@article{DegenSpoonerScheckWenderothetal.2021, author = {Degen, Denise and Spooner, Cameron and Scheck-Wenderoth, Magdalena and Cacace, Mauro}, title = {How biased are our models?}, series = {Geoscientific model development : an interactive open access journal of the European Geosciences Union}, volume = {14}, journal = {Geoscientific model development : an interactive open access journal of the European Geosciences Union}, number = {11}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1991-959X}, doi = {10.5194/gmd-14-7133-2021}, pages = {7133 -- 7153}, year = {2021}, abstract = {Geophysical process simulations play a crucial role in the understanding of the subsurface. This understanding is required to provide, for instance, clean energy sources such as geothermal energy. However, the calibration and validation of the physical models heavily rely on state measurements such as temperature. In this work, we demonstrate that focusing analyses purely on measurements introduces a high bias. This is illustrated through global sensitivity studies. The extensive exploration of the parameter space becomes feasible through the construction of suitable surrogate models via the reduced basis method, where the bias is found to result from very unequal data distribution. We propose schemes to compensate for parts of this bias. However, the bias cannot be entirely compensated. Therefore, we demonstrate the consequences of this bias with the example of a model calibration.}, language = {en} } @article{KulahciCichyTemeletal.2021, author = {Kulahci, Gullu Deniz and Cichy, Sarah Bettina and Temel, Abidin and Spallanzani, Roberta}, title = {Pre-eruptive PTX fluid-conditions of the Afyon Volcanic Complex (Western Anatolia, Turkey)}, series = {Lithos : an international journal of mineralogy, petrology, and geochemistry}, volume = {398}, journal = {Lithos : an international journal of mineralogy, petrology, and geochemistry}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0024-4937}, doi = {10.1016/j.lithos.2021.106297}, pages = {12}, year = {2021}, abstract = {This study is trying to understand the pre-eruptive magma storage and crystallization conditions of the Middle Miocene aged, silica-saturated trachytic rocks of the Afyon Volcanic Complex (AVC) in Western Anatolia, Turkey. Those rocks can be divided by their high K2O, K2O/Na2O ratio and Mg\# into two groups, namely the intermediate-potassic (IPG) and the ultrapotassic (UPG). Here we are comparing calculated pressure (P) - temperature (T) conditions derived from geothermobarometric calculations of natural samples with results of high-pressure, high-temperature phase equilibria experiments. IPG samples are richer in silica (57-64 wt\% SiO2), whereas UPG samples show intermediate SiO2 contents of 56-58 wt\%. UPG are having high K2O contents ((>)9 wt \%), K2O/Na2O ratios ((>)10 wt\%) and Mg\# values (75-77). IPG phenocrysts comprise plagioclase + biotite + amphibole + clinopyroxene +/- orthopyroxene +/- sanidine +/- phlogopite and oxides, while UPG mineralogical assemblage consists of amphibole + phlogopite + clinopyroxene + olivine + sanidine and oxides. IPG and UPG are enriched in Large-Ion Lithophile Elements (LILE), and both have negative anomalies in Nb, Sr, Zr and Ti elements. Additionally, IPG shows positive anomalies in Pb. Both IPG and UPG display enrichment in Light Rare Earth Elements (LREE), while IPG shows a more significant negative anomaly in Eu when compared to UPG. Plagioclase fractionation may play a role in magma generation. In IPG samples Ni and Cr values range between (3.3-18.8 ppm) and (2.6-27.8 ppm), respectively; whereas UPG samples have (119.1-120.7 ppm) Ni and (212.1-219.9 ppm) Cr. Dy/Yb ratios of IPG and UPG are higher than 2 and may indicate that garnet was present in the source. Geothermobarometric calculations for natural IPG clinopyroxene-melt pairs imply higher PT conditions (Dogan-Kulahci et al., 2015), while in this study high-pressure/high-temperature (HP/HT) phase equilibria experiments recreated the natural mineral assemblage at 2-4 kbar, 6-9 km and c. 900 degrees C. New plagioclase-melt calculations have confirmed lower mean magma storage temperatures, which are closer to the experimental results but still slightly elevated. Thus, trace element results of the natural rocks and experimental data may imply that a deep garnet-bearing magma source mixed with shallower magmas (IPG) was feeding the volcanic eruption.}, language = {en} } @article{NwosuRoeserYangetal.2021, author = {Nwosu, Ebuka Canisius and Roeser, Patricia Angelika and Yang, Sizhong and Pinkerneil, Sylvia and Ganzert, Lars and Dittmann, Elke and Brauer, Achim and Wagner, Dirk and Liebner, Susanne}, title = {Species-level spatio-temporal dynamics of cyanobacteria in a hard-water temperate lake in the Southern Baltics}, series = {Frontiers in microbiology}, volume = {12}, journal = {Frontiers in microbiology}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2021.761259}, pages = {17}, year = {2021}, abstract = {Cyanobacteria are important primary producers in temperate freshwater ecosystems. However, studies on the seasonal and spatial distribution of cyanobacteria in deep lakes based on high-throughput DNA sequencing are still rare. In this study, we combined monthly water sampling and monitoring in 