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Während des frühen bis mittleren Devon (ca. 418-383 Mio. Jahre) herrschten Treibhausverhältnisse auf der Erde. Die Klimaentwicklung zu jener Zeit führte schließlich zu einem Höhepunkt an Diversität, Größe und Verbreitung von Riffen im mittleren Devon (Eifelium und Givetium). Doch auch während des Klimax im Mittel-Devon kam es vermehrt zu Klimaschwankungen, die in mehr oder weniger schweren biotischen Krisen resultierten. Eine dieser Krisenzeiten entspricht dem Kacak-Event während des späten Eifelium, der als Schwarzschiefer und Hornstein-Horizont in marinen Sedimenten global nachgewiesen ist. Das mehrphasige dysoxische/anoxische Ereignisintervall beschränkt sich auf die kockelianus und ensensis Biozone (Conodontenzonierung) und entspricht in etwa einer Dauer von 200+-10 Tausend Jahren. Der Event ist geprägt von markanten Faunenwechsel, die mit signifikanten Exkursionen im geochemischen und geophysikalischen Signal gekoppelt sind. Bisher durchgeführte Untersuchungen haben gezeigt, dass vor allem benthische Organismen aus tiefer marinen Ablagerungen auf die veränderten Umweltbedingungen reagiert haben. Neuere Erkenntnisse über diesen Event basieren vor allem auf Conodonten-Stratigraphie, sowie der Studie von stabilen Isotopen und Untersuchungen zur Magneto-Suszeptibilität von Sedimenten. Im Rahmen des vorgeschlagenen Projektes sollen Veränderungen in tropischen Korallen-Vergesellschaftungen (im speziellen von rugosen Korallen) während der Kacak-Krise untersucht werden. Die Lokalitäten der ausgewählten Gebiete (Karnische Alpen, Grazer Paläozoikum, Barrandium und Mähren) befanden sich zur damaligen Zeit, als Teile des Kontinentalschelfs von Nord-Gondwana, an unterschiedlichen Positionen in den niederen Breiten. Vor allem aus dem Mittel-Devon der Karnischen Alpen und des Grazer Paläozoikums sind fossile Kollektionen bekannt, die eine reiche und vielfältige rugose Korallenfauna beinhalten. Neben einer Menge an nicht bearbeitetem Material, welches sich in den Sammlungen wieder findet, gibt es unter den beschriebenen Korallen auch Arten, die Unstimmigkeiten hinsichtlich ihrer taxonomischen Stellung sowie der stratigraphischen Reichweite aufzeigen. Dazu kommt noch umfangreiches Material an rugosen Korallen aus Mähren, welches bis heute noch keiner detaillierten Bearbeitung unterzogen werden konnte. Ziel dieses Projektes ist es, einen Überblick über die rugosen Korallen geben zu können, die vom Kacak-Event betroffen waren. Dadurch sollen Fragen zur Resonanz von Klima empfindlichen Organismen auf sich verändernden Umweltbedingungen geklärt werden. Zusätzlich soll die Berechnung von Meerwasser Temperaturen aus unterschiedlich niederen Breiten und die Anwendung von geochemischen und geophysikalischen Methoden dazu beitragen, Ursachen die für den Kacak-Event verantwortlich waren, heraus zu finden. usw.
