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  • 101
    Publication Date: 2024-01-26
    Description: The inconsistent pattern of precipitation, a shift in the seasonality of river flows, and the early onset of snow and glacier melt in recent decades across river basins of High Mountain Asia (HMA) has compelled us to further investigate future variations in sources of runoff under projected climate change scenarios. This will help in determining the timing and magnitude of runoff components and this will help in management of future water resources. The current study employed the University of British Columbia Watershed Model (UBC WM) to estimate the spatiotemporal variations in simulated runoff components (i.e. snowmelt, glacier melt, rainfall-runoff, and baseflow) and their relative contribution to total runoff of Gilgit River regarding the baseline period (1981–2010) in near (2021–2050) and far future (2071–2100) under low (SSP1), medium (SSP2) and high (SSP5) emission scenarios. A significant increase in the magnitude of mean annual temperature and precipitation is expected in the near future (2021–2050) than far future (2071–2100) under most SSPs. Moreover, high-altitude stations of the Gilgit River basin are expected to experience more warming in the near and far future than low altitudes under all SSPs. On average, regarding the baseline period, the simulated runoff is projected to increase in the near (27%, 30%, and 33%) and far future (30%, 53%, and 91%) under SSP1, SSP2, and SSP5, respectively. Moreover, an early onset of snow/glacier melting is predicted in the far future due to an increase in summer air temperature and a decline in winter (DJF) precipitation. Besides, the rise in high altitude temperature is expected to cause the melting of snow/glaciers even above 6000 m elevation in the far future.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 102
    Publication Date: 2024-01-26
    Description: Abstract
    Description: Teleseismic back-projection imaging has emerged as a powerful tool for understanding the rupture propagation of large earthquakes. However, its application often suffers from artifacts related to the receiver array geometry. We developed a teleseismic back-projection technique that can accommodate data from multiple arrays. Combined processing of P and pP waveforms may further improve the resolution. The method is suitable for defining arrays ad-hoc to achieve a good azimuthal distribution for most earthquakes. We present a catalog of short-period rupture histories (0.5-2.0 Hz) for all earthquakes from 2010 to 2022 with Mw {greater than or equal to} 7.5 and depth less than 200 km (56 events). The method provides automatic estimates of rupture length, directivity, speed, and aspect ratio, a proxy for rupture complexity. We obtained short-period rupture length scaling relations that are in good agreement with previously published relations based on estimates of total slip. Rupture speeds were consistently in the sub-Rayleigh regime for thrust and normal earthquakes, whereas a tenth of strike-slip events propagated at supershear speeds. Many rupture histories exhibited complex behaviors, e.g., rupture on conjugate faults, bilateral propagation, and dynamic triggering by a P wave. For megathrust earthquakes, ruptures encircling asperities were frequently observed, with down-dip, up-dip, and balanced patterns. Although there is a preference for short-period emissions to emanate from central and down-dip parts of the megathrust, emissions up-dip of the main asperity are more frequent than suggested by earlier results. The data are presented as follows (and described in detail in the associated README): SUPPORTING DATA SET S1 (2024-001_Vera-et-al_Supporting-Data-S1.zip) This Data Set (S1) consists of *.bp files containing (1) short-period earthquake rupture patterns, (2) energy radiated maps, and (3) source time functions derived from back-projections (0.5-2.0 Hz). The Data Set S1 includes 56 folders, representing 56 processed earthquakes between 2010 and 2022 with a moment magnitude (Mw) greater than or equal to 7.5 and a depth less than 200 km. These folders are labeled in the format YYYYMMDDhhmm_EVENT_NAME_REGION (UTC) in *.bp format. SUPPORTING DATA SET S2 (2024-001_Vera-et-al_Supporting-Data-S2.csv) This Data Set (S2) comprises a *.csv file containing earthquake source information used in the back-projection and the resulting rupture parameter estimates based on **visually determined** rupture end times. The *.csv file includes rupture parameter estimates for each of the 56 earthquake back-projections presented in Data Set S1. SUPPORTING DATA SET S3 (2024-001_Vera-et-al_Supporting-Data-S3.csv) This Data Set (S3) comprises a *.csv file containing earthquake source information used in the back-projection and the resulting rupture parameter estimates based on **automatic** rupture end times. Note: The main difference from Data Set S2 is that rupture parameter estimates in S3 are derived from **automated** rupture end times, whereas S2 provided estimates relative to **visually determined** rupture end times.
    Keywords: teleseismic back-projection ; large earthquakes ; megathrust earthquakes ; complex ruptures ; supershear ruptures ; earthquake rupture catalog ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 EARTHQUAKES
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  • 103
    Publication Date: 2024-01-29
    Type: Book chapter , PeerReviewed
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  • 104
    Publication Date: 2024-01-29
    Description: Several inorganic compounds of nitrogen (N) and phosphorus (P) are key to ocean ecology because, among other effects, they sustain primary production. After discovering in the 1980s that sponges can be both source and sink of such nutrients, much has been learned, including that fluxes derive from the metabolic integration of the sponge tissues and the assemblage of prokaryotic microbes living in them (i.e., the microbiota). The advent of molecular techniques revealed exceptional phylogenetic biodiversity in the microbiota and allowed the identification of genes coding for enzymes transforming N and P compounds. However, the accumulated information remains relatively inarticulate and its ecological dimension is uncharted. Herein we summarize the basics of N and P cycling in the marine environment to further address nutrient flux rates compiled from 92 sponge species. Ammonium release or 198consumption, followed by nitrite release, emerged as the most common fluxes in sponges. Phosphate release was also prevalent. A difficulty with the available information is a bias towards tropical shallow-water demosponges and the use of non-comparable units. A total of 63 prokaryotic phyla are known from sponge microbiomes. Collectively, they have the genetic potential for all aerobic and anaerobic N transformations, facilitating the formation of closed circuits for N to recycle within the holobionts (i.e., sponge + microbiota). Often, such circuits are fueled by important production/consumption of ammonium. Phosphorus cycling remains understudied, with evidence of phosphate and (organic) phosphonate utilization. Phosphate does not appear to limit sponge microbiomes, with polyphosphate (Poly-P) probably serving more as energy storage than as a P reservoir. Dissimilatory phosphite oxidation (DPO), which would explain the phosphate efflux from the sponges, has not been detected and the causes of the efflux (perhaps anoxic Poly-P degradation) remain uncertain. A relevant benefit provided by the microbiome, in addition to recycling sponge N wastes and provisioning vitamins and some organic C and N compounds through fixation, is to serve as energetically inexpensive particulate food, liberating sponges from strict dependence on inputs of external food. To facilitate co-existence and cooperation between aerobic and anaerobic microbial lineages, sponges modulate pumping activity and have evolved special cells (bacteriocytes) to enclose microbes. Species-specific metabolic integration between sponges and their microbiome yields singular holobionts with remarkable roles in the benthic-pelagic coupling of N and P cycles. Some sponge aggregations can achieve higher denitrification rates per unit area than sediments; others have higher ammonium consumption rates than eutrophic phytoplanktonic communities. Through their microbiomes, some sponge species may also cope with low oxygen conditions and modify local N and P nutrient concentrations, unchaining a cascade of ecological changes that may lead to the exclusion of competitors. Identified gaps in knowledge related to: (i) how the nutrients going in and out of the holobiont are quantitatively connected to the microbial processes occurring inside; (ii) how microbes interact with each other; and (iii) how sponges co-evolved to facilitate co-existence and functional networking in the microbiome.
    Type: Book chapter , PeerReviewed
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  • 105
    Publication Date: 2024-01-29
    Description: Abstract
    Description: 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).
    Keywords: carbon dioxide emission ; CO2 emission ; methane emission ; CH4 emission ; peatland ; wetland ; eddy covariance ; rewetting ; emission factor ; mitigation ; EARTH SCIENCE 〉 BIOSPHERE 〉 TERRESTRIAL ECOSYSTEMS 〉 WETLANDS 〉 PEATLANDS ; In Situ Land-based Platforms 〉 GROUND-BASED OBSERVATIONS
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  • 106
    Publication Date: 2024-01-29
    Description: Abstract
    Description: The dataset contains source parameters of acoustic emission (AE) events recorded during triaxial friction (stick-slip) experiments performed on the Westerly Granite sample WgN05. In addition we provide raw waveform data of AE events recorded in triggered mode with a network of 16 AE sensors. Basic seismic catalog associated with the stick-slip experiment contains origin time, hypocentral location in local Cartesian coordinate system of the sample (with associated uncertainties), and AE-derived magnitude. In addition, for a subset of AEs we provide full moment tensors. This catalog include information on fault parameters (strike, dip and rake of the two nodal planes), percentage of isotropic, compensated linear vector dipole and double-couple components of the full moment tensor, P, T, B axes orientations in the coordinate system of the sample, uncertainty assessment, as well as the six independent moment tensor components. Finally, we provide a time series of axial stress values as presented in the Kwiatek et al. (2023) as well as the coordinates of the AE sensors. The catalog and parametric data is supplemented with the raw waveform recordings stored in HDF5 format from 16 acoustic emission sensors placed on the surface of the sample.
