Change in winter climate will affect dissolved organic carbon and water fluxes in mid-to-high latitude catchments

2013 ◽  
Vol 27 (5) ◽  
pp. 700-709 ◽  
Author(s):  
Hjalmar Laudon ◽  
Doerthe Tetzlaff ◽  
Chris Soulsby ◽  
Sean Carey ◽  
Jan Seibert ◽  
...  
2020 ◽  
Vol 17 (3) ◽  
pp. 581-595
Author(s):  
Keri L. Bowering ◽  
Kate A. Edwards ◽  
Karen Prestegaard ◽  
Xinbiao Zhu ◽  
Susan E. Ziegler

Abstract. Boreal forests are subject to a wide range of temporally and spatially variable environmental conditions driven by season, climate, and disturbances such as forest harvesting and climate change. We captured dissolved organic carbon (DOC) from surface organic (O) horizons in a boreal forest hillslope using passive pan lysimeters in order to identify controls and hot moments of DOC mobilization from this key C source. We specifically addressed (1) how DOC fluxes from O horizons vary on a weekly to seasonal basis in forest and paired harvested plots and (2) how soil temperature, soil moisture, and water input relate to DOC flux trends in these plots over time. The total annual DOC flux from O horizons contain contributions from both vertical and lateral flow and was 30 % greater in the harvested plots than in the forest plots (54 g C m−2 vs. 38 g C m−2, respectively; p=0.008). This was despite smaller aboveground C inputs and smaller soil organic carbon stocks in the harvested plots but analogous to larger annual O horizon water fluxes measured in the harvested plots. Water input, measured as rain, throughfall, and/or snowmelt depending on season and plot type, was positively correlated to variations in O horizon water fluxes and DOC fluxes within the study year. Soil temperature was positively correlated to temporal variations of DOC concentration ([DOC]) of soil water and negatively correlated with water fluxes, but no relationship existed between soil temperature and DOC fluxes at the weekly to monthly scale. The relationship between water input to soil and DOC fluxes was seasonally dependent in both plot types. In summer, a water limitation on DOC flux existed where weekly periods of no flux alternated with periods of large fluxes at high DOC concentrations. This suggests that DOC fluxes were water-limited and that increased water fluxes over this period result in proportional increases in DOC fluxes. In contrast, a flushing of DOC from O horizons (observed as decreasing DOC concentrations) occurred during increasing water input and decreasing soil temperature in autumn, prior to snowpack development. Soils of both plot types remained snow-covered all winter, which protected soils from frost and limited percolation. The largest water input and soil water fluxes occurred during spring snowmelt but did not result in the largest fluxes of DOC, suggesting a production limitation on DOC fluxes over both the wet autumn and snowmelt periods. While future increases in annual precipitation could lead to increased DOC fluxes, the magnitude of this response will be dependent on the type and intra-annual distribution of this increased precipitation.


2006 ◽  
Vol 33 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jacques Finlay ◽  
Jason Neff ◽  
Sergei Zimov ◽  
Anna Davydova ◽  
Sergei Davydov

2019 ◽  
Vol 12 (8) ◽  
pp. 3503-3521 ◽  
Author(s):  
Simon P. K. Bowring ◽  
Ronny Lauerwald ◽  
Bertrand Guenet ◽  
Dan Zhu ◽  
Matthieu Guimberteau ◽  
...  

Abstract. Few Earth system models adequately represent the unique permafrost soil biogeochemistry and its respective processes; this significantly contributes to uncertainty in estimating their responses, and that of the planet at large, to warming. Likewise, the riverine component of what is known as the “boundless carbon cycle” is seldom recognised in Earth system modelling. The hydrological mobilisation of organic material from a ∼1330–1580 PgC carbon stock to the river network results in either sedimentary settling or atmospheric “evasion”, processes widely expected to increase with amplified Arctic climate warming. Here, the production, transport, and atmospheric release of dissolved organic carbon (DOC) from high-latitude permafrost soils into inland waters and the ocean are explicitly represented for the first time in the land surface component (ORCHIDEE) of a CMIP6 global climate model (Institut Pierre Simon Laplace – IPSL). The model, ORCHIDEE MICT-LEAK, which represents the merger of previously described ORCHIDEE versions MICT and LEAK, mechanistically represents (a) vegetation and soil physical processes for high-latitude snow, ice, and soil phenomena and (b) the cycling of DOC and CO2, including atmospheric evasion, along the terrestrial–aquatic continuum from soils through the river network to the coast at 0.5 to 2∘ resolution. This paper, the first in a two-part study, presents the rationale for including these processes in a high-latitude-specific land surface model, then describes the model with a focus on novel process implementations, followed by a summary of the model configuration and simulation protocol. The results of these simulation runs, conducted for the Lena River basin, are evaluated against observational data in the second part of this study.