2019, amplicon sequence variants analysis (ASVs; a proxy for different species) and quantitative PCR targeting overall cyanobacteria abundance to describe the seasonal and spatial dynamics of cyanobacteria in the deep hard-water oligo-mesotrophic Lake Tiefer See, NE Germany. We observed significant seasonal variation in the cyanobacterial community composition (p < 0.05) in the epi- and metalimnion layers, but not in the hypolimnion. In winter-when the water column is mixed-picocyanobacteria (Synechococcus and Cyanobium) were dominant. With the onset of stratification in late spring, we observed potential niche specialization and coexistence among the cyanobacteria taxa driven mainly by light and nutrient dynamics. Specifically, ASVs assigned to picocyanobacteria and the genus Planktothrix were the main contributors to the formation of deep chlorophyll maxima along a light gradient. While Synechococcus and different Cyanobium ASVs were abundant in the epilimnion up to the base of the euphotic zone from spring to fall, Planktothrix mainly occurred in the metalimnetic layer below the euphotic zone where also overall cyanobacteria abundance was highest in summer. Our data revealed two potentially psychrotolerant (cold-adapted) Cyanobium species that appear to cope well under conditions of lower hypolimnetic water temperature and light as well as increasing sediment-released phosphate in the deeper waters in summer. The potential cold-adapted Cyanobium species were also dominant throughout the water column in fall and winter. Furthermore, Snowella and Microcystis-related ASVs were abundant in the water column during the onset of fall turnover. Altogether, these findings suggest previously unascertained and considerable spatiotemporal changes in the community of cyanobacteria on the species level especially within the genus Cyanobium in deep hard-water temperate lakes.}, language = {en} } @article{GhaniSobelZeilingeretal.2021, author = {Ghani, Humaad and Sobel, Edward and Zeilinger, Gerold and Glodny, Johannes and Irum, Irum and Sajid, Muhammad}, title = {Spatio-temporal structural evolution of the Kohat fold and thrust belt of Pakistan}, series = {Journal of structural geology}, volume = {145}, journal = {Journal of structural geology}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, issn = {0191-8141}, doi = {10.1016/j.jsg.2021.104310}, pages = {16}, year = {2021}, abstract = {The Kohat fold and thrust belt in Pakistan shows a significantly different structural style due to the structural evolution on the double d{\´e}collement compared to the rest of the Subhimalaya. In order to better understand the spatio-temporal structural evolution of the Kohat fold and thrust belt, we combine balanced cross sections with apatite (U?Th-Sm)/He (AHe) and apatite fission track (AFT) dating. The AHe and AFT ages appear to be totally reset, allowing us to date exhumation above structural ramps. The results suggest that deformation began on the frontal Surghar thrust at-15 Ma, predating or coeval with the development of the Main Boundary thrust at-12 Ma. Deformation propagated southward from the Main Boundary thrust on double de?collements between 10 Ma and 2 Ma, resulting in a disharmonic structural style inside the Kohat fold and thrust belt. Thermal modeling of the thermochronologic data suggest that samples inside Kohat fold and thrust belt experienced cooling due to formation of the duplexes; this deformation facilitated tectonic thickening of the wedge and erosion of the Miocene to Pliocene foreland strata. The spatial distribution of AHe and AFT ages in combination with the structural forward model suggest that, in the Kohat fold and thrust belt, the wedge deformed in-sequence as a supercritical wedge (-15-12 Ma), then readjusted by out-sequence deformation (-12-0 Ma) within the Kohat fold and thrust belt into a sub-critical wedge.}, language = {en} } @misc{KumarHesseRaoetal.2020, author = {Kumar, Rohini and Hesse, Fabienne and Rao, P. Srinivasa and Musolff, Andreas and Jawitz, James and Sarrazin, Francois and Samaniego, Luis and Fleckenstein, Jan H. and Rakovec, Oldrich and Thober, S. and Attinger, Sabine}, title = {Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-54987}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-549875}, pages = {12}, year = {2020}, abstract = {Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75\% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50\%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes.}, language = {en} } @article{KumarHesseRaoetal.2020, author = {Kumar, Rohini and Hesse, Fabienne and Rao, P. Srinivasa and Musolff, Andreas and Jawitz, James and Sarrazin, Francois and Samaniego, Luis and Fleckenstein, Jan H. and Rakovec, Oldrich and Thober, S. and Attinger, Sabine}, title = {Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe}, series = {Nature Communications}, volume = {11}, journal = {Nature Communications}, number = {1}, publisher = {Nature Publishing Group UK}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-020-19955-8}, pages = {1 -- 10}, year = {2020}, abstract = {Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75\% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50\%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes.