Wetland microtopography alters response of potential net CO2 and CH4 production to temperature and moisture: Evidence from a laboratory experiment

0545753 - ÚVGZ 2022 RIV NL eng J - Journal Article
Minick, K. J. - Mitra, B. - Li, X. - Fischer, Milan - Aguilos, M. - Prajapati, P. - Noormets, A. - King, J. S.
Wetland microtopography alters response of potential net CO2 and CH4 production to temperature and moisture: Evidence from a laboratory experiment.
Geoderma. Roč. 402, NOV (2021), č. článku 115367. ISSN 0016-7061. E-ISSN 1872-6259
Research Infrastructure: CzeCOS III - 90123
Institutional support: RVO:86652079
Keywords : greenhouse-gas emissions * solid-state fermentation * phenol oxidase activity * sea-level rise * organic-matter * carbon-dioxide * manganese peroxidase * methane production * soil respiration * peat soils * Methanogenesis * Anaerobic respiration * Peat * Stable carbon isotopes * Extracellular enzyme activity * forested wetland
OECD category: Microbiology
Impact factor: 7.422, year: 2021
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S001670612100447X?via%3Dihub

Coastal wetlands store significant amounts of carbon (C) belowground, which may be altered through effects of rising temperature and changing hydrology on CO2 and CH4 fluxes and related microbial activities. Wetland microtopography (hummock-hollow) also plays a critical role in mediating plant growth, microbial activity, and thus cycling of C and nutrients and may interact with rising seas to influence coastal wetland C dynamics. Recent evidence suggests that CH4 production in oxygenated surface soils of freshwater wetlands may contribute substantially to global CH4 production, but comprehensive studies linking potential CH4 production to environmental and microbial variables in temperate freshwater forested wetlands are lacking. This study investigated effects of temperature, moisture, and microtopography on potential net CO2 and CH4 production and extracellular enzyme activity (beta-glucosidase, xylosidase, phenol oxidase, and peroxidase) in peat soils collected from a freshwater forested wetland in coastal North Carolina, USA. Soils were retrieved from three microsites (hummock, hollow, and subsurface peat soils (approximately 20-40 cm below surface)) and incubated at two temperatures (27 degrees C and 32 degrees C) and soil water contents (65% and 100% water holding capacity (WHC)). Hummocks had the highest cumulative potential net CO2 (13.7 +/- 0.90 mg CO2-C g soil(-1)) and CH4 (1.8 +/- 0.42 mg CH4-C g soil(-1)) production and enzyme activity, followed by hollows (8.7 +/- 0.91 mg CO2-C g soil(-1) and 0.5 +/- 0.12 mg CH4-C g soil(-1)) and then subsurface soils (5.7 +/- 0.70 mg CO2-C g soil(-1) and 0.04 +/- 0.019 mg CH4-C g soil(-1)). Fully saturated soils had lower potential net CO2 production (50-80%) and substantially higher potential net CH4 production compared to non-saturated soils (those incubated at 65% WHC). Soils incubated at 32 degrees C increased potential net CO2 (24-34%) and CH4 (56-404%) production under both soil moisture levels compared to those incubated at 27 degrees C. The Q(10) values for potential net CO2 and CH4 production ranged from 1.5 to 2.3 and 3.3-8.8, respectively, and did not differ between any microsites or soil water content. Enrichment of delta(CO2)-C-13-C was found in saturated soils from all microsites (-24.4 to 29.7 parts per thousand) compared to non-saturated soils (-31.1 to 32.4 parts per thousand), while delta(CH4)-C-13-C ranged from62 to55 parts per thousand in saturated soils. Together, the CO2 and CH4 delta C-13 data suggest that acetoclastic methanogenesis is an important pathway for CH4 production in these wetlands. A positive relationship (Adj. R-2 = 0.40) between peroxidase activity and CH(4 )production was also found, indicating that peroxidase activity may be important in providing fermented C substrates to acetoclastic methanogenic communities and contribute to anaerobic C mineralization.
Permanent Link: http://hdl.handle.net/11104/0322412