    Keywords: acoustic emission ; rock mechanics ; earthquake precursors ; stick-slip ; earthquake preparation ; seismomechanics ; intermittent criticallity ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 EARTHQUAKE OCCURRENCES ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 EARTHQUAKE PREDICTIONS ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 SEISMIC PROFILE 〉 SEISMIC BODY WAVES ; hazard ; hazard 〉 natural hazard ; monitoring 〉 seismic monitoring ; physical property 〉 inversion ; physical property 〉 pressure ; physical property 〉 rock mechanics
    Type: Dataset , Dataset
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  • 107
    Publication Date: 2024-01-29
    Description: Abstract
    Description: 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.
    Description: Other
    Description: GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 Copyright (C) 2023 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany (Aram Kalhori). Kalhori2023_Rewetted Peatland_GHG Analysis is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see 〈https://www.gnu.org/licenses/〉.
    Keywords: carbon dioxide emission ; CO2 emission ; methane emission ; CH4 emission ; peatland ; wetland ; eddy covariance ; rewetting ; emission factor ; mitigation ; EARTH SCIENCE 〉 BIOSPHERE 〉 TERRESTRIAL ECOSYSTEMS 〉 WETLANDS 〉 PEATLANDS ; In Situ Land-based Platforms 〉 GROUND-BASED OBSERVATIONS
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  • 108
    Publication Date: 2024-01-30
    Description: In this report, the European Scientific Advisory Board on Climate Change recommends a series of actions to put the EU on track towards climate neutrality. Based on an assessment of more than 80 indicators, the Advisory Board found that more efforts are needed across all sectors to achieve the EU climate objectives from 2030 to 2050, and particularly in buildings, transport, agriculture and forestry. The Advisory Board acknowledges the potential of the Fit for 55 policy package to speed up EU’s decarbonisation, but warns that additional measures are imperative if the EU is to achieve its climate neutrality objective by 2050 at the latest. With this in mind, the Advisory Board outlines 13 key recommendations for a more effective implementation and design of the EU climate policy framework. This will require action in the coming years, both to effectively implement recently agreed legislation and to start preparations for the post-2030 climate policy framework.
    Language: English
    Type: info:eu-repo/semantics/report
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  • 109
    Publication Date: 2024-01-30
    Description: Eine Teilung des deutschen Marktgebietes würde die Marktwerte erneuerbarer Energien beeinflussen. Wind und Photovoltaik (PV) im Süden Deutschlands würden an Wert gewinnen, während Erneuerbare im Norden Erlöse einbüßen würden. Bei einer auch zukünftig stärkeren Konzentration von erneuerbaren Energien im Norden bedeutet dies insgesamt einen höheren Förderbedarf für PV – Wind wäre trotz niedriger Marktwerte in den meisten Regionen wirtschaftlich. Wenn eine regionale Steuerung erreicht werden soll, müsste die auszuzahlende Förderung für neue PV-Anlagen anhand des zonenübergreifenden Referenzmarktwertes berechnet werden. Durchschnittliche Börsenstrompreise würden durch eine Gebotszonenteilung im Süden Deutschlands leicht angehoben und im Norden gesenkt, die Effekte auf Endkundenpreise und damit verbundene Anreize zur Standortwahl von Industrieunternehmen sind allerdings als gering einzuschätzen.
    Language: German
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  • 110
    Publication Date: 2024-01-30
    Description: Abstract
    Description: This data set contains the results from a 2023 GFZ Innovative Research Expedition project to explore for natural hydrogen gas (H2) occurrences in the NW Pyrenean foreland, near the town of Biarritz in France. The data represent in-situ measurements of soil and spring water gas, as well as in-situ spring water property measurements, complemented with laboratory analysis results of gas contents and noble gas isotopic compositions of gas and spring water samples collected during the expedition. This GFZ Innovative Research Expedition was inspired by previous exploration efforts in the region by Lefeuvre et al. (2021, 2022). These authors detected elevated concentrations of natural H2 gas in the soil and interpreted this natural H2 to be derived from serpentinizing mantle rocks below the Pyrenees. The main aims of this expedition were the following: (1) in-situ measuring soil gas contents and taking soil gas samples for laboratory analysis at a site near the town of Peyrehorade in the NW of the general study area of Lefeuvre et al. (2021), thus improving the soil gas data coverage along the NW end of the North Pyrenean Frontal Thrust (NPFT); (2) taking gas samples from degassing springs (or water samples from non-degassing springs to be degassed in the lab) in the general Lefeuvre et al. (2021) study area for additional laboratory analysis of gas contents and noble gas isotopic compositions, which may be indicative of (deep) gas origins; and (3) performing a detailed soil gas analysis by means of a portable mass spectrometer at Sauveterre-de-Béarn, a site along the NPFT where Lefeuvre et al. (2022) measured elevated concentrations of natural H2 in the soil. Furthermore, we also measured the properties of the visited springs (temperature, pH, conductivity) while on site, and performed additional in-situ soil gas measurements from manual drillholes. Details on the measurement and sampling methods, on the laboratory analyses, as well as the results of these measurements and analyses are provided in the data description file The expedition involved six field days in July 2023, during which a total of 26 sites were visited. These sites were selected for their vicinity near a major geological contact or fault zone that could have facilitated upward circulation of gas or (thermal) water from the (deep) subsurface (i.e., potentially from the mantle).
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  • 111
    Publication Date: 2024-01-30
    Description: Abstract
    Description: The EU funded project CRM-geothermal aims to establish an overview of the potential for critical raw materials (CRM) in geothermal fluids across the EU and third countries (Ref). Within this framework, the geothermal sites of Tuzla, Seferihisar and Dikili in eastern Turkey have been visited in March 2023. To estimate the potential of CRM at these sites, a comprehensive sampling program was performed. Rock samples (drill gravel) of the production borehole and scaling from gas-water separators were obtained. Furthermore, sampling of geothermal fluids (gas and brine) and precipitates (salt) along the production line was performed. Here, the results of the geochemical analyses of solid sample materials (drill gravel, scales and salt) are presented. All analyses were performed in the ElMiE-Lab (Elements and Minerals of the Earth Laboratory) at German Research Centre for Geosciences Potsdam, Germany (https://labinfrastructure.geo-x.net/laboratories/8). For their major and minor element compositions, bulk samples of drill gravel and scales were analyzed with XRF and ICP-MS, respectively. Salt precipitates were analyzed for dry loss and mineral composition using XRD.
    Description: Methods
    Description: Sampling of drill gravel: Drill core gravel from Tuzla geothermal site was obtained from existing samples taken during drilling in 2010. For the analyses, three samples of the geothermal reservoir horizon at different depth and from two different drill holes were chosen. Sampling of scales: Scales were sampled during geothermal power plant maintenance in 2023 in Tuzla and in 2022 in Seferihisar. It was analyzed from all water-gas separators from the three drill holes in Tuzla. For Seferihisar, fresh scales were obtained from inside a tube, a pump and a fitter. Sampling of salt precipitates: During the visits, fresh salt precipitates were taken from outside the pipeline that transports geothermal brine to the power plant. The sampling points were located near the production well. Here, few connectors were slightly leaking which is negligible for the geothermal power production. Over time, the small amounts of brine release causes salt precipitation, due to brine cooling and evaporation. The residual salts occurs in form of fine crystalline precipitations around the pipe connectors or, stalactite-like salt tubings. Sampling of fresh, slightly moist material was performed by either scratching material off the precipitate deposit or breaking off juvenile stalactite outgrowth. The sample were stored and transported in air-tight zipper plastic bags to avoid sample alteration by atmospheric air.
    Keywords: critical raw materials ; geothermal power plant eastern turkey ; drill gravel ; scales ; salt precipitates ; geochemistry ; XRF ; ICP-MS ; XRD ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 ECONOMIC RESOURCES 〉 ENERGY PRODUCTION/USE 〉 GEOTHERMAL ENERGY PRODUCTION/USE ; energy 〉 energy type 〉 non-conventional energy 〉 geothermal energy ; Models/Analyses 〉 CRM
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  • 112
    Publication Date: 2024-01-30
    Description: The Mediterranean Sea has been sampled irregularly by research vessels in the past, mostly by national expeditions in regional waters. To monitor the hydrographic, biogeochemical and circulation changes in the Mediterranean Sea, a systematic repeat oceanographic survey programme called Med-SHIP was recommended by the Mediterranean Science Commission (CIESM) in 2011, as part of the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP). Med-SHIP consists of zonal and meridional surveys with different frequencies, where comprehensive physical and biogeochemical properties are measured with the highest international standards. The first zonal survey was done in 2011 and repeated in 2018. In addition, a network of meridional (and other key) hydrographic sections were designed: the first cycle of these sections was completed in 2016, with three cruises funded by the EU project EUROFLEETS2. This paper presents the physical and chemical data of the meridional and key transects in the Western and Eastern Mediterranean Sea collected during those cruises.
