scholarly journals Going Beyond the “Whole Wetland”: Small-Scale Within-Wetland Heterogeneity, Translates To Big Difference in Methane Flux Dynamics and Regulation

2021 ◽  
Author(s):  
Gil Bohrer
Keyword(s):  
Methane Flux ◽  
Small Scale ◽  
Flux Dynamics

Methane flux dynamics in a submerged aquatic vegetation zone in a subtropical lake

2019 ◽  
Vol 672 ◽  
pp. 400-409
Author(s):  
Mi Zhang ◽  
Qitao Xiao ◽  
Zhen Zhang ◽  
Yunqiu Gao ◽  
Jiayu Zhao ◽  
...  
Keyword(s):  
Submerged Aquatic Vegetation ◽  
Aquatic Vegetation ◽  
Methane Flux ◽  
Flux Dynamics ◽  
Vegetation Zone ◽  
Subtropical Lake

scholarly journals Modeling micro-topographic controls on boreal peatland hydrology and methane fluxes

2015 ◽  
Vol 12 (19) ◽  
pp. 5689-5704 ◽  
Author(s):  
F. Cresto Aleina ◽  
B. R. K. Runkle ◽  
T. Kleinen ◽  
L. Kutzbach ◽  
J. Schneider ◽  
...  
Keyword(s):  
Poor Performance ◽  
Methane Flux ◽  
Methane Emissions ◽  
Energy Budgets ◽  
Small Scale ◽  
Local Data ◽  
Model Version ◽  
Methane Fluxes ◽  
Micro Topography ◽  
Scale Surface

Abstract. Small-scale surface heterogeneities can influence land-atmosphere fluxes and therefore carbon, water and energy budgets on a larger scale. This effect is of particular relevance for high-latitude ecosystems, because of the great amount of carbon stored in their soils. We introduce a novel micro-topographic model, the Hummock-Hollow (HH) model, which explicitly represents small-scale surface elevation changes. By computing the water table at the small scale, and by coupling the model with a process-based model for soil methane processes, we are able to model the effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. In order to assess the effect of micro-topography on water the balance and methane emissions of the peatland we compare two versions of the model, one with a representation of micro-topography and a classical single-bucket model version, and show that the temporal variability in the model version with micro-topography performs better if compared with local data. Accounting for micro-topography almost triples the cumulative methane flux over the simulated time-slice. We found that the single-bucket model underestimates methane emissions because of its poor performance in representing hydrological dynamics. The HH model with micro-topography captures the spatial dynamics of water and methane fluxes, being able to identify the hotspots for methane emissions. The model also identifies a critical scale (0.01 km2) which marks the minimal resolution for the explicit representation of micro-topography in larger-scale models.

scholarly journals Topography-based modelling reveals high spatial variability and seasonal emission patches in forest floor methane flux

2020 ◽  
Author(s):  
Elisa Vainio ◽  
Olli Peltola ◽  
Ville Kasurinen ◽  
Antti-Jussi Kieloaho ◽  
Eeva-Stiina Tuittila ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Boreal Forest ◽  
Forest Floor ◽  
Methane Flux ◽  
Early Summer ◽  
Ground Vegetation ◽  
Small Scale ◽  
Ch4 Flux ◽  
Ch4 Uptake

Abstract. Boreal forest soils are globally an important sink for methane (CH4), while these soils are also capable to emit CH4 under favourable conditions. Soil wetness is a well-known driver of CH4 flux, and the wetness can be estimated with several terrain indices developed for the purpose. The aim of this study was to quantify the spatial variability of the forest floor CH4 flux with a topography-based upscaling method connecting the flux with its driving factors. We conducted spatially extensive forest floor CH4 flux and soil moisture measurements, complemented with ground vegetation classification, in a boreal pine forest. We then modelled the soil moisture with a Random Forest model using topography, based on which we upscaled the forest floor CH4 flux – this was performed for two seasons: May–July and August–October. Our results demonstrate high spatial heterogeneity in the forest floor CH4 flux, resulting from the soil moisture variability, as well as on the related ground vegetation. The spatial variability in the soil moisture and consequently in the CH4 flux was higher in the early summer compared to the autumn period, and overall the CH4 uptake rate was higher in autumn compared to early summer. In the early summer there were patches emitting high amounts of CH4, however, these wet patches got drier and smaller in size towards the autumn, which was enough for changing their dynamics to CH4 uptake. The results highlight the small-scale spatial variability of the boreal forest floor CH4 flux, and the importance of soil chamber placement in order to obtain spatially representative CH4 flux results. We recommend that a site of similar size and topographical variation would require 15–20 sample points in order to achieve accurate forest floor CH4 flux.

