scholarly journals Non-flooded riparian Amazon trees are a regionally significant methane source

2021 ◽  
Vol 380 (2215) ◽  
Author(s):  
Vincent Gauci ◽  
Viviane Figueiredo ◽  
Nicola Gedney ◽  
Sunitha Rao Pangala ◽  
Tainá Stauffer ◽  
...  
Keyword(s):  
Water Table ◽  
Amazon Basin ◽  
Soil Column ◽  
Forested Wetlands ◽  
Strong Relationship ◽  
Spatial Extent ◽  
Tree Roots ◽  
Broad Leaf ◽  
Methane Source ◽  
Tree Stem

Inundation-adapted trees were recently established as the dominant egress pathway for soil-produced methane (CH 4 ) in forested wetlands. This raises the possibility that CH 4 produced deep within the soil column can vent to the atmosphere via tree roots even when the water table (WT) is below the surface. If correct, this would challenge modelling efforts where inundation often defines the spatial extent of ecosystem CH 4 production and emission. Here, we examine CH 4 exchange on tree, soil and aquatic surfaces in forest experiencing a dynamic WT at three floodplain locations spanning the Amazon basin at four hydrologically distinct times from April 2017 to January 2018. Tree stem emissions were orders of magnitude larger than from soil or aquatic surface emissions and exhibited a strong relationship to WT depth below the surface (less than 0). We estimate that Amazon riparian floodplain margins with a WT < 0 contribute 2.2–3.6 Tg CH 4  yr −1 to the atmosphere in addition to inundated tree emissions of approximately 12.7–21.1 Tg CH 4  yr −1 . Applying our approach to all tropical wetland broad-leaf trees yields an estimated non-flooded floodplain tree flux of 6.4 Tg CH 4  yr −1 which, at 17% of the flooded tropical tree flux of approximately 37.1 Tg CH 4  yr −1 , demonstrates the importance of these ecosystems in extending the effective CH 4 emitting area beyond flooded lands. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.

scholarly journals A soil column model for predicting the interaction between water table and evapotranspiration

2017 ◽  
Vol 53 (7) ◽  
pp. 5877-5898 ◽  
Author(s):  
Mathilde Maquin ◽  
Emmanuel Mouche ◽  
Claude Mügler ◽  
Marie-Claire Pierret ◽  
Daniel Viville
Keyword(s):  
Water Table ◽  
Soil Column ◽  
Column Model

scholarly journals Modelling of shallow water table dynamics using conceptual and physically based integrated surface-water–groundwater hydrologic models

2019 ◽  
Vol 23 (5) ◽  
pp. 2245-2260 ◽  
Author(s):  
Mohammad Bizhanimanzar ◽  
Robert Leconte ◽  
Mathieu Nuth
Keyword(s):  
Shallow Water ◽  
Groundwater Recharge ◽  
Water Table ◽  
Soil Column ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Dimensional Case ◽  
Shallow Water Table ◽  
Mike She ◽  
Physically Based

Abstract. We present a new conceptual scheme of the interaction between unsaturated and saturated zones of the MOBIDIC (MOdello Bilancio Idrologico DIstributo e Continuo) hydrological model which is applicable to shallow water table conditions. First, MODFLOW was coupled to MOBIDIC as the physically based alternative to the conceptual groundwater component of the MOBIDIC–MODFLOW. Then, assuming a hydrostatic equilibrium moisture profile in the unsaturated zone, a dynamic specific yield that is dependent on the water table level was added to MOBIDIC–MODFLOW, and calculation of the groundwater recharge in MOBIDIC was revisited using a power-type equation based on the infiltration rate, soil moisture deficit, and a calibration parameter linked to the initial water table depth, soil type, and rainfall intensity. Using the water table fluctuation (WTF) method for a homogeneous soil column, the parameter of the proposed groundwater recharge equation was determined for four soil types, i.e. sand, loamy sand, sandy loam, and loam under a pulse of rain with different intensities. The fidelity of the introduced modifications in MOBIDIC–MODFLOW was assessed by comparison of the simulated water tables against those of MIKE SHE, a physically based integrated hydrological modelling system simulating surface and groundwater flow, in two numerical experiments: a two-dimensional case of a hypothetical watershed in a vertical plane (constant slope) under a 1 cm d−1 uniform rainfall rate and a quasi-real three-dimensional watershed under 1 month of a measured daily rainfall hyetograph. The comparative analysis confirmed that the simplified approach can mimic simple and complex groundwater systems with an acceptable level of accuracy. In addition, the computational efficiency of the proposed approach (MIKE SHE took 180 times longer to solve the three-dimensional case than the MOBIDIC–MODFLOW framework) demonstrates its applicability to real catchment case studies.

scholarly journals An Unsaturated/Saturated Coupled Hydrogeological Model for the Llamara Salt Flat, Chile, to Investigate Prosopis tamarugo Survival