}, language = {en} } @phdthesis{Lilienkamp2024, author = {Lilienkamp, Henning}, title = {Enhanced computational approaches for data-driven characterization of earthquake ground motion and rapid earthquake impact assessment}, doi = {10.25932/publishup-63195}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-631954}, school = {Universit{\"a}t Potsdam}, pages = {x, 145}, year = {2024}, abstract = {Rapidly growing seismic and macroseismic databases and simplified access to advanced machine learning methods have in recent years opened up vast opportunities to address challenges in engineering and strong motion seismology from novel, datacentric perspectives. In this thesis, I explore the opportunities of such perspectives for the tasks of ground motion modeling and rapid earthquake impact assessment, tasks with major implications for long-term earthquake disaster mitigation. In my first study, I utilize the rich strong motion database from the Kanto basin, Japan, and apply the U-Net artificial neural network architecture to develop a deep learning based ground motion model. The operational prototype provides statistical estimates of expected ground shaking, given descriptions of a specific earthquake source, wave propagation paths, and geophysical site conditions. The U-Net interprets ground motion data in its spatial context, potentially taking into account, for example, the geological properties in the vicinity of observation sites. Predictions of ground motion intensity are thereby calibrated to individual observation sites and earthquake locations. The second study addresses the explicit incorporation of rupture forward directivity into ground motion modeling. Incorporation of this phenomenon, causing strong, pulse like ground shaking in the vicinity of earthquake sources, is usually associated with an intolerable increase in computational demand during probabilistic seismic hazard analysis (PSHA) calculations. I suggest an approach in which I utilize an artificial neural network to efficiently approximate the average, directivity-related adjustment to ground motion predictions for earthquake ruptures from the 2022 New Zealand National Seismic Hazard Model. The practical implementation in an actual PSHA calculation demonstrates the efficiency and operational readiness of my model. In a follow-up study, I present a proof of concept for an alternative strategy in which I target the generalizing applicability to ruptures other than those from the New Zealand National Seismic Hazard Model. In the third study, I address the usability of pseudo-intensity reports obtained from macroseismic observations by non-expert citizens for rapid impact assessment. I demonstrate that the statistical properties of pseudo-intensity collections describing the intensity of shaking are correlated with the societal impact of earthquakes. In a second step, I develop a probabilistic model that, within minutes of an event, quantifies the probability of an earthquake to cause considerable societal impact. Under certain conditions, such a quick and preliminary method might be useful to support decision makers in their efforts to organize auxiliary measures for earthquake disaster response while results from more elaborate impact assessment frameworks are not yet available. The application of machine learning methods to datasets that only partially reveal characteristics of Big Data, qualify the majority of results obtained in this thesis as explorative insights rather than ready-to-use solutions to real world problems. The practical usefulness of this work will be better assessed in the future by applying the approaches developed to growing and increasingly complex data sets.}, language = {en} } @article{BueyuekakpınarAktarPetersenetal.2021, author = {B{\"u}y{\"u}kakp{\i}nar, P{\i}nar and Aktar, Mustafa and Petersen, Gesa Maria and K{\"o}seoğlu, Ay{\c{s}}eg{\"u}l}, title = {Orientations of broadband stations of the KOERI seismic network (Turkey) from two independent methods}, series = {Seismological research letters / Seismological Society of America}, volume = {92}, journal = {Seismological research letters / Seismological Society of America}, number = {3}, publisher = {Seismological Society of America}, address = {Boulder, Colo.}, issn = {0895-0695}, doi = {10.1785/0220200362}, pages = {1512 -- 1521}, year = {2021}, abstract = {The correct orientation of seismic sensors is critical for studies such as full moment tensor inversion, receiver function analysis, and shear-wave splitting. Therefore, the orientation of horizontal components needs to be checked and verified systematically. This study relies on two different waveform-based approaches, to assess the sensor orientations of the broadband network of the Kandilli Observatory and Earthquake Research Institute (KOERI). The network is an important backbone for seismological research in the Eastern Mediterranean Region and provides a comprehensive seismic data set for the North Anatolian fault. In recent years, this region became a worldwide field laboratory for continental transform faults. A systematic survey of the sensor orientations of the entire network, as presented here, facilitates related seismic studies. We apply two independent orientation tests, based on the polarization of P waves and Rayleigh waves to 123 broadband seismic stations, covering a period of 15 yr (2004-2018). For 114 stations, we obtain stable results with both methods. Approximately, 80\% of the results agree with each other within 10 degrees. Both methods indicate that about 40\% of the stations are misoriented by more than 10 degrees. Among these, 20 stations are misoriented by more than 20 degrees. We observe temporal changes of sensor orientation that coincide with maintenance work or instrument replacement. We provide time-dependent sensor misorientation correction values for the KOERI network in the supplemental material.