scholarly journals Detailed Patterns of Methane Distribution in the German Bight

2021 ◽  
Vol 8 ◽  
Author(s):  
Ingeborg Bussmann ◽  
Holger Brix ◽  
Götz Flöser ◽  
Uta Ködel ◽  
Philipp Fischer
Keyword(s):  
Spatial Resolution ◽  
German Bight ◽  
Methane Concentration ◽  
Spatial Dynamics ◽  
Methane Flux ◽  
Accurate Estimation ◽  
Small Scale ◽  
Input Concentration ◽  
Temporal And Spatial ◽  
Methane Distribution

Although methane is a widely studied greenhouse gas, uncertainties remain with respect to the factors controlling its distribution and diffusive flux into the atmosphere, especially in highly dynamic coastal waters. In the southern North Sea, the Elbe and Weser rivers are two major tributaries contributing to the overall methane budget of the southern German Bight. In June 2019, we continuously measured methane and basic hydrographic parameters at a high temporal and spatial resolution (one measurement per minute every 200–300 m) on a transect between Cuxhaven and Helgoland. These measurements revealed that the overall driver of the coastal methane distribution is the dilution of riverine methane-rich water with methane-poor marine water. For both the Elbe and Weser, we determined an input concentration of 40–50 nmol/L compared to only 5 nmol/L in the marine area. Accordingly, we observed a comparatively steady dilution pattern of methane concentration toward the marine realm. Moreover, small-scale anomalous patterns with unexpectedly higher dissolved methane concentrations were discovered at certain sites and times. These patterns were associated with the highly significant correlations of methane with oxygen or turbidity. However, these local anomalies were not consistent over time (days, months). The calculated diffusive methane flux from the water into the atmosphere revealed local values approximately 3.5 times higher than background values (median of 36 and 128 μmol m–2 d–1). We evaluate that this occurred because of a combination of increasing wind speed and increasing methane concentration at those times and locations. Hence, our results demonstrate that improved temporal and spatial resolution of methane measurements can provide a more accurate estimation and, consequently, a more functional understanding of the temporal and spatial dynamics of the coastal methane flux.

Methane flux dynamics in relation to methanogenic and methanotrophic populations in the soil of Indian Sundarban mangroves

2018 ◽  
Vol 39 (2) ◽  
pp. e12493 ◽  
Author(s):  
Subhajit Das ◽  
Dipnarayan Ganguly ◽  
Sabyasachi Chakraborty ◽  
Abhishek Mukherjee ◽  
Tarun Kumar De
Keyword(s):  
Methane Flux ◽  
Flux Dynamics ◽  
Indian Sundarban

scholarly journals Characterizing Peatland Microtopography Using Gradient and Microform-Based Approaches

Ecosystems ◽  
2020 ◽  
Vol 23 (7) ◽  
pp. 1464-1480 ◽  
Author(s):  
Jake D. Graham ◽  
Nancy F. Glenn ◽  
Lucas P. Spaete ◽  
Paul J. Hanson
Keyword(s):  
Spatial Variability ◽  
Quantitative Methods ◽  
Spatial Scales ◽  
Methane Flux ◽  
Small Scale ◽  
Classification Methods ◽  
Ecological Processes ◽  
Elevation Gradients ◽  
C Cycle ◽  
Gradient Based

AbstractPeatlands represent an important component of the global carbon cycle, storing 180–621 Gt of carbon (C). Small-scale spatial variations in elevation, frequently referred to as microtopography, influence ecological processes associated with the peatland C cycle, including Sphagnum photosynthesis and methane flux. Microtopography can be characterized with measures of topographic variability and by using conceptual classes (microforms) linked to function: most commonly hummocks and hollows. However, the criteria used to define these conceptual classes are often poorly described, if at all, and vary between studies. Such inconsistencies compel development of explicit quantitative methods to classify microforms. Furthermore, gradient-based characterizations that describe spatial variability without the use of microforms are lacking in the literature. Therefore, the objectives of this study were to (1) calculate peatland microtopographical elevation gradients and measures of spatial variability, (2) develop three microform classification methods intended for specific purposes, and (3) evaluate and contrast classification methods. Our results suggest that at spatial scales much larger than microforms, elevation distributions are unimodal and are well approximated with parametric probability density functions. Results from classifications were variable between methods and years and exhibited significant differences in mean hollow areal coverages of a raised ombrotrophic bog. Our results suggest that the conceptualization and classification of microforms can significantly influence microtopographic structural metrics. The three explicit methods for microform classification described here may be used and built upon for future applications.