Geosciences ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Alex Samuel ◽  
Nicole Blin ◽  
José F. Muñoz ◽  
Francisco Suárez
Keyword(s):  
Soil Moisture ◽  
Water Table ◽  
Management Tool ◽  
Health State ◽  
Hydrogeological Model ◽  
Tree Roots ◽  
Groundwater Exploitation ◽  
Groundwater Levels ◽  
Applied Model ◽  
Current Water

The Propopis tamarugo Phil, also known as Tamarugo, is an endemic and protected tree that survives in the Atacama Desert—a hyper arid and highly saline environment. The Tamarugo is threatened because of groundwater overexploitation, and its preservation depends on the soil moisture in the vadose zone, as many of the tree roots do not reach the current water table levels. To improve the estimation of soil moisture available for the Tamarugo trees, we applied a hydrogeological model that couples the unsaturated and saturated zones. The model was used to represent different groundwater exploitation and recharge scenarios between February 2006 and September 2030 to predict simultaneously groundwater levels and soil moisture. The model results show that even at locations where water table depletion is relatively small (~1–1.5 m), soil moisture can drastically decrease (0.25–0.30 m3/m3). Therefore, Tamarugo survival can be better addressed, as the applied model provides a management tool to estimate response of Tamarugo trees to changing soil moisture. To further improve the model and its use to assess Tamarugo survival, more field data, such as soil hydrodynamic properties and soil moisture, should be collected. Additionally, relationships between the state of the Tamarugo trees and soil moisture should be further constructed. In this way, the developed model will be able to predict future conditions associated to the Tamarugo’s health state.

scholarly journals Sensitivity Analysis of Multi-Temporal Sentinel-1 SAR Parameters to Crop Height and Canopy Coverage

2019 ◽  
Vol 9 (4) ◽  
pp. 655 ◽  
Author(s):  
Rouhollah Nasirzadehdizaji ◽  
Fusun Balik Sanli ◽  
Saygin Abdikan ◽  
Ziyadin Cakir ◽  
Aliihsan Sekertekin ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Early Stage ◽  
Strong Relationship ◽  
Synthetic Aperture ◽  
Crop Height ◽  
Canopy Coverage ◽  
Broad Leaf ◽  
Multi Temporal ◽  
Low Sensitivity ◽  
Aperture Radar

The Polarimetric Synthetic Aperture Radar technique has provided various opportunities and challenges in agricultural activities mainly on crop management. The aim of this study is to investigate the sensitivity of 10 parameters derived from multi-temporal Sentinel-1 Synthetic Aperture Radar (SAR) data, to crop height and canopy coverage (CC) of maize, sunflower, and wheat. The correlation coefficient values indicate a high correlation for maize during the early growing stage. The coefficient determinations (R2) of 0.82 and 0.81 indicate that there is a strong relationship between the maize height and SAR parameters including VV + VH and VV, respectively. The maize CC is well correlated with VV parameter (R2 = 0.73), but it is observed that at the later growing stage the correlation became weaker. This means that the sensitivity decreases with increasing vegetation cover growth. Compared to maize, the sensitivity of SAR parameters to wheat variables is often good at the early stage. However, the highest correlation with wheat height represented by Alpha (α) decomposition parameter (R2 = 0.67). The sunflower height has an insignificant correlation with the majority of SAR parameters and only VH polarization shows low sensitivity (R2 = 0.31). The sunflower CC shows relatively higher correlation with VV polarization (R2 = 0.46) at the early stage while no considerable correlation is observed at the later stage. It is found that Sentinel-1 has a high potential for estimation of crop height and CC of the maize as a broad-leaf crop. The same is not true for sunflower as another broad-leaf crop.

Research of Effect of Groundwater Table Fluctuation on Migration Law of Cadmium

2012 ◽  
Vol 599 ◽  
pp. 455-461
Author(s):  
Xiang Li ◽  
Shun Guo Bai ◽  
Bei Dou Xi ◽  
Zhi Ye Yuan ◽  
Yue Ying Wang
Keyword(s):  
Water Table ◽  
Soil Column ◽  
Column Experiment ◽  
Dominant Factor ◽  
Cadmium Nitrate ◽  
Temporal And Spatial Distribution ◽  
Water Table Fluctuation ◽  
Cadmium Ions ◽  
Soil Column Experiment ◽  
Migration Law

In this paper, we conduct the soil-column experiment on underground soil in a laboratory of Changping, Beijing, to simulate the effect of water table fluctuation on the cadmium migration law after twice pollution. The main job of the experience is to test the adsorption and desorption characteristics of the soil as well as the temporal and spatial distribution of cadmium ions in soil column. The experimental data show that (1) the two kinds of soil used in the test both have a strong adsorption capacity to cadmium ions, and the values could reach to 1026mg/kg and 2804mg/kg. (2) The dominant factor on cadmium ions migration under water table fluctuation is the soil adsorption when a small amount of cadmium ions are poured into soil column. On the other hand, convection plays a significant role in migration when plenty of cadmium ions are injected. (3) When plenty of cadmium nitrate are injected, the concentrations of cadmium ions in fluctuating zone increase with water table rise, and decrease with water table decline. The concentrations of cadmium ions, which exist in the saturated zone decrease when the water table rises and increase with water table decline.

