Influence of soil frost on the character and degradability of dissolved organic carbon in boreal forest soils

Selvam, Balathandayuthabani Panneer; Laudon, Hjalmar; Guillemette, François; Berggren, Martin

doi:10.1002/2015jg003228

Cited by 24 publications

(6 citation statements)

References 69 publications

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“…The regression of R SOC against temperature is not statistically significant ( p = .101). Global warming may reduce the extent and duration of frost (Liu et al, 2018; Panneer Selvam, Laudon, Guillemette, & Berggren, 2016). Forests would then have a longer growth period, which could facilitate the accumulation of above‐ground biomass and may decrease the R SOC (Figures 3 and 4).…”

Section: Discussionmentioning

confidence: 99%

Determinants of soil organic carbon sequestration and its contribution to ecosystem carbon sinks of planted forests

Wang

Huang

2020

Global Change Biology

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The area of forest established through afforestation/reforestation has been increasing on a global scale, which is particularly important as these planted forests attenuate climate change by sequestering carbon. However, the determinants of soil organic carbon (SOC) sequestration and their contribution to the ecosystem carbon sink of planted forests remain uncertain. By using globally distributed data extracted from 154 peer‐reviewed publications and a total of 355 sampling points, we investigated above‐ground biomass carbon (ABC) sequestration and SOC sequestration across three different climatic zones (tropical, warm temperate, and cold temperate) through correlation analysis, regression models, and structural equation modeling (SEM). We found that the proportion of SOC sequestration in the ecosystem C sequestration averaged 14.1% globally, being the highest (27.0%) in the warm temperate and the lowest (10.7%) in the tropical climatic zones. The proportion was mainly affected by latitude. The sink rate of ABC (RABC) in tropical climates (2.48 Mg C ha−1 year−1) and the sink rate of SOC (RSOC) in warm temperate climates (0.96 Mg C ha−1 year−1) were higher than other climatic zones. The main determinants of RSOC were the number of frost‐free days, latitude, mean annual precipitation (MAP), and SOC density (SOCD) at the initial observation; however, these variables depended on the climatic zone. According to the SEM, frost‐free period, mean annual temperature (MAT) and MAP are the dominant driving factors affecting RSOC in Chinese plantations. MAT has a positive effect on RSOC, and global warming may increase RSOC of temperate plantations in China. Our findings highlight the determinants of SOC sequestration and quantitatively reveal the substantial global contribution of SOC sequestration to ecosystem carbon sink provided by planted forests. Our results help managers identify and control key factors to increase carbon sequestration in forest ecosystems.

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Section: Discussionmentioning

confidence: 99%

Determinants of soil organic carbon sequestration and its contribution to ecosystem carbon sinks of planted forests

Wang

Huang

2020

Global Change Biology

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“…While the mechanisms underlying net production of NH 4 + in this study cannot be resolved with our current data, we did observe significantly lower C:N ratios at this depth (Figure S1 in the supporting information), consistent with a localized change in biogeochemical processing. Moreover, a recent study of DOC processing with soil depth at this same site also reported peaks in bacterial production, carbon consumption, and growth efficiency at 25 cm [ Panneer Selvam et al ., ]. These results suggest the potential for comparatively high rates of nutrient turnover in soils where, at least for some portion of the year, biological nutrient demand (including root uptake) is likely constrained by low redox conditions, thus leading to a hot spot of net NH 4 + production.…”

Section: Discussionmentioning

confidence: 99%

“…Ultimately, multiple factors within this zone may interact to foster sustained net NH 4 + production in these soil layers. For example, soil frost, which has been reported as extending down to 29 cm at this site [ Panneer Selvam et al ., ], may stimulate DOC production [ Haei et al ., ] and soil N turnover [ Brooks et al ., ] for strata that are subsequently inundated/anoxic throughout the spring, leading to NH 4 + production in excess of demand. In addition, fluctuations in redox state alone may drive elevated rates of SOM degradation [ Hall et al ., ] and lead to a greater net release of NH 4 + [ Aller , ] when compared to environments that are permanently oxic or anoxic.…”