}, language = {en} } @article{KaiserGrosseBoikeetal.2021, author = {Kaiser, Soraya and Grosse, Guido and Boike, Julia and Langer, Moritz}, title = {Monitoring the transformation of Arctic landscapes}, series = {Remote sensing / Molecular Diversity Preservation International (MDPI)}, volume = {13}, journal = {Remote sensing / Molecular Diversity Preservation International (MDPI)}, number = {14}, publisher = {MDPI}, address = {Basel}, issn = {2072-4292}, doi = {10.3390/rs13142802}, pages = {19}, year = {2021}, abstract = {Water bodies are a highly abundant feature of Arctic permafrost ecosystems and strongly influence their hydrology, ecology and biogeochemical cycling. While very high resolution satellite images enable detailed mapping of these water bodies, the increasing availability and abundance of this imagery calls for fast, reliable and automatized monitoring. This technical work presents a largely automated and scalable workflow that removes image noise, detects water bodies, removes potential misclassifications from infrastructural features, derives lake shoreline geometries and retrieves their movement rate and direction on the basis of ortho-ready very high resolution satellite imagery from Arctic permafrost lowlands. We applied this workflow to typical Arctic lake areas on the Alaska North Slope and achieved a successful and fast detection of water bodies. We derived representative values for shoreline movement rates ranging from 0.40-0.56 m yr(-1) for lake sizes of 0.10 ha-23.04 ha. The approach also gives an insight into seasonal water level changes. Based on an extensive quantification of error sources, we discuss how the results of the automated workflow can be further enhanced by incorporating additional information on weather conditions and image metadata and by improving the input database. The workflow is suitable for the seasonal to annual monitoring of lake changes on a sub-meter scale in the study areas in northern Alaska and can readily be scaled for application across larger regions within certain accuracy limitations.}, language = {en} } @article{TawfikOndrakWinterleitneretal.2022, author = {Tawfik, Ahmed Y. and Ondrak, Robert and Winterleitner, Gerd and Mutti, Maria}, title = {Source rock evaluation and petroleum system modeling of the East Beni Suef Basin, north Eastern Desert, Egypt}, series = {Journal of African earth sciences}, volume = {193}, journal = {Journal of African earth sciences}, publisher = {Elsevier}, address = {Oxford}, issn = {1464-343X}, doi = {10.1016/j.jafrearsci.2022.104575}, pages = {21}, year = {2022}, abstract = {This study deals with the East Beni Suef Basin (Eastern Desert, Egypt) and aims to evaluate the source-generative potential, reconstruct the burial and thermal history, examine the most influential parameters on thermal maturity modeling, and improve on the models already published for the West Beni Suef to ultimately formulate a complete picture of the whole basin evolution. Source rock evaluation was carried out based on TOC, Rock-Eval pyrolysis, and visual kerogen petrography analyses. Three kerogen types (II, II/III, and III) are distinguished in the East Beni Suef Basin, where the Abu Roash "F" Member acts as the main source rock with good to excellent source potential, oil-prone mainly type II kerogen, and immature to marginal maturity levels. The burial history shows four depositional and erosional phases linked with the tectonic evolution of the basin. A hiatus (due to erosion or non-deposition) has occurred during the Late Eocene-Oligocene in the East Beni Suef Basin, while the West Beni Suef Basin has continued subsiding. Sedimentation began later (Middle to Late Albian) with lower rates in the East Beni Suef Basin compared with the West Beni Suef Basin (Early Albian). The Abu Roash "F" source rock exists in the early oil window with a present-day transformation ratio of about 19\% and 21\% in the East and West Beni Suef Basin, respectively, while the Lower Kharita source rock, which is only recorded in the West Beni Suef Basin, has reached the late oil window with a present-day transformation ratio of about 70\%. The magnitude of erosion and heat flow have proportional and mutual effects on thermal maturity. We present three possible scenarios of basin modeling in the East Beni Suef Basin concerning the erosion from the Apollonia and Dabaa formations. Results of this work can serve as a basis for subsequent 2D and/or 3D basin modeling, which are highly recommended to further investigate the petroleum system evolution of the Beni Suef Basin.