Flüchtige organische Kohlenstoffverbindungen (sog. VOCs) beeinflussen die chemischen und physikalischen Eigenschaften der Atmosphäre und damit das Klima. Emittiert werden diese durch menschliche Aktivitäten und der Biosphäre, der bei weitem größte Teil der Emissionen stammt von Pflanzen. In der Vergangenheit wurden vor allem Kohlenwasserstoffverbindungen, wie Methan oder Isoprenoide, detailliert untersucht. Biogene oxygenierte VOCs (sog. BOVOCs), wie Methanol, Acetaldehyd und Aceton, wurden hingegen kaum untersucht obwohl diese in signifikanten Mengen in der Atmosphäre vorkommen und deren geschätzte gemeinsame Quellenstärke sich ungefähr auf die Hälfte jener von Isopren, welches die globalen VOC-Emissionen dominiert, beläuft. Dementsprechend unsicher sind die globalen Budgets von Methanol, Acetaldehyd und Aceton, und insbesondere die Abschätzung ihrer biogenen Senken/Quellengrößen. Das übergeordnete Ziel des beantragten Projektes ist es daher das Verständnis über den Austausch von Methanol, Acetaldehyd und Aceton zwischen terrestrischen Ökosystemen und der Atmosphäre zu erhöhen und damit die Fähigkeit diese Prozesse zu simulieren zu verbessern. Dazu wird eine Studie die experimentelle Aspekte mit Simulationsstudien kombiniert für ein Grünlandökosystem im Stubaital (Österreich) durchgeführt. Im Detail werden dabei folgende Zielsetzungen verfolgt: (i) Quantifizierung der saisonalen Flüsse von Methanol, Acetaldehyd und Aceton. In der Vergangenheit wurden VOC-Austauschmessungen häufig im Rahmen von kurzen intensiven Kampagnen bzw. maximal über eine Vegetationsperiode durchgeführt was eine Analyse der interannuellen Variabilität nicht zulässt. Im Rahmen des beantragten Projektes ist daher geplant für zwei weitere Jahre BOVOC-Flussmessungen durchzuführen um so, unter Einbeziehung von zwei Jahren Daten aus einem Vorgängerprojekt, erstmals die interannuelle Variabilität dieser Flüsse untersuchen zu können. (ii) Quantifizierung der Beiträge der Vegetation und des Bodens zum gesamten BOVOC-Austausch. Dazu werden, sowohl im Labor wie im Freiland, BOVOC-Austauschmessungen an Blättern der vorkommenden Pflanzenarten, wie auch, unter Einsatz einer neuartigen nicht destruktiven Methode, vom/zum Boden durchgeführt. (iii) Hochskalierung der unter (ii) erhobenen Daten auf Ökosystemebene mittels eines prozess orientierten Modells und Vergleich der Modellsimulationen mit den unter (i) mit einer unabhängigen Methode erhobenen Ökosystemflüsse. Dieser Vergleich stellt den ultimativen Test unseres Prozessverständnisses über den Austausch zwischen Biosphäre und Atmosphäre dieser drei wichtigen BOVOCs dar.
With respect to their role in the global carbon cycle, natural peatlands are characterized by their ability to sequester atmospheric carbon. This trait is strongly connected to the water regime of these ecosystems. Large parts of the soil profile in natural peatlands are water-saturated, leading to anoxic conditions and to a diminished decomposition of plant litter. In functioning peatlands, the rate of carbon fixation by plant photosynthesis is larger than the decomposition rate of dead organic material. Over time, the amount of carbon that remains in the soil and is not converted back to carbon dioxide grows. Land use of peatlands often goes along with water level manipulations and thereby with alterations of carbon flux dynamics. In this study, carbon dioxide (CO2) and methane (CH4) flux measurements from a bog site in NW Germany that has been heavily degraded by peat mining are presented. Two contrasting types of management have been implemented at the site: (1) drainage during ongoing peat-harvesting on one half of the central bog area and (2) rewetting on the other half that had been taken out of use shortly before measurements commenced. The submitted two-year data set was collected with an eddy covariance (EC) system set up on a central railroad dam that divides the two halves of the (former) peat harvesting area. The data set contains the relative contributions of the surface classes "drained", "rewetted" and "vegetated" to the EC footprint.
