Emissions of N2O, CH4 and CO2 from undisturbed and drained peatlands in Estonia Jüri-Ott Salm*1,2, Kai Kimmel1, Ain Kull1, Merje Lesta1, Ülo Mander1
1Department
of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia (
[email protected]) 2Estonian Fund for Nature, 3 Magasini St., 51005 Tartu, Estonia
This paper aims to estimate emissions of greenhouse gases (GHG) N2O, CH4, and CO2 in Estonian transitional fens and ombrotrophic bogs according to their disturbance due to drainage. These changes are related to changes in land use and directly affect the sequestering and emission of these greenhouse gases (Mosier et al., 1991). The analysis GHG emissions has been performed mainly on the basis of the literature data from boreal regions of Fennoscandia and North America, which are comparable to Estonian conditions considering biophysical factors, mire types and flora (Salm et al., 2009). Also, data is collected from our field investigations (closed chamber method, gas-chromatograph analysis (Hutchinson & Livingston, 1993) (Fig. 1) — 6 field study sites of undisturbed and altered mire types and peat mining areas. The following cartographic sources were used to estimate the total area of transitional fens and raised bogs: (1) Digital land cover database created by the CORINE Land Cover project covering the whole of Estonia (1997); (2) Landscape maps; (3) Map layer for drained areas. The annual emission of CO2, CH4 and N2O in Estonia is estimated to be 779,740 t CO2 eq, of which CO2 makes up 403,390 CO2 eq (403,390 t CO2 yr1), CH4 359,692 CO2 eq (17,128 t CH4 yr1) and N2O 16,659 CO2 eq (56 t N2O yr1). Figure 1. Field work site in Valgeraba mire The annual efflux from the drained area is 647,796 CO2 eq, and 131,944 t CO2 eq from the undrained area. Comparing GHG emissions (CO2 eq) from the areas under drainage (15% of the total area) with undisturbed areas (85%), the former contribute 83% of total emissions, whereas the reduction of CH4 efflux due to drainage does not compensate the increase in CO2 emissions. Literature Cited Hutchinson, G.L. & Livingston, G.P. (1993) Use of chamber systems to measure trace gas fluxes. In: Harper, L.A., Mosier, R.A., Duxbury, J.M. & Rolston, D.E. (Eds.) Agricultural Eecosystem Effects on Trace Gases and Global Climate Change, ASA Special Publication 55: Madison, WI, pp. 63–78. Mosier A. D., Schimel, D. Valentine, K. Bronson, and W. Parton. (1991) Methane and nitrous oxide fluxes in native, fertilized and cultivated grasslands. Nature 350: 330–332. Salm, J.-O., Kimmel, K. and Mander, Ü. (2009, in press) Changes in the ecosystem services of mires in Estonia, estimated on the basis of CO2, CH4 and N2O emissions. Wetlands.
Variable Peat and Carbon Accumulation Rates in WestCentral Canadian Sub-Arctic Peat Plateaus A. Britta K. Sannel* and Peter Kuhry
Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden (
[email protected])
Peatlands in the northern circumpolar permafrost zone are important reservoirs of soil organic carbon, containing ~277 Pg carbon (Schuur et al., 2008). As a result of global warming the highest increases in temperature are predicted to take place at high northern latitudes, affecting permafrost peatlands in many ways; e.g., through increased thaw depth, changes in carbon accumulation, and methane emissions (ACIA 2005). The aim of this study is to better understand the long-term carbon dynamics in subarctic peat plateaus in relation to vegetation and permafrost conditions. Peat and net carbon accumulation rates in two subarctic peat plateaus of west-central Canada have been studied through plant macrofossil and geochemical analyses and AMS radiocarbon dating (Sannel and Kuhry 2008, 2009). The longterm peat and carbon accumulation rates for the studied peat profiles are 0.30-0.31 mm/yr and 12.5-12.7 gC/m2yr. Extensive radiocarbon dating of one profile (SL1) shows that accumulation rates are variable over time and that abrupt shifts in accumulation rates occur when the vegetation composition in the peat changes (Fig. 1). Peat accumulation rates are up to 6 times higher and net carbon accumulation rates up to 4 times higher in S. fuscum than in rootlet stages. In both profiles carbon/ nitrogen ratios in Sphagnum peat are relatively high (c. 90-140) and remain rather stable throughout most of the profiles, indicating that the organic material that has been incorporated into the permafrost has a low degree of Fig. 1. Peat and net carbon accumulation rates for decomposition. Persistently dry profile SL1. The age-depth model shows variable surfaces as a result of stable accumulation rates over time according to net carbon accumulation rates. Error bars for calibrated permafrost conditions since the peat ages represent 68% confidence intervals. (Sannel and plateaus developed suggest that these Kuhry 2009). peatlands have been negligible as methane sources throughout their history. However, in a future warmer climate thermokarst can increase, shifting these ecosystems into methane sources.