    Type: Article , PeerReviewed
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  • 113
    Publication Date: 2024-01-30
    Description: Coastal German waters contain about 1.6 million tons of dumped munition, mostly left after World Wars. This study investigated the benthic macrofauna around the 'Kolberger Heide' munition dumpsite (Baltic Sea). A total of 93 macrofauna grab samples were obtained in the proximity of the munition dumpsite and in reference areas. Environmental variables analysed included the latitude/longitude, depth, terrain ruggedness, sediment grainsize distribution, TNT concentration in the bottom water and distance to the centre of munition dumpsite. The overall abundance, biomass and diversity varied among these groups, though demonstrated no clear differences regarding the proximity to munition and modelled near-bottom dissolved TNT. Among individual taxa, however, a total of 16 species demonstrated significant correlation with TNT concentration. Moreover, TNT may serve as a predictor for the distribution of three species: molluscs Retusa truncatula, Varicorbula gibba and polychaete Spio goniocephala. Possible reasons for the species distribution including their biological traits are discussed.
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  • 114
    Publication Date: 2024-01-30
    Description: Highlights • Global primitive arc lavas (Mg# ≥60) display notable δ49/47Ti heterogeneity. • Residual rutile imposes high δ49/47Ti of 0.24 ± 0.06 ‰ on hydrous, silicic slab melts. • Primitive Aleutian rhyodacites have the same δ49/47Ti as predicted for slab melts. • A variably diluted signature of slab melts is found in all eight subduction zones. • A slab melt component is required to generate silicic primitive arc lavas. Abstract It is still a matter of intense debate to what extent partial melting of the subducting slab contributes to arc magmatism in modern subduction zones. In particular, it is difficult to differentiate between silicate melts formed by partial melting of the slab, and aqueous fluids released during subsolidus dehydration as the main medium for slab-to-mantle wedge mass transfer. Here we use δ49/47Ti (the deviation in 49Ti/47Ti of a sample to the OL-Ti reference material) as a robust geochemical tracer of slab melting. Hydrous partial melting of subducted oceanic crust and the superjacent sedimentary layer produces silicic melts in equilibrium with residual rutile. Modelling shows that such silicic slab melts have notably higher δ49/47Ti (+0.24 ± 0.06 ‰) than their protolith due to the strong preference of rutile for the lighter isotopes of Ti. In contrast, even highly saline fluids cannot carry Ti from the slab and hence hydrous peridotite partial melts have δ49/47Ti similar to mid-ocean ridge basalts (MORB; ca. 0 ‰). Primitive (Mg# ≥60) arc lavas from eight subduction zones that are unaffected by fractional crystallisation of Fe-Ti oxides show a more than tenfold larger variation in δ49/47Ti than found in MORB. In particular, primitive arc lavas display a striking correlation between SiO2 content and δ49/47Ti that ranges from island arc basalts overlapping with MORB, to primitive rhyodacites with δ49/47Ti up to 0.26 ‰ erupted in the western Aleutian arc. The elevated δ49/47Ti of these primitive arc lavas provides conclusive evidence for partial melts of the slab as a key medium for mass transfer in subduction zones. The Aleutian rhyodacites represent a rare example of slab melts that have traversed the mantle wedge with minimal modification. More commonly, slab melts interact with the mantle wedge to form an array of primary arc magmas that are a blend of slab- and peridotite-derived melt. We identify primitive arc lavas with a clearly resolvable slab melt signature in all eight subduction zone localities, confirming that slab melting is prevalent in modern subduction zones.
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  • 115
    Publication Date: 2024-01-30
    Description: Artificial upwelling has been discussed as a nature-based solution to fertilize currently unproductive areas of the ocean to enhance food web productivity and atmospheric CO2 sequestration. The efficacy of this approach may be closely tied to the nutrient stoichiometry of the upwelled water, as Si-rich water upwelling should benefit the growth of diatoms, who are key players for primary production, carbon export and food web efficiency. With a mesocosm experiment in subtropical waters, we assessed the physiological and functional responses of an oligotrophic phytoplankton community to artificial upwelling under varying Si:N ratios (0.07-1.33). Deep water fertilization led to strongly enhanced primary productivity rates and net autotrophy across Si scenarios. At the community level, Si-rich upwelling temporarily increased primary production and consistently enhanced diatom growth, producing up to 10-fold higher abundances compared to Si-deficient upwelling. At the organism level, contrasting effects were observed. On the one hand, silicification and size of diatom cells remained unaffected by Si:N, which is surprising given the direct dependency of these traits on Si. On the other hand, diatom Chlorophyll a density and carbon density were strongly reduced and particulate matter C:N was elevated under Si-rich upwelling. This suggests a reduced nutritional value for higher trophic levels under high Si:N ratios. Despite these strong qualitative changes under high Si, diatom cells appeared healthy and showed high photosynthetic efficiency. Our findings reveal great physiological plasticity and adaptability in phytoplankton under artificial upwelling, with Si-dependent trade-offs between primary producer quantity and quality.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 116
    Publication Date: 2024-01-30
    Description: Highlights • An event-scale, complete lithostratigraphic column for the Miocene BFVA was created through extensive field volcanology. • Field volcanology was supplemented by volcanic glass geochemistry to separate the eruptions. • An example is presented how to undertake lithostratigraphy-based classification in poorly preserved, deeply eroded volcanic terrains. • In the ancient BFVA landscape, sea cover during eruptions and terrestrial deposition is evident. Abstract This study documents the volcanic evolution of the Miocene silicic Bükk Foreland Volcanic Area (BFVA), Northern Hungary (Central Europe) at an event-scale. The BFVA is a deeply eroded and dissected volcanic field dominated by multiple, several 10-m thick, valley-filling silicic ignimbrite units, which are chemically and texturally very similar to each other. Hence, establishing lateral correlation is a real challenge due to the sporadic and small-scale outcrops and lack of stratotypes. Detailed field observations allowed us to identify eleven lithological members including fourteen eruption events and establish a nearly complete lithostratigraphic correlation between fifteen outcrops across the BFVA. Primary pyroclastic material of each member was sampled, and volcanic glass was geochemically analyzed for major and trace element composition. The geochemical results confirm the field-based classification of the members and enable the correlation of distinct outcrops. The major and trace element composition of the glassy pyroclasts of each member of the BFVA served as basis to create a field-wide chemical reference database for regional correlational studies. Here, a new lithostratigraphic classification scheme (consisting of one lithostratigraphic formation and eleven members) is presented, which reflects the challenges unraveling the stratigraphy of ancient volcanic terrains. The field-based event-scale lithostratigraphy of the BFVA suggests a wet, partly sea-covered depositional environment in the close vicinity of the eruption centers providing favorable conditions to ‘fuel’ silicic explosive phreatomagmatism. On the contrary, paleosol horizons formed after almost each major eruption event or sequence suggests an overall near-coast terrestrial environment for the BFVA, where the emplacement of the pyroclastic material occurred.