}, language = {en} } @article{KhuranaHesseHildebrandtetal.2022, author = {Khurana, Swamini and Heße, Falk and Hildebrandt, Anke and Thullner, Martin}, title = {Predicting the impact of spatial heterogeneity on microbially mediated nutrient cycling in the subsurface}, series = {Biogeosciences}, volume = {19}, journal = {Biogeosciences}, number = {3}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-19-665-2022}, pages = {665 -- 688}, year = {2022}, abstract = {The subsurface is a temporally dynamic and spatially heterogeneous compartment of the Earth's critical zone, and biogeochemical transformations taking place in this compartment are crucial for the cycling of nutrients. The impact of spatial heterogeneity on such microbially mediated nutrient cycling is not well known, which imposes a severe challenge in the prediction of in situ biogeochemical transformation rates and further of nutrient loading contributed by the groundwater to the surface water bodies. Therefore, we used a numerical modelling approach to evaluate the sensitivity of groundwater microbial biomass distribution and nutrient cycling to spatial heterogeneity in different scenarios accounting for various residence times. The model results gave us an insight into domain characteristics with respect to the presence of oxic niches in predominantly anoxic zones and vice versa depending on the extent of spatial heterogeneity and the flow regime. The obtained results show that microbial abundance, distribution, and activity are sensitive to the applied flow regime and that the mobile (i.e. observable by groundwater sampling) fraction of microbial biomass is a varying, yet only a small, fraction of the total biomass in a domain. Furthermore, spatial heterogeneity resulted in anaerobic niches in the domain and shifts in microbial biomass between active and inactive states. The lack of consideration of spatial heterogeneity, thus, can result in inaccurate estimation of microbial activity. In most cases this leads to an overestimation of nutrient removal (up to twice the actual amount) along a flow path. We conclude that the governing factors for evaluating this are the residence time of solutes and the Damkohler number (Da) of the biogeochemical reactions in the domain. We propose a relationship to scale the impact of spatial heterogeneity on nutrient removal governed by the logioDa. This relationship may be applied in upscaled descriptions of microbially mediated nutrient cycling dynamics in the subsurface thereby resulting in more accurate predictions of, for example, carbon and nitrogen cycling in groundwater over long periods at the catchment scale.}, language = {en} } @article{PorȩbaRacioppiGarbarinoetal.2022, author = {Porȩba, Tomasz and Racioppi, Stefano and Garbarino, Gaston and Morgenroth, Wolfgang and Mezouar, Mohamed}, title = {Investigating the structural symmetrization of CsI3 at high pressures through combined X-ray diffraction experiments and theoretical analysis}, series = {Inorganic chemistry}, volume = {61}, journal = {Inorganic chemistry}, number = {28}, publisher = {American Chemical Society}, address = {Washington}, issn = {0020-1669}, doi = {10.1021/acs.inorgchem.2c01690}, pages = {10977 -- 10985}, year = {2022}, abstract = {ABSTRACT: Structural evolution of cesium triiodide at high pressures has been revealed by synchrotron single-crystal X-ray diffraction. Cesium triiodide undergoes a first-order phase transition above 1.24(3) GPa from an orthorhombic to a trigonal system. This transition is coupled with severe reorganization of the polyiodide network from a layered to three-dimensional architecture. Quantum chemical calculations show that even though the two polymorphic phases are nearly isoenergetic under ambient conditions, the PV term is decisive in stabilizing the trigonal polymorph above the transition point. Phonon calculations using a non-local correlation functional that accounts for dispersion interactions confirm that this polymorph is dynamically unstable under ambient conditions. The high-pressure behavior of crystalline CsI3 can be correlated with other alkali metal trihalides, which undergo a similar sequence of structural changes upon load.}, language = {en} } @article{FalkowskiEhlersMadellaetal.2021, author = {Falkowski, Sarah and Ehlers, Todd and Madella, Andrea and Glotzbach, Christoph and Georgieva, Viktoria and Strecker, Manfred}, title = {Glacial catchment erosion from detrital zircon (U-Th)/He thermochronology}, series = {GR / AGU, American Geophysical Union: Earth surface}, volume = {126}, journal = {GR / AGU, American Geophysical Union: Earth surface}, number = {10}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {2169-9003}, doi = {10.1029/2021JF006141}, pages = {26}, year = {2021}, abstract = {Alpine glacial erosion exerts a first-order control on mountain topography and sediment production, but its mechanisms are poorly understood. Observational data capable of testing glacial erosion and transport laws in glacial models are mostly lacking. New insights, however, can be gained from detrital tracer thermochronology. Detrital tracer thermochronology works on the premise that thermochronometer bedrock ages vary systematically with elevation, and that detrital downstream samples can be used to infer the source elevation sectors of sediments. We analyze six new detrital samples of different grain sizes (sand and pebbles) from glacial deposits and the modern river channel integrated with data from 18 previously analyzed bedrock samples from