Literature Cited ACIA (2005) Arctic Climate Impact Assessment. Cambridge University Press. 1042 pp. Sannel, A. B. K. and Kuhry, P. (2008) Long-term stability of permafrost in subarctic peat plateaus, westcentral Canada. The Holocene 18: 589-601. Sannel, A. B. K. and Kuhry, P. (2009) Holocene peat growth and decay dynamics in sub-arctic peat plateaus, west-central Canada. Boreas 38: 13-24. Schuur, E.A.G. et al. (2008) Vulnerability of permafrost carbon to climate change: Implications for the global carbon cycle. Bioscience 58: 701-714.
Managing Peatlands to Reduce Carbon Emissions 1School
Alexandra Savage*1, Joseph Holden1, and John Wainwright2
of Geography, University of Leeds, Leeds, LS2 9JT, UK (
[email protected]) 2Department of Geography, University of Sheffield, Sheffield, S10 2TN, UK
Carbon cycling in peat is governed by four principal factors: “environmental conditions, substrate quality, nutrients, and microbes” (Laiho, 2006). Changes in one or more of these drivers will impact on the carbon budget of peat. Carbon budget calculations for unmanaged peatlands have demonstrated that peatlands are carbon sinks. Carbon budget calculations carried out by Worrall et al. (2003) indicate that carbon dioxide accounts for the greatest loss of carbon from peat ecosystems, followed by methane, once the global warming potential of this greenhouse gas is taken into account. If climate change predictions are realised, peatlands are expected to become sources of carbon as rising temperatures and falling water tables will result in increased rates of carbon mineralisation. Land management practices have historically been engaged on areas of peatlands in order to provide an income for the rural population. As the need to preserve carbon stocks rises on the political agenda, questions are being asked about how peatlands should be managed in the future to preserve these precious carbon stocks. At present, little is known about how management affects carbon emissions, and whether one strategy might be favoured over another in the future from a perspective of preserving carbon stocks. A field study was carried out in the British uplands to determine how carbon emissions vary between differently managed peatlands, and to identify some of the underlying causes for such variations. The study focussed on three of the driving factors identified by Laiho (2006); substrate quality, environmental conditions, and nutrients. In addition, the physical properties of the peat – bulk density and air filled porosity that will control rates of gas and water movement within the peat profile, were studied. This paper will present the results of the work that was carried out at the Moor House, National Nature Reserve. The work involved collection of peat cores from burnt, grazed, drained, afforested, and unmanaged areas of peat. The chemical and physical properties of the peat that are relevant to carbon cycling (e.g., nutrients, metals, substrate quality, air filled porosity) were analysed and compared between sites, and correlated with carbon emissions which were measured on a fortnightly basis; and meteorological and hydrological data which were collected throughout the study period. Based on these results, suggestions for peatland management strategies that preserve carbon stocks will be presented.
Literature cited Laiho, R. (2006) Decomposition in peatlands: Reconciling seemingly contrasting results on the impacts of lowered water levels. Soil Biology & Biochemistry 38: 2011-2024. Worrall, F. et al. (2003) Carbon budget for a British upland peat catchment. Science of the Total Environment 312: 133-146.
Climate Change Impacts on Ombrotrophic Bog Plant Communities: The Role of Desiccation and NDeposition on Sphagnum Growth and Restoration Success Sebastian R. Schmidt*1, Marion Vanselow-Algan2, Claudia Fiencke2, Eva-Maria Pfeiffer2 and Kai Jensen1 University of Hamburg, Biocenter Klein Flottbek, Applied Plant Ecology, Ohnhorststr. 18, 22609 Hamburg (
[email protected]). University of Hamburg, Institute of Soil Science, Allende-Platz 2, 20146 Hamburg, Germany
Precipitation and nitrogen availability are key factors affecting plant growth. Climate change scenarios indicate an increasing risk of summer droughts in northern Germany due to less summer precipitation (10 to 30% less in summer while the annual amount of rain remains constant). Nitrogen deposition is already a current threat to species adapted to low nitrogen habitats like bogs. It is well known that desiccation plays an important role for Sphagnum growth and may alter the competitive balance between species. Water table drawdown negatively affects Sphagnum growth and CO2 assimilation, even varying for hummock and hollow species and favouring hummock species over hollow species. On the other hand, high N-deposition favours the invasion of vascular plants such as Molinia caerulea into ombrotrophic bogs. We are conducting a two-factorial field experiment on two sites of each ecosystem: Firstly we are reducing summer precipitation by 25% with rainout shelters and secondly we are imitating nitrogen deposition by fertilization (equal to 35 kg N ha-1 a-1). Further, we are combining both treatments and installing control plots. The experiment will run with seven replicates per site. The two experimental sites of each ecosystem are situated along a continental gradient (one site under sub-oceanic and one under sub-continental climatic conditions) to determine if plants living under more continental conditions today are already pre-adapted to summer drought. We will analyse shifts in species composition as well as changes in biomass production and Caccumulation. Additionally, we will measure the greenhouse gas fluxes (CO2, CH4, N2O) between soil and atmosphere to estimate 1) the impact of climate change on ombrotrophic and 2) a reverse feedback of bogs on climate change. In combination with hydrological observations these measurements will give information about the function of bogs as sinks and/ or sources of carbon and nitrogen. Further, the results may help to enhance the success of ongoing and future restoration efforts.
