The full greenhouse gas balance of an abandoned peat meadow

Abstract. Globally, peat lands are considered to be a sink of CO2, but a source when drained. Additionally, wet peat lands are thought to emit considerable amounts of CH4 and N2O. Hitherto, reliable and integrated estimates of emissions and emission factors for this type of area have been lacking and the effects of wetland restoration on methane emissions have been poorly quantified. In this paper we estimate the full GHG balance of a restored natural peat land by determining the fluxes of CO2, CH4 and N2O through atmosphere and water, while accounting for the different GWP's. This site is an abandoned agricultural peat meadow, which has been converted into a wetland nature reserve ten years ago by raising the water level. GHG fluxes were measured continuously with an eddy-correlation system (CO2) and flux chamber measurements (CH4 and N2O). Meteorological and hydrological measurements were done as well. With growing seasons of respectively 192 and 155 days, the net annual CO2 uptake was 276±61 g C m−2 for 2004 and 311±58 g C m−2 for 2005. Ecosystem respiration was estimated as 887±668 g C m−2 for 2004 and 866±666 g C m−2 for 2005. CH4 fluxes from water, saturated land and relatively dry land varied: total annual CH4 fluxes are 10.4±19.2 g C m−2 yr−1, 101 g C m−2 yr−1±30 and 37.3±10.9 g C m−2 yr−1, respectively, and a annual weighed total CH4 emission of 31.27±20.44 g C m−2 yr−1. N2O fluxes were too low to be of significance. The carbon-balance consists for the largest part of CO2 uptake, CO2 respiration and CH4 emission from wet land and water. CO2 emission has decreased significantly as result of the raised water table, while CH4 fluxes have increased. In global warming potentials the area is a very small sink of 71 g CO2-equiv m−2 (over a 100-year period).

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The full greenhouse gas balance of an abandoned peat meadow

Biogeosciences ◽

10.5194/bg-4-411-2007 ◽

2007 ◽

Vol 4 (3) ◽

pp. 411-424 ◽

Cited By ~ 143

Author(s):

D. M. D. Hendriks ◽

J. van Huissteden ◽

A. J. Dolman ◽

M. K. van der Molen

Keyword(s):

Greenhouse Gas ◽

Ecosystem Respiration ◽

Net Ecosystem Exchange ◽

Co2 Uptake ◽

Flux Chamber ◽

Greenhouse Gas Balance ◽

Dry Land ◽

Ch4 Emissions ◽

Growing Seasons ◽

Ch4 And N2o

Abstract. Globally, peat lands are considered to be a sink of CO2, but a source when drained. Additionally, wet peat lands are thought to emit considerable amounts of CH4 and N2O. Hitherto, reliable and integrated estimates of emissions and emission factors for this type of land cover have been lacking and the effects of wetland restoration on methane emissions have been poorly quantified. In this paper we estimate the full greenhouse gas (GHG) balance of a restored natural peat land by determining the fluxes of CO2, CH4 and N2O through atmosphere and water, while accounting for the different Global Warming Potentials (GWP's). The site is an abandoned agricultural peat meadow, which has been converted into a wetland nature reserve ten years ago, after which the water level was raised. GHG fluxes were measured continuously with an eddy covariance system (CO2) and flux chamber measurements (CH4 and N2O). Meteorological and hydrological measurements were collected as well. With growing seasons of respectively 192, 168 and 129 days, the annual net ecosystem exchange of CO2 (NEE) was −446+±83 g C m−2 yr−1 for 2004, −311±58 g C m−2 yr−1 for 2005 and −232±57 g m−2 yr−1 for 2006. Ecosystem respiration (Reco) was estimated as 869±668 g C m−2 yr−1 for 2004, 866±666 g C m−2 yr−1 for 2005 and 924±711 g C m−2 yr−1 for 2006. CH4 emissions from the saturated land and water surfaces were high compared to the relatively dry land. Annual weighted CH4 emissions were 31.27±20.40 g C m−2 yr−1 for 2005 and 32.27±21.08 g C m−2 yr−1 for 2006. N2O fluxes were too low to be of significance. The water balance of the area was dominated by precipitation and evapotranspiration and therefore fluxes of carbon and CH4 through seepage, infiltration and drainage were relatively small (17.25 g C m−2 yr−1). The carbon-balance consisted for the largest part of CO2 uptake, CO2 respiration and CH4 emission from water saturated land and water. CO2 emission has decreased significantly as result of the raised water table, while CH4 fluxes have increased. In GWP's the area was a small net GHG sink given as CO2-equiv. of −86 g m−2 yr−1 (over a 100-year period).