an elevation transect in the Leones Valley, Northern Patagonian Icefield, Chile (46.7 degrees S). We present 622 new detrital zircon (U-Th)/He (ZHe) single-grain analyses and 22 new bedrock ZHe analyses for two of the bedrock samples to determine age reproducibility. Results suggest that glacial erosion was focused at and below the Last Glacial Maximum and neoglacial equilibrium line altitudes, supporting previous modeling studies. Furthermore, grain age distributions from different grain sizes (sand, pebbles) might indicate differences in erosion mechanisms, including mass movements at steep glacial valley walls. Finally, our results highlight complications and opportunities in assessing glacigenic environments, such as dynamics of sediment production, transport, transient storage, and final deposition, that arise from settings with large glacio-fluvial catchments.}, language = {en} } @article{KloseGuillemoteauVignolietal.2022, author = {Klose, Tim and Guillemoteau, Julien and Vignoli, Giulio and Tronicke, Jens}, title = {Laterally constrained inversion (LCI) of multi-configuration EMI data with tunable sharpness}, series = {Journal of applied geophysics}, volume = {196}, journal = {Journal of applied geophysics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0926-9851}, doi = {10.1016/j.jappgeo.2021.104519}, pages = {9}, year = {2022}, abstract = {Frequency-domain electromagnetic (FDEM) data are commonly inverted to characterize subsurface geoelectrical properties using smoothness constraints in 1D inversion schemes assuming a layered medium. Smoothness constraints are suitable for imaging gradual transitions of subsurface geoelectrical properties caused, for example, by varying sand, clay, or fluid content. However, such inversion approaches are limited in characterizing sharp interfaces. Alternative regularizations based on the minimum gradient support (MGS) stabilizers can, instead, be used to promote results with different levels of smoothness/sharpness selected by simply acting on the so-called focusing parameter. The MGS regularization has been implemented for different kinds of geophysical data inversion strategies. However, concerning FDEM data, the MGS regularization has only been implemented for vertically constrained inversion (VCI) approaches but not for laterally constrained inversion (LCI) approaches. We present a novel LCI approach for FDEM data using the MGS regularization for the vertical and lateral direction. Using synthetic and field data examples, we demonstrate that our approach can efficiently and automatically provide a set of model solutions characterized by different levels of sharpness and variable lateral consistencies. In terms of data misfit, the obtained set of solutions contains equivalent models allowing us also to investigate the non-uniqueness of FDEM data inversion.}, language = {en} } @article{MitzscherlingMacLeanLipusetal.2022, author = {Mitzscherling, Julia and MacLean, Joana and Lipus, Daniel and Bartholom{\"a}us, Alexander and Mangelsdorf, Kai and Lipski, Andr{\´e} and Roddatis, Vladimir and Liebner, Susanne and Wagner, Dirk}, title = {Nocardioides alcanivorans sp. nov., a novel hexadecane-degrading species isolated from plastic waste}, series = {International journal of systematic and evolutionary microbiology}, volume = {72}, journal = {International journal of systematic and evolutionary microbiology}, number = {4}, publisher = {Microbiology Society}, address = {London}, issn = {1466-5026}, doi = {10.1099/ijsem.0.005319}, pages = {11}, year = {2022}, abstract = {Strain NGK65(T), a novel hexadecane degrading, non-motile, Gram-positive, rod-to-coccus shaped, aerobic bacterium, was isolated from plastic polluted soil sampled at a landfill. Strain NGK65(T) hydrolysed casein, gelatin, urea and was catalase-positive. It optimally grew at 28 degrees C. in 0-1\% NaCl and at pH 7.5-8.0. Glycerol, D-glucose, arbutin, aesculin, salicin, potassium 5-ketogluconate. sucrose, acetate, pyruvate and hexadecane were used as sole carbon sources. The predominant membrane fatty acids were iso-C-16:0 followed by iso-C(17:)0 and C-18:1 omega 9c. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and hydroxyphosphatidylinositol. The cell-wall peptidoglycan type was A3 gamma, with LL-diaminopimelic acid and glycine as the diagnostic amino acids. MK 8 (H-4) was the predominant menaquinone. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NGK65(T) belongs to the genus Nocardioides (phylum Actinobacteria). appearing most closely related to Nocardioides daejeonensis MJ31(T) (98.6\%) and Nocardioides dubius KSL-104(T) (98.3\%). The genomic DNA G+C content of strain NGK65(T) was 68.2\%. Strain NGK65(T) and the type strains of species involved in the analysis had average nucleotide identity values of 78.3-71.9\% as well as digital DNA-DNA hybridization values between 22.5 and 19.7\%, which clearly indicated that the isolate represents a novel species within the genus Nocardioides. Based on phenotypic and molecular characterization, strain NGK65(T) can clearly be differentiated from its phylogenetic neighbours to establish a novel species, for which the name Nocardioides alcanivorans sp. nov. is proposed. The type strain is NGK65(T) (=DSM 113112(T)=NCCB 100846(T)).