Environmental Controls on Carbon Dioxide Fluxes of a Boreal Peatland, Komi Republic, NW Russia Julia Schneider1*, Michal Gazovic1, Lars Kutzbach1,2, Ulrike Wolf3, Michail Miglovec4, Oleg Michajlov4, Christian Wille1,2, Peter Schreiber1,2, Jens Ibendorf1, and Martin Wilmking1
1Institute
of Botany and Landscape Ecology, Ernst Moritz Arndt University Greifswald, Grimmer Straße 88, 17487 Greifswald, Germany (
[email protected]); 2now at Institute of Soil Science, University of Hamburg, Germany. 3Department of Landscape Ecology, Georg August University Göttingen, Germany. 4Insitute of Biology, Komi Science Centre, Russian Academy of Sciences, Syktyvkar, Russia
Recently, boreal peatlands have been subject to many speculations regarding climate change effects and greenhouse gas exchange. Peatlands are well known to be a long-term sink for atmospheric carbon dioxide, but in a changing climate, the CO2 fluxes can significantly change, and peatlands may even become an atmospheric carbon source. The Russian boreal zone covers vast areas, and peatlands are one of the major ecosystems of this region. However, only little scientific evidence is available from this region. In order to address this uncertainty, landscape-scale measurements as well as investigations of the small-scale variability of CO2 fluxes are necessary. Our study site is located at 61°56'N, 50°13'E in the European part of northern Russia. CO2 flux measurements by eddy covariance technique were carried out from April to October 2008 and by closed chamber technique at six different microsite types within the eddy covariance footprint on 84 days within that time period. While it is important to quantify the CO2 fluxes, we also need to improve our understanding on how the ecosystem-atmosphere interactions are controlled. To do so, we measured a wide range of meteorological parameters and quantified vegetation characteristics by measuring the foliage cover (LAI) and green area of vascular leaves. The few studies reporting CO2 fluxes from boreal peatlands in Russia all focus on measurements during summer time. However, to improve our understanding of CO2 flux dynamics of peatlands over the year, further research on the CO2 dynamics during the spring and autumn seasons is needed. Here, we compare the environmental control mechanisms on CO2 fluxes identified for the landscape and microsite scales during spring, summer and autumn seasons.
Biotic and Abiotic Controls on Methane Release Pathways from Thermokarst Peatlands Kathleen Shea*, Merritt Turetsky Department of Integrative Biology; Science ComplexUniversity of Guelph 50 Stone Rd. E, Guelph, ON, Canada N1G 2W1 (
[email protected]) Peatlands currently store ~20% of global soil carbon, and are therefore large potential sources of atmospheric methane (CH4) (Vasander & Kettunen, 2006). Due to the multiple, interacting factors affecting total CH4 emission rates in peatlands, the effects of climate change on total CH4 flux are difficult to predict. This is especially true in regions affected by thermokarst since subsidence associated with ground ice thawing may significantly affect peatland
hydrology, soil temperatures, and soil organic matter quality (e.g., Hinzman et al., 2005; Christensen et al., 2004). In 2005, the Alaska Peatland Experiment (APEX) was established to study soil hydroclimate controls on vegetation and ecosystem carbon cycling in an intermediate rich fen within the Tanana Valley of Interior Alaska. In 2007, the APEX was expanded to include two additional sites: a forested peatland underlain by surface permafrost and an adjacent thermokarst bog. Initial results suggest that while water table position may be correlated with CH4 emissions in the rich fen (RF), it does not appear to be a strong controller of fluxes at the thermokarst bog (TB) (Figure 1). Additionally, the mean seasonal co-efficient of variation (CV) for CH4 emissions is higher at the TB than at the RF (86 and 107%, respectively), suggesting that temporal and microform variation following permafrost thaw may be essential for understanding site-level CH4 emissions in northern wetlands. Our ongoing research examines the interactions between the soil environment, peat properties, and vegetation communities that govern CH4 fluxes from thermokarst peatlands in Alaska. Specific objectives include: (i) quantification of the total CH4 flux of a thermokarst peatland in the interior of Alaska; (ii) establishing the relative importance of the three modes of CH4 release to total flux rate in these systems (diffusion, ebullition and plant mediated transport); and (iii) identification of key biotic and abiotic controls on each transport mechanism. Literature Cited Christenson, T., Johansson, T., Akerman, H.J. and Mastepanov, M. (2004) Thawing sub-arctic permafrost: Effects on vegetation and methane emissions. Geophysical Research Letters 31: 1-4. Hinzman, L.D., Viereck L.A., Adams P.C., Romanovsky V.E. and Yoshikawa K. (2006) Climate and permafrost dynamics of the Alaskan boreal forest. In Chapin, FS III, Oswood MW, Van Cleve K, Viereck LA, and Verbyla DL, eds. Alaska’s Changing Boreal Forest. Oxford University Press, New York. Vasander, H. and Kettunen, A. (2006) Carbon in boreal peatlands. Ecological Studies: Analysis and Synthesis 188: 165-194.
