scholarly journals Field-scale CH<sub>4</sub> emission at a sub-arctic mire with heterogeneous permafrost thaw status

2021 ◽  
Author(s):  
Patryk Łakomiec ◽  
Jutta Holst ◽  
Thomas Friborg ◽  
Patrick Crill ◽  
Niklas Rakos ◽  
...  
Keyword(s):  
Water Table ◽  
Methane Emission ◽  
Gross Primary Production ◽  
Methane Emissions ◽  
Climatic Conditions ◽  
Field Scale ◽  
Flux Footprint ◽  
Eddy Covariance Method ◽  
Eastern Sector ◽  
Methane Fluxes

Abstract. The Artic is exposed to faster temperature changes than most other areas on Earth. Constantly increasing temperature will lead to thawing permafrost and changes in the CH4 emissions from wetlands. One of the places exposed to those changes is the Abisko-Stordalen Mire in northern Sweden, where climate and vegetation studies have been conducted from the 1970s.In our study, we analyzed field-scale methane emissions measured by the eddy covariance method at Abisko-Stordalen Mire for three years (2014–2016). The site is a subarctic mire mosaic of palsas, thawing palsas, fully thawed fens, and open water bodies. A bimodal wind pattern prevalent at the site provides an ideal opportunity to measure mire patches with different permafrost statuses with one flux measurement system. The flux footprint for westerly winds is dominated by elevated palsa plateaus, while the footprint is almost equally distributed between palsas and thawing bog-like areas for easterly winds. As these patches are exposed to the same climatic conditions, we analyzed the differences in the responses of their methane emission for environmental parameters.The methane fluxes followed a similar annual cycle over the three study years, with a gentle rise during spring and a decrease during autumn and with no emission burst at either end of the ice-free season. The peak emission during the ice-free season differed significantly for the mire with two permafrost statuses: the palsa mire emitted 24 mg-CH4 m−2 d−1 and the thawing wet sector 56 mg-CH4 m−2 d−1. Factors controlling the methane emission were analyzed using generalized linear models. The main driver for methane fluxes was peat temperature for both wind sectors. Soil water content above the water table emerged as an explanatory variable for the three years for western sectors and the year 2016 in the eastern sector. Water table level showed a significant correlation with methane emission for the year 2016 as well. Gross primary production, however, did not show a significant correlation with methane emissions. Annual methane emissions were estimated based on four different gap-filing methods. The different methods generally resulted in very similar annual emissions. The mean annual emission based on all models was 4.2 ± 0.4 g-CH4 m−2 a−1 for western sector and 7.3 ± 0.7 g-CH4 m−2 a−1 for the eastern sector. The average annual emissions, derived from this data and a footprint climatology, were 3.6 ± 0.7 g-CH4 m−2 a−1 and 11 ± 2 g-CH4 m−2 a−1 for the palsa and thawing surfaces, respectively. Winter fluxes were relatively high, contributing 27–45 % to the annual emissions.

Methane emissions from a palsa-mire underlayed by sporadic permafrost under rapid degradation

2020 ◽  
Author(s):  
Patryk Łakomiec ◽  
Jutta Holst ◽  
Janne Rinne
Keyword(s):  
Methane Emission ◽  
Large Scale ◽  
Climate Changes ◽  
Environmental Parameters ◽  
Methane Emissions ◽  
Climate Feedbacks ◽  
Flux Footprint ◽  
Surface Type ◽  
Westerly Winds ◽  
Methane Fluxes

&lt;p&gt;Methane is one of the most important greenhouse gases. The largest natural source of this gas are wetlands. Quantification emission from this source, especially from subarctic regions, which are exposed to fast climate changes, is important for our understanding of biogeochemical climate feedbacks. Abisko Stordalen is one of few mires in this climatic zone in which the methane emission is being measured continuously. Here we analyze eddy covariance data from the ICOS Sweden site with respect to environmental parameters possibly controlling the methane emissions.&lt;/p&gt;&lt;p&gt;Due to the large scale topography at Abisko, wind is channeled along the valley, resulting in to two main wind directions. This divides the measurements into two different surface type groups. On easterly winds, the flux footprint is dominated by permafrost features, while for westerly winds it is dominated by non-permafrost fen. Measured methane fluxes from these to wetland types, exposed for the same environmental conditions, differ considerably being higher from non-permafrost area. &amp;#160;We will further analyze the differences in the annual methane emission from the two systems, and their dependencies from environmental parameters.&lt;/p&gt;