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  • 117
    Publication Date: 2024-01-30
    Description: Hydrothermal fluids in ultramafic‐hosted hydrothermal systems associated with oceanic detachment faults can be more oxidizing compared to mafic‐hosted vent sites. These fluids form a mineral assemblage of pyrite, magnetite and hematite. At 13°30′N on the Mid‐Atlantic Ridge, chlorite‐quartz breccias recovered from an exposed fault scarp contain pyrite, with abundant magnetite and hematite, indicating that the redox of the fluids was variable. In primary micron‐scale zonations in pyrite, Ni, Co, and Se have a decoupled relationship, recording fluctuations in the chemical composition and temperature of hydrothermal fluid as the grains grew. Secondary zonations that erase and overprint primary zonations are limited to the grain margin and permeable regions within the grain core. Secondary zonations formed via two processes: (a) grain dissolution followed by overgrowth, and (b) remobilization of metals during oxidizing fluid flow events. In both instances, Ni and Co have been mobilized and concentrated, and are not lost to the hydrothermal fluid. Superimposed on these features is evidence of grain scale deformation related to periods of fault movement along the detachment surface. Sulfur isotope ratios (δ 34 S) in pyrite systematically decrease from the grain margin to the grain core, indicating that increased amounts of sulfur were derived from thermochemical sulfate reduction of seawater. Thus, pyrite records the evolution of fluid flow and deformation events during exhumation along the detachment surface from ∼1 to 2 km below the seafloor at the base of the lava pile, with temporal fluctuations in fluid redox identified as an important process in controlling Ni and Co enrichment in pyrite. Plain Language Summary Detachment faults are long lived faults that can expose ultramafic rocks at the seafloor. We aim to investigate the links between hydrothermal activity and detachment fault formation. To do this we use pyrite as a tape recorder for past fluid flow events. Across individual mineral grains, distinct zonations in metal content and sulfur isotope ratios show that the incursion of seawater occurred periodically during pyrite growth, increasing during fault movement events that lead to changes in the temperature and pH of the fluids in the fault zone. These changes concentrated metals toward the center of individual mineral grains. Zonations were then overprinted by later deformation‐related events, providing evidence that the samples formed at deeper crustal levels below the seafloor and were progressively exhumed at the seafloor over time. Key Points Microtextural, geochemical, and isotopic variations in subseafloor pyrite record the history of sample exhumation along a detachment fault Nickel and Co are remobilized and concentrated in pyrite across individual mineral grains in response to fluctuating fluid redox conditions Evidence of pyrite deformation and alteration mineralogy of samples indicates sample exhumation from a depth of 1–2 km
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  • 118
    Publication Date: 2024-01-30
    Description: Coastal upwelling areas are extraordinarily productive environments where prokaryotic communities, the principal remineralizers of dissolved organic matter (DOM), rapidly respond to phytoplankton bloom and decay dynamics. Nevertheless, the extent of variability of key microbial functions in such dynamic waters remains largely unconstrained. Our metatranscriptomics analyses of 162 marker genes encoding ecologically relevant prokaryotic functions showed distinct spatial-temporal patterns in the NW Iberian Peninsula upwelling area. Short-term (daily) changes in specific bacterial functions associated with changes in biotic and abiotic factors were superimposed on seasonal variability. Taxonomic and functional specialization of prokaryotic communities, based mostly on different resource acquisition strategies, was observed. Our results uncovered the potential influence of prokaryotic functioning on phytoplankton bloom composition and development (e.g., Cellvibrionales and Flavobacteriales increased relative gene expression related to vitamin B12 and siderophore metabolisms during Chaetoceros and Dinophyceae summer blooms). Notably, bacterial adjustments to C- or N-limitation and DMSP availability during summer phytoplankton blooms and different spatial-temporal patterns of variability in the expression of genes with different phosphate affinity indicated a complex role of resource availability in structuring bacterial communities in this upwelling system. Also, a crucial role of Cellvibrionales in the degradation of DOM (carbohydrate metabolism, TCA cycle, proteorhodopsin, ammonium, and phosphate uptake genes) during the summer phytoplankton bloom was found. Overall, this dataset revealed an intertwined mosaic of microbial interactions and nutrient utilization patterns along a spatial-temporal gradient that needs to be considered if we aim to understand the biogeochemical processes in some of the most productive ecosystems in the world´s oceans.
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  • 119
    Publication Date: 2024-02-01
    Description: Biological invasions pose a growing threat to ecosystems, biodiversity, and socio-economic interests. In the European Union, the introduction of non-native species through trade, tourism, and other pathways has led to unintended consequences. Among these non-native species, a subset exhibits negative impacts and is commonly referred to as ‘invasive’. However, the number of non-native species and the proportion considered invasive vary across different member states of the European Union. Classifications and definitions of invasive species also differ among countries potentially leading to an underrepresentation. Here, we use Germany as a case study to highlight gaps in invasive species classifications. The number of non-native species reported as invasive in Germany remains low (~ 14%) compared to other European Union member states (~ 22%), despite Germany’s strong economy, significant research investments, and well-established trade networks. This disparities may be attributed to complex and multifaceted factors, encompassing differences in classifications, variations in research effort and focus, and diverse national priorities. We further propose that the impacts of non-native species on resources and biodiversity may be more likely to be overlooked, principally in large economies reliant on international trade, such as Germany. This oversight could negatively affect conservation efforts and funding for research aimed at improving understanding invasive species threats. We suggest that this underreporting may stem from a focus on maintaining economic growth, which might have taken precedence over addressing the potential ecological and economic impacts of invasive species.
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  • 120
    Publication Date: 2024-02-01
    Description: Regime shifts in the diatom–dinoflagellate composition have occurred in the Baltic Sea (BS) and Bohai Sea (BHS) under eutrophication and have affected the entire coastal ecosystem, damaging the regulatory, provisioning, cultural, and supporting service functions of marine ecosystems. Therefore, finding a solution to restore the balance of phytoplankton community composition and mitigate eutrophication is of utmost importance. In this study, the Driver (per capita gross domestic product)-Pressure (terrestrial inputs)-State (seawater environmental parameters)-Impact (proportions of diatoms and dinoflagellates)-Response (eutrophication governance projects) framework served as a guide for our analysis of the causal relationship among various environmental components in the coastal system. The relevant data in BS and BHS spanning from the 1950s to the 2010s were collected and used to construct a diatom–dinoflagellate composition single index, which allowed us to identify the shifts in regimes (mutation points and phases) of the diatom–dinoflagellate composition and environmental factors using sequential t-test analysis. We also identified key environmental factors that moderated the diatom–dinoflagellate composition using redundancy analysis and analyzed the partial effects of the main environmental factors on the diatom–dinoflagellate composition using a generalized additive model. Finally, the regulation of the eutrophication governance investment on diatom–dinoflagellate composition was investigated. We found that (1) BS is a “time machine,” with coastal eutrophication governance and regime shift of diatom–dinoflagellate composition and environmental factors two decades earlier than that in BHS; (2) in BS, the key moderation factor of diatom proportion is SiO3-Si and those of dinoflagellates are sea surface salinity and N:P ratio; in BHS, the key moderation factors of diatom proportion are PO4-P and Si:N ratio and those of dinoflagellate are dissolved inorganic nitrogen and N:P and Si:P ratios; (3) it is projected that BHS will enter its recovery phase from eutrophication after mid-2020s. In summary, the N/P/Si stoichiometric relationships should be given greater consideration, with the exception of the “dose-response” relationship in both sea areas. Our results indicate an urgent need for an improved mechanistic understanding of how phytoplankton biodiversity changes in response to changes in nutrient load and how we should ultimately deal with the challenges that arise.
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  • 121
    Publication Date: 2024-02-01
    Description: The element silicon is everywhere! In fact, silicon is the second most abundant element in Earth’s crust. Silicon in rocks and minerals breaks down and is transported from rivers and streams into the world’s oceans. Many marine organisms need silicon as it is a crucial nutrient to build their skeletons. Silicon eventually reaches the seafloor, but its journey into the abyss is not straightforward due to biological, physical, and chemical processes. All these processes transport and transform silicon, creating a cycle that we call the marine silicon cycle. The silicon cycle is directly connected to the carbon cycle, making silicon a key player in the regulation of Earth’s climate. In this article, we discuss why we need to understand the marine silicon cycle, explain the steps that happen in the ocean, and demonstrate how the marine silicon cycle affects humans.
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  • 122
    Publication Date: 2024-02-01
    Description: There is growing concern surrounding the pervasive impacts of microplastic pollution, but despite increasing interest in this area there remains limited understanding of its disruption to biological communities and the ecosystem services they provide. One such service is the breakdown of leaf litter in freshwaters by invertebrate shredders, such as Gammarus spp., that directly and indirectly provides resources for many other species. This study investigates the effect of microplastic exposure on leaf consumption by two Gammarus species in Ireland, the native Gammarus duebeni celticus, and the invasive Gammarus pulex. Individuals were exposed to 40-48 mu m polyethylene particles for 24 h at a range of concentrations (20-200,000 MP/L), with the amount of leaf consumption in that time frame recorded. Microplastics did not affect the feeding rate of either species at environmentally relevant concentrations, indicating that ecosystem services currently provided by our study species are sustainable. However, at higher microplastic concentrations the feeding rate of G. d. celticus was significantly reduced, whereas G. pulex remained unaffected, drawing attention to species-specific and native-invader differences in microplastic impacts. The results of our study further contribute to the observed pattern that invasive species, including various amphipod species, often display a higher tolerance to environmental stressors compared to their native counterparts. This research highlights the need for mitigation of ongoing and increasing microplastic pollution that could differentially influence key ecosystem services and functions.
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  • 123
    Publication Date: 2024-02-01
    Description: Anthropogenic disturbances, including non-indigenous species (NIS) and climate change, have considerably affected ecosystems and socio-economies globally. Despite the widely acknowledged individual roles of NIS and global warming in biodiversity change, predicting the connection between the two still remains a fundamental challenge and requires urgent attention due to a timely importance for proper conservation management. To improve our understanding of the interaction between climate change and NIS on biological communities, we conducted laboratory experiments to test the temperature and pCO2 tolerance of four gammarid species: two native Baltic Sea species (Gammarus locusta and G. salinus), one Ponto‐Caspian NIS (Pontogammarus maeoticus) and one North American NIS (Gammarus tigrinus). Our results demonstrated that an increase in pCO2 level was not a significant driver of mortality, neither by itself nor in combination with increased temperature, for any of the tested species. However, temperature was significant, and differentially affected the tested species. The most sensitive was the native G. locusta which experienced 100% mortality at 24 °C. The second native species, G. salinus, performed better than G. locusta, but was still significantly more sensitive to temperature increase than either of the NIS. In contrast, NIS performed better than native species with warming, whereby particularly the Ponto-Caspian P. maeoticus did not demonstrate any difference in its performance between the temperature treatments. With the predicted environmental changes in the Baltic Sea, we may expect shifts in distributions of native taxa towards colder areas, while their niches might be filled by NIS, particularly those from the Ponto-Caspian region. Although, northern colder areas may be constrained by lower salinity. Additional studies are needed to confirm our findings across other NIS, habitats and regions to make more general inferences.
