| 1. |
- Franz, D, et al.
(författare)
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Towards long-term standardised carbon and greenhouse gas observations for monitoring Europe´s terrestrial ecosystems: a review
- 2018
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Ingår i: International Agrophysics. - : Walter de Gruyter GmbH. - 0236-8722 .- 2300-8725. ; 32, s. 439-455
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Tidskriftsartikel (refereegranskat)abstract
- Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System combines carbon and greenhouse gas (GHG; CO2, CH4, N2O, H2O) observations within the atmosphere, terrestrial ecosystems and oceans. High-precision measurements are obtained using standardised methodologies, are centrally processed and openly available in a traceable and verifiable fashion in combination with detailed metadata. The Integrated Carbon Observation System ecosystem station network aims to sample climate and land-cover variability across Europe. In addition to GHG flux measurements, a large set of complementary data (including management practices, vegetation and soil characteristics) is collected to support the interpretation, spatial upscaling and modelling of observed ecosystem carbon and GHG dynamics. The applied sampling design was developed and formulated in protocols by the scientific community, representing a trade-off between an ideal dataset and practical feasibility. The use of open-access, high-quality and multi-level data products by different user communities is crucial for the Integrated Carbon Observation System in order to achieve its scientific potential and societal value.
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| 2. |
- Poyatos, R., et al.
(författare)
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Global transpiration data from sap flow measurements: the SAPFLUXNET database
- 2021
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Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 13:6, s. 2607-2649
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Tidskriftsartikel (refereegranskat)abstract
- Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.
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| 3. |
- Jansen, Joachim, 1989-, et al.
(författare)
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Monitoring of carbon-water fluxes at Eurasian meteorological stations using random forest and remote sensing
- 2023
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Ingår i: Scientific Data. - : Springer Nature. - 2052-4463. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Simulating the carbon-water fluxes at more widely distributed meteorological stations based on the sparsely and unevenly distributed eddy covariance flux stations is needed to accurately understand the carbon-water cycle of terrestrial ecosystems. We established a new framework consisting of machine learning, determination coefficient (R2), Euclidean distance, and remote sensing (RS), to simulate the daily net ecosystem carbon dioxide exchange (NEE) and water flux (WF) of the Eurasian meteorological stations using a random forest model or/and RS. The daily NEE and WF datasets with RS-based information (NEE-RS and WF-RS) for 3774 and 4427 meteorological stations during 2002-2020 were produced, respectively. And the daily NEE and WF datasets without RS-based information (NEE-WRS and WF-WRS) for 4667 and 6763 meteorological stations during 1983-2018 were generated, respectively. For each meteorological station, the carbon-water fluxes meet accuracy requirements and have quasi-observational properties. These four carbon-water flux datasets have great potential to improve the assessments of the ecosystem carbon-water dynamics.
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| 4. |
- de Beeck, M. O., et al.
(författare)
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Soil-meteorological measurements at ICOS monitoring stations in terrestrial ecosystems
- 2018
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Ingår i: International Agrophysics. - : Walter de Gruyter GmbH. - 0236-8722 .- 2300-8725. ; 32:4, s. 619-631
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Tidskriftsartikel (refereegranskat)abstract
- The Integrated Carbon Observation System is a pan-European research infrastructure providing standardized, long-term observations of greenhouse gas concentrations and earth-atmosphere greenhouse gas interactions. The terrestrial component of Integrated Carbon Observation System comprises a network of monitoring stations in terrestrial ecosystems where the principal activity is the measurement of ecosystem-atmosphere fluxes of greenhouse gases and energy by means of the eddy covariance technique. At each station a large set of ancillary variables needed for the interpretation of observed fluxes and for process studies is additionally monitored. This set includes a subset of variables that describe the thermal and moisture conditions of the soil and which are here conveniently referred to as soil-meteorological variables: soil temperature, volumetric soil water content, water table depth, and soil heat flux density. This paper describes the standard methodology that has been developped for the monitoring of these variables at the ecosystem stations.
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| 5. |
- Rees, R. M., et al.
(författare)
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Nitrous oxide emissions from European agriculture; an analysis of variability and drivers of emissions from field experiments
- 2012
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Ingår i: Biogeosciences Discussions. - : Copernicus GmbH. - 1810-6277. ; 9:7, s. 9259-9288
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Tidskriftsartikel (refereegranskat)abstract
- Nitrous oxide emissions from a network of agricultural experiments in Europe and Zimbabwe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared 5 within replicated experimental designs in plot based experiments. Arable experiments were conducted at Beano in Italy, El Encin in Spain, Foulum in Denmark, Logården in Sweden, Maulde in Belgium, Paulinenaue in Germany, Harare in Zimbabwe and Tulloch in the UK. Grassland experiments were conducted at Crichton, Nafferton and Peaknaze in the UK, Gödöllö in Hungary, Rzecin in Poland, Zarnekow in Germany and 10 Theix in France. Nitrous oxide emissions were measured at each site over a period of at least two years using static chambers. Emissions varied widely between sites and as a result of manipulation treatments. Average site emissions (throughout the study period) varied between 0.04 and 21.21 kg N2O-N ha−1 yr−1, with the largest fluxes and variability associated with the grassland sites. Total nitrogen addition was found to be 15 the single most important determinant of emissions, accounting for 15% of the variance (using linear regression) in the data from the arable sites (p < 0.0001), and 77% in the grassland sites. The annual emissions from arable sites were significantly greater than those that would be predicted by IPCC default emission factors. Variability in N2O within sites that occurred as a result of manipulation treatments was greater than that 20 resulting from site to site and year to year variation, highlighting the importance of management interventions in contributing to greenhouse gas mitigation.