Methane flux dynamics during mire succession

Oecologia ◽  
2010 ◽  
Vol 165 (2) ◽  
pp. 489-499 ◽  
Author(s):  
Mirva Leppälä ◽  
Jari Oksanen ◽  
Eeva-Stiina Tuittila
Keyword(s):  
Methane Flux ◽  
Flux Dynamics

scholarly journals Modeling micro-topographic controls on boreal peatland hydrology and methane fluxes

2015 ◽  
Vol 12 (13) ◽  
pp. 10195-10232 ◽  
Author(s):  
F. Cresto Aleina ◽  
B. R. K. Runkle ◽  
T. Kleinen ◽  
L. Kutzbach ◽  
J. Schneider ◽  
...  
Keyword(s):  
Poor Performance ◽  
Methane Flux ◽  
Methane Emissions ◽  
Energy Budgets ◽  
Small Scale ◽  
Local Data ◽  
Model Version ◽  
Methane Fluxes ◽  
Micro Topography ◽  
Scale Surface

Abstract. Small-scale surface heterogeneities can influence land–atmosphere fluxes and therefore carbon, water and energy budgets on larger scale. This effect is of particular relevance for high-latitude ecosystems, because of the great amount of carbon stored in their soils. We introduce a novel micro-topographic model, the Hummock–Hollow (HH) model, which explicitly represents small-scale surface elevation changes. By computing the water table at the small scale, and by coupling the model with a process-based model for soil methane processes, we are able to model effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. In order to assess the effect of micro-topography on water balance and methane emissions of the peatland we compare two versions of the model, one with a representation of micro-topography and a classical single-bucket model version, and show that the temporal variability in the model version with micro-topography performs better if compared with local data. Accounting for micro-topography almost triples the cumulative methane flux over the simulated time-slice. We found that the single-bucket model underestimates methane emissions because of its poor performance in representing hydrological dynamics. The HH model with micro-topography captures the spatial dynamics of water and methane fluxes, being able to identify the hotspots for methane emissions. The model also identifies a critical scale (0.01 km2) which marks the minimal resolution for the explicit representation of micro-topography in larger-scale models.

Using an advanced robotic chamber system to detect spatio-temporal short-term responses in measured CO2 exchange to soil manipulation and N fertilization

2021 ◽  
Author(s):  
Mathias Hoffmann ◽  
Shrijana Vaidya ◽  
Marten Schmidt ◽  
Norbert Bonk ◽  
Peter Rakowski ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Temporal Variability ◽  
Agricultural Practices ◽  
N Fertilization ◽  
Soil Types ◽  
Small Scale ◽  
Chamber System ◽  
Short Term ◽  
Flux Dynamics ◽  
Spatio Temporal

<p>Improved agricultural practices sequestering additional atmospheric C within the soil are considered as one of the potential solution for mitigating global climate change. However, agricultural used landscapes are complex and their capacity to sequester additional atmospheric C differs substantially in time and space. Hence, accurate and precise information on the complex spatio-temporal CO<sub>2</sub> flux pattern is needed to evaluate the effects/benefits of new agricultural practices aiming towards increasing soil organic carbon.</p><p>To date, different approaches are used to measure and quantify CO<sub>2</sub> flux dynamics of agricultural landscapes, such as e.g. eddy covariance, as well as manual and automatic chamber systems. However, all these methods fail to some extend in either accounting for small scale spatial heterogeneity (e.g., eddy covariance and automatic chambers) or short-term temporal variability (e.g., manual chambers). Although, automatic chambers are in principle capable to detect small-scale spatial differences of CO<sub>2 </sub>flux dynamics in a sufficient temporal resolution, these systems are usually limited to only a few spatial repetitions which is not sufficient to represent small scale soil heterogeneity such as present within the widespread hummocky ground moraine landscape of NE-Germany.</p><p>To overcome these challenges, we developed a novel robotic chamber system. This system was used to detect small-scale spatial heterogeneity and short-term temporal variability of CO<sub>2</sub> flux dynamics in a full factorial experimental setup for a range of three different soil types, two N fertilization forms (2; mineral vs. organic) and two soil manipulation status, representing two different tillage practices. Here, we present measured CO<sub>2</sub> flux dynamics and cumulative emissions for the 3 repetitions of the 12 randomized treatments (36 subplots) directly following soil manipulation and N fertilization during summer 2020. Our results show distinct differences between the three measured soil types as well as a clear response of all three soil types to conducted soil manipulation, yielding in significantly lower ecosystem respiration (R<sub>eco</sub>) and net ecosystem exchange (NEE) for manipulated vs. non-manipulated subplots. No clear difference, however, was obtained in case of N fertilization.</p>

Methane flux dynamics in an Irish lowland blanket bog

2007 ◽  
Vol 299 (1-2) ◽  
pp. 181-193 ◽  
Author(s):  
Anna Laine ◽  
David Wilson ◽  
Gerard Kiely ◽  
Kenneth A. Byrne
Keyword(s):  
Methane Flux ◽  
Flux Dynamics ◽  
Blanket Bog
Sign in / Sign up

Export Citation Format

Share Document