}, language = {en} } @article{WilhelmsBoersigYangetal.2022, author = {Wilhelms, Andre and B{\"o}rsig, Nicolas and Yang, Jingwei and Holbach, Andreas and Norra, Stefan}, title = {Insights into phytoplankton dynamics and water quality monitoring with the BIOFISH at the Elbe River, Germany}, series = {Water}, volume = {14}, journal = {Water}, number = {13}, publisher = {MDPI}, address = {Basel}, issn = {2073-4441}, doi = {10.3390/w14132078}, pages = {20}, year = {2022}, abstract = {Understanding the key factors influencing the water quality of large river systems forms an important basis for the assessment and protection of cross-regional ecosystems and the implementation of adapted water management concepts. However, identifying these factors requires in-depth comprehension of the unique environmental systems, which can only be achieved by detailed water quality monitoring. Within the scope of the joint science and sports event "Elbschwimmstaffel" (swimming relay on the river Elbe) in June/July 2017 organized by the German Ministry of Education and Research, water quality data were acquired along a 550 km long stretch of the Elbe River in Germany. During the survey, eight physiochemical water quality parameters were recorded in high spatial and temporal resolution with the BIOFISH multisensor system. Multivariate statistical methods were applied to identify and delineate processes influencing the water quality. The BIOFISH dataset revealed that phytoplankton activity has a major impact on the water quality of the Elbe River in the summer months. The results suggest that phytoplankton biomass constitutes a substantial proportion of the suspended particles and that photosynthetic activity of phytoplankton is closely related to significant temporal changes in pH and oxygen saturation. An evaluation of the BIOFISH data based on the combination of statistical analysis with weather and discharge data shows that the hydrological and meteorological history of the sampled water body was the main driver of phytoplankton dynamics. This study demonstrates the capacity of longitudinal river surveys with the BIOFISH or similar systems for water quality assessment, the identification of pollution sources and their utilization for online in situ monitoring of rivers.}, language = {en} } @article{SmithTraxlBoers2022, author = {Smith, Taylor and Traxl, Dominik and Boers, Niklas}, title = {Empirical evidence for recent global shifts in vegetation resilience}, series = {Nature climate change}, volume = {12}, journal = {Nature climate change}, number = {5}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-022-01352-2}, pages = {477 -- 484}, year = {2022}, abstract = {The authors demonstrate that a vegetation system's ability to recover from disturbances-its resilience-can be estimated from its natural variability. Global patterns of resilience loss and gains since the early 1990s reveal shifts towards widespread resilience loss since the early 2000s. The character and health of ecosystems worldwide is tightly coupled to changes in Earth's climate. Theory suggests that ecosystem resilience-the ability of ecosystems to resist and recover from external shocks such as droughts and fires-can be inferred from their natural variability. Here, we quantify vegetation resilience globally with complementary metrics based on two independent long-term satellite records. We first empirically confirm that the recovery rates from large perturbations can be closely approximated from internal vegetation variability across vegetation types and climate zones. On the basis of this empirical relationship, we quantify vegetation resilience continuously and globally from 1992 to 2017. Long-term vegetation resilience trends are spatially heterogeneous, with overall increasing resilience in the tropics and decreasing resilience at higher latitudes. Shorter-term trends, however, reveal a marked shift towards a global decline in vegetation resilience since the early 2000s, particularly in the equatorial rainforest belt.}, language = {en} } @article{PalmerGregoryBaggeetal.2020, author = {Palmer, Matthew D. and Gregory, Jonathan and Bagge, Meike and Calvert, Daley and Hagedoorn, Jan Marius and Howard, Tom and Klemann, Volker and Lowe, Jason A. and Roberts, Chris and Slangen, Aimee B. A. and Spada, Giorgio}, title = {Exploring the drivers of global and local sea-level change over the 21st century and beyond}, series = {Earth's future}, volume = {8}, journal = {Earth's future}, number = {9}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {2328-4277}, doi = {10.1029/2019EF001413}, pages = {1 -- 25}, year = {2020}, abstract = {We present a new set of global and local sea-level projections at example tide gauge locations under the RCP2.6, RCP4.5, and RCP8.5 emissions scenarios. Compared to the CMIP5-based sea-level projections presented in IPCC AR5, we introduce a number of methodological innovations, including (i) more comprehensive treatment of uncertainties, (ii) direct traceability between global and local projections, and (iii) exploratory extended projections to 2300 based on emulation of individual CMIP5 models. Combining the projections with observed tide gauge records, we explore the contribution to total variance that arises from sea-level variability, different emissions scenarios, and model uncertainty. For the period out to 2300 we further