Measurements of methane emission from a temperate wetland by the eddy covariance method

2013 ◽  
Vol 27 (3) ◽  
pp. 283-290 ◽  
Author(s):  
N. Kowalska ◽  
B.H. Chojnicki ◽  
J. Rinne ◽  
S. Haapanala ◽  
P. Siedlecki ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Water Table ◽  
Methane Emission ◽  
Strong Correlation ◽  
Vegetation Types ◽  
Diurnal Pattern ◽  
Eddy Covariance Method ◽  
Temperate Wetland ◽  
Eddy Covariance System ◽  
Methane Efflux

Abstract Methane emission from a wetland was measured with the eddy covariance system. The location of the system allowed observation of methane efflux from areas that were covered by different vegetation types. The data presented in this paper were collected in the period between the13th of June and the 31st of August 2012. During the warmest months of the summer, there was no strong correlation between methane emissions and either the water table depth or peat temperature. The presence of reed and cattail contributed to a pronounced diurnal pattern of the flux and lower methane emission, while areas covered by sedges emitted higher amounts more with no clear diurnal pattern.

scholarly journals Revisiting factors controlling methane emissions from high-Arctic tundra

2013 ◽  
Vol 10 (7) ◽  
pp. 5139-5158 ◽  
Author(s):  
M. Mastepanov ◽  
C. Sigsgaard ◽  
T. Tagesson ◽  
L. Ström ◽  
M. P. Tamstorf ◽  
...  
Keyword(s):  
Water Table ◽  
Methane Emission ◽  
Climatic Factors ◽  
Growing Season ◽  
High Arctic ◽  
Methane Emissions ◽  
Soil Freezing ◽  
The Arctic ◽  
Cumulative Emission ◽  
Late Season

Abstract. The northern latitudes are experiencing disproportionate warming relative to the mid-latitudes, and there is growing concern about feedbacks between this warming and methane production and release from high-latitude soils. Studies of methane emissions carried out in the Arctic, particularly those with measurements made outside the growing season, are underrepresented in the literature. Here we present results of 5 yr (2006–2010) of automatic chamber measurements at a high-Arctic location in Zackenberg, NE Greenland, covering both the growing seasons and two months of the following freeze-in periods. The measurements show clear seasonal dynamics in methane emission. The start of the growing season and the increase in CH4 fluxes were strongly related to the date of snowmelt. Within each particular growing season, CH4 fluxes were highly correlated with the soil temperature (R2 > 0.75), which is probably explained by high seasonality of both variables, and weakly correlated with the water table. The greatest variability in fluxes between the study years was observed during the first part of the growing season. Somewhat surprisingly, this variability could not be explained by commonly known factors controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4 coinciding with soil freezing in the autumn were observed during at least three years. The cumulative emission during the freeze-in CH4 bursts was comparable in size with the growing season emission for the year 2007, and about one third of the growing season emissions for the years 2009 and 2010. In all three cases the CH4 burst was accompanied by a corresponding episodic increase in CO2 emission, which can compose a significant contribution to the annual CO2 flux budget. The most probable mechanism of the late-season CH4 and CO2 bursts is physical release of gases accumulated in the soil during the growing season. In this study we discuss possible links between growing season and autumn fluxes. Multiannual dynamics of the subsurface CH4 storage pool are hypothesized to be such a link and an important driver of intearannual variations in the fluxes, capable of overruling the conventionally known short-term control factors (temperature and water table). Our findings suggest the importance of multiyear studies with a continued focus on shoulder seasons in Arctic ecosystems.

Evaluation of the current status of operating and closed landfills in Russia, Finland and Ireland with regard to water pollution and methane emission

2003 ◽  
Vol 48 (4) ◽  
pp. 37-44 ◽  
Author(s):  
S. Kalyuzhnyi ◽  
A. Epov ◽  
K. Sormunen ◽  
R. Kettunen ◽  
J. Rintala ◽  
...  
Keyword(s):  
Methane Emission ◽  
State Of The Art ◽  
Methane Emissions ◽  
Climatic Conditions ◽  
Current Status ◽  
The European Union ◽  
Municipal Solid Wastes ◽  
Methane Recovery ◽  
Msw Management ◽  
Nitrogen Contents

