scholarly journals Effect of water table drawdown on northern peatland methane dynamics: Implications for climate change

2004 ◽  
Vol 18 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. Strack ◽  
J. M. Waddington ◽  
E.-S. Tuittila
2012 ◽  
Vol 112 (1-3) ◽  
pp. 677-677
Author(s):  
M. L. Macrae ◽  
K. J. Devito ◽  
M. Strack ◽  
J. M. Waddington

2012 ◽  
Vol 112 (1-3) ◽  
pp. 661-676 ◽  
Author(s):  
M. L. Macrae ◽  
K. J. Devito ◽  
M. Strack ◽  
J. M. Waddington

2014 ◽  
Vol 11 (3) ◽  
pp. 807-820 ◽  
Author(s):  
T. M. Munir ◽  
B. Xu ◽  
M. Perkins ◽  
M. Strack

Abstract. Northern peatland ecosystems represent large carbon (C) stocks that are susceptible to changes such as accelerated mineralization due to water table lowering expected under a climate change scenario. During the growing seasons (1 May to 31 October) of 2011 and 2012 we monitored CO2 fluxes and plant biomass along a microtopographic gradient (hummocks-hollows) in an undisturbed dry continental boreal treed bog (control) and a nearby site that was drained (drained) in 2001. Ten years of drainage in the bog significantly increased coverage of shrubs at hummocks and lichens at hollows. Considering measured hummock coverage and including tree incremental growth, we estimate that the control site was a sink of −92 in 2011 and −70 g C m−2 in 2012, while the drained site was a source of 27 and 23 g C m−2 over the same years. We infer that, drainage-induced changes in vegetation growth led to increased biomass to counteract a portion of soil carbon losses. These results suggest that spatial variability (microtopography) and changes in vegetation community in boreal peatlands will affect how these ecosystems respond to lowered water table potentially induced by climate change.


2021 ◽  
Author(s):  
Lin Li ◽  
Hu Liu ◽  
Yang Yu ◽  
Wenzhi Zhao

<p><strong>Abstract: </strong>Wetlands remaining in the arid inland river landscapes of northwestern China suffer degradation and their resilience and ability to continue functioning under hydrologic and land use changes resulting from climate change may be significantly inhibited. Information on the desert-oasis wetlands, however, is sparse and knowledge of how ecological functioning and resilience may change under climate change and water-resource management is still lacking. Research in oasis wetland areas of the Northwestern China identified linkages between subsurface flow, plant transpiration, and water levels. In this study, we present an ecohydrological analysis of the energy and water balance in the wetland ecosystem. A process-based stochastic soil moisture model developed for groundwater-dependent ecosystems was employed to modelling the interactions between rainfall, water table fluctuations, soil moisture dynamics, and vegetation, and to investigate the ecohydrology of arid inland wetlands system. Field measured groundwater levels, vertical soil moisture profiles, soil water potentials, and root biomass allocation and transpiration of pioneer species in the wetlands were used to calibrate and validate the stochastic model. The parameterized model was then running to simulate the probability distributions of soil moisture and root water uptake, and quantitative descript the vegetation–water table–soil moisture interplay in the hypothesized scenarios of future. Our analysis suggested the increasing rates of water extraction and regulation of hydrologic processes, coupled with destruction of natural vegetation, and climate change, are jeopardizing the future persistence of wetlands and the ecological and socio-economic functions they support. To understand how climate change will impact on the ecohydrological functioning of wetlands, both hydrological and land use changes need to be considered in future works.</p><p><strong>Keywords: </strong>Wetland ecosystem, groundwater, soil moisture dynamics, water balances, Heihe River Basin</p>


2020 ◽  
Vol 263 ◽  
pp. 121293
Author(s):  
Jie Zhu ◽  
Xuan Wang ◽  
Qingwen Zhang ◽  
Yunlong Zhang ◽  
Dan Liu ◽  
...  
Keyword(s):  

2013 ◽  
Vol 18 (9) ◽  
pp. 1070-1076 ◽  
Author(s):  
Yonghua Zhu ◽  
Liliang Ren ◽  
Haishen Lü ◽  
Sam Drake ◽  
Zhongbo Yu ◽  
...  