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| 6. |
- Rees, R. M., et al.
(författare)
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Nitrous oxide emissions from European agriculture - an analysis of variability and drivers of emissions from field experiments
- 2013
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 10:4, s. 2671-2682
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Tidskriftsartikel (refereegranskat)abstract
- Nitrous oxide emissions from a network of agricultural experiments in Europe and Zimbabwe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot based experiments. Arable experiments were conducted at Beano in Italy, El Encin in Spain, Foulum in Denmark, Logården in Sweden, Maulde in Belgium, Paulinenaue in Germany, Harare in Zimbabwe and Tulloch in the UK. Grassland experiments were conducted at Crichton, Nafferton and Peaknaze in the UK, Gödöllö in Hungary, Rzecin in Poland, Zarnekow in Germany and Theix in France. Nitrous oxide emissions were measured at each site over a period of at least two years using static chambers. Emissions varied widely between sites and as a result of manipulation treatments. Average site emissions (throughout the study period) varied between 0.04 and 21.21 kg N2O-N ha−1 yr−1, with the largest fluxes and variability associated with the grassland sites. Total nitrogen addition was found to be the single most important determinant of emissions, accounting for 15% of the variance (using linear regression) in the data from the arable sites (p < 0.0001), and 77% in the grassland sites. The annual emissions from arable sites were significantly greater than those that would be predicted by IPCC default emission factors. Variability in N2O within sites that occurred as a result of manipulation treatments was greater than that resulting from site to site and year to year variation, highlighting the importance of management interventions in contributing to greenhouse gas mitigation.
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| 7. |
- Rinne, J., et al.
(författare)
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Effect of the 2018 European drought on methane and carbon dioxide exchange of northern mire ecosystems
- 2020
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Ingår i: Philosophical Transactions of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 375:1810
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Tidskriftsartikel (refereegranskat)abstract
- We analysed the effect of the 2018 European drought on greenhouse gas (GHG) exchange of five North European mire ecosystems. The low precipitation and high summer temperatures in Fennoscandia led to a lowered water table in the majority of these mires. This lowered both carbon dioxide (CO2) uptake and methane (CH4) emission during 2018, turning three out of the five mires from CO(2)sinks to sources. The calculated radiative forcing showed that the drought-induced changes in GHG fluxes first resulted in a cooling effect lasting 15-50 years, due to the lowered CH(4)emission, which was followed by warming due to the lower CO(2)uptake. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
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| 8. |
- Smith, K.A., et al.
(författare)
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Oxidation of atmospheric methane in Northern European soils, comparison with other ecosystems, and uncertainties in the global terrestrial sink
- 2000
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 6:7, s. 791-803
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports the range and statistical distribution of oxidation rates of atmospheric CH4 in soils found in Northern Europe in an international study, and compares them with published data for various other ecosystems. It reassesses the size, and the uncertainty in, the global terrestrial CH4 sink, and examines the effect of land-use change and other factors on the oxidation rate. Only soils with a very high water table were sources of CH4, all others were sinks. Oxidation rates varied from 1 to nearly 200 µg CH4 m-2 h-1, annual rates for sites measured for =1 y were 0.1-9.1 kg CH4 ha-1 y-1, with a log-normal distribution (log-mean ~ 1.6 kg CH4 ha-1 y-1). Conversion of natural soils to agriculture reduced oxidation rates by two-thirds - closely similar to results reported for other regions. N inputs also decreased oxidation rates. Full recovery of rates after these disturbances takes > 100 y. Soil bulk density, water content and gas diffusivity had major impacts on oxidation rates. Trends were similar to those derived from other published work. Increasing acidity reduced oxidation, partially but not wholly explained by poor diffusion through litter layers which did not themselves contribute to the oxidation. The effect of temperature was small, attributed to substrate limitation and low atmospheric concentration. Analysis of all available data for CH4 oxidation rates in situ showed similar log-normal distributions to those obtained for our results, with generally little difference between different natural ecosystems, or between short-and longer-term studies. The overall global terrestrial sink was estimated at 29 Tg CH4 y-1, close to the current IPCC assessment, but with a much wider uncertainty range (7 to > 100 Tg CH4 y-1). Little or no information is available for many major ecosystems, these should receive high priority in future research.