Various Litter Species and High Water-Table Levels Hamper Type II Methanotrophs in a Bare Peatland Regeneration Experiment Andy Siegenthaler*1, Andreas Gattinger2, André-Jean Francez3, Daniel Gilbert4, Alexandre Buttler1, Mauro Tonolla5, and Edward Mitchell6
1EPFL
and Swiss Federal Research Institute WSL, Wetlands Research GroupStation 2, CH-1015 Lausanne-Ecublens, Switzerkland (
[email protected] ); 2Institut für Bodenökologie, GSFForschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; 3Campus de Beaulieu, U.M.R.- C.N.R.S. n° 6553 "Ecobio" , CAREN, bâtiment 14BF - 35 042 Rennes cedex Rennes, France; 4Laboratoire de Chrono-environnement, Université de Franche-Comté, 4 place Tharradin, BP 71427, F-25 211 MONTBELIARD cedex, France; 5Istituto Cantonale di Microbiologia, Via Mirasole 22 A, CH-6500 Bellinzona, Switzerland; 6Laboratory of Soil Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2009 Neuchâtel, Switzerland
Significant areas of temperate bogs have been damaged by peat harvesting. After abandonment and spontaneous regeneration, these secondary mires can become important methane sources towards the atmosphere (Basiliko et al., 2007). Recent studies have shown the importance of methane oxidising bacteria (MOB) for the recycling of carbon from methane effluxes (e.g., Dedysh et al., 2001; Raghoebarsing et al., 2005). We set up a factorial experiment that allowed us to tests the effects of three levels of naturally fluctuating water table depths (13, 22, 35 cm) crossed with the effects of four different litter types (control, E. vaginatum, E. angustifolium, S. fallax). With help of improved 16 rRNA fluorescent in-situ hybridisation techniques we quantified the number of type II methane oxidising bacteria (MOB) living at different depths and just bellow the surface. The results show that the water table can strongly influence the active type II methan-otrophs living in the first 5 cm of the regenerating bare peat. These methane oxidis-ing bacteria were also hampered by the presence of plant litter placed on top of the bare peat surface. This could have important implication for the methane oxidation potential of methane and on restoration management practices. Literature Cited Basiliko, N., Blodau, C., Roehm, C., Bengtson, P., and Moore, T.R. (2007) Regulation of decomposition and methane dynamics across natural, commercially mined, and restored northern peatlands. Ecosystems 10: 1148-1165.
Figure 1: Modeled least square means of the number of living type II methanotrophs per gram fresh weight in fonction of : a) the water table depths (High=13 ; Interm=22 ; Low=35) and b) various litter species (CT=control ; EA=E. angustifolium ; EV=E. vaginatum ; S=Sphagnum fallax). Square-root transformed values. Error bars = ± SEM
Dedysh, S.N., Derakshani, M., and Liesack, W. (2001) Detection and enumeration of methanotrophs in acidic Sphagnum peat by 16S rRNA fluorescence in situ hybridization, including the use of newly developed oligonucleotide probes for Methylocella palustris. Applied and Environmental Microbiology 67: 4850-4857. Raghoebarsing, A.A., Smolders, A.J.P., Schmid, M.C., Rijpstra, W.I.C., Wolters-Arts, M., Derksen, J., Jetten, M.S.M., Schouten, S., Damste, J.S.S., Lamers, L.P.M., Roelofs, J.G.M., den Camp, H., and Strous, M. (2005) Methanotrophic symbionts provide carbon for photosynthesis in peat bogs. Nature 436: 1153-1156.