The annual production of municipal solid wastes (MSW) in Russia, Finland and Ireland in the late 1990s accounts for 37.5, 2.5 and 2.05 mln. tonnes or 252, 488 and 566 kg per capita, respectively. 96.5, 64 and 91% of these wastes (for Russia, Finland and Ireland, correspondingly) are currently disposed of via landfilling. However, nowadays, MSW management in these countries is undergoing drastic changes (source separation, closure of old landfills, reduction of the number of landfills etc.) forced by recent legislation set by the European Union and Russian authorities. This paper evaluates the current status of MSW landfills, as well as information on current leachate and methane emissions in the three above mentioned countries. Landfill leachates are highly variable in each country and between different countries due to different rainfall and climatic conditions and also due to poor landfill top insulation/cover. Leachates in poorly structured landfills are very dilute, whereas leachates with total COD and nitrogen contents as high as 33,700 mg COD/l and 4,030 mg N/l, respectively, have been detected from state-of-the-art sites. Currently, on-site treatment of leachates exists at only a few landfills in Russia, Finland and Ireland but this situation will be considerably improved during the next years. The annual methane emissions from landfills are estimated as 500-900 and 77 ktonnes for Russia and Finland, respectively. Recent estimates from Ireland suggest an annual landfill methane emission of c. 2.1 Mt CO2 equivalent. Several systems of methane recovery have been developed in all three countries and these are currently in different stages of implementation.

scholarly journals Revisiting factors controlling methane emissions from high-arctic tundra

2012 ◽  
Vol 9 (11) ◽  
pp. 15853-15900 ◽  
Author(s):  
M. Mastepanov ◽  
C. Sigsgaard ◽  
T. Tagesson ◽  
L. Ström ◽  
M. P. Tamstorf ◽  
...  
Keyword(s):  
Water Table ◽  
Methane Emission ◽  
Seasonal Dynamics ◽  
Growing Season ◽  
High Arctic ◽  
Methane Emissions ◽  
Soil Freezing ◽  
The Arctic ◽  
Late Season ◽  
Ch4 Emissions

Abstract. Among the numerous studies of methane emission from northern wetlands the number of measurements carried on at high latitudes (north of the Arctic Circle) is very limited, and within these there is a bias towards studies of the growing season. Here we present results of five years of automatic chamber measurements at a high-arctic location in Zackenberg, NE Greenland covering both the growing seasons and two months of the following freeze-in period. The measurements show clear seasonal dynamics in methane emission. The start of the growing season increase in CH4 fluxes were strongly related to the date of snow melt. The greatest variation in fluxes between the study years were observed during the first part of the growing season. Somewhat surprisingly this variability could not be explained by commonly known factors controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4 coinciding with soil freezing in the autumn were observed at least during three years between 2006 and 2010. The accumulated emission during the freeze-in CH4 bursts was comparable in size with the growing season emission for the year 2007, and about one third of the growing season emissions for the years 2009 and 2010. In all three cases the CH4 burst was accompanied by a~corresponding episodic increase in CO2 emission, which can compose a significant contribution to the annual CO2 flux budget. The most probable mechanism of the late season CH4 and CO2 bursts is physical release of gases, accumulated in the soil during the growing season. In this study we investigate the drivers and links between growing season and late season fluxes. The reported surprising seasonal dynamics of CH4 emissions at this site show that there are important occasions where conventional knowledge on factors controlling methane emissions is overruled by other processes, acting in longer than seasonal time scales. Our findings suggest the importance of multiyear studies with continued focus on shoulder seasons.

Exploring the variation in ecosystem scale methane fluxes and its drivers within a boreal mire complex

2021 ◽  
Author(s):  
Koffi Dodji Noumonvi ◽  
Joshua L. Ratcliffe ◽  
Mats Öquist ◽  
Mats B. Nilsson ◽  
Matthias Peichl
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Chemical Properties ◽  
Growing Season ◽  
Small Scale ◽  
Atmospheric Methane ◽  
Flux Footprint ◽  
Growing Season Length ◽  
Methane Fluxes ◽  
Northern Peatlands

&lt;p&gt;Northern peatlands cover a small fraction of the earth&amp;#8217;s land surface, and yet they are one of the most important natural sources of atmospheric methane. With climate change causing rising temperatures, changes in water balance and increased growing season length, peatland contribution to atmospheric methane concentration is likely to increase, justifying the increased attention given to northern peatland methane dynamics. Northern peatlands often occur as heterogeneous complexes characterized by hydromorphologically distinct features from &lt; 1 m&amp;#178; to tens of km&amp;#178;, with differing physical, hydrological and chemical properties. The more commonly understood small-scale variation between hummocks, lawns and hollows has been well explored using chamber measurements. Single tower eddy covariance measurements, with a typical 95% flux footprint of &lt; 0.5 km&amp;#178;, have been used to assess the ecosystem scale methane exchange. However, how representative single tower flux measurements are of an entire mire complex is not well understood. To address this knowledge gap, the present study takes advantage of a network of four eddy covariance towers located less than 3 km apart at four mires within a typical boreal mire complex in northern Sweden. The variation of methane fluxes and its drivers between the four sites will be explored at different temporal scales, i.e. half-hourly, daily and at a growing-season scale.&lt;/p&gt;

scholarly journals Small waterbodies reduce the carbon sink of a polygonal tundra landscape

