Effects of soil rewetting and thawing on soil gas fluxes: a review of current literature and suggestions for future research

Abstract

<jats:p>Abstract. The rewetting of dry soils and the thawing of frozen soils are short-term, transitional phenomena in terms of hydrology and the thermodynamics of soil systems. The impact of these short-term phenomena on larger scale ecosystem fluxes is increasingly recognized, and a growing number of studies show that these events affect fluxes of soil gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ammonia (NH3) and nitric oxide (NO). Global climate models predict that future climatic change is likely to alter the frequency and intensity of drying-rewetting events and thawing of frozen soils. These future scenarios highlight the importance of understanding how rewetting and thawing will influence dynamics of these soil gases. This study summarizes findings using a new database containing 338 studies conducted from 1956 to 2011, and highlights open research questions. The database revealed conflicting results following rewetting and thawing in various terrestrial ecosystems and among soil gases, ranging from large increases in fluxes to non-significant changes. Studies reporting lower gas fluxes before rewetting tended to find higher post-rewetting fluxes for CO2, N2O and NO; in addition, increases in N2O flux following thawing were greater in warmer climate regions. We discuss possible mechanisms and controls that regulate flux responses, and recommend that a high temporal resolution of flux measurements is critical to capture rapid changes in gas fluxes after these soil perturbations. Finally, we propose that future studies should investigate the interactions between biological (i.e., microbial community and gas production) and physical (i.e., porosity, diffusivity, dissolution) changes in soil gas fluxes, apply techniques to capture rapid changes (i.e., automated measurements), and explore synergistic experimental and modelling approaches.</jats:p>

Effects of soil warming, rainfall reduction and water table level on CH 4 emissions from the Zoige peatland in China

“…These changes decreased CH 4 emissions and increased CO 2 emissions (Gao et al, 2011;Wang et al, 2010). As climate warming continues, the thawing permafrost and subsurface carbon emissions from peatlands will also alter the carbon balance of CH 4 and CO 2 emissions in this region (Dorrepaal et al, 2009;Kim et al, 2012;Knoblauch et al, 2013). In our study, the plots exposed to the combination of soil warming and reduced precipitation showed lower CH 4 emissions.…”

“…Second, the combination of warming and decreased precipitation can make peatlands drier, accelerating their decomposition and CH 4 oxidation (Dorrepaal et al, 2009;Fenner and Freeman, 2011;Fenner et al, 2001). Third, any climate change that affects substrates, especially dissolved organic carbon export, may influence CH 4 emissions (Chen et al, 2011;Fenner et al, 2007;Kane et al, 2013;Kim et al, 2012;Strack et al, 2008;Worrall and Burt, 2007).…”

Top-down constraints on global N&lt;sub&gt;2&lt;/sub&gt;O emissions at optimal resolution: application of a new dimension reduction technique

“…Because microbial nitrification and denitrification, and the subsequent soil-atmosphere N 2 O flux, depend strongly on factors such as soil moisture, temperature, physical characteristics, and N availability (e.g., Potter et al, 1996;Bouwman, 1998;Kim et al, 2012;Bouwman et al, 2013;Butterbach-Bahl et al, 2013;Griffis et al, 2017), N 2 O emissions can exhibit major temporal and spatial variability. For example, Wagner-Riddle et al (2017) found that shortduration freeze-thaw cycles can account for 35-65 % of the annual direct N 2 O emissions from seasonally frozen croplands and that neglecting this contribution would lead to a 17-28 % underestimate of the global N 2 O source (direct + indirect) from agricultural soils.…”

Orman Örtüsü Altindaki̇ Topraklarin Karbondi̇oksi̇t Emi̇syonunun Ölçülmesi̇

“…Bu kaynaklar yıl boyunca değişmektedir ve (Atarashi-Andoh et al, 2012) bu değişim genel olarak toprak nemiyle sıcaklığına bağlıdır (Xu and Luo., 2012). Toprak nemi ve sıcaklığı mikrobiyal aktiviteyi etkilemektedir (Kim et al, 2012). Ayrıca toprak solunumu vejetasyon tipine, toprak yönetim pratiklerine, çevre koşullarına ve arazi kullanım tiplerine bağlı olarak değişmektedir (Giardina et al, 2014;Angert et al, 2015).…”