With respect to their role in the global carbon cycle, natural peatlands are characterized by their ability to sequester atmospheric carbon. This trait is strongly connected to the water regime of these ecosystems. Large parts of the soil profile in natural peatlands are water-saturated, leading to anoxic conditions and to a diminished decomposition of plant litter. In functioning peatlands, the rate of carbon fixation by plant photosynthesis is larger than the decomposition rate of dead organic material. Over time, the amount of carbon that remains in the soil and is not converted back to carbon dioxide grows. Land use of peatlands often goes along with water level manipulations and thereby with alterations of carbon flux dynamics. In this study, carbon dioxide (CO2) and methane (CH4) flux measurements from a bog site in NW Germany that has been heavily degraded by peat mining are presented. Two contrasting types of management have been implemented at the site: (1) drainage during ongoing peat-harvesting on one half of the central bog area and (2) rewetting on the other half that had been taken out of use shortly before measurements commenced. The submitted two-year data set was collected with an eddy covariance (EC) system set up on a central railroad dam that divides the two halves of the (former) peat harvesting area. The data set contains the relative contributions of the surface classes "drained", "rewetted" and "vegetated" to the EC footprint.
This publication provides the codes produced for the article "Temporally dynamic carbon dioxide and methane emission factors for rewetted peatlands. Nature Communications Earth and Environment" by Aram Kalhori, Christian Wille, Pia Gottschalk, Zhan Li, Josh Hashemi, Karl Kemper, and Torsten Sachs (https://doi.org/10.1038/s43247-024-01226-9). In the article, the authors estimate the cumulative GHG emissions of a rewetted peatland in Germany using the long-term ecosystem flux measurements. They observe a source-to-sink transition of annual carbon dioxide (CO2) fluxes and decreasing trend of methane (CH4) emissions. This software is written in R and MATLAB. Running the codes ([R files and .m files](Code)) and loading the data files ([CSV files and .mat files](Data)) requires the pre-installation of [R and RStudio] (https://posit.co/downloads/) and ([MATLAB]. The RStudio 2022.07.2 Build 576 version has been used for the R scripts. The land cover classification work was performed in QGIS, v.3.16.11-Hannover. Data were analyzed in both MATLAB and R and plots created with R (R Core Development Team 2020) in RStudio®. The following external packages are required to be incorporated into the codes in order to run the provided codes: "zyp" package; "missForest" package;"REddyProc" package and explained in detail in the README. Files: Codes/Kalhori2023_SenSlopes_fig2.r "zyp" package, Maintainer David Bronaugh <bronaugh@uvic.ca> Depends R (>= 2.4.0), Kendall License: LGPL-2.1 https://CRAN.R-project.org/package=zyp Files: Codes/Kalhori2023_gapfillingMF_validation_figSI1.r "missForest" package, Maintainer Daniel J. Stekhoven <stekhoven@stat.math.ethz.ch> Depends randomForest,foreach,itertools License: GPL (>= 2) https://www.r-project.org, https://github.com/stekhoven/missForest Files: Codes/Kalhori2023_NEEpartitioning.r "REddyProc" package, Maintainer Thomas Wutzler <twutz@bgc-jena.mpg.de> Depends R (>= 3.0.0), methods Imports Rcpp, dplyr, purrr, rlang, readr, tibble, magrittr, solartime, bigleaf (>= 0.7) License: GPL (>= 2) https://cran.r-project.org/web/packages/REddyProc/index.html Data are provided as .shp, CSV or text files. The MATLAB scripts for footprint calculation and the R scripts used for gapfilling (missForest) and flux partitioning (REddyProc) are also included.The full description of the data and methods is provided in the manuscript.
The data provided here is an exemplary dataset for the flux site Zarnekow from one year (2018). The complete dataset that is needed to run the codes for all the years can be obtained from the European Fluxes Database Cluster under site ID DE-Zrk (Sachs et al., 2016) or provided upon request. This repository is intended to provide the necessary MATLAB and R code to reproduce the results by Kalhori et al. (2024). The data are provided as zip folder containing (1) a csv file with associated definition of variables and units (file: 2023-004_Kalhori-et-al_README_2018_units.txt), (2) a shapefile (file: 2023-004_Kalhori-et-al_2018_LAiV_DOP.shp) and (3) a Geotiff (file: 2023-004_Kalhori-et-al_2018_LAiV_DOP.tiff). In addition, we provide a second zip folder containing the data that produced the figures of the related article (Kalhori et al., 2024, https://doi.org/10.1038/s43247-024-01226-9).