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  • 124
    Publication Date: 2024-02-01
    Description: Silicon is a crucial nutrient that can join with the element oxygen to form a substance commonly called silica. Silica, commonly known as glass, is found in rocks in the Earth’s crust and dissolves into the oceans, where organisms like algae and sponges use it to build their glassy skeletons. This process, called biosilicification, is extremely important in the silica cycle. Over time, organisms have changed the silica cycle. Today, because of these organisms, the oceans no longer contain much silica. However, when the Earth was younger and these organisms had not evolved yet, no biological processes affected silica in the oceans. The evolution of these oceanic organisms across time has removed silica from the oceans. In this article, we discuss how the evolution of silicon-using sponges, as well as tiny organisms called zooplankton and algae, have changed the amount of silica in the world’s oceans through geologic time.
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  • 125
    Publication Date: 2024-02-01
    Description: This study was the first to investigate the key reproductive traits of the electric lantern fish Electrona risso (Myctophidae, n = 918) and the bigscale fishes (Melamphaidae) Melamphaes polylepis (n = 260) and Scopelogadus mizolepis (n = 649). Specimens of these mesopelagic species were collected in March and April 2015 in the eastern Central Atlantic (0–24° N, 20–26° W). Sex ratio was not significantly different from 1:1 in E. risso and M. polylepis but significantly skewed toward female dominance in S. mizolepis. Reproductive phases were determined macroscopically and by histological analyses on selected individuals. Female length at 50% maturity (L50) was 55.1 mm standard length (LS) in E. risso, with an observed female maximum length (Lmax) of 81.2 mm LS. M. polylepis females had an L50 of 40.2 mm LS and an Lmax of 86.7 mm LS. S. mizolepis had an L50 of 46 mm LS and an Lmax of 97.9 mm LS. The three species show histological features of iteroparity, but the E. risso population appears to occur in two year-classes and experience only one spawning season per lifetime in the study region. All three species are batch-spawners. A batch fecundity of 2668 eggs was estimated from one E. risso individual, with a relative batch fecundity of 369 eggs g−1 gonad-free body mass. M. polylepis had a batch fecundity of 1027 eggs and a relative batch fecundity of 149 eggs g−1 (n = 3). S. polylepis had a batch fecundity of 1545 eggs and a relative batch fecundity of 215 eggs g−1 (n = 21). The median gonado-somatic index during the actively spawning phase of E. risso was 4.5, significantly lower than that of M. polylepis (7.5) and S. mizolepis (7.1). No regressing or regenerating phases were observed in this study. Batch-spawning in all three species is suggested to be advantageous to cope with intra-annual variability in food supply and other risks for offspring survival. With what appears to be in effect a (facultative) semelparous strategy in combination with a short life span in E. risso, interannual differences would have a great effect on population dynamics of this species. Knowledge is still lacking on temporal aspects of reproduction such as the duration of the spawning season and the frequency of spawning, as well as age and growth.
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  • 126
    Publication Date: 2024-02-01
    Description: Statistics of regional sterodynamic sea level variability are analyzed in terms of probability density functions of a 100-member ensemble of monthly mean sea surface height (SSH) timeseries simulated with the low-resolution Max Planck Institute Grand Ensemble. To analyze the impact of climate change on sea level statistics, fields of SSH variability, skewness and excess kurtosis representing the historical period 1986-2005 are compared with similar fields from projections for the period 2081-2100 under moderate (RCP4.5) and strong (RCP8.5) climate forcing conditions. Larger deviations of the models SSH statistics from Gaussian are limited to the western and eastern tropical Pacific. Under future climate warming conditions, SSH variability of the western tropical Pacific appear more Gaussian in agreement with weaker zonal easterly wind stress pulses, suggesting a reduced El Nino Southern Oscillation activity in the western warm pool region. SSH variability changes show a complex amplitude pattern with some regions becoming less variable, e.g., off the eastern coast of the north American continent, while other regions become more variable, notably the Southern Ocean. A west (decrease)-east (increase) contrast in variability changes across the subtropical Atlantic under RCP8.5 forcing is related to changes in the gyre circulation and a declining Atlantic Meridional Overturning Circulation in response to external forcing changes. In addition to global mean sea-level rise of 16 cm for RCP4.5 and 24 cm for RCP8.5, we diagnose regional changes in the tails of the probability density functions, suggesting a potential increased in variability-related extreme sea level events under global warmer conditions.
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  • 127
    Publication Date: 2024-02-01
    Description: Large explosive volcanic eruptions from island arcs pour pyroclastic currents into marine basins, impacting ecosystems and generating tsunamis that threaten coastal communities and infrastructures. Risk assessments require robust records of such highly hazardous events, which is challenging as most of the products lie buried under the sea. Here we report the discovery by IODP Expedition 398 of a giant rhyolitic pumice deposit emplaced 520 ± 10 ky ago at water depths of 200 to 1000 m during a high-intensity, shallow submarine eruption of ancestral Santorini Volcano. Pyroclastic currents discharged into the sea transformed into turbidity currents and slurries, forming a 〉89 ± 8 km 3 volcaniclastic megaturbidite up to 150 m thick in the surrounding marine basins, while breaching of the sea surface by the eruption column laid down veneers of ignimbrite on three islands. The eruption is one of the largest recorded on the South Aegean Volcanic Arc, and highlights the hazards from submarine explosive eruptions.
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  • 128
    Publication Date: 2024-02-01
    Description: Deep, rapid cuts in greenhouse gas emissions are needed to limit future global temperature increases to 1·5°C above pre-industrial levels, but current progress is inadequate to achieve the goals of the Paris Climate Agreement and to reduce future risks from climate change. Many actions to mitigate greenhouse gas emissions can also deliver near-term health co-benefits, for example from reduced air pollution, consumption of healthy diets, and increased physical activity. High-quality evidence on the type and magnitude of co-benefits that can be realised and improved knowledge of how to promote the implementation of such actions can support progress towards net-zero greenhouse gas emissions by 2050. The Lancet Pathfinder Commission was established to collate and assess the evidence on the near-term health effects of greenhouse gas mitigation, including both modelling studies and evaluated implemented actions. The Commission's aim is to assess the potential and achieved magnitude of the benefits for health and climate of different mitigation actions and, where possible, the factors facilitating or impeding implementation.
    Language: English
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  • 129
    Publication Date: 2024-02-01
    Description: The HERA high-resolution pan-European hydrological reanalysis (1950-2020) dataset is the result of a joint effort between the JRC and PIK to produce a long term hydrological reanalysis with downscaled and bias-corrected climate reanalysis (ERA5-land) and dynamic socioeconomic inputs. It includes maps of climate variables (evaporation, evapotranspiration, precipitation, temperature), dynamic socioeconomic inputs (land use, water demand, reservoir maps) required for hydrological modelling with LISFLOOD and river discharge with European extent at 1 arc minute (~1.5 km) grid resolution and 6-hourly time step. The dataset builds on recent development within the European Flood Awareness System (EFAS) associated to the EFAS v5.0 reanalysis (http://data.europa.eu/89h/76b4b9de-a5c6-4344-8d88-c4bed7752ce3), notably the LISFLOOD static and parameters maps for Europe (http://data.europa.eu/89h/f572c443-7466-4adf-87aa-c0847a169f23) and the EMO (European Meteorological Observations) dataset (http://data.europa.eu/89h/0bd84be4-cec8-4180-97a6-8b3adaac4d26). HERA also benefits from major improvements to the open-source hydrological model LISFLOOD and a new model calibration. Furthermore, for ungauged catchments, a parameter regionalization was performed transferring parameter sets from donor catchments based on spatial and climatological proximity to ensure the best possible simulation of river flows for all catchments in the European domain. Along with improved resolution and modelling performances, the length of the modelled period (71 years) and the inclusion of dynamic socioeconomic conditions enables the analysis of hydrological dynamics related to extremes, human influences, and climate change at a continental scale while keeping local relevance. Detailed technical information on the dataset can be found in the associated scientific article (under review).
