Search results for "sphagnum"
showing 10 items of 27 documents
Methane production and oxidation potentials in relation to water table fluctuations in two boreal mires
1999
We studied the response of methane production and oxidation potentials in a minerotrophic and an ombrotrophic mire to water table fluctuations. In profiles where water table had not varied, the water-saturated layers showed significant potentials while the unsaturated layers did not. The production potentials in the saturated layers below water level ranged from 0.1 to 2.4 m gC H4 h ˇ1 (g d.w.) ˇ 1 and oxidation potentials (first order reaction rate constants) betweenˇ0.010 andˇ0.120 h ˇ1 (g d.w.) ˇ 1 . In profiles with constant water level, the maximal production potential occurred 20 cm and maximal oxidation potential 10 cm below water level. When water table varied only a little, product…
Carbon accumulation rate in a raised bog in Latvia, NE Europe, in relation to climate warming
2018
The carbon accumulation rate (CAR) over the last 180 years was estimated by measuring carbon concentrations in 1-cm layers in a fine-resolution dated and analysed peat sequence in Teiči Bog, Latvia, NE Europe. We used the Granger causality test to examine the temporal (lagged) relationships between the CAR and the historical climate variables. Our results showed that the average CAR was 192 g C m–2 yr–1 during the last 180 years and 169 g C m–2 yr–1 when excluding the acrotelm where decomposition and the stock of carbon are still not in the balance. The Granger causality test showed significant positive temporal associations between the temperature and the CAR, indicating that the temperatu…
A review of climate reconstructions from terrestrial climate archives covering the first millennium AD in northwestern Europe
2018
AbstractLarge changes in landscape, vegetation, and culture in northwestern (NW) Europe during the first millennium AD seem concurrent with climatic shifts. Understanding of this relation requires high-resolution palaeoclimate reconstructions. Therefore, we compiled available climate reconstructions from sites across NW Europe (extent research area: 10°W–20°E, 45°–60°N) through review of literature and the underlying data, to identify supraregional climatic changes in this region. All reconstructions cover the period from AD 1 to 1000 and have a temporal resolution of ≤50 yr. This resulted in 22 climate reconstructions/proxy records based on different palaeoclimate archives: chironomids (1)…
Emergence phenology and ecology of aquatic and semi-terrestrial insects on a boreal raised bog in Central Finland
1988
Emergence of peatland insects was studied in Central Finland by sampling insects on a raised bog with tent traps from five different surfaces: muddy hollow without vegetation; hollow covered with Sphagnum; deep (0.7-0.9 m) open-water pool; shallow (about 0.3 m) pool with bottom covered by Carex vegetation; shallow (about 0.3 m) pool with bare muddy bottom. The material was collected at two-days intervals from 13 May until 31 August in 1981. Biomass emerging from the sites varied considerably. In general, aquatic sites were clearly more productive than semi-terrestrial sites. Corrected total biomass values for deep pools, shallow Carex pools, and shallow mud pools were 2.471, 1.066, and 0.51…
Impact of drainage and hydrological restoration on vegetation structure in boreal spruce swamp forests
2014
Drainage to increase timber production is a major cause of degradation of boreal peatlands in Europe. As a consequence of the forestry drainage, the area of pristine spruce swamp forests has declined drastically in northern Europe over the past century. In restoration by rewetting, drainage ditches are blocked to restore the pre-disturbance hydrological regime and, ultimately, the biodiversity values and ecosystem functions of pristine spruce swamp forests. In this study, we quantify vegetation recovery and examine mechanisms behind the changes in plant community composition. For this, we surveyed the understorey vegetation of 9 undrained, 9 drained and 18 rewetted spruce swamp forest sites…
Experimental climate warming alters the relationship between fungal root symbiosis and Sphagnum litter phenolics in two peatland microhabitats
2017
International audience; Belowground interactions between plants and microorganisms are involved in numerous ecosystems processes such as carbon and nutrient cycling. Understanding their responses to on-going climate warming is thus of paramount importance to better predict future ecosystem functioning. We hypothesized that climate warming alters the interactions between Sphagnum litter phenolics and the fungal root symbiosis of the Ericale plant Andromeda polifolia in a Jura mountain peatland (France). We initiate a climate warming treatment (+1°C) in April 2008 in two microhabitats (lawns and hummocks). We measured polyphenolic contents, mycorrhizal and dark septate endophyte (DSE) root co…
The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses
2018
Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documented for many bacteria. However, the role of nitrogen-fixing methanotrophs in nitrogen supply to Sphagnum peat mosses is not well explored. Here, we investigated the role of both oxygen and methane on nitrogen fixation in subarctic Sphagnum peat mosses. Five species of Sphagnum mosses were sampled from two mesotrophic and three oligotrophic sites within the Lakkasuo peatland in Orivesi, central Finland. Mo…
Last Millennium hydro-climate variability in Central–Eastern Europe (Northern Carpathians, Romania)
2015
Proxy-based reconstructions of climate variability over the last millennium provide important insights for understanding current climate change within a long-term context. Past hydrological changes are particularly difficult to reconstruct, yet rainfall patterns and variability are among the most critical environmental variables. Ombrotrophic bogs, entirely dependent on water from precipitation and sensitive to changes in the balance between precipitation and evapotranspiration, are highly suitable for such hydro-climate reconstructions. We present a multi-proxy analysis (testate amoebae, plant macrofossils, stable carbon isotopes in Sphagnum, pollen, spores and macroscopic charcoal) from …
Drivers of peat accumulation rate in a raised bog: impact of drainage, climate, and local vegetation composition
2017
We used variation partitioning to assess the relative importance of drainage, climate and local vegetation composition for the development of a raised bog. As a case study we selected Teici (Teici) Bog in Latvia (north-east Europe). Explanatory variables together explained 74 % of the variation in peat accumulation and only the residue of 26 % remained unexplained. Our study showed that the local vegetation composition and dominant Sphagnum species significantly influence peat accumulation rates. The results of linear models revealed that, under natural conditions, minor drainage and even strong drainage of the peat is associated with a positive growth balance of the system. However, draina…
Integrating Decomposers, Methane-Cycling Microbes and Ecosystem Carbon Fluxes Along a Peatland Successional Gradient in a Land Uplift Region
2021
AbstractPeatlands are carbon dioxide (CO2) sinks that, in parallel, release methane (CH4). The peatland carbon (C) balance depends on the interplay of decomposer and CH4-cycling microbes, vegetation, and environmental conditions. These interactions are susceptible to the changes that occur along a successional gradient from vascular plant-dominated systems to Sphagnum moss-dominated systems. Changes similar to this succession are predicted to occur from climate change. Here, we investigated how microbial and plant communities are interlinked with each other and with ecosystem C cycling along a successional gradient on a boreal land uplift coast. The gradient ranged from shoreline to meadows…