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Greenhouse gas balance of cropland conversion to bioenergy poplar short-rotation coppice

Biogeosciences ◽

10.5194/bg-13-95-2016 ◽

2016 ◽

Vol 13 (1) ◽

pp. 95-113 ◽

Cited By ~ 18

Author(s):

S. Sabbatini ◽

N. Arriga ◽

T. Bertolini ◽

S. Castaldi ◽

T. Chiti ◽

...

Keyword(s):

Greenhouse Gas ◽

Arable Land ◽

Hybrid Poplar ◽

Ghg Emissions ◽

Net Ecosystem Exchange ◽

Short Rotation Coppice ◽

Co2 Uptake ◽

Greenhouse Gas Balance ◽

Short Rotation ◽

Ch4 And N2o

Abstract. The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short-rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. This period corresponded to a single rotation of the SRC site. The REF site was a crop rotation between grassland and winter wheat, i.e. the same management of the SRC site before the conversion to short-rotation coppice. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (FCO2), whereas chambers were used to measure N2O and CH4 emissions from soil. The measurements began 2 years after the conversion of arable land to SRC so that an older poplar plantation was used to estimate the soil organic carbon (SOC) loss due to SRC establishment and to estimate SOC recovery over time. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled. A GHG emission offset, due to the substitution of natural gas with SRC biomass, was credited to the GHG budget of the SRC site. Emissions generated by the use of biomass (FEXP) were also considered. Suitability was finally assessed by comparing the GHG budgets of the two sites. CO2 uptake was 3512 ± 224 g CO2 m−2 at the SRC site in 2 years, and 1838 ± 107 g CO2 m−2 at the REF site. FEXP was equal to 1858 ± 240 g CO2 m−2 at the REF site, thus basically compensating for FCO2, while it was 1118 ± 521 g CO2 m−2 at the SRC site. The SRC site could offset 379.7 ± 175.1 g CO2eq m−2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN made up 2 and 4 % in the GHG budgets of SRC and REF sites respectively, while the SOC loss was 455 ± 524 g CO2 m−2 in 2 years. Overall, the REF site was close to neutrality from a GHG perspective (156 ± 264 g CO2eq m−2), while the SRC site was a net sink of 2202 ± 792 g CO2eq m−2. In conclusion the experiment led to a positive evaluation from a GHG viewpoint of the conversion of cropland to bioenergy SRC.

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Carbon dioxide and methane exchange of a patterned subarctic fen during two contrasting growing seasons

Biogeosciences ◽

10.5194/bg-18-873-2021 ◽

2021 ◽

Vol 18 (3) ◽

pp. 873-896

Author(s):

Lauri Heiskanen ◽

Juha-Pekka Tuovinen ◽

Aleksi Räsänen ◽

Tarmo Virtanen ◽

Sari Juutinen ◽

...

Keyword(s):

Carbon Dioxide ◽

Ecosystem Respiration ◽

Growing Season ◽

Drought Event ◽

Flux Chamber ◽

Ch4 Emissions ◽

Growing Seasons ◽

Ecosystem Level ◽

Community Types ◽

Carbon Dioxide Co2

Abstract. The patterned microtopography of subarctic mires generates a variety of environmental conditions, and carbon dioxide (CO2) and methane (CH4) dynamics vary spatially among different plant community types (PCTs). We studied the CO2 and CH4 exchange between a subarctic fen and the atmosphere at Kaamanen in northern Finland based on flux chamber and eddy covariance measurements in 2017–2018. We observed strong spatial variation in carbon dynamics between the four main PCTs studied, which were largely controlled by water table level and differences in vegetation composition. The ecosystem respiration (ER) and gross primary productivity (GPP) increased gradually from the wettest PCT to the drier ones, and both ER and GPP were larger for all PCTs during the warmer and drier growing season 2018. We estimated that in 2017 the growing season CO2 balances of the PCTs ranged from −20 g C m−2 (Trichophorum tussock PCT) to 64 g C m−2 (string margin PCT), while in 2018 all PCTs were small CO2 sources (10–22 g C m−2). We observed small growing season CH4 emissions (< 1 g C m−2) from the driest PCT, while the other three PCTs had significantly larger emissions (mean 7.9, range 5.6–10.1 g C m−2) during the two growing seasons. Compared to the annual CO2 balance (−8.5 ± 4.0 g C m−2) of the fen in 2017, in 2018 the annual balance (−5.6 ± 3.7 g C m−2) was affected by an earlier onset of photosynthesis in spring, which increased the CO2 sink, and a drought event during summer, which decreased the sink. The CH4 emissions were also affected by the drought. The annual CH4 balance of the fen was 7.3 ± 0.2 g C m−2 in 2017 and 6.2 ± 0.1 g C m−2 in 2018. Thus, the carbon balance of the fen was close to zero in both years. The PCTs that were adapted to drier conditions provided ecosystem-level resilience to carbon loss due to water level drawdown.