Contrasted Relationships Between Type I and Type II Methanotrophs, The Conditions Found in Typical Regeneration Stages Across European Peatlands and the Elapsed Time Since Abandonment of the Peat Cutting Andy Siegenthaler1, Rebekka Artz2, André-Jean Francez, Alexandre Buttler1, Emanuela Samaritani1, Daniel Gilbert3, Mika Yli-Petays4, Estelle Bortoluzzi5, Mauro Tonolla6, and Edward Mitchell7 1EPFL
and Swiss Federal Research Institute WSL, Wetlands Research Group Station 2, CH-1015 Lausanne-Ecublens, Switzerkland (
[email protected]); 2Macaulay Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK; Campus de Beaulieu, UMR-CNRS 6553 "Ecobio" , CAREN, bâtiment 14B, F 35 042 Rennes cedex Rennes, France; 3Laboratoire de Chrono-environnement, Université de FrancheComté, 4 place Tharradin, BP 71427, F-25 211 Monbelliard cedex, France; 4Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014 Finland; 5Laboratoire de Chronoécologie, Université de Franche-Comte, La Bouloie, 25030, Besancon CEDEX; 6Istituto Cantonale di Microbiologia, Via Mirasole 22 A, CH-6500 Bellinzona, Switzerland; and 7Laboratory of Soil Biology, University of Neuchâtel, Rue Emile Argand 11, CH-2009 Neuchâtel, Switzerland
Significant areas of temperate bogs have been damaged by peat harvesting. After
Fig. 1. Number of living methane oxidizing bacteria (MOB) per gram fresh weight of peat related to the regeneration time after abandonment of the peat cutting (TAPC), one of the most explanatory descriptor found in the multivariate analyses expressing the multiple ecological gradients four along four European peatlands. MOB I = type I methanotrophs (probes: M-84 and M-705), MOB II = type II methanotrophs (probe: M-450), AcidM181 = Methylocystys palustris and M. acidiphila B2 (includes the older: Mcaps 1032 and Mcell1026).
abandonment and spontaneous regeneration, these secondary mires can become important methane sources towards the atmosphere (Basiliko et al., 2007). Recent studies have shown the importance of methane oxidising bacteria (MOBs) for the recycling of carbon from methane effluxes (e.g., Dedysh et al., 2001; Raghoebarsing et al., 2005) but very little information has been gathered on the ecology of these climatically important organisms along regeneration gradients (Artz et al., 2007). The relationship between MOBs and the conditions found in typical regeneration stages was investigated at four European peatlands (CH, F, UK, FIN), each with up to five sites representing a gradient of natural regeneration stages. These sites were extensively characterized with physico-chemical and plant biological descriptors. With help of refined 16 rRNA fluorescent in-situ hybridisation techniques we quantified the number of various types of MOBs (Type I, Type II, AcidM181) living between 5 and 10 cm below the active Sphagnum carpet. The main axes of explained variance were also compared to methane effluxes. The restricted multivariate analyses show that next to important physico-chemical explanations there is a clear correlation between the time since abandonment of the peat cutting (TAPC) and the various functional groups of active MOBs. For exemple, the type I MOBs were negatively - while type II MOBs were positively - related to time. The AcidM181 MOBs show no significant relationship to time. These different strategies in the ecology of MOBs could have important implications for the oxidation of the effusing methane in this particular type of restoration management practice. Literature Cited Artz, R.R.E., Anderson, I.C., Chapman, S.J., Hagn, A., Schloter, M., Potts, J.M., and Campbell, C.D. (2007) Changes in fungal community composition in response to vegetational succession during the natural regeneration of cutover peatlands. Microbial Ecology 54: 508-522. Basiliko, N., Blodau, C., Roehm, C., Bengtson, P., and Moore, T.R. (2007) Regulation of decomposition and methane dynamics across natural, commercially mined, and restored northern peatlands. Ecosystems 10: 1148-1165. Dedysh, S.N., Derakshani, M., and Liesack, W. (2001) Detection and enumeration of methanotrophs in acidic Sphagnum peat by 16S rRNA fluorescence in situ hybridization, including the use of newly developed oligonucleotide probes for Methylocella palustris. Applied and Environmental Microbiology 67: 4850-4857. Raghoebarsing, A.A., Smolders, A.J.P., Schmid, M.C., Rijpstra, W.I.C., Wolters-Arts, M., Derksen, J., Jetten, M.S.M., Schouten, S., Damste, J.S.S., Lamers, L.P.M., Roelofs, J.G.M., den Camp, H., and Strous, M. (2005) Methanotrophic symbionts provide carbon for photosynthesis in peat bogs. Nature 436: 1153-1156.
