Blog
About

5
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found
      Is Open Access

      Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands – responses to climatic and environmental changes

      Read this article at

      ScienceOpenPublisher
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          <p><strong>Abstract.</strong> In this study, we compare annual fluxes of methane (CH<sub>4</sub>), nitrous oxide (N<sub>2</sub>O) and soil respiratory carbon dioxide (CO<sub>2</sub>) measured at nine European peatlands (<i>n</i> = 4) and shrublands (<i>n</i> = 5). The sites range from northern Sweden to Spain, covering a span in mean annual air temperature from 0 to 16 °C, and in annual precipitation from 300 to 1300 mm yr<sup>−1</sup>. The effects of climate change, including temperature increase and prolonged drought, were tested at five shrubland sites. At one peatland site, the long-term (> 30 yr) effect of drainage was assessed, while increased nitrogen deposition was investigated at three peatland sites. <br><br> The shrublands were generally sinks for atmospheric CH<sub>4</sub>, whereas the peatlands were CH<sub>4</sub> sources, with fluxes ranging from −519 to +6890 mg CH<sub>4</sub>-C m<sup>−2</sup> yr<sup>−1</sup> across the studied ecosystems. At the peatland sites, annual CH<sub>4</sub> emission increased with mean annual air temperature, while a negative relationship was found between net CH<sub>4</sub> uptake and the soil carbon stock at the shrubland sites. Annual N<sub>2</sub>O fluxes were generally small ranging from −14 to 42 mg N<sub>2</sub>O-N m<sup>−2</sup> yr<sup>−1</sup>. Highest N<sub>2</sub>O emission occurred at the sites that had highest nitrate (NO<sub>3</sub><sup>−</sup>) concentration in the soil water. Furthermore, experimentally increased NO<sub>3</sub><sup>−</sup> deposition led to increased N<sub>2</sub>O efflux, whereas prolonged drought and long-term drainage reduced the N<sub>2</sub>O efflux. Soil CO<sub>2</sub> emissions in control plots ranged from 310 to 732 g CO<sub>2</sub>-C m<sup>−2</sup> yr<sup>−1</sup>. Drought and long-term drainage generally reduced the soil CO<sub>2</sub> efflux, except at a hydric shrubland where drought tended to increase soil respiration. <br><br> In terms of fractional importance of each greenhouse gas to the total numerical global warming response, the change in CO<sub>2</sub> efflux dominated the response in all treatments (ranging 71–96%), except for NO<sub>3</sub><sup>−</sup> addition where 89% was due to change in CH<sub>4</sub> emissions. Thus, in European peatlands and shrublands the effect on global warming induced by the investigated anthropogenic disturbances will be dominated by variations in soil CO<sub>2</sub> fluxes.</p>

          Related collections

          Most cited references 44

          • Record: found
          • Abstract: found
          • Article: not found

          A meta-analysis of the response of soil respiration, net nitrogen mineralization, and aboveground plant growth to experimental ecosystem warming

          Climate change due to greenhouse gas emissions is predicted to raise the mean global temperature by 1.0-3.5°C in the next 50-100 years. The direct and indirect effects of this potential increase in temperature on terrestrial ecosystems and ecosystem processes are likely to be complex and highly varied in time and space. The Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme has recently launched a Network of Ecosystem Warming Studies, the goals of which are to integrate and foster research on ecosystem-level effects of rising temperature. In this paper, we use meta-analysis to synthesize data on the response of soil respiration, net N mineralization, and aboveground plant productivity to experimental ecosystem warming at 32 research sites representing four broadly defined biomes, including high (latitude or altitude) tundra, low tundra, grassland, and forest. Warming methods included electrical heat-resistance ground cables, greenhouses, vented and unvented field chambers, overhead infrared lamps, and passive night-time warming. Although results from individual sites showed considerable variation in response to warming, results from the meta-analysis showed that, across all sites and years, 2-9 years of experimental warming in the range 0.3-6.0°C significantly increased soil respiration rates by 20% (with a 95% confidence interval of 18-22%), net N mineralization rates by 46% (with a 95% confidence interval of 30-64%), and plant productivity by 19% (with a 95% confidence interval of 15-23%). The response of soil respiration to warming was generally larger in forested ecosystems compared to low tundra and grassland ecosystems, and the response of plant productivity was generally larger in low tundra ecosystems than in forest and grassland ecosystems. With the exception of aboveground plant productivity, which showed a greater positive response to warming in colder ecosystems, the magnitude of the response of these three processes to experimental warming was not generally significantly related to the geographic, climatic, or environmental variables evaluated in this analysis. This underscores the need to understand the relative importance of specific factors (such as temperature, moisture, site quality, vegetation type, successional status, land-use history, etc.) at different spatial and temporal scales, and suggests that we should be cautious in "scaling up" responses from the plot and site level to the landscape and biome level. Overall, ecosystem-warming experiments are shown to provide valuable insights on the response of terrestrial ecosystems to elevated temperature.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Ecosystem carbon storage in arctic tundra reduced by long-term nutrient fertilization.

            Global warming is predicted to be most pronounced at high latitudes, and observational evidence over the past 25 years suggests that this warming is already under way. One-third of the global soil carbon pool is stored in northern latitudes, so there is considerable interest in understanding how the carbon balance of northern ecosystems will respond to climate warming. Observations of controls over plant productivity in tundra and boreal ecosystems have been used to build a conceptual model of response to warming, where warmer soils and increased decomposition of plant litter increase nutrient availability, which, in turn, stimulates plant production and increases ecosystem carbon storage. Here we present the results of a long-term fertilization experiment in Alaskan tundra, in which increased nutrient availability caused a net ecosystem loss of almost 2,000 grams of carbon per square meter over 20 years. We found that annual aboveground plant production doubled during the experiment. Losses of carbon and nitrogen from deep soil layers, however, were substantial and more than offset the increased carbon and nitrogen storage in plant biomass and litter. Our study suggests that projected release of soil nutrients associated with high-latitude warming may further amplify carbon release from soils, causing a net loss of ecosystem carbon and a positive feedback to climate warming.
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              The Limits to Peat Bog Growth

               R. S. Clymo (1984)
                Bookmark

                Author and article information

                Journal
                Biogeosciences
                Biogeosciences
                Copernicus GmbH
                1726-4189
                2012
                October 04 2012
                : 9
                : 10
                : 3739-3755
                Article
                10.5194/bg-9-3739-2012
                © 2012

                https://creativecommons.org/licenses/by/3.0/

                Product

                Comments

                Comment on this article