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| 9. |
- Weslien, P., et al.
(författare)
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Nitrogen losses following application of pig slurry to arable land
- 1998
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Ingår i: Soil use and management. - 0266-0032 .- 1475-2743. ; 14:4, s. 200-208
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Tidskriftsartikel (refereegranskat)abstract
- Emissions of ammonia (NH3) and nitrous oxide (N2O), and nitrate (NO3/-) leaching were measured in two field experiments following application of pig slurry at rates corresponding to 83-96kg NH4-N ha-1 before sowing. In spring and in autumn 1994, slurry was applied by four methods: trenching (T), shallow injection (S), band spreading immediately followed by harrowing (B/H) and band spreading (B). NH3 emission measurements were made during the first week after application in both experiments. In the spring experiment N2O emissions and NO3/- leaching were measured during 6 and 52 weeks after spreading respectively, and during 11-and 33 weeks after spreading in the autumn experiment. In spring, the increased N2O emissions (i.e. control subtracted) ranged from 0.27% (T) to 0.45% (B/H), and in the autumn study from 0.92% (T) to 1.14% (B/H), of applied NH4-N, although showing no statistically significant differences. In order to validate the chamber measurements, a 'megachamber' (21 m2) was used together with an infrared spectrometer. The emissions agreed well for (B/H), while (B) resulted in lower emissions compared with the smaller chambers. Emissions of NH3 were about one order of magnitude higher. In spring, (B) gave the highest emission, reaching 19.5% of applied NH4-N, whereas (S), and (B/H) gave the lowest emissions, reaching 1.2 and 3.5% of applied NH4-N, respectively. NH3 emissions in autumn were 15-20% lower compared with spring. In spring the increased nitrate leaching ranged from 10.1 (T) to 24.9 kg ha-1 (B/H) and from 29.5 (B) to 37.8 kg ha-1 (T) in the autumn experiment, showing no statistically significant differences. Estimations of indirect N2O emissions due to ammonia deposition and nitrate leaching, suggested that the N2O contribution from NH3 deposition was relatively small, while the indirect N2O emissions from NO3/- leaching were of the same order of magnitude or higher than the direct N2O emissions.
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| 10. |
- Balathandayuthabani, Sivakiruthika, et al.
(författare)
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Methane in Two Stream Networks: Similar Contributions From Groundwater and Local Sediments While Oxidation Was a Large Sink Controlling Atmospheric Emissions
- 2024
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Ingår i: Journal of Geophysical Research - Biogeosciences. - : AMER GEOPHYSICAL UNION. - 2169-8953 .- 2169-8961. ; 129:8
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Tidskriftsartikel (refereegranskat)abstract
- Streams are important sources of methane (CH4) to the atmosphere but magnitudes and regulation of stream CH4 fluxes remain uncertain. Stream CH4 can come from groundwater and/or produced in anoxic sediments. A fraction can be microbially oxidized to carbon dioxide (CO2) when passing redox gradients in soil, sediment, or water, while the fraction escaping oxidation is emitted to the atmosphere. The relative importance of the CH4 sources (groundwater inputs vs. sediment production) and the fraction oxidized is typically unknown, yet key for the regulation and magnitude of stream emissions. In this study, we followed the transport of CH4 from below-stream soils to the stream water surface and to the atmosphere using a combination of CH4 concentration and stable carbon isotope gradient measurements, high resolution stream flux and discharge assessments, and inverse mass-balance modeling. Sampling was done in multiple locations in the stream network of two independent catchments in Sweden to consider spatial variability. We show that the surface water, sub-surface, and groundwater CH4 concentration, CH4 oxidation, and emission were highly variable in space. Our results indicate that the variability could be related to stream morphology and soil characteristics. Of the total CH4 input into the streams, roughly half of it was estimated to come from groundwater CH4 in both catchments (39% and 57%; the rest from sediment production), and most of the CH4 was oxidized (97%-99%) before emission to the atmosphere. Our results indicate that CH4 oxidation is a major sink for CH4 in the studied streams. Streams emit a large amount of the greenhouse gas methane to the atmosphere. Sources of this methane can be groundwater and/or production in stream sediments. A part of the methane can be oxidized by microbes into carbon dioxide and the rest can evade to the atmosphere as methane. The relative magnitudes of the sources, oxidation, and emission are usually unknown but important for understanding the regulation of stream methane emissions. In this study in two stream networks of Sweden, inverse mass-balance modeling was done using multiple measurements and we show that the sources of methane, its oxidation and emission were highly variable in space. About half of the methane in the streams was contributed by groundwater and the rest was estimated to be produced in the sediments. Most of the methane was oxidized in the streams and only a small fraction escaped to the atmosphere. Large spatial variability in CH4 concentration, net inputs, oxidation and emission was observed Roughly half of the CH4 inputs in the streams were contributed by groundwater and the rest by sediment production Most of the total potential stream CH4 input was oxidized before reaching the atmosphere
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