2021 ◽  
Author(s):  
Lutz Beckebanze ◽  
Zoé Rehder ◽  
David Holl ◽  
Charlotta Mirbach ◽  
Christian Wille ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Budget ◽  
Carbon Sink ◽  
Open Water ◽  
Methane Emissions ◽  
The Arctic ◽  
Sink Strength ◽  
Small Waterbodies ◽  
Methane Fluxes ◽  
The Impact

Abstract. Arctic permafrost landscapes have functioned as a global carbon sink for millennia. These landscapes are very heterogeneous, and the omnipresent waterbodies are a carbon source within them. Yet, only a few studies focus on the impact of these waterbodies on the landscape carbon budget. We compare carbon dioxide and methane fluxes from small waterbodies to fluxes from the surrounding tundra using eddy covariance measurements from a tower located between a large pond and semi-terrestrial vegetated tundra. When taking the open-water areas of small waterbodies into account, the carbon dioxide sink strength of the landscape was reduced by 11 %. While open-water methane emissions were similar to the tundra emissions, some parts of the studied pond's shoreline exhibited much higher emissions, underlining the high spatial variability of methane emissions. We conclude that gas fluxes from small waterbodies can contribute significantly to the carbon budget of arctic tundra landscapes. Consequently, changes in arctic hydrology and the concomitant changes in the waterbody distribution may substantially impact the overall carbon budget of the Arctic.

scholarly journals Consequences of Increased Variation in Peatland Hydrology for Carbon Storage: Legacy Effects of Drought and Flood in a Boreal Fen Ecosystem

2021 ◽  
Vol 8 ◽  
Author(s):  
Evan S. Kane ◽  
Catherine M. Dieleman ◽  
Danielle Rupp ◽  
Kevin H. Wyatt ◽  
Allison R. Rober ◽  
...  
Keyword(s):  
Water Table ◽  
Algal Biomass ◽  
Gross Primary Production ◽  
Temporal Trends ◽  
Sink Strength ◽  
Legacy Effects ◽  
Algal Production ◽  
Rich Fen ◽  
C Cycling

Globally important carbon (C) stores in boreal peatlands are vulnerable to altered hydrology through changes in precipitation and runoff patterns, groundwater inputs, and a changing cryosphere. These changes can affect the extent of boreal wetlands and their ability to sequester and transform C and other nutrients. Variation in precipitation patterns has also been increasing, with greater occurrences of both flooding and drought periods. Recent work has pointed to the increasing role of algal production in regulating C cycling during flooded periods in fen peatlands, but exactly how this affects the C sink-strength of these ecosystems is poorly understood. We evaluated temporal trends in algal biomass, ecosystem C uptake and respiration (using static and floating chamber techniques), and spectroscopic indicators of DOM quality (absorbance and fluorescence) in a boreal rich-fen peatland in which water table position had been experimentally manipulated for 13 years. Superimposed on the water table treatments were natural variations in hydrology, including periods of flooding, which allowed us to examine the legacy effects of flooding on C cycling dynamics. We had a particular focus on understanding the role of algae in regulating C cycling, as the relative contribution of algal production was observed to significantly increase with flooding. Ecosystem measures of gross primary production (GPP) increased with algal biomass, with higher algal biomass and GPP measured in the lowered water table treatment two years after persistent flooding. Prior to flooding the lowered treatment was the weakest C sink (as CO2), but this treatment became the strongest sink after flooding. The lower degree of humification (lower humification index, HIX) and yet lower bioavailability (higher spectral slope ratio, Sr) of DOM observed in the raised treatment prior to flooding persisted after two years of flooding. An index of free or bound proteins (tyrosine index, TI) increased with algal biomass across all plots during flooding, and was lowest in the raised treatment. As such, antecedent drainage conditions determined the sink-strength of this rich fen—which was also reflected in DOM characteristics. These findings indicate that monitoring flooding history and its effects on algal production could become important to estimates of C balance in northern wetlands.

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