Bleuten, W., Vasiliev, S.V. and Yefremov, S.P. - The West Siberian Peat Accumulating Ecosystems, The Missing Sink For Atmospheric Carbon Depletion.
World scale carbon budget models for prediction of climate change include only limited data from West Siberian lowland, where about 50% of the world peat-forming (carbon accumulating) ecosystems are situated. This area is a hardly quantified buffer against atmospheric carbon dioxide. Although undisturbed peat ecosystems emit substantial quantities of Methane, the net storage of Carbon by biomass production can not be denied in global change modeling. By measurements of peat layer thickness, vertical content of organic carbon, plant remnants and 14C dating, the historical Carbon fixation in the peat layers of West Siberia have been measured in key areas, in e sequence oriented by latitude (N56o-64o). Based on available peat maps, validated with these core data, the total Carbon pool stored in West Siberian peat was estimated to be 51 Gton Carbon. At least half of the missing volume of Carbon-dioxide in the world models for prediction of climate change can be explained by the yearly fixation by peat forming ecosystems in Siberia only. However, by drainage and land reclamation this carbon pool will be released to the atmosphere again.
Heijmans, M.M.P.D. and Berendse, F. - Effects of Elevated CO2 and Increased Nitrogen Deposition on A Bog Ecosystem In The Netherlands.
The effects of elevated CO2 and increased N deposition on the plant species composition of a bog community in the Netherlands were studied for three growing seasons as part of the European BERI-project. Large peat monoliths with intact bog vegetation were kept outside in large containers. Elevated CO2 conditions were established by MiniFACE technology. Increased N deposition was simulated by adding dissolved NH4 NO3.
Elevated CO2 had a positive effect on Sphagnum length growth, while vascular plant growth was stimulated by increased N deposition. In the third growing season Sphagnum growth was significantly reduced in the high-N plots, probably as a consequence of the increased vascular plant abundance during the experiment. We found a significant negative correlation between vascular plant cover and Sphagnum growth.
The interactions between peat mosses and vascular plants have important consequences for the carbon balance of the bog ecosystem. Sphagnum contributes more to peat accumulation than vascular plants. This means that the reduced Sphagnum growth as a result of high N deposition will lead to reduced carbon sequestration in bog ecosystems.
Jaya, A., Page, S.E., Rieley, J.O. and Limin, S. - Impact Of Forest Fires On Carbon Storage In Tropical Peatlands.
A key function of tropical peatlands is carbon storage, with implications for global climate change. In 1997, extensive peatswamp forest fires related to the Mega Rice Project (MRP) in Central Kalimantan, Indonesia, are believed to have released a large amount of carbon into the atmosphere. A 568,625 ha study area in the MRP was used to provide a more accurate assessment of carbon loss. Calculations of pre-fire carbon storage in forest vegetation and peat and post-fire carbon emissions have been conducted by combining data from remote sensed images, field measurements and laboratory analyses. Initial results indicate the severest fires occurred close to canals constructed as part of the MRP; loss of vegetation was greatest in areas previously logged; surface peat burnt to depths of at least 40 cm. Data are presented for estimated total carbon losses.
Tomassen, H.B.M., Smolders, A.J.P., Lamers, L.P.M. and Roelofs, J.G.M. - Conservation Of Ombrotrophic Bog Vegetation: The Effects Of High Nitrogen Deposition.
Ombrotrophic bogs, receiving most of their nutrients from the atmosphere, are probably extremely sensitive to air-borne nitrogen loads. In the Netherlands, present nitrogen deposition rates amount to 20-60 kg N /ha /yr. This elevated nitrogen load probably causes the increase of nitrogen-dependant fast growing grasses like Molinia caerulea and trees like Betula pubescens in ombrotrophic vegetations. To determine the effects of nitrogen deposition, a laboratory experiment was carried out. Sods from a floating ombrotrophic bog were exposed to 0, 2.5, 5, 10, 20 and 40 kg N /ha /yr during two years. The vegetation consisted of Sphagnum recurvum and introduced Betula and Molinia caerulea plants. During the first year of treatment, the added nitrogen was completely absorbed by S. recurvum. The nitrogen content in S. recurvum showed a clear positive correlation with the nitrogen deposition. The surplus of nitrogen was stored in nitrogen-rich free amino acids like arginine, asparagine and glutamine. The second year Betula and Molinia showed a stimulated growth due to increased nitrogen deposition. It seems that after nitrogen saturation of the Sphagnum layer, nitrogen becomes available for rooting plant species. From that moment on the growth of the highly-competitive Betula and Molinia will be stimulated, and decline of characteristic species may be expected.
Turunen, J., Pitkänen, A., Tahvanainen, T. and Tolonen, K. - Carbon Accumulation In West Siberian Peatlands, Russia.