Continuous measurements of carbon, water and energy fluxes are performed using the eddy covariance (EC) method in a mixed-beech forest ecosystem in central Germany (52° 5'12N, 11°13'20E, 193 m asl), accompanied by relevant abiotic measurements. The site was established in the Bode catchment as part of the TERENO Harz/Central German Lowland Observatory, a mesoscale water catchment within the Elbe river basin covering an area of approximately 3300 km². The forest area Hohes Holz is the only larger forested area in the otherwise agriculturally intensively-farmed western part of the Magdeburger Börde with an area of about 1500 ha [Wollschläger et al., 2017]. The forest is a protected area with the centre (150 ha) being a nature reserve (Natura 2000) and is dominated by common beech (Fagus sylvatica L.), sessile oak (Quercus petraea) and hornbeam (Carpinus betulus L.) of about 90 years in age, an average tree height of 23.5 m and a stand density of 260 trees/ha. The long term average of annual precipitation is 563 mm and mean annual temperature is 9.1 °C (1981 – 2010 DWD station Ummendorf, #5158). The eddy covariance system consists of a CSAT-3 anemometer (Campbell Scientific Inc., Logan, UT, USA) and a LI-7500 gas analyser (Li-Cor Inc., Lincoln, NE, USA), established in 2014 in 49 m on a scaffolding tower within the research area. Data presented here comprise energy, water (H and LE), and carbon fluxes (NEE) from the EC-system since 2015 as well as gross primary productivity (GPP) and ecosystem respiration (Reco) derived from partitioning of NEE-data. Complimentary data from the turbulence data set and prioritized driver variables as a basis for ecosystem process analysis are added. High-frequency data (20Hz) were acquired with a Campbell data logger and the Eddymeas data acquisition software [Kolle and Rebmann, 2007]. Flux computation from high frequency raw data was performed with the Eddy-Pro® software (v. 7.0.6). After removing physically unrealistic flux values from the time series, subsequent post-processing steps such as estimating the u*-threshold, gap-filling and flux partitioning were performed according to Wutzler et al. [2018] with the REddyProc package. Full details of site instrumentation, metadata information and R-packages used for processing can be found in the supplementary material. Since January 2019 the site is approved as an ICOS ecosystem class 1 station (DE-HoH). ICOS standard procedures required an additional EC-setup consisting of a Gill HS-50 ultrasonic anemometer (Gill Instruments Ltd., Lymington, Hampshire, UK) and a LI-7200 gas analyser which runs in parallel to the above described system (see ICOS carbon portal: https://www.icos-cp.eu/data-products/ecosystem-release).
Continuous measurements of carbon, water and energy fluxes are performed using the eddy covariance (EC) method in a mixed-beech forest ecosystem in central Germany (52° 5'12N, 11°13'20E, 193 m asl), accompanied by relevant abiotic measurements. The site was established in the Bode catchment as part of the TERENO Harz/Central German Lowland Observatory, a mesoscale water catchment within the Elbe river basin covering an area of approximately 3300 km². The forest area Hohes Holz is the only larger forested area in the otherwise agriculturally intensively-farmed western part of the Magdeburger Börde with an area of about 1500 ha [Wollschläger et al., 2017]. The forest is a protected area with the centre (150 ha) being a nature reserve (Natura 2000) and is dominated by common beech (Fagus sylvatica L.), sessile oak (Quercus petraea) and hornbeam (Carpinus betulus L.) of about 90 years in age, an average tree height of 23.5 m and a stand density of 260 trees/ha. The long term average of annual precipitation is 563 mm and mean annual temperature is 9.1 °C (1981 – 2010 DWD station Ummendorf, #5158). The eddy covariance system consists of a CSAT-3 anemometer (Campbell Scientific Inc., Logan, UT, USA) and a LI-7500 gas analyser (Li-Cor Inc., Lincoln, NE, USA), established in 2014 in 49 m on a scaffolding tower within the research area. Data presented here comprise energy, water (H and