1969 ◽  
Vol 60 (2) ◽  
pp. 228-237
Author(s):  
Raúl Pérez Escolar ◽  
William F. Allison

The effect of water table depth on yield of sugarcane varieties PR 980, PR 1028, PR 1059, PR 1141, PR 64-610, PR 61-632 and PR 64-2705 was studied in lysimeter tanks in the field. Using plastic drains at varying distances and depths, variety PR 980 was studied on a 5-ha farm. Results obtained show that varieties differ in their response to water table conditions. Varieties PR 980, PR 1059, PR 64-610, PR 61-632 and PR 64-2705 yielded significantly more cane and sugar when the water table was lowered. Varieties PR 1028 and PR 1141 did not show statistically significant differences among treatment differentials. Under actual field conditions, using perforated plastic drains, variety PR 980 yielded significantly more sugar than in undrained plots. The results obtained in the lysimeter tanks are in accord with those observed under commercial production.


2020 ◽  
Author(s):  
Maria Prieto Espinoza ◽  
Sylvain Weill ◽  
Raphaël Di chiara ◽  
Benjamin Belfort ◽  
François Lehmann ◽  
...  

<p>Reactive transport in porous media involves a complex interplay of multiple processes relative to flow of water and gases, transport of elements, chemical reactions and microbial activities. In surface-groundwater interfaces, the role of the capillary fringe is of particular interest as water table variations can strongly impact the transfer of gases (e.g. oxygen), the evolution of redox conditions and the evolution/adaptation of bacterial/microbial populations that control biodegradation pathways of contaminants. Although the understanding of individual processes is advanced, their interactions are not yet fully understood challenging the development of efficient reactive transport models (RTM) for predictive applications. In this context, the combination of microbial approaches with isotope measurements and modelling may be useful to understand reactive transport of halogenated pollutants in hydrogeological dynamic systems, to improve processes representation in RTMs, and to reduce model equifinality. Dichloromethane (DCM) is a toxic and volatile halogenated compound frequently detected in multi-contaminated aquifers. Although mechanisms of DCM microbial degradation under both aerobic and anaerobic conditions have been described, little is known about the relationships between the hydrogeochemical variations caused by water table fluctuations, as well as their effects on the diversity and distribution of bacterial communities and degradation pathways.<br>            In this study, two laboratory aquifers fed by contaminated groundwater from the industrial site Thermeroil (France) were designed to collect water samples at high-resolution to investigate the reactive transport of DCM in porous media under steady and dynamic hydrogeological conditions. The effect of water table variations on hydrochemical, microbial and isotopic composition (δ<sup>13</sup>C and δ<sup>37</sup>Cl) was examined to derive DCM mass removal and potential changes in degradation pathways. For the latter, Compound-Stable Isotope Analysis (CSIA) has been used as a tool to evaluate natural degradation of halogenated hydrocarbons. A RTM model (CubicM) is currently being developed to include dual-element CSIA and biological processes - such as growth, decay, attachment, detachment or dormancy – and relate changes in redox conditions with the evolution of DCM degrading populations. A two-phase flow model (i.e. water and gas) has been developed to account for the volatilization and the associated transport processes of halogenated volatile compounds in porous media. Currently, the model is tested on the experimental results to assist in the interpretation of DCM dissipation and the observed biogeochemical and microbial processes to determine the best-suited formalism to address the effect of water table fluctuations on DCM reactive transport in porous media. Such model will enable to assess natural attenuation of DCM at contaminated sites accounting for dynamic hydrogeological conditions.</p>


2008 ◽  
Vol 318 (1-2) ◽  
pp. 229-242 ◽  
Author(s):  
Kerry J. Dinsmore ◽  
Ute M. Skiba ◽  
Michael F. Billett ◽  
Robert M. Rees

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