Ten-year water table recovery after clearcutting and draining boreal forested wetlands of eastern Canada

2008 ◽  
Vol 22 (20) ◽  
pp. 4163-4172 ◽  
Author(s):  
Philippe Marcotte ◽  
Vincent Roy ◽  
André P. Plamondon ◽  
Isabelle Auger
Keyword(s):  
Water Table ◽  
Forested Wetlands ◽  
Eastern Canada

scholarly journals Soil organic carbon mobility in equatorial podzols: soil column experiments

2021 ◽  
Author(s):  
Patrica Merdy ◽  
Yves Lucas ◽  
Bruno Coulomb ◽  
Adolpho J. Melfi ◽  
Célia R. Montes
Keyword(s):  
Organic Carbon ◽  
Water Table ◽  
Soil Column ◽  
Metal Mobility ◽  
Evergreen Forest ◽  
Column Experiments ◽  
Complexing Capacity ◽  
Order Of Magnitude ◽  
Deep Horizon ◽  
Carbon Balances

Abstract. Transfer of organic carbon from topsoil horizons to deeper horizons and to water table is still little documented, in particular in equatorial environments despite the high primary productivity of the evergreen forest. Due to its complexing capacity, organic carbon also plays a key role in the transfer of metals in the soil profile and therefore in pedogenesis and for metal mobility. We were interested in equatorial podzols, which are known to play a significant role in carbon cycling. We carried out soil column experiments using soil material and percolating solution sampled in an Amazonian podzol area. The dissolved organic matter (DOM) produced in the topsoil was not able to percolate through the clayey, kaolinitic material from the deep horizons and was retained in it. When it previously percolated through the Bh material, there was production of fulvic-like, protein-like compounds and small carboxylic acids able to percolate through the clayey material and increasing the mobility of Al, Fe and Si. Podzolic processes in the Bh can therefore produce a DOM likely to be transferred to the deep water table, playing a role in the carbon balances at the profile scale, and owing to its complexing capacity, playing a role in deep horizon pedogenesis and weathering. The order of magnitude of carbon concentration in the solution percolating in depth was around 1.5–2.5 mg L−1.

scholarly journals Modeling the Potential Impacts of Climate Change on the Hydrology of Selected Forested Wetlands in the Southeastern United States

2017 ◽  
Author(s):  
Jie Zhu ◽  
Ge Sun ◽  
Wenhong Li ◽  
Yu Zhang ◽  
Guofang Miao ◽  
...  
Keyword(s):  
Climate Change ◽  
United States ◽  
Water Table ◽  
Potential Evapotranspiration ◽  
Southeastern United States ◽  
Forested Wetlands ◽  
Wetland Hydrology ◽  
Wildlife Habitat ◽  
Future Climate Change ◽  
Impacts Of Climate Change

Abstract. Riverine floodplains and coastal margins of the southeastern United States host extensive forested wetlands, providing myriad ecosystem services including carbon sequestration, water quality improvement, groundwater recharge, and wildlife habitat. However, these ecosystems, which are closely dependent on wetland hydrology, are at risk due to human-made climate change. This study develops site-specific empirical hydrologic models for five forested wetlands with different characteristics by synthesizing long-term observed meteorological and hydrological data. These wetlands represent typical Cypress Ponds/Swamps, Carolina Bays, Pine Flatwoods, and Wet Pine, and natural Bottomland Hardwoods ecosystems. The validated empirical models are then applied at each wetland to predict future water table changes using climate projections from 20 General Circulation Models (GCMs) participating in the Coupled Model Inter-comparison Project 5 (CMIP5) under both Regional Concentration Pathways (RCP) 4.5 and RCP 8.5 greenhouse gas emission scenarios. We show that projected combined changes in precipitation and potential evapotranspiration would significantly alter wetland groundwater dynamics in the 21st century. Compared to the historical period, all five studied wetlands are predicted to become drier by the end of this century. The water table depth increases vary from 4 cm to 22 cm due to global warming. The large decrease in water availability (i.e., precipitation minus potential evapotranspiration) will cause a drop in the water table in all the five studied wetlands by the late 21st century. Among the five examined wetlands, the depression wetland in hot and humid Florida appears to be most sensitive to climate change. This modeling study provides quantitative information on the potential magnitude of wetland hydrological response to future climate change for typical forested wetlands in the southern U.S. Study results suggest that the ecosystem functions of southern forested wetlands will be substantially impacted by future climate change due to hydrological changes that are the key control to wetland biogeochemical cycles, vegetation distribution, fire regimes, and wildlife habitat. We conclude that climate change assessment on wetland forest ecosystems and adaptation management planning in the southeastern U.S. must first evaluate the impacts of climate change on wetland hydrology.

Sign in / Sign up

Export Citation Format

Share Document