic N2O cycle. Anaerobic N2O consumption occurred ubiquitously (pH 6.4-3.7), with proportions of diverse clade II N2O-reducers increasing with consumption rates. Our findings show denitrification in tropical peat soils is not a purely biological process, but rather a "mosaic" of abiotic and biotic reduction reactions. We predict hydrological and temperature fluctuations differentially affect abiotic and biotic drivers and further contribute to the high N2O flux variation in the region.

Bacterial denitrification drives elevated N 2 O emissions in arid southern California drylands

“…5). Chemodenitrification could have reduced native soil NO 2 − ( 15 , 16 , 45 ), elevating SP values to those observed in the laboratory incubation (Fig. 5).…”

Temperature‐mediated microbial carbon utilization in China's lakes

“…This shift likely destabilized interactions among microbial taxa, resulting in a large amount of carbon being actively used rather than inhibited by microorganisms under higher temperatures (Tiedje et al, 2022). Hydrogenophaga has been found previously to release few extracellular carbon substrates (Buessecker et al, 2022;Liu et al, 2022;Taubert et al, 2022). Rhodobacteraceae has similarly been found to be associated with the production rather than utilization of the amino acid leucine in the ocean (Arandia-Gorostidi et al, 2020).…”

Revisiting the relationships between soil nitrous oxide emissions and microbial functional gene abundances

“…The complexity of N 2 O production stresses the importance in further partitioning N 2 O‐producing pathways. In addition to the N 2 O‐ 15 N site preference analysis that Wei et al (2023) used, a novel method was developed to distinguish between biotic and abiotic N 2 O emissions, that is in‐situ 15 N‐tracing experiment with zinc chloride‐poisoned/gamma‐irradiated protocol (Buessecker et al, 2022). Moreover, N 2 O produced by ammonia‐oxidizing archaea and bacteria can be distinguished by using 1‐octyne inhibitor, but this technique is only conducted in laboratory experiments (Prosser et al, 2020).…”

“…Funding information H2020 Marie Skłodowska-Curie Actions, Grant/Award Number: 839806; National Natural Science Foundation of China, Grant/Award Number: 32130069 Nitrous oxide (N 2 O) is a long-lived greenhouse gas and stratospheric ozone-depleting substance with significant influence on the planetary nitrogen boundary (Buessecker et al, 2022). It has been generally thought that N 2 O emissions are regulated by microbial functional genes encoding the enzymes of N 2 O production and consumption (Richardson et al, 2009;Spiro, 2012).…”