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Carbon dioxide and methane exchange of a patterned subarctic fen during two contrasting growing seasons

10.5194/bg-2020-370 ◽

2020 ◽

Author(s):

Lauri Heiskanen ◽

Juha-Pekka Tuovinen ◽

Aleksi Räsänen ◽

Tarmo Virtanen ◽

Sari Juutinen ◽

...

Keyword(s):

Carbon Dioxide ◽

Plant Community ◽

Ecosystem Respiration ◽

Growing Season ◽

Vegetation Composition ◽

Flux Chamber ◽

Growing Seasons ◽

Community Types ◽

Eddy Covariance Measurements ◽

Carbon Dioxide Co2

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Exchange of CO<sub>2</sub> in Arctic tundra: impacts of meteorological variations and biological disturbance

10.5194/bg-2016-506 ◽

2016 ◽

Author(s):

Efrén López-Blanco ◽

Magnus Lund ◽

Mathew Williams ◽

Mikkel P. Tamstorf ◽

Andreas Westergaard-Nielsen ◽

...

Keyword(s):

Ecosystem Respiration ◽

Gross Primary Production ◽

Net Ecosystem Exchange ◽

Variable Coefficients ◽

The Arctic ◽

Sink Strength ◽

Co2 Uptake ◽

Growing Seasons ◽

Meteorological Effect ◽

Major Pest

Abstract. An improvement in our process-based understanding of carbon (C) exchange in the Arctic, and its climate sensitivity, is critically needed for understanding the response of tundra ecosystems to a changing climate. In this context, we analyzed the net ecosystem exchange (NEE) of CO2 in West Greenland tundra (64° N) across eight snow-free periods in eight consecutive years, and characterized the key processes of net ecosystem exchange, and its two main modulating components: gross primary production (GPP) and ecosystem respiration (Reco). Overall, the ecosystem acted as a consistent sink of CO2, accumulating −30 g C m−2 on average (range −17 to −41 g C m−2) during the years 2008–2015, except 2011 that was associated with a major pest outbreak. The results do not reveal a marked meteorological effect on the net CO2 uptake despite the high inter-annual variability in the timing of snowmelt, start and duration of the growing season. The ranges in annual GPP (−182 to −316 g C m−2) and Reco (144 to 279 g C m−2) were > 5 fold larger and they were also more variable (Coefficients of variation are 3.6 and 4.1 % respectively) than for NEE (0.7 %). GPP and Reco were sensitive to insolation and temperatures; and there was a tendency towards larger GPP and Reco during warmer and wetter years. The relative lack of sensitivity of NEE to climate was a result of the correlated meteorological response of GPP and Reco. During the 2011 anomalous year, the studied ecosystem released 41 g C m−2 as biological disturbance reduced GPP more strongly than Reco. With continued warming temperatures and longer growing seasons, tundra systems will increase rates of C cycling although shifts in sink strength will likely be triggered by factors such as biological disturbances, events that will challenge the forecast of upcoming C states.

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Exchange of CO<sub>2</sub> in Arctic tundra: impacts of meteorological variations and biological disturbance

Biogeosciences ◽

10.5194/bg-14-4467-2017 ◽

2017 ◽

Vol 14 (19) ◽

pp. 4467-4483 ◽

Cited By ~ 16

Author(s):

Efrén López-Blanco ◽

Magnus Lund ◽

Mathew Williams ◽

Mikkel P. Tamstorf ◽

Andreas Westergaard-Nielsen ◽

...

