Reconciliation of top-down and bottom-up CO 2 fluxes in Siberian larch forest

Greenhouse gas evasion from inland waters is a globally significant yet highly uncertain flux, especially in regard to effects of wetlands and hydrologic variability. We sampled five first‐order and two second‐order streams with variable wetland influence during storm events for dissolved CO2, CH4, and N2O. We also calculated gas evasion rates. In first‐order streams, pCO2 and pN2O were significantly higher in the stream with the most wetland influence (mean ± 1 std: 3,965 ± 1,504 and 1.18 ± 0.37 μatm, respectively) than the forested stream (2,927 ± 439 and 0.47 ± 0.08 μatm, respectively). In second‐order streams, pCO2, pCH4, and pN2O were higher in the 14% wetland stream (3,274 ± 825, 501 ± 207, and 1.37 ± 0.43 μatm, respectively) than in the 2% wetland stream (1,858 ± 423, 137 ± 53, and 0.37 ± 0.08 μatm, respectively). In first‐order streams, pCO2 in streams with wetland influence increased during rain events, while pCO2 in streams with little to no wetland influence decreased or remained constant. Generally, pCH4 and pN2O followed the same trend, except in one stream with intermediate wetland influence. Gas transfer velocity increased in all streams during storm events. However, the forested streams had higher gas transfer velocities than the wetland streams due to steeper topography. CO2, CH4, and N2O evasion peaked in one of the intermediate wetland streams at high flow (maximum: 66 g C·m−2·day−1, 177 mg C·m−2·day−1, and 9.7 mg N·m−2·day−1, respectively). These findings suggest that gases are shunted downstream in flatter, wetland streams, while gases are evaded closer to their source in steeper, forested streams.

Section: Resultsmentioning

confidence: 99%

Differential Response of Greenhouse Gas Evasion to Storms in Forested and Wetland Streams

Aho

Raymond

2019

“…Likewise, in the larch forests near Yakutsk in eastern Siberia, numerous larch trees ( L . cajanderi ) growing in topographic depressions perished in 2007 after an extremely wet summer followed by heavy snow in the winter (Iwasaki et al., 2010; Nogovitcyn et al., 2022), and CO 2 uptake by larch forests decreased after 2008 due to abnormal waterlogging (Takata et al., 2017). Li and Sugimoto (2018) also found reduced photosynthesis in larch seedlings ( L .…”

Section: Discussionmentioning

confidence: 99%

Arctic Plant Responses to Summer Climates and Flooding Events: A Study of Carbon and Nitrogen‐Related Larch Growth and Ecosystem Parameters in Northeastern Siberia

Liang,

Sugimoto,

Tei

et al. 2023

Self Cite

Built upon a 5‐year field investigation and a 13‐year satellite data set, this study examines the intricate interrelationships among ecophysiological parameters of Larix gmelinii trees and the prevailing ecosystem, climatic, and environmental factors present in the Indigirka lowlands of northeastern Siberia. It identified spatial‐temporal patterns in July needle nitrogen (N) content as an indicator of N availability from 2009 to 2013. Needle N content (%) revealed distinct yearly values: 2012 (1.31 ± 0.24), 2013 (1.67 ± 0.39), 2009 (1.72 ± 0.15), 2011 (1.84 ± 0.34), and 2010 (2.08 ± 0.25). Positive correlations were found between ecosystem and larch parameters, as well as between September temperature or February/May precipitation and subsequent July ecosystem productivity. Soil moisture (SM) primarily influences N availability across sites, with higher SM levels reducing N availability. However, July air temperature (AT) is the primary driver of interannual N availability changes, with higher temperatures enhancing N availability. Larch photosynthesis is mainly influenced by solar radiation (SR), temperature, N availability, and SM. Annual fluctuations in SR positively impact larch photosynthesis, while high temperatures or wetting events impose limitations on photosynthesis, even if N availability has increased. Consequently, a moderate correlation exists between N availability and photosynthesis across various sites and years (r = 0.422, P = 0.133, n = 14). In summary, this research provides valuable insights into climatic and environmental impacts on larch trees and ecosystems, emphasizing the significance of SM, AT, and SR for predicting future growth patterns of larch.

“…An integrated observational and modeling study identified deepening of the ALT caused by the combined effects of higher snow insulation and snowmelt‐induced soil wetting in the study site (Iijima et al., 2010). The wetted soil also contributed to high vegetation productivity and ET in the study site (Ohta et al., 2014; Takada et al., 2017; Kotani et al., 2019). These results underscore the impact of changing P G regimes on ecohydrological processes of boreal forests.…”

Section: Introductionmentioning

confidence: 93%

Quantitative Separation of Precipitation and Permafrost Waters Used for Evapotranspiration in a Boreal Forest: A Numerical Study Using Tracer Model

Park¹,

Tanoue

Sugimoto

et al. 2021

Self Cite

Arctic precipitation (PG) that occurs as rainfall (Prain) or snowfall (Psnow) depending on the prevailing climatic conditions results in seasonally specific hydrological events. Climate change can affect the PG‐ and permafrost‐originated water (Pice) regimes, resulting in change to ecohydrological processes. However, the relative influences of source waters (i.e., Prain, Psnow, and Pice) on terrestrial hydrological processes have not yet been fully established. Here, we report the development and implementation of a numerical water tracer model designed to quantify changes in the storages and fluxes of the source waters and the hydrogen and oxygen isotopic tracers associated with hydrometeorological events. The presented tracer model was used to illustrate the spatiotemporal variability of the tracers in the surface–subsurface system of a deciduous needleleaf boreal forest and to separate the contribution rates of the tracer waters to evapotranspiration (ET). Although Psnow accounted for 22%–57% of ET and the subcomponents, the contribution rates to soil evaporation and transpiration were significant only during spring. The major source water for soil moisture was Prain, which accounted for 69.2% of ET and showed an increasing trend during 1980–2016. Additionally, Prain also accounted for 77.2% of transpiration. Under the present conditions of warming permafrost, Pice demonstrated negligibly low impact on ET. The tracer model was shown capable of quantifying the contribution rates of tracer waters to ET, highlighting the advantages of the tracer model for a similar quantitative separation regarding future climate change.