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- Fiedler, Jan, et al.
(author)
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Introduction of a guideline for measurements of greenhouse gas fluxes from soils using non-steady-state chambers
- 2022
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In: Journal of Plant Nutrition and Soil Science. - : Wiley. - 1436-8730 .- 1522-2624. ; 185, s. 447-461
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Journal article (peer-reviewed)abstract
- Method Soils represent a major global source and sink of greenhouse gases (GHGs). Many studies of GHG fluxes between soil, plant and atmosphere rely on chamber measurements. Different chamber techniques have been developed over the last decades, each characterised by different requirements and limitations. In this manuscript, we focus on the non-steady-state technique which is widely used for manual measurements but also in automatic systems. Although the measurement method appears very simple, experience gained over the years shows that there are many details which have to be taken into account to obtain reliable measurement results. Aim This manuscript aims to share lessons learnt and pass on experiences in order to assist the reader with possible questions or unexpected challenges, ranging from the planning of the design of studies and chambers to the practical handling of the chambers and the quality assurance of the gas and data analysis. This concise introduction refers to a more extensive Best Practice Guideline initiated by the Working Group Soil Gases (AG Bodengase) of the German Soil Science Society (Deutsche Bodenkundliche Gesellschaft). The intention was to collect and aggregate the expertise of different working groups in the research field. As a compendium, this Best Practice Guideline is intended to help both beginners and experts to meet the practical and theoretical challenges of measuring soil gas fluxes with non-steady-state chamber systems and to improve the quality of the individual flux measurements and thus entire GHG studies by reducing sources of uncertainty and error.
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- Jordan, Sabine, et al.
(author)
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Ecosystem respiration, methane and nitrous oxide fluxes from ecotopes in a rewetted extracted peatland in Sweden
- 2016
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In: Mires and Peat. - 1819-754X. ; 17
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Journal article (peer-reviewed)abstract
- Ecosystem respiration (carbon dioxide; CO2), methane (CH4) and nitrous oxide (N2O) fluxes to the atmosphere were determined using an opaque closed chamber method within various ecotopes (vegetation covered, bare peat and open water) in a rewetted extracted peatland and within an adjacent open poor fen in Sweden. Ecotopes had a significant impact on CO2 and CH4 fluxes to the atmosphere. Ecosystem respiration and CH4 emissions from the bare peat site, the constructed shallow lake and the open poor fen were low but were much higher from ecotopes with Eriophorum vaginatum tussocks and Eriophorum angustifolium. A combination of vascular plant cover and high soil temperatures enhanced ecosystem respiration, while a combination of vascular plant cover, high water table levels and high soil temperatures enhanced CH4 emissions. N2O emissions contributed little to total greenhouse gas (GHG) fluxes from the soil-plant-water systems to the atmosphere. However, the overall climate impact of CH4 emissions from the study area did not exceed the impact of soil and plant respiration. With regard to management of extracted peatlands, the construction of a nutrient-poor shallow lake showed great potential for lowering GHG fluxes to the atmosphere.
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- Jordan, Sabine, et al.
(author)
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Methane and Nitrous Oxide Emission Fluxes Along Water Level Gradients in Littoral Zones of Constructed Surface Water Bodies in a Rewetted Extracted Peatland in Sweden
- 2020
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In: Soil systems. - : MDPI AG. - 2571-8789. ; 4
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Journal article (peer-reviewed)abstract
- Rewetted extracted peatlands are sensitive ecosystems and they can act as greenhouse gas (GHG) sinks or sources due to changes in hydrology, vegetation, and weather conditions. However, studies on GHG emissions from extracted peatlands after rewetting are limited. Methane (CH4) and nitrous oxide (N2O) emission fluxes were determined using the opaque closed chamber method along water level gradients from littoral zones to the open water body of constructed shallow lakes with different vegetation zones in a nutrient-rich rewetted extracted peatland in Sweden. Vegetation communities and their position relative to water level, together with short-term water level fluctuations, such as inundation events and seasonal droughts, and temperature had a significant impact on CH4 emissions fluxes. During "normal" and "dry" conditions and high soil temperatures, CH4 emissions were highest from Carex spp.-Typha latifolia L. communities. During inundation events with water levels > 30 cm, sites with flooded Graminoids-Scirpus spp.-Carex spp. emitted most CH4. Methane emissions from the water body of the constructed shallow lakes were low during all water level conditions and over the temperature ranges observed. Nitrous oxide emissions contributed little to the emission fluxes from the soil-plant-water systems to the atmosphere, and they were only detectable from the sites with Graminoids. In terms of management, the construction of shallow lakes showed great potential for lowering GHG emission fluxes from nutrient rich peatlands after peat extraction, even though the vegetated shore emitted some N2O and CH4.
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| 7. |
- Vinnepand, Mathias, et al.
(author)
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Decoding geochemical signals of the Schwalbenberg Loess-Palaeosol-Sequences — A key to Upper Pleistocene ecosystem responses to climate changes in western Central Europe
- 2022
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In: Catena. - : Elsevier BV. - 0341-8162. ; 212
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Journal article (peer-reviewed)abstract
- Loess deposits are the most extent continental archives of climatic- and environmental change and represent important components of local and global dust systems. Consequently, their geochemistry provides an excellent basis for studying climate oscillations on land and how these affect processes in the terrestrial system. It is, however, challenging to assess information archived in loess records due to complexities in their formation, causing interfering geochemical signatures. In particular, the use of element ratios to derive weathering indices may be complicated since dust sources change through time, and since ecosystems respond differently to changing conditions. Whilst this complexity appears as limiting factor, the explanatory potential of proxies increases when the diversity of geochemical processes is acknowledged. To make use of this potential, we integrate the decadic logarithm of element ratios indicative for provenance shifts, mineral sorting during transport and sediment reworking as well as weathering into multivariate statistical analysis. We test, if the sensitivity of Principal Component Analyses (PCA) and Linear Discriminant Analysis (LDA) can be increased by applying both to sub-datasets of diagnostic Stratigraphic Units (SU) of the Schwalbenberg Loess-Palaeosol-Sequences (Middle Rhine valley, Germany). The selected site recorded sub-millennial Upper Pleistocene ecological changes in an unprecedented resolution for Central European LPS. Differences in operating functions of PCA and LDA and our age model highlight timing and intensity of provenance shifts, sediment relocation, decalcification, redox dynamic and clay-mineral formation associated with Atlantic-driven climate oscillations. Based on this we provide evidence for the accretionary character of interstadial palaeosols caused by a close interplay of dust input and soil formation. Automated re-detection of SU across the site using LDA functions contributes important insights into slope dynamics through regional erosion events. Overall, our approach provides a key for tracing ecological changes during climate oscillations across continents.
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