2014 ◽  
Vol 35 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Natalia Tesón ◽  
Víctor H Conzonno ◽  
Marcelo F Arturi ◽  
Jorge L Frangi

2009 ◽  
Vol 37 (3) ◽  
pp. 218-224 ◽  
Author(s):  
Zhongming Zheng ◽  
Shuanglin Dong ◽  
Xiangli Tian ◽  
Fang Wang ◽  
Qinfeng Gao ◽  
...  

2010 ◽  
Vol 7 (3) ◽  
pp. 4857-4886 ◽  
Author(s):  
A. Ågren ◽  
M. Haei ◽  
S. Köhler ◽  
K. Bishop ◽  
H. Laudon

Abstract. We show that long cold winters enhanced the stream water dissolved organic carbon (DOC) concentrations during the following spring flood. Using a 15 year stream record from a boreal catchment, we demonstrate that the interannual variation in DOC concentrations during spring flood was related to the discharge, and winter climate. That discharge is important for DOC concentration agrees with previous studies. By controlling for discharge we could detect that the winter climatic conditions during the preceding winter affected the soil water DOC concentrations, which in turn affected the concentrations in the stream. The results from the stream time-series were also supported by a riparian soil frost experiment, which showed that a long period of soil frost promoted high DOC concentrations in the soil water.


2020 ◽  
Vol 13 (2) ◽  
pp. 507-520 ◽  
Author(s):  
Simon P. K. Bowring ◽  
Ronny Lauerwald ◽  
Bertrand Guenet ◽  
Dan Zhu ◽  
Matthieu Guimberteau ◽  
...  

Abstract. In this second part of a two-part study, we performed a simulation of the carbon and water budget of the Lena catchment with the land surface model ORCHIDEE MICT-LEAK, enabled to simulate dissolved organic carbon (DOC) production in soils and its transport and fate in high-latitude inland waters. The model results are evaluated for their ability to reproduce the fluxes of DOC and carbon dioxide (CO2) along the soil–inland-water continuum and the exchange of CO2 with the atmosphere, including the evasion outgassing of CO2 from inland waters. We present simulation results over the years 1901–2007 and show that the model is able to broadly reproduce observed state variables and their emergent properties across a range of interacting physical and biogeochemical processes. These include (1) net primary production (NPP), respiration and riverine hydrologic amplitude, seasonality, and inter-annual variation; (2) DOC concentrations, bulk annual flow, and their volumetric attribution at the sub-catchment level; (3) high headwater versus downstream CO2 evasion, an emergent phenomenon consistent with observations over a spectrum of high-latitude observational studies. These quantities obey emergent relationships with environmental variables like air temperature and topographic slope that have been described in the literature. This gives us confidence in reporting the following additional findings: of the ∼34 Tg C yr−1 left over as input to soil matter after NPP is diminished by heterotrophic respiration, 7 Tg C yr−1 is leached and transported into the aquatic system. Of this, over half (3.6 Tg C yr−1) is evaded from the inland water surface back into the atmosphere and the remainder (3.4 Tg C yr−1) flushed out into the Arctic Ocean, mirroring empirically derived studies. These riverine DOC exports represent ∼1.5 % of NPP. DOC exported from the floodplains is dominantly sourced from recent more “labile” terrestrial production in contrast to DOC leached from the rest of the watershed with runoff and drainage, which is mostly sourced from recalcitrant soil and litter. All else equal, both historical climate change (a spring–summer warming of 1.8 ∘C over the catchment) and rising atmospheric CO2 (+85.6 ppm) are diagnosed from factorial simulations to contribute similar significant increases in DOC transport via primary production, although this similarity may not hold in the future.


2019 ◽  
Author(s):  
Simon P. K. Bowring ◽  
Ronny Lauerwald ◽  
Bertrand Guenet ◽  
Dan Zhu ◽  
Matthieu Guimberteau ◽  
...  