Keyword(s):

Ecosystem Respiration ◽

Gross Primary Production ◽

Net Ecosystem Exchange ◽

Variable Coefficients ◽

The Arctic ◽

Correlated Response ◽

Sink Strength ◽

Co2 Uptake ◽

Growing Seasons ◽

Major Pest

Abstract. An improvement in our process-based understanding of carbon (C) exchange in the Arctic and its climate sensitivity is critically needed for understanding the response of tundra ecosystems to a changing climate. In this context, we analysed the net ecosystem exchange (NEE) of CO2 in West Greenland tundra (64° N) across eight snow-free periods in 8 consecutive years, and characterized the key processes of net ecosystem exchange and its two main modulating components: gross primary production (GPP) and ecosystem respiration (Reco). Overall, the ecosystem acted as a consistent sink of CO2, accumulating −30 g C m−2 on average (range of −17 to −41 g C m−2) during the years 2008–2015, except 2011 (source of 41 g C m−2), which was associated with a major pest outbreak. The results do not reveal a marked meteorological effect on the net CO2 uptake despite the high interannual variability in the timing of snowmelt and the start and duration of the growing season. The ranges in annual GPP (−182 to −316 g C m−2) and Reco (144 to 279 g C m−2) were > 5 fold larger than the range in NEE. Gross fluxes were also more variable (coefficients of variation are 3.6 and 4.1 % respectively) than for NEE (0.7 %). GPP and Reco were sensitive to insolation and temperature, and there was a tendency towards larger GPP and Reco during warmer and wetter years. The relative lack of sensitivity of NEE to meteorology was a result of the correlated response of GPP and Reco. During the snow-free season of the anomalous year of 2011, a biological disturbance related to a larvae outbreak reduced GPP more strongly than Reco. With continued warming temperatures and longer growing seasons, tundra systems will increase rates of C cycling. However, shifts in sink strength will likely be triggered by factors such as biological disturbances, events that will challenge our forecasting of C states.

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Effect of Irrigation on Intercropping Systems of Wheat (Triticum aestivum L.) with Pea (Pisum sativum L.)

Agronomy ◽

10.3390/agronomy11020283 ◽

2021 ◽

Vol 11 (2) ◽

pp. 283

Author(s):

Chrysanthi Pankou ◽

Anastasios Lithourgidis ◽

Christos Dordas

Keyword(s):

Soil Health ◽

Triticum Aestivum L ◽

Agricultural Practice ◽

Environmental Resources ◽

Dry Land ◽

Land Equivalent Ratio ◽

Adaptation Capacity ◽

Growing Seasons ◽

Pisum Sativum L ◽

High Adaptation

Intercropping is an old and commonly used agricultural practice and involves the cultivation of two or more crops in the same area of land at the same time and may improve yield, the use of the environmental resources, product quality, and soil health. The objective of the present study was to study the effect of water availability of wheat-pea intercrops using agronomic and physiological characteristics. The experiment was conducted at the farm of Aristotle University of Thessaloniki, Greece during two growing seasons 2017–2018 and 2018–2019 using two different cultivars from pea (Isard and Olympos) and wheat (Yecora E and Elissavet) and two irrigation regimes. The availability of water increased grain yield and affected most of the characteristics that were studied. In terms of total Land Equivalent Ratio (LER) there was a yield advantage of intercrops over monocrops, which indicates the efficiency of intercropping for using the environmental resources. Both wheat cultivars, the pea cultivar Olympos and their intercrops indicated high adaptation capacity to rainfed conditions, whereas Isard and its intercrops performed better under irrigation. Therefore, the intercropping of wheat with pea uses the water resources of the environment more efficiently and can be used in dry land conditions for higher yield.

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Carbon dioxide fluxes over an ancient broadleaved deciduous woodland in southern England

Biogeosciences ◽

10.5194/bg-8-1595-2011 ◽

2011 ◽

Vol 8 (6) ◽

pp. 1595-1613 ◽

Cited By ~ 36

Author(s):

M. V. Thomas ◽

Y. Malhi ◽

K. M. Fenn ◽

J. B. Fisher ◽

M. D. Morecroft ◽

...

Keyword(s):