breakdown the model uncertainty by sea-level component and consider the dependence on geographic location, time horizon, and emissions scenario. Our analysis highlights the importance of local variability for sea-level change in the coming decades and the potential value of annual-to-decadal predictions of local sea-level change. Projections to 2300 show a substantial degree of committed sea-level rise under all emissions scenarios considered and highlight the reduced future risk associated with RCP2.6 and RCP4.5 compared to RCP8.5. Tide gauge locations can show large ( > 50\%) departures from the global average, in some cases even reversing the sign of the change. While uncertainty in projections of the future Antarctic ice dynamic response tends to dominate post-2100, we see substantial differences in the breakdown of model variance as a function of location, time scale, and emissions scenario.}, language = {en} } @misc{PalmerGregoryBaggeetal.2020, author = {Palmer, Matthew D. and Gregory, Jonathan and Bagge, Meike and Calvert, Daley and Hagedoorn, Jan Marius and Howard, Tom and Klemann, Volker and Lowe, Jason A. and Roberts, Chris and Slangen, Aimee B. A. and Spada, Giorgio}, title = {Exploring the drivers of global and local sea-level change over the 21st century and beyond}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {9}, issn = {1866-8372}, doi = {10.25932/publishup-54988}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-549881}, pages = {27}, year = {2020}, abstract = {We present a new set of global and local sea-level projections at example tide gauge locations under the RCP2.6, RCP4.5, and RCP8.5 emissions scenarios. Compared to the CMIP5-based sea-level projections presented in IPCC AR5, we introduce a number of methodological innovations, including (i) more comprehensive treatment of uncertainties, (ii) direct traceability between global and local projections, and (iii) exploratory extended projections to 2300 based on emulation of individual CMIP5 models. Combining the projections with observed tide gauge records, we explore the contribution to total variance that arises from sea-level variability, different emissions scenarios, and model uncertainty. For the period out to 2300 we further breakdown the model uncertainty by sea-level component and consider the dependence on geographic location, time horizon, and emissions scenario. Our analysis highlights the importance of local variability for sea-level change in the coming decades and the potential value of annual-to-decadal predictions of local sea-level change. Projections to 2300 show a substantial degree of committed sea-level rise under all emissions scenarios considered and highlight the reduced future risk associated with RCP2.6 and RCP4.5 compared to RCP8.5. Tide gauge locations can show large ( > 50\%) departures from the global average, in some cases even reversing the sign of the change. While uncertainty in projections of the future Antarctic ice dynamic response tends to dominate post-2100, we see substantial differences in the breakdown of model variance as a function of location, time scale, and emissions scenario.}, language = {en} } @misc{KaempfPlessenLauterbachetal.2019, author = {K{\"a}mpf, Lucas and Plessen, Birgit and Lauterbach, Stefan and Nantke, Carla and Meyer, Hanno and Chapligin, Bernhard and Brauer, Achim}, title = {Stable oxygen and carbon isotopes of carbonates in lake sediments as a paleoflood proxy}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-55000}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-550004}, pages = {7}, year = {2019}, abstract = {Lake sediments are increasingly explored as reliable paleoflood archives. In addition to established flood proxies including detrital layer thickness, chemical composition, and grain size, we explore stable oxygen and carbon isotope data as paleoflood proxies for lakes in catchments with carbonate bedrock geology. In a case study from Lake Mondsee (Austria), we integrate high-resolution sediment trapping at a proximal and a distal location and stable isotope analyses of varved lake sediments to investigate flood-triggered detrital sediment flux. First, we demonstrate a relation between runoff, detrital sediment flux, and isotope values in the sediment trap record covering the period 2011-2013 CE including 22 events with daily (hourly) peak runoff ranging from 10 (24) m(3) s(-1) to 79 (110) m(3) s(-1). The three- to ten-fold lower flood-triggered detrital sediment deposition in the distal trap is well reflected by attenuated peaks in the stable isotope values of trapped sediments. Next, we show that all nine flood-triggered detrital layers deposited in a sediment record from 1988 to 2013 have elevated isotope values compared with endogenic calcite. In addition, even two runoff events that did not cause the deposition of visible detrital layers are distinguished by higher isotope values. Empirical thresholds in the isotope data allow estimation of magnitudes of the majority of floods, although in some cases flood magnitudes are overestimated because local effects can result in too-high isotope values. Hence we present a proof of concept for stable isotopes as reliable tool for reconstructing flood frequency and, although with some limitations, even for flood magnitudes.}, language = {en} }