Abstract. Few Earth System models adequately represent the unique permafrost soil biogeochemistry and its respective processes; this significantly contributes to uncertainty in estimating their responses, and that of the planet at large, to warming. Likewise, the riverine component of what is known as the "boundless carbon cycle" is seldom recognized in Earth System modeling. Hydrological mobilization of organic material from a ~ 1330–1580 PgC carbon stock to the river network results either in sedimentary settling or atmospheric "evasion", processes widely expected to increase with amplified Arctic climate warming. Here, the production, transport and atmospheric release of dissolved organic carbon (DOC) from high-latitude permafrost soils into inland waters and the ocean is explicitly represented for the first time in the land surface component (ORCHIDEE) of a CMIP6 global climate model (IPSL). The model, ORCHIDEE MICT-LEAK, mechanistically represents (a) vegetation and soil physical processes for high latitude snow, ice and soil phenomena, and (b) the cycling of DOC and CO2, including atmospheric evasion, along the terrestrial-aquatic continuum from soils through the river network to the coast, at 0.5° to 2° resolution. This paper, the first in a two-part study, presents the rationale for including these processes in a high latitude specific land surface model, then describes the model with a focus on novel process implementations, followed by a summary of the model configuration and simulation protocol. The results of these simulation runs, conducted for the Lena River basin, are evaluated against observational data in the second part of this study.


2019 ◽  
Author(s):  
Keri Bowering ◽  
Kate A. Edwards ◽  
Xinbiao Zhu ◽  
Susan E. Ziegler

Abstract. Boreal forests are subject to a wide range of temporally and spatially variable environmental conditions driven by seasonal and regional climate variations, in addition to disturbances such as forest harvesting and climate change. Among the various ecological mechanisms affected by disturbance, is the transport rate of dissolved organic carbon (DOC) from surface soil organic (O) horizons to deeper mineral SOC pools and the adjacent aquatic systems. Here, we examine the transport of DOC from surface O horizons across a boreal forest landscape using passive pan lysimeters in order to identify controls and hot moments of DOC mobilization from this key C source. To do so, we specifically addressed (1) how DOC fluxes from O horizons vary on a weekly to seasonal basis in both forest and harvested plots, and (2) how soil temperature, soil moisture and water inputs relate to DOC fluxes in these plots over time. The total annual DOC flux from O horizons was greater in the warmer harvested plots than in the forest plots (54 g C m−2 vs 38 g C m−2 respectively; p = 0.008), despite smaller aboveground C inputs and smaller SOC stocks in the harvested plots. Water input, measured as rain, throughfall and/or snowmelt depending on season, was positively correlated to temporal variations in soil water and DOC fluxes. Soil temperature was positively correlated to temporal variations of DOC concentration ([DOC]) of soil water and negatively correlated with water fluxes, but no relationship existed between soil temperature and DOC fluxes. Soil moisture was negatively correlated to temporal variations in [DOC] in the harvested plots only. The relationship between water input to soil and DOC fluxes was seasonally dependent in both plot types. In summer, a water limitation on DOC flux existed where weekly periods of no flux alternated with periods of large fluxes, suggesting that increased water fluxes over this period would result in proportional increases in DOC fluxes. In contrast, a flushing of O horizons occurred during increasing water inputs and decreasing soil temperatures in autumn, prior to snowpack development. Soils of both plot types remained snow-covered all winter, which protected soils from frost and limited winter soil water fluxes. The largest water input and soil water fluxes occurred during spring snowmelt, but did not result in the largest fluxes of DOC, suggesting a production limitation on DOC fluxes over both the wet autumn and snowmelt periods. While future increases in annual precipitation could lead to increased DOC fluxes, the response may be dependent on the intra-annual distribution of this increase. Increased water input during the already wet autumn, for instance, may not lead to increased fluxes if the DOC pool is not replenished. Potential reductions in snow cover, however, leading to a reduction in soil insulation and increased occurrence of soil frost in addition to increases in winter-time water fluxes, could be an important mechanism of increased DOC production and fluxes from O horizons in winter.


2010 ◽  
Vol 7 (9) ◽  
pp. 2901-2913 ◽  
Author(s):  
A. Ågren ◽  
M. Haei ◽  
S. J. Köhler ◽  
K. Bishop ◽  
H. Laudon

Abstract. Using a 15 year stream record from a northern boreal catchment, we demonstrate that the inter-annual variation in dissolved organic carbon (DOC) concentrations during snowmelt was related to discharge, winter climate and previous DOC export. A short and intense snowmelt gave higher stream water DOC concentrations, as did long winters, while a high previous DOC export during the antecedent summer and autumn resulted in lower concentrations during the following spring. By removing the effect of discharge we could detect that the length of winter affected the modeled soil water DOC concentrations during the following snowmelt period, which in turn affected the concentrations in the stream. Winter climate explained more of the stream water DOC variations than previous DOC export during the antecedent summer and autumn.


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