Land Use and C-gas Emissions from Peatlands in Russia Andrey Sirin*1, Maxim Chistotin2, Mikhail Glagolev3, Tatiana Minayeva4, and Gennady Suvorov1 1Institute
of Forest Science Russian Academy of Sciences, Uspenskoye, Moscow region, 143030 Russia (
[email protected]). 2Pryanishnikov All-Russian Institute of Agrochemistry Russian Academy of Agricultural Sciences, Prynishnikova str 31a, Moscow, 127550 Russia. 3Faculty of Soil Science Moscow State University, Vorobievy Gory, Moscow, 119899 Russia, 4Wetlands International, Nikoloyamskaya 19 bd 3, Moscow, 109240 Russia
The Russian Federation possesses vast areas of peatlands that could be responsible for the largest part of C-gas exchange between peatlands and the atmosphere in the world. Russian peatlands present a variety of natural conditions from permafrost mires to bogs, fens, and swamps within boreal, temperate, steppe, and semi-arid zones. These zones have quite different flux rates of C-gas. The large areas of virgin mires are often considered pristine, but in the central European part of Russia, West Siberia, and the Far East the appreciable part of peatlands have been disturbed and it is these we will study. Peatlands were traditionally used for peat extraction (c 1.5 million ha); agriculture (c 3 million ha), and forestry (c 3 million ha) (Minayeva & Sirin, 2005). Most regions present a combination of different disturbances; under extraction, agriculture, forestry, abandoned and restored areas. C-gas fluxes from peatlands with different land uses were analyzed using available Russian data along with the results of two pilot regions in Central European Russia and West Siberia. These included both modified and pristine control sites. The effect of peatland drainage and the use afterward on the Figure. Carbon dioxide and methane emissions from studied intact and disturbed by land use peatlands in the southern part of West Siberia, Russia. emission of carbon The range between 1 and 3 quartiles are shown. CO sequestration by peat 2 dioxide and methane formation and vegetation growth not included. (Glagolev et al., 2008). was studied using the chamber method in the southern regions of Tomsk region during 2003 (Glagolev et al., 2008). The measurements were taken on peatlands drained for agricultural use and peat cutting (both abandoned and recultivated) and a wide range of undrained mires; along with burned peatland areas of different ages. The analysis of the data (Figure) indicated a higher emission of carbon dioxide from disturbed sites to undrained sites. Some drained peatlands were characterized by considerable methane emission rates, which was enhanced by the efflux from drainage ditches (see fig.). Similar results were shown by studies conducted starting in 2005 in the Moscow region, where carbon dioxide and methane fluxes from peatlands under extraction, abandoned, and control intact sites were measured during all seasons of the year (by chamber method) (partly published by Chistotin et al. 2006). Unexpected methane flux was measured from highly drained peatlands under extraction and one used as a hayfield. The elevated sites of the intact peatland with dwarf-shrub pine vegetation were often a weak methane sink. Our results show that disturbed peatlands can become significant sources of carbon dioxide and that they do not totally stop emitting methane, which is still intensively released from drainage ditches and under warm wet conditions. The study was partly supported by Russian Foundation for Basic Researches (Project 09-05-01113-а). Literature Cited Сhistotin, M.V., Siгin, A.A., and Dulov, L.Е. (2006) Sеasonal dynamiсs of caгbon dioхidе and mеthanе emission from a pеatland in Mosсow Rеgion drainеd for pеat eхtraсtion and agriсultural usе. Agrochemistry (Agrokhimija), N 6: 54–62. (in Russian)
Glagolev M.V., Chistotin M.V., Shnyrev N.A., and Sirin A.A. (2008) The emission of carbon dioxide and methane from drained peatlands changed by economic use and from natural mires during the summer-fall period (on example of a region of Tomsk Oblast). Agrochemistry (Agrokhimija), N 5: 46–58. (in Russian). Minayeva T., A. Sirin. (2005) Use and Conservation of Mires in Russia / Mires – from Siberia to Tierra del Fuego". Denisia 16, zugleich Kataloge der OÖ. Landesmuseen Neue Serie 2: 275–292.