    Language: English
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  • 130
    Publication Date: 2024-02-02
    Description: This study examines how the expansion of mobile phone networks affects rural development in Mongolia. The database is a detailed household panel survey with four waves implemented in western Mongolia, spanning the 2012-2021 period, which we combine with data on mobile phone towers. Our identification strategy exploits the uneven roll-out of mobile phone networks across rural areas over time. Using a two-way fixed effects approach, we show that network expansion strongly and significantly increases total household income of pastoralist households. The effect is driven by increased income from agriculture, particularly by higher producer prices for animal byproducts, improved access to transfer income, and increased household mobility. The expansion of mobile phone networks decreases income diversification among pastoralists. Instead, households specialize in agriculture. While findings suggest that investments in telecommunication infrastructure can help rural households to sustain a livelihood in the agricultural sector, the specialization in agriculture may increase households’ vulnerability to climate change.
    Language: English
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  • 131
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    GEOMAR
    Publication Date: 2024-02-02
    Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024
    Type: Report , NonPeerReviewed
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  • 132
    Publication Date: 2024-02-02
    Description: Gelatinous zooplankton are increasingly recognized to play a key role in the ocean's biological carbon pump. Appendicularians, a class of pelagic tunicates, are among the most abundant gelatinous plankton in the ocean, but it is an open question how their contribution to carbon export might change in the future. Here, we conducted an experiment with large volume in situ mesocosms (~55–60 m3 and 21 m depth) to investigate how ocean acidification (OA) extreme events affect food web structure and carbon export in a natural plankton community, particularly focusing on the keystone species Oikopleura dioica, a globally abundant appendicularian. We found a profound influence of O. dioica on vertical carbon fluxes, particularly during a short but intense bloom period in the high CO2 treatment, during which carbon export was 42%–64% higher than under ambient conditions. This elevated flux was mostly driven by an almost twofold increase in O. dioica biomass under high CO2. This rapid population increase was linked to enhanced fecundity (+20%) that likely resulted from physiological benefits of low pH conditions. The resulting competitive advantage of O. dioica resulted in enhanced grazing on phytoplankton and transfer of this consumed biomass into sinking particles. Using a simple carbon flux model for O. dioica, we estimate that high CO2 doubled the carbon flux of discarded mucous houses and fecal pellets, accounting for up to 39% of total carbon export from the ecosystem during the bloom. Considering the wide geographic distribution of O. dioica, our findings suggest that appendicularians may become an increasingly important vector of carbon export with ongoing OA.
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  • 133
    Publication Date: 2024-02-05
    Description: A La Niña condition in the equatorial Pacific began in the early summer of 2020 and has lasted more than two and a half years (referred to as the 2020 La Niña hereafter). Predicting its temporal evolution had attracted a lot of attention. Considering the possible phase-locked impact of the 11-year solar cycle on the tropical Pacific variability, in this study the authors present the possible modulations by the solar cycle 25 (SC25) started from December 2019, on the future temporal evolution of the 2020 La Niña. Based on statistical features of historical solar cycles, the authors propose three possible scenarios of the timing of the SC25 maximum year and discuss its possible impacts on the temporal evolution of the 2020 La Niña in the next two years. The ongoing ascending phase of SC25 dampens the development of a super El Niño condition to some extent in 2023.
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  • 134
    Publication Date: 2024-02-05
    Description: Non-technical summary Scenarios compatible with the Paris agreement's temperature goal of 1.5 °C involve carbon dioxide removal measures - measures that actively remove CO2 from the atmosphere - on a massive scale. Such large-scale implementations raise significant ethical problems. Van Vuuren et al. (2018), as well as the current IPCC scenarios, show that reduction in energy and or food demand could reduce the need for such activities. There is some reluctance to discuss such societal changes. However, we argue that policy measures enabling societal changes are not necessarily ethically problematic. Therefore, they should be discussed alongside techno-optimistic approaches in any kind of discussions about how to respond to climate change. Technical summary The 1.5 °C goal has given impetus to carbon dioxide removal (CDR) measures, such as bioenergy combined with carbon capture and storage, or afforestation. However, land-based CDR options compete with food production and biodiversity protection. Van Vuuren et al. (2018) looked at alternative pathways including lifestyle changes, low-population projections, or non-CO2 greenhouse gas mitigation, to reach the 1.5 °C temperature objective. Underlined by the recently published IPCC AR6 WGIII report, they show that demand-side management measures are likely to reduce the need for CDR. Yet, policy measures entailed in these scenarios could be associated with ethical problems themselves. In this paper, we therefore investigate ethical implications of four alternative pathways as proposed by Van Vuuren et al. (2018). We find that emission reduction options such as lifestyle changes and reducing population, which are typically perceived as ethically problematic, might be less so on further inspection. In contrast, options associated with less societal transformation and more techno-optimistic approaches turn out to be in need of further scrutiny. The vast majority of emission reduction options considered are not intrinsically ethically problematic; rather everything rests on the precise implementation. Explicitly addressing ethical considerations when developing, advancing, and using integrated assessment scenarios could reignite debates about previously overlooked topics and thereby support necessary societal discourse. Social media summary Policy measures enabling societal changes are not necessarily as ethically problematic as commonly presumed and reduce the need for large-scale CDR
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  • 135
    Publication Date: 2024-02-05
    Description: Seamounts are thought to function as hotspots of megafauna diversity due to their topology and environmental characteristics. However, assessments of megafauna communities inhabiting seamounts, including diversity and density, are scarce. In this study, we provide megafauna diversity and density estimates for a recently discovered, not yet characterized seamount region (Boetius seamounts) west of Cape Verde (N17° 16′, W29° 26′). We investigated the distribution of epibenthic megafauna over a large depth gradient from the seamount’s summit at 1400 m down to 3200 m water depth and provided qualitative and quantitative analyses based on quantified video data. In utilizing an ocean floor observation system (OFOS), calibrated videos were taken as a horizontal transect from the north-eastern flank of the seamount, differentiating between an upper, coral-rich region (−1354/−2358 m) and a deeper, sponge-rich region (−2358/−3218 m). Taxa were morphologically distinguished, and their diversity and densities were estimated and related to substrate types. Both the upper and deeper seamount region hosted unique communities with significantly higher megafauna richness at the seamount’s summit. Megafauna densities differed significantly between the upper (0.297 ± 0.167 Ind./m 2 ) and deeper community (0.112 ± 0.114 Ind./m). The seamount showed a vertical zonation with dense aggregations of deep-sea corals dominating the seamount’s upper region and colonies of the glass sponges Poliopogon amadou dominating the deeper region. The results are discussed in light of detected substrate preferences and co-occurrence of species and are compared with findings from other Atlantic seamounts.
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  • 136
  • 137
    Publication Date: 2024-02-06
    Description: Abstract
    Description: The dataset is the basis for describing a 60-year-long evolution of groundwater dynamics and thermal field in the North German Basin beneath the Federal State of Brandenburg (NE Germany), covering the period between 1953 and 2014 with monthly increments. It was produced by one-way coupling of a near-surface distributed hydrologic model to a 3D basin-scale thermohydraulic groundwater model with the goal of investigating feedbacks between climate-driven forcing (in terms of time- and space-varying recharge and temperature), basin-scale geology, and topographic gradients. Modeled pressure and temperature distributions are validated against published groundwater level and temperature time series from observation wells. Our results indicate the spatio-temporal extent of the groundwater system subjected to nonlinear interactions between local geological variability and climate conditions. The dataset comprises of input files and scripts required to run the groundwater model in GOLEM and output files from the transient thermo-hydraulic simulations in EXODUS format. The input and output data is organized as separate archived folders (*.gz format).
    Description: Methods
    Description: Hydrological fluxes are simulated via mesoscale Hydrological Model (mHM) (Samaniego et al., 2010), a spatially distributed hydrologic modeling tool. We make use of the results from a Germany-wide realization of mHM to derive time and space varying water fluxes, which we translate into boundary conditions at the top of our groundwater model. All groundwater simulations were conducted with GOLEM, a Finite Element Method (FEM) modelling platform for thermal-hydraulic-mechanical and non-reactive chemical processes in fully-saturated porous media (Cacace and Jacquey, 2017). Steady-state conditions were derived by solving separately for the hydraulic and the thermal cases. These uncoupled steady-state simulations have been used as initial conditions to run a coupled pseudo-transient simulation, the results of which have been later imposed to initialize the pore pressure and the temperature in the final transient simulation.
    Description: TechnicalInfo
    Description: The dataset comprises of output fluxes from the hydrological model, input files and scripts required to run the groundwater model, output files from the transient thermo-hydraulic simulations, references to validation data, and workflows for data pre-conditioning and post-processing. The 3D structural model built for groundwater modeling covers an area of 28800 km2, extends down to 6000 m below sea level, and contains 12 stratigraphic units from pre-Permian to Quaternary. It was built using structural surfaces from an earlier basin-scale structural model of Brandenburg (Noack et al., 2013). The model captures large-scale geological features controlling the regional groundwater flow, including salt structures, permeable glacial valleys, and aquitard discontinuities. The simulated finite element mesh has a resolution of 1 km x 1 km. It is divided into 54 computational layers and consists of 1.9 million nodes, giving a total of 3 million degrees of freedom.