Carbon Dioxide ◽

Primary Productivity ◽

Management Practices ◽

Net Primary Productivity ◽

Deciduous Forest ◽

Carbon Sink ◽

Ecosystem Respiration ◽

Flux Chamber ◽

Southern England ◽

Temperate Deciduous

Abstract. We present results from a study of canopy-atmosphere fluxes of carbon dioxide from 2007 to 2009 above a site in Wytham Woods, an ancient temperate broadleaved deciduous forest in southern England. Gap-filled net ecosystem exchange (NEE) data were partitioned into gross primary productivity (GPP) and ecosystem respiration (Re) and analysed on daily, monthly and annual timescales. Over the continuous 24 month study period annual GPP was estimated to be 21.1 Mg C ha−1 yr−1 and Re to be 19.8 Mg C ha−1 yr−1; net ecosystem productivity (NEP) was 1.2 Mg C ha−1 yr−1. These estimates were compared with independent bottom-up estimates derived from net primary productivity (NPP) and flux chamber measurements recorded at a plot within the flux footprint in 2008 (GPP = 26.5 ± 6.8 Mg C ha−1 yr−1, Re = 24.8 ± 6.8 Mg C ha−1 yr−1, biomass increment = ~1.7 Mg C ha−1 yr−1). Over the two years the difference in seasonal NEP was predominantly caused by changes in ecosystem respiration, whereas GPP remained similar for equivalent months in different years. Although solar radiation was the largest influence on daily values of CO2 fluxes (R2 = 0.53 for the summer months for a linear regression), variation in Re appeared to be driven by temperature. Our findings suggest that this ancient woodland site is currently a substantial sink for carbon, resulting from continued growth that is probably a legacy of past management practices abandoned over 40 years ago. Our GPP and Re values are generally higher than other broadleaved temperate deciduous woodlands and may represent the influence of the UK's maritime climate, or the particular species composition of this site. The carbon sink value of Wytham Woods supports the protection and management of temperate deciduous woodlands (including those managed for conservation rather than silvicultural objectives) as a strategy to mitigate atmospheric carbon dioxide increases.

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Greenhouse gas flux measurements in a forestry-drained peatland indicate a large carbon sink

Biogeosciences ◽

10.5194/bg-8-3203-2011 ◽

2011 ◽

Vol 8 (11) ◽

pp. 3203-3218 ◽

Cited By ~ 66

Author(s):

A. Lohila ◽

K. Minkkinen ◽

M. Aurela ◽

J.-P. Tuovinen ◽

T. Penttilä ◽

...

Keyword(s):

Carbon Sink ◽

Accumulation Rate ◽

Peat Soil ◽

Net Ecosystem Exchange ◽

Flux Measurement ◽

Co2 Exchange ◽

Co2 Uptake ◽

Flux Measurements ◽

Ch4 And N2o ◽

Carbon Dioxide Co2

Abstract. Drainage for forestry purposes increases the depth of the oxic peat layer and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) change: due to the accelerated decomposition of peat in the presence of oxygen, drained peatlands are generally considered to lose peat carbon (C). We measured CO2 exchange with the eddy covariance (EC) method above a drained nutrient-poor peatland forest in southern Finland for 16 months in 2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2–5-week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was −870 ± 100 g CO2 m−2 yr−1 in the calendar year 2005, indicating net CO2 uptake from the atmosphere. The site was a small sink of CH4 (−0.12 g CH4 m−2 yr−1) and a small source of N2O (0.10 g N2O m−2 yr−1). Photosynthesis was detected throughout the year when the air temperature exceeded −3 °C. As the annual accumulation of C in the above and below ground tree biomass (175 ± 35 g C m−2) was significantly lower than the accumulation observed by the flux measurement (240 ± 30 g C m−2), about 65 g C m−2 yr−1 was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown by EC measurements to occur in a forestry-drained peatland. Our results suggest that forestry-drainage may significantly increase the CO2 uptake rate of nutrient-poor peatland ecosystems.

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CO2 uptake decreased and CH4 emissions increased in first two years of peatland seismic line restoration

10.21203/rs.3.rs-759056/v1 ◽

2021 ◽

Author(s):

Megan Schmidt ◽

Scott J. Davidson ◽

Maria Strack

Keyword(s):

Oil And Gas ◽

Ecosystem Respiration ◽

Tree Seedlings ◽

Co2 Uptake ◽

Seismic Line ◽

Oil And Gas Exploration ◽

Net Productivity ◽

The Impact ◽

Seismic Lines ◽

Reference Areas

Abstract Oil and gas exploration has resulted in over 300,000 km of linear disturbances known as seismic lines, throughout boreal peatlands across Canada. Sites are left with altered hydrologic and topographic conditions that prevent tree re-establishment. Restoration efforts have concentrated on tree recovery through mechanical mounding to re-create microtopography and support planted tree seedlings to block sightlines and deter predator use, but little is known about the impact of seismic line disturbance or restoration on peatland carbon cycling. This study looked at two mounding treatments and compared carbon dioxide and methane fluxes to untreated lines and natural reference areas in the first two years post-restoration. We found no significant differences in net ecosystem CO2 exchange, but untreated seismic lines were slightly more productive than natural reference areas and mounding treatments. Both restoration treatments increased ecosystem respiration, decreased net productivity by 6–21 gCO2m− 2d− 1, and created areas of increased methane emissions, including an increase in the contribution of ebullition, of up to 2000 mgCH4m− 2d− 1. Further research on this site to assess the longer-term impacts of restoration, as well as application on other sites with varied conditions, will help determine if these restoration practices are effective.

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