Carbon accumulation in West Siberian peatlands have not been accurately studied. The large range in the carbon estimates mainly reflects uncertainty in the dry bulk densities of the peat deposits. The long-term rates of carbon accumulation (LORCA) were studied at 11 sites of the Salym-Yugan Mire, in central West Siberia (60.10N, 72.50E), which is part of the Great Vasyugan Mire (5.4 million hectares). Mire types of the area were predominantly ridge-hollow pine bogs, Sphagnum fuscum pine bogs and dwarf-shrub pine bogs. Peat samples for dry bulk density measurements and for carbon and nitrogen contents analyses were collected from the dominant mire site types with a box sampler and a Russian pattern side-cutting peat sampler. A total of 30 peat samples were taken for 14C dating. The average LORCA of the bog sites was 17.1 g /m2 /yr. The mean depth of the studied mires was 277 cm, and the average dry bulk density of peat 92.7 g dm3. Averages of bulk density and carbon content of Russian raised bog deposits were similar to those obtained from other peat deposits in the boreal region. However, the height increment and carbon accumulation of the studied Siberian peatlands were considerably lower than previous estimates.
Van den Bos, R. M. - Human Influence On Carbon Fluxes In Coastal Peatlands.
Large quantities of carbon have been fixed in peat areas in coastal lowlands such as found in the western part of the Netherlands. Part of this stored carbon gradually disappears as a result of natural biochemical decomposition processes as carbon dioxide (CO2) and methane (CH4) fluxes back to the atmosphere. By large-scale dewatering of polders and intensified drainage of agricultural peat, man has influenced nutrient cycling and ultimately the total carbon balance in these peat areas. However, limited quantitative information is available concerning the different processes involved and on the amount of carbon stored in these coastal peatlands. CO2 and CH4 fluxes from 3 sites in the Western-Netherlands were monitored since 1998 using closed chambers, gas chromatography and a portable infra-red gas analyzer, and related to temperature and groundwater level. CO2 fluxes were varying throughout the year from about 25 to 2000 mg /m2 /hr and are strongly correlated with temperature. CH4 fluxes were varying from max. 0.5 mg /m2 /hr at sites with low groundwater tables up to 6.2 mg /m2 /hr with high groundwater levels. It can be concluded that most coastal peatlands in the Netherlands act as a carbon source and therefore contribute to Global Warming.
Virtanen, K.S. and Hänninen, P. - The Estimated Peat Reserves of Finland.
The GSF (Geological Survey of Finland) is giving new estimations of peat reserves in Finland. The GSF's peat research program has been developed to promote the use of bioenergy in Finland, in line with the energy strategy of the EU. The GSF has taken inventory of 1.7 million hectares of mire. There are still about 3.5 million hectares of the potential area of geological mire where an inventory has not yet been made. Inventory work has concerned 12 000 mire basins and data at more than 1 million sampling points have been stored on data registers. Nearly 1/3 of Finland's surface area is mire (8.9 million ha; about 33 500 separate mires > 20 ha). About 800 000 ha of mires is usable for the peat industry. The energy content of Finland's usable peat reserves (600 million toe) is larger than the proven oil reserves of the North Sea. Because Finnish mires are shallow, (average depth is only 1.4 m), about 90 % of the mires would remain untouched by peat industry.
Yu Z., Vitt D. H., Campbell, C. and Campbell, I.D. - Pattern And Processes Of Peat Accumulation In Continental Rich Fens: Hypothesis And Preliminary Results.
The production and decomposition of organic matter are major processes in determining peat accumulation. The Clymo bog growth model is based on the concave shape of cumulative peat versus age curves from oceanic raised bogs. There are, however, limited data from continental peatlands to test the applicability of this model. Here we present high-resolution Holocene peat accumulation data from two rich fens in west-central Alberta and discuss the significance of these results. Preliminary results from these two cores and published studies on other continental fens and bogs indicate convex peat - age curves, in disagreement with the Clymo model. We carried out sensitivity analysis to determine what processes might cause this pattern. The analysis shows that changes in production, which is determined by climatically sensitive processes (e.g., photosynthesis and acrotelm decay), would affect both old and young catotelm peat, but in contrast, a change in decay rate has more influence on old peat. Thus, we hypothesize that the wiggles in peat profiles were caused by fluctuations in production and that a unidirectional/secular decrease in production would result in the convex accumulation curve. This convex pattern is likely associated with moisture-limited continental climate and consequent local hydrology and nutrient availability. This new conceptual model has important implications for building simulation models and for projecting future peat carbon dynamics.
Bubier, J. and Moore, T. - Biomass Allocation and Net Ecosystem CO2 Exchange In A Boreal Bog And Temperate Poor Fen.
Above and below ground biomass was measured in Mer Bleue Bog, a raised, ombrotrophic peatland near Ottawa, Ontario and Sallie's Fen, a minerotrophic poor fen in southeastern New Hampshire. Understanding carbon allocation in peatlands is important in order to predict the effects of climate change on net ecosystem CO2 exchange and carbon accumulation. Total biomass was greater in the poor fen, but below:above ground biomass ratios were similar in both sites ranging from 5:1 to 10:1 emphasizing the importance of roots in the total plant carbon pool. Roots generally penetrated deeper in the Carex-dominated fen peat compared with the shrub-dominated bog. Most of the coarse and fine woody roots occurred above the average water table position, while sedge and other herbaceous plant roots extended well below the water table. Net ecosystem CO2 exchange (NEE) was measured with a climate-controlled chamber and LI-6200 photosynthesis system. NEE, photosynthesis and respiration were analyzed and compared with photosynthetically active radiation (PAR), peat temperature, water table position, plant community type and biomass allocation patterns.