    Keywords: groundwater modeling ; groundwater level ; geothermal potential ; groundwater recharge ; mesoscale Hydrologic Model (mHM) ; North German Basin ; Brandenburg ; climate ; EARTH SCIENCE 〉 TERRESTRIAL HYDROSPHERE 〉 GROUND WATER 〉 PERCOLATION ; hydrosphere 〉 water (geographic) 〉 groundwater
    Type: Dataset , Dataset
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  • 138
    Publication Date: 2024
    Description: We, the editors of the Code4Lib Journal, sincerely apologize for the recent incident in which Personally Identifiable Information (PII) was released through the publication of an article in issue 58.
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  • 139
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    GEOMAR
    Publication Date: 2024-02-07
    Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024
    Type: Report , NonPeerReviewed
    Format: text
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  • 140
    Publication Date: 2024-02-08
    Description: Riverine nutrient export is an important process in marine coastal biogeochemistry and also impacts global marine biology. The nitrogen cycle is a key player here. Internal feedbacks regulate not only nitrogen distribution, but also primary production and thereby oxygen concentrations. Phosphorus is another essential nutrient and interacts with the nitrogen cycle via different feedback mechanisms. After a previous study of the marine nitrogen cycle response to riverine nitrogen supply, we here additionally include phosphorus from river export with different phosphorus burial scenarios and study the impact of phosphorus alone and in combination with nitrogen in a global 3-D ocean biogeochemistry model. Again, we analyse the effects on near coastal and open ocean biogeochemistry. We find that the addition of bio-available riverine phosphorus alone or together with nitrogen affects marine biology on millennial timescales more than riverine nitrogen alone. Biogeochemical feedbacks in the marine nitrogen cycle are strongly influenced by the additional phosphorus. Where bio-available phosphorus is increased by river input, nitrogen concentrations increase as well, except for regions with high denitrification rates. High phosphorus burial rates decrease biological production significantly. Globally, riverine phosphorus leads to elevated primary production rates in the coastal and open oceans.
    Type: Article , NonPeerReviewed , info:eu-repo/semantics/article
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  • 141
    Publication Date: 2024-02-08
    Description: With ongoing anthropogenic CO2 emissions, the Greenland ice sheet approaches critical thresholds of inevitable, long-term mass loss. Future technologies might be able to efficiently remove CO2 from the atmosphere and thereby cool down our planet. We explore whether and to what extent a realization of this concept could lead to a regrowth of the Greenland ice sheet once it has partly melted. Using the fully coupled Earth system model of intermediate complexity CLIMBER-X, emission pulses between 0 and 4000 GtC are released into the atmosphere, and 1 kyr, 2 kyr, and 5 kyr, the atmospheric CO2 concentration is reduced back to its pre-industrial value. We find that independent of a specific trajectory, once the southern part of the Greenland ice sheet has partly melted with a total mass loss of more than 0.4 m sea level equivalent, regrowth is inhibited. Uncertainties preclude determination of precise thresholds, but model results indicate that cumulative industrial-era emissions approaching 1000 to 1500 GtC and beyond increasingly risk irreversible mass loss of the Greenland ice sheet. Once this threshold is passed, artificial atmospheric carbon removal would need to be utilised within the next centuries at massive scale. Beyond that, artificial atmospheric carbon removal has limited abilities to avoid long-term mass loss of the Greenland ice sheet. In conclusion, keeping cumulative anthropogenic emissions below 1000 to 1500 GtC is the only safe way to avoid irreversible mass loss of the Greenland ice sheet.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 142
    Publication Date: 2024-02-08
    Description: Traditionally, power grids have relied on synchronous generators, large rotating masses, for energy supply and stability. Currently, renewable energy sources, connected via programmable machines called inverters, are beginning to take the lead. Understanding the changes of grid dynamics brought by these new actors is crucial for a successful energy transition. Modern power grids, with components like solar cells, wind parks and batteries, present a challenge in ensuring stability. To address this complexity, the authors introduce a universal model, offering a surprisingly simple yet robust representation of the entire grid. This model enables the description of systems with different agents through a rather simple system of differential equations. Using analytical tools from various fields, such as dynamical systems, networks, and control theory, it is expected to enable universal statements about the stability of large, interconnected power systems. As a demonstration, a control law is developed to stabilize the power grid in extreme conditions, ensuring a stable energy supply even as power grids become more complex.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 143
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    Unknown
    In:  Physical Review E
    Publication Date: 2024-02-08
    Description: We study the dynamics of a piecewise-linear second-order delay differential equation that is representative of feedback systems with relays (switches) that actuate after a fixed delay. The system under study exhibits strong multirhythmicity, the coexistence of many stable periodic solutions for the same values of the parameters. We present a detailed study of these periodic solutions and their bifurcations. Starting from an integrodifferential model, we show how to reduce the system to a set of finite-dimensional maps. We then demonstrate that the parameter regions of existence of periodic solutions can be understood in terms of discontinuity-induced bifurcations and their stability is determined by smooth bifurcations. Using this technique, we are able to show that slowly oscillating solutions are always stable if they exist. We also demonstrate the coexistence of stable periodic solutions with quasiperiodic solutions.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 144
    Publication Date: 2024-02-08
    Description: Climate tipping elements are large-scale subsystems of the Earth that may transgress critical thresholds (tipping points) under ongoing global warming, with substantial impacts on biosphere and human societies. Frequently studied examples of such tipping elements include the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), permafrost, monsoon systems, and the Amazon rainforest. While recent scientific efforts have improved our knowledge about individual tipping elements, the interactions between them are less well understood. Also, the potential of individual tipping events to induce additional tipping elsewhere, or stabilize other tipping elements is largely unknown. Here, we map out the current state of the literature on the interactions between climate tipping elements and review the influences between them. To do so, we gathered evidence from model simulations, observations and conceptual understanding, as well as examples of paleoclimate reconstructions where multi-component or spatially propagating transitions were potentially at play. While un- certainties are large, we find indications that many of the interactions between tipping elements are destabilizing. Therefore, we conclude that tipping elements should not only be studied in isolation, but more emphasis has to be put on potential interactions. This means that tipping cascades can neither be ruled out on centennial to millennial timescales at global warming levels between 1.5–2.0◦C, nor on shorter timescales if global warming would surpass 2.0◦C. At these higher levels of global warming, tipping cascades may then include fast tipping elements such as the AMOC or the Amazon rainforest. To address crucial knowledge gaps in tipping element interactions, we propose four strategies forward combining observation-based approaches, Earth system modeling expertise, computational advances, and expert knowledge.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 145
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    Unknown
    CDRmare Research Mission
    Publication Date: 2024-02-09
    Description: Dieser Policy Brief beruht auf den Factsheets der Forschungsmission CDRmare der Deutschen Allianz Meeresforschung (DAM), die vom Bundesministerium für Bildung und Forschung (BMBF) und den norddeutschen Bundesländern gefördert wird. In diesem Policy Brief betrachten wir die marine Kohlendioxid-Abscheidung und -Speicherung (Carbon Capture and Storage, CCS). Version 2
    Type: Report , NonPeerReviewed
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  • 146
    Publication Date: 2024-02-09
    Type: Report , NonPeerReviewed
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  • 147
    Publication Date: 2024-02-20
    Description: The Agulhas Leakage (AL) transports warm and salty Indian Ocean waters into the Atlantic Ocean and as such is an important component of the global ocean circulation. These waters are part of the upper limb of the Atlantic Meridional Overturning Circulation (AMOC) and AL variability has been linked to AMOC variability. The AL is expected to increase under a warming climate due to a shift in the Southern Hemisphere westerlies, which could further influence the AMOC dynamics. This study investigates the AL transport variability on long time scales in the pre-industrial and under a warming climate and its relation to the AMOC. It uses a high-resolution configuration of the Community Earth System Model (CESM) with a nominal horizontal resolution of 0.1° for the ocean and sea-ice and 0.25° for the atmosphere and land, which resolves the necessary spatial scales. The simulated AL transport of 19.7 ± 3 Sv lies well within the observed range of 21.3 ± 4.7 Sv. A positive correlation between the Agulhas Current and the AL is shown, meaning that an increase of the Agulhas Current transport leads to an increase in AL. Furthermore, the salt flux associated with the AL influences AMOC dynamics through the salt-advection feedback by reducing the AMOC’s freshwater transport at 34°S. In a warming climate, the AL transport was indeed found to increase due to strengthened and southward shifting winds while the Agulhas Current transport was found to decrease. Consequently, a larger fraction of the Agulhas Current will flow into the Atlantic Ocean rather than being recirculated into the Indian Ocean. The increase in AL is accompanied by a higher salt flux into the Atlantic Ocean, which destabilises the AMOC within the salt-advection-feedback. But whether and to what extent this additional salt advected to the North Atlantic could also dampen an AMOC weakening induced by increased meltwater input under climate change still needs further research.