The Role of Natural Pipes in Carbon Transfer in Northern Peatlands Richard Smart*1, Joseph Holden1, Pippa Chapman1, Mike Billett2, Kerry Dinsmore2, and Andy Baird1 1 School
of Geography, University of Leeds, Woodhouse Lane, Leeds, UK, LS2 9JT, (
[email protected]). 2Centre for Ecology and Hydrology, Edinburgh Research Station, Bush Estate, Penicuik, Midlothian, EH26 0QB, Scotland
Natural pipes have been found to be ubiquitous in UK peatlands (Holden, 2005c). However, no one has studied carbon exports from natural pipe waters in deep peats. Hence the results from this study will help to elucidate the proportion of streamwater carbon from natural pipes in blanket bog drainage waters. Pipes form complex undulating networks within the peat profile (Holden 2005c) and may, under differing flow conditions, collect water from various depths within the peat. Holden (2005a, 2005b, 2006) has shown that environmental change in peatlands can lead to increased pipe densities. Pipes therefore have the potential to release greater amounts of carbon from deep within the peat to the aquatic and atmospheric systems, thus becoming a positive feedback mechanism in terms of climate change. This study is based at Cottage Hill Sike, a 20-hectare peat covered catchment in the Moor House National Nature Reserve in the UK North Pennines. The mean annual DOC flux has been measured at 218 kg ha-1 yr-1 (1993 – 2002) (Clark et al., 2005). Over 80 pipe outlets have been found within this catchment, of which we have chosen eight representative pipes and the catchment outlet to monitor both routinely and during rainfall events (Table 1). Pipe and stream waters are routinely (bi-weekly) sampled and analysed for DOC, POC, pH, conductivity, CO2 and CH4 and storm samples are analysed for DOC, POC, pH and conductivity. Flow is also measured at these points. Table 1. Physical characteristics and mean DOC, POC, CO2, and CH4 of flow gauged pipes and stream within Cottage Hill Sike. E = ephemeral, C = continuous flow, all flows measured in L s-1,. Pipes marked with an * also have autosamplers installed. Site CHS * P1 P3 * P5 * P6 P9 P32 * P35 * P39 * Pipe outlet diameter (cm) NA 17 3 30 6.5 1 20.5 10 10 Pipe roof depth from peat NA 47 75 25 60 100 100 30 160 surface (cm) Flow characteristics C E E C E E C C E Maximum recorded flow 4460 0.39 0.015 10.8 0.012 0.013 0.29 0.32 2.01 Minimum recorded flow 0.05 0 0 0.006 0 0 0.005 0.0007 0 Mean DOC 27.93 29.75 27.88 25.41 22.39 24.36 25.90 45.88 33.12 Mean POC 1.00 1.49 1.02 0.62 0.99 2.36 25.90 45.88 33.12 Mean CO 2 2.63 0.83 1.94 2.31 1.04 1.22 9.36 3.34 2.20 Mean CH 4 0.025 0.009 0.005 0.012 0.008 0.014 4.877 0.389 0.081
Results so far show that 20 to 30% of the flow recorded at the catchment outlet can be accounted for by pipe flow, 53% of DOC exported in the stream is produced by the pipes and 200% of the exported POC in the stream is produced by the pipes (not all of the POC leaving the pipes makes it’s way to the stream and some of it is held in storage). Literature Cited Clark JM et al. (2005). Global Change Biology 11: 791-809. Holden, J. (2005a) Philosophical Transactions of the Royal Society A., doi: 10.1098/rsta.2005.1671. Holden J (2005b) Water Resources Research 41, doi: 10.1029/2004WR003909. Holden J (2005c) Journal of Geophysical Research 110, doi: 10.1029/2004JF000143.
CH 4 Ebullition from Northern Peatlands: Spatial and Temporal Variability in Flux Rates from a SphagnumRich Raised Bog in West Wales . Imelda Stamp*1, Andrew J. Baird2, and Catherine M. Heppell1
1Department
of Geography, Queen Mary University of London, Mile End, London E1 4NS, UK (
[email protected]). 2School of Geography, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
CH4 is transported to the atmosphere from peatlands by three main mechanisms: plant transport, matrix diffusion, and bubble ebullition. Until recently, the dynamics of CH4 bubble production and release from peatlands received little attention and ebullition has remained poorly represented in peatland CH4 flux models. Several recent peatland studies have suggested that ebullition may be the dominant pathway for CH4 flux to the atmosphere, exceeding emissions via plant transport and matrix diffusion. However, rates of loss via ebullition vary between 0 and 35,000 mg CH4 m-2 d-1 (e.g., Baird et al., 2004; Glaser et al., 2004; Tokida et al., 2007). Such wide-ranging estimates reflect, in part, the highly variable nature of ebullition that occurs non-randomly across a peatland via the continuous loss of small surface bubbles and via larger-scale episodic or cyclical events (e.g., during low pressure weather systems). Capturing this spatial and temporal variability in CH4 flux models presents a significant challenge which can only be met through further investigation into the dynamics of free-phase CH4 production, storage and loss from a range of peat types. This poster presents preliminary results from a study investigating ebullition losses from a Sphagnum-rich raised bog in West Wales. Estimates are based on ebullition fluxes recorded between April 2008 and August 2009 using 20 chambers and 30 surface-funnels located across a range of peatland microforms (hummocks, hollows, lawns, and pools). Spatial and temporal variability in ebullition fluxes was determined by weekly/bi-weekly chamber sampling from April 2008 - March 2009 and by weekly surface-funnel observations between May and August 2009. High-frequency chamber sampling was carried out from June - August 2009 to assess the role of low pressure systems as “triggers” for larger-scale episodic ebullition events. Literature Cited Baird A.J., Beckwith C.W., Waldron S., and Waddington J.M. (2004) Ebullition of methane-containing gas bubbles from near-surface Sphagnum peat, Geophysical Research Letters 31: L21505, doi:10.1029/ 2004GL021157.