Section: Discussionmentioning

confidence: 99%

Evaluating hillslope and riparian contributions to dissolved nitrogen (N) export from a boreal forest catchment

et al. 2017

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Catchment science has long held that the chemistry of small streams reflects the landscapes they drain. However, understanding the contribution of different landscape units to stream chemistry remains a challenge which frequently limits our understanding of export dynamics. For limiting nutrients such as nitrogen (N), an implicit assumption is that the most spatially extensive landscape units (e.g., uplands) act as the primary sources to surface waters, while near‐stream zones function more often as sinks. These assumptions, based largely on studies in high‐gradient systems or in regions with elevated inputs of anthropogenic N, may not apply to low‐gradient, nutrient‐poor, and peat‐rich catchments characteristic of many northern ecosystems. We quantified patterns of N mobilization along a hillslope transect in a northern boreal catchment to assess the extent to which organic matter‐rich riparian soils regulate the flux of N to streams. Contrary to the prevailing view of riparian functioning, we found that near‐stream, organic soils supported concentrations and fluxes of ammonium (NH4+) and dissolved organic nitrogen that were much higher than the contributing upslope forest soils. These results suggest that stream N chemistry is connected to N mobilization and mineralization within the riparian zone rather than the wider landscape. Results further suggest that water table fluctuation in near‐surface riparian soils may promote elevated rates of net N mineralization in these landscapes.

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“…Seasonal freezing and thawing affect over half of the Northern Hemisphere. Landscape freeze-thaw (FT) state transitions show highly variable spatial and temporal patterns, with measurable influences to climate (IPCC, 2014;Peng et al, 2016;Poutou et al, 2004), hydrological (Gouttevin et al, 2012Gray et al, 1984), ecological (Kumar et al, 2013;Black et al, 2000) and biogeochemical processes (Panneer Selvam et al, 2016;Xu et al, 2013;Schaefer et al, 2011). The surface FT state affects the latent heat exchange and the energy balance at the interface between the soil surface and the overlying medium.…”

Section: Introductionmentioning

confidence: 99%

Northern Hemisphere surface freeze–thaw product from Aquarius L-band radiometers

Prince

Roy

Brucker

et al. 2018

Earth Syst. Sci. Data

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Abstract. In the Northern Hemisphere, seasonal changes in surface freeze–thaw (FT) cycles are an important component of surface energy, hydrological and eco-biogeochemical processes that must be accurately monitored. This paper presents the weekly polar-gridded Aquarius passive L-band surface freeze–thaw product (FT-AP) distributed on the Equal-Area Scalable Earth Grid version 2.0, above the parallel 50° N, with a spatial resolution of 36 km × 36 km. The FT-AP classification algorithm is based on a seasonal threshold approach using the normalized polarization ratio, references for frozen and thawed conditions and optimized thresholds. To evaluate the uncertainties of the product, we compared it with another satellite FT product also derived from passive microwave observations but at higher frequency: the resampled 37 GHz FT Earth Science Data Record (FT-ESDR). The assessment was carried out during the overlapping period between 2011 and 2014. Results show that 77.1 % of their common grid cells have an agreement better than 80 %. Their differences vary with land cover type (tundra, forest and open land) and freezing and thawing periods. The best agreement is obtained during the thawing transition and over forest areas, with differences between product mean freeze or thaw onsets of under 0.4 weeks. Over tundra, FT-AP tends to detect freeze onset 2–5 weeks earlier than FT-ESDR, likely due to FT sensitivity to the different frequencies used. Analysis with mean surface air temperature time series from six in situ meteorological stations shows that the main discrepancies between FT-AP and FT-ESDR are related to false frozen retrievals in summer for some regions with FT-AP. The Aquarius product is distributed by the U.S. National Snow and Ice Data Center (NSIDC) at https://nsidc.org/data/aq3_ft/versions/5 with the DOI https://doi.org/10.5067/OV4R18NL3BQR.

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Influence of soil frost on the character and degradability of dissolved organic carbon in boreal forest soils

Cited by 24 publications

References 69 publications

Determinants of soil organic carbon sequestration and its contribution to ecosystem carbon sinks of planted forests

Determinants of soil organic carbon sequestration and its contribution to ecosystem carbon sinks of planted forests

Evaluating hillslope and riparian contributions to dissolved nitrogen (N) export from a boreal forest catchment

Northern Hemisphere surface freeze–thaw product from Aquarius L-band radiometers

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