LE), and carbon fluxes (NEE) from the EC-system since 2015 as well as gross primary productivity (GPP) and ecosystem respiration (Reco) derived from partitioning of NEE-data. Complimentary data from the turbulence data set and prioritized driver variables as a basis for ecosystem process analysis are added. High-frequency data (20Hz) were acquired with a Campbell data logger and the Eddymeas data acquisition software [Kolle and Rebmann, 2007]. Flux computation from high frequency raw data was performed with the Eddy-Pro® software (v. 7.0.6). After removing physically unrealistic flux values from the time series, subsequent post-processing steps such as estimating the u*-threshold, gap-filling and flux partitioning were performed according to Wutzler et al. [2018] with the REddyProc package. Full details of site instrumentation, metadata information and R-packages used for processing can be found in the supplementary material. Since January 2019 the site is approved as an ICOS ecosystem class 1 station (DE-HoH). ICOS standard procedures required an additional EC-setup consisting of a Gill HS-50 ultrasonic anemometer (Gill Instruments Ltd., Lymington, Hampshire, UK) and a LI-7200 gas analyser which runs in parallel to the above described system (see ICOS carbon portal: https://www.icos-cp.eu/data-products/ecosystem-release).
Continuous measurements of carbon, water and energy fluxes are performed using the eddy covariance (EC) method in a mixed-beech forest ecosystem in central Germany (52° 5'12N, 11°13'20E, 193 m asl), accompanied by relevant abiotic measurements. The site was established in the Bode catchment as part of the TERENO Harz/Central German Lowland Observatory, a mesoscale water catchment within the Elbe river basin covering an area of approximately 3300 km². The forest area Hohes Holz is the only larger forested area in the otherwise agriculturally intensively-farmed western part of the Magdeburger Börde with an area of about 1500 ha [Wollschläger et al., 2017]. The forest is a protected area with the centre (150 ha) being a nature reserve (Natura 2000) and is dominated by common beech (Fagus sylvatica L.), sessile oak (Quercus petraea) and hornbeam (Carpinus betulus L.) of about 90 years in age, an average tree height of 23.5 m and a stand density of 260 trees/ha. The long term average of annual precipitation is 563 mm and mean annual temperature is 9.1 °C (1981 – 2010 DWD station Ummendorf, #5158). The eddy covariance system consists of a CSAT-3 anemometer (Campbell Scientific Inc., Logan, UT, USA) and a LI-7500 gas analyser (Li-Cor Inc., Lincoln, NE, USA), established in 2014 in 49 m on a scaffolding tower within the research area. Data presented here comprise energy, water (H and LE), and carbon fluxes (NEE) from the EC-system since 2015 as well as gross primary productivity (GPP) and ecosystem respiration (Reco) derived from partitioning of NEE-data. Complimentary data from the turbulence data set and prioritized driver variables as a basis for ecosystem process analysis are added. High-frequency data (20Hz) were acquired with a Campbell data logger and the Eddymeas data acquisition software [Kolle and Rebmann, 2007]. Flux computation from high frequency raw data was performed with the Eddy-Pro® software (v. 7.0.6). After removing physically unrealistic flux values from the time series, subsequent post-processing steps such as estimating the u*-threshold, gap-filling and flux partitioning were performed according to Wutzler et al. [2018] with the REddyProc package. Full details of site instrumentation, metadata information and R-packages used for processing can be found in the supplementary material. Since January 2019 the site is approved as an ICOS ecosystem class 1 station (DE-HoH). ICOS standard procedures required an additional EC-setup consisting of a Gill HS-50 ultrasonic anemometer (Gill Instruments Ltd., Lymington, Hampshire, UK) and a LI-7200 gas analyser which runs in parallel to the above described system (see ICOS carbon portal: https://www.icos-cp.eu/data-products/ecosystem-release).
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