Glaser P.H., Chanton J.P., Rosenberry D.O., Morin P.J., Siegel D.I., Ruud O., Reeve A.S., and Chasar L. (2004) Surface Deformations as Indicators of Deep Ebullition Fluxes in a Large Northern Peatland, Global Biogeochemical Cycles 18: GB1003, doi: 10.1029/2003GB002069. Tokida T, Miyazaki T, Mizoguchi M, Nagata O, Takakai F, Kagemoto A, and Hatano R. (2007) Falling atmospheric pressure as a trigger for methane ebullition from a peatland. Global Biogeochemical Cycles 21: GB2003, doi: 10.1029/2006GB002790.
Cyanobacteria Associated With Sphagnum riparium (Ångstr.) Enhance Biomass Growth of the Moss by Transfer of Fixed Nitrogen. Bo H Svensson*, Andreas Berg
Department of Water and Enviromental Studies, Linkoping University sE-58183 Linkoping, Sweden (
[email protected])
Sphagnum mosses are spatially dominant species and are important in the formation of peatlands. They strongly influence carbon dynamics through CO2 fixation, peat formation, and the production of CO2 and CH4 when the Sphagnum litter degrades. Sphagnum growth in northern peatlands is limited by low levels of nitrogen, which is why an input from nitrogen fixation has the capacity to influence Sphagnum growth greatly and, consequently, to affect the carbon dynamics of peatlands. Cyanobacteria are found associated with Sphagnum mosses in many ecosystems, from polar to tropical biomes. They are found living both as epiphytes on the moss and inside the hyaline cells. Many Sphagnum-dominated ecosystems have low inputs of nitrogen and nitrogen fixation has been shown to contribute 25-82% (Chapin & Bledsoe, 1992) of the total nitrogen supply in these habitats. Despite the general assumption that nitrogen fixed by associated cyanobacteria will be readily utilised for growth by the Sphagnum, no empirical evidence is available in the literature. By cultivating Sphagnum riparium (Ångstr.) with and without cyanobacteria, we show that over 50% of the nitrogen fixed by cyanobacteria is directly transferred to the newly formed moss biomass. This nitrogen resulted in an increase in the growth of Sphagnum biomass compared to controls and, thus, we show that nitrogen fixation by cyanobacteria associated with Sphagnum mosses, influences moss growth rates by transfer of fixed nitrogen to the moss. Table 1. Nitrogen content and biomass growth for Sphagnum riparium plants with and without associated cyanobacteria
With cyanobacteria
Before incubation
n N-content (%)
Mean S.d.
Dry mass Mean per length S.d. -1 (g m )
No cyanobacteria
After 57 days of incubation
Before incubation
All moss
Old shoots
New shoots
16
31
31
31
1.6 0.2
-
2.1 0.38
0.47 0.11
0.61 0.22
-
After 57 days of incubation
All moss
Old shoots
New shoots
16
34
34
34
2.9 0.52
2.8 0.34
-
2.4 0.32
3.0 0.61
-
0.33 0.08
0.33 0.11
-
-
.
It is obvious that nitrogen fixation will increase the input of nitrogen to Sphagnum dominated ecosystems. Our results show that, in northern habitats, fixed nitrogen becomes available to the moss during a time-span shorter than one growing season. Thus, apart from causing a long-term increase in the nitrogen pool, nitrogen fixation can have an instant effect on carbon assimilation by Sphagnum mosses. Hence, short-term changes in nitrogen fixation can have direct effects on the growth dynamics of Sphagnum under nitrogen limited conditions. Literature cited Chapin DM and Bledsoe CS (1992) Nitrogen fixation in Arctic plant communities. In: Chapin FS, Jefferies RL, Reynolds JF, Shaver GR, and Svoboda J eds. Arctic Ecosystems in a Changing Climate. San Diego, Academic Press, pp. 301-319.