    Keywords: Course of study: MSc Climate Physics
    Type: Thesis , NonPeerReviewed
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  • 148
    Publication Date: 2024-02-21
    Description: Abstract
    Description: A high-resolution Digital Terrain Model (DTM) has been processed for the Tillandsia landbeckii study sites at Arica. The original source data have been obtained from drone flight images. The final resolution of the DTM is of about 14 cm. We acknowledge support in the field and during data processing from Alexander Siegmund (PH Heidelberg). RE Stein and D Jäger contributed equally to the work.
    Description: TableOfContents
    Description: The zip.file contains the following 5 files: 1) Arica.blend 2) Arica_Ortho_clipped_0-5res.tif 3) DEM_Arica_final_clipped_rescale2.tif 4) DEM_Arica_final_clipped_rescale2_0-5res_raw.tif 5) DEM_Arica_final_clipped_rescale2_0-5res_rendered.tif Please do not change file names nor file extensions when loading files for viewing in BLENDER version 4.0 (https://www.blender.org/download/releases/4-0/). The "0-5res" file-versions refer to a 0.5m/px resolution (EPSG:32719 - WGS 84 / UTM Zone 19S). File DEM_Arica_final_clipped_rescale2.tif was processed to a final resolution of 1.35e-06 °degrees (c. 0.143 m) [EPSG:4326 - WGS 84].
    Description: Other
    Description: Short introduction into the methods: Very-high resolution images were captured using an unmanned aerial vehicle (UAVs) [drone: DJI Matrice 200; DJI Zenmuse X5S RGB camera]. With processing of the UAV data images are merged according to their geographical position by means of the Structure-from-Motion (SfM) algorithm and a digital elevation model was created (Micheletti et al. 2015; Westoby et al. 2012). High-resolution topographic surveying using the Structure-from-Motion (SfM) algorithm is a low-cost and user-friendly photogrammetric technique to obtain high-resolution datasets. The SfM method solves the camera pose and scene geometry simultaneously and automatically, using highly redundant bundle adjustment based on matching features in multiple overlapping, offset images (Westoby et al. 2012). SfM-Processing was performed using Agisoft Metashape Professional (Version 1.6.1 64 bit). Agisoft Metashape Professional performs well to reconstruct landscape 3D point clouds and the different steps of the process are configurable and can be controlled (Laporte-Fauret et al. 2019). Images were fed into the software and the quality (tool “estimate image quality”) and position was determined respectives images were chosen to cover the study area. Using the “Aling Photos” tool images were aligned creating tie points (2D) and a Depth Maps (high quality, mild filtering) was created (3D). With the help of the Build Dense Cloud tool, set to high quality, the data points were created that represent the study area in 3D. Consecutively an orthomosaic of the study area was created using the Build Orthomosaic tool. An orthomosaic is a photogrammetrically orthorectified image product that has been mosaicked from a collection of images and corrected for geometric distortion to create a seamless mosaic dataset. Due to the high-resolution input data and the processing without compression a high-resolution orthomosaic was achieved with a pixel size of 2.1 cm/pix covering the study area. This detailed, high-resolution geolocated photo representation of the study site is the basis for the following analytical steps. A digital elevation model (DEM) was computed using the “Build DEM” tool. Its dimensions resulted herein in a 14 cm/pix size to cover the entire study site. Final adjustment of elevation has been done using the Copernicus Digital Elevation Model (https://spacedata.copernicus.eu/de/collections/copernicus-digital-elevation-model) using Q-GIS (https://www.qgis.org/de/site/). Laporte-Fauret, Q., et al. (2019). "Low-Cost UAV for high-resolution and large-scale coastal dune change monitoring using photogrammetry." Journal of Marine Science and Engineering 7(3): 63. Micheletti, N., Chandler, J. H., & Lane, S. N. (2015). Structure from motion (SFM) photogrammetry. In L. E. Clarke, & J. M. Nield (Eds.), Geomorphological techniques (Online Edition) (pp. 1–12, Chapter 2.2.2). British Society for Geomorphology Westoby, M. J., et al. (2012). "‘Structure-from-Motion’photogrammetry: A low-cost, effective tool for geoscience applications." Geomorphology 179: 300-314.
    Keywords: Biota ; Landscape Evolution ; Biodiversity
    Type: Dataset , Sub data for DTM configuration
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  • 149
    Publication Date: 2024-02-21
    Description: Abstract
    Description: A high-resolution Digital Terrain Model (DTM) has been processed for the Tillandsia landbeckii study sites at Arica. The original source data have been obtained from drone flight images. The final resolution of the DTM is of about 16 cm/px. We acknowledge support in the field and during data processing from Alexander Siegmund (PH Heidelberg).
    Description: TableOfContents
    Description: The zip.file contains the following 5 files: 1) Caldera.blend 2) Caldera_Ortho_0-5res_clipped.tif 3) Caldera_DEM_clipped_rescale.tif 4) Caldera_DEM_clipped_rescale_0-5res.tif 5) Caldera_DEM_clipped_rescale_0-5res_rendered.tif Please do not change file names nor file extensions when loading files for viewing in BLENDER version 4.0 (https://www.blender.org/download/releases/4-0/). The "0-5res" file-versions refer to a 0.5m/px resolution (EPSG:32719 - WGS 84 / UTM Zone 19S). File Caldera_DEM_clipped_rescale.tif was processed to a final resolution of 1.67e-06 °degrees (c. 0.165 m) [EPSG:4326 - WGS 84].
    Description: Other
    Description: Short introduction into the methods: Very-high resolution images were captured using an unmanned aerial vehicle (UAVs) [drone: DJI Matrice 200; DJI Zenmuse X5S RGB camera]. With processing of the UAV data images are merged according to their geographical position by means of the Structure-from-Motion (SfM) algorithm and a digital elevation model was created (Micheletti et al. 2015; Westoby et al. 2012). High-resolution topographic surveying using the Structure-from-Motion (SfM) algorithm is a low-cost and user-friendly photogrammetric technique to obtain high-resolution datasets. The SfM method solves the camera pose and scene geometry simultaneously and automatically, using highly redundant bundle adjustment based on matching features in multiple overlapping, offset images (Westoby et al. 2012). SfM-Processing was performed using Agisoft Metashape Professional (Version 1.6.1 64 bit). Agisoft Metashape Professional performs well to reconstruct landscape 3D point clouds and the different steps of the process are configurable and can be controlled (Laporte-Fauret et al. 2019). Images were fed into the software and the quality (tool “estimate image quality”) and position was determined respectives images were chosen to cover the study area. Using the “Aling Photos” tool images were aligned creating tie points (2D) and a Depth Maps (high quality, mild filtering) was created (3D). With the help of the Build Dense Cloud tool, set to high quality, the data points were created that represent the study area in 3D. Consecutively an orthomosaic of the study area was created using the Build Orthomosaic tool. An orthomosaic is a photogrammetrically orthorectified image product that has been mosaicked from a collection of images and corrected for geometric distortion to create a seamless mosaic dataset. Due to the high-resolution input data and the processing without compression a high-resolution orthomosaic was achieved with a pixel size of 2.1 cm/pix covering the study area. This detailed, high-resolution geolocated photo representation of the study site is the basis for the following analytical steps. A digital elevation model (DEM) was computed using the “Build DEM” tool. Its dimensions resulted herein in a 16.5 cm/pix size to cover the entire study site. Final adjustment of elevation has been done using the Copernicus Digital Elevation Model (https://spacedata.copernicus.eu/de/collections/copernicus-digital-elevation-model) using QGIS (https://www.qgis.org/de/site/). Laporte-Fauret, Q., et al. (2019). "Low-Cost UAV for high-resolution and large-scale coastal dune change monitoring using photogrammetry." Journal of Marine Science and Engineering 7(3): 63. Micheletti, N., Chandler, J. H., & Lane, S. N. (2015). Structure from motion (SFM) photogrammetry. In L. E. Clarke, & J. M. Nield (Eds.), Geomorphological techniques (Online Edition) (pp. 1–12, Chapter 2.2.2). British Society for Geomorphology Westoby, M. J., et al. (2012). "‘Structure-from-Motion’photogrammetry: A low-cost, effective tool for geoscience applications." Geomorphology 179: 300-314.
    Keywords: Biota ; Landscape Evolution
    Type: Dataset , Sub data for DTM configuration
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  • 150
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    GEOMAR Helmholtz Centre for Ocean Research
    Publication Date: 2024-02-12
    Description: RUMMs is a tool for explosive ordnance disposal (EOD) risk assessment (RA). It uses 34 factors of unexploded ordnance (UXO) and the environment in which EOD takes place, RUMMs calculates three output values: the Probability of an Undesired Detonation, the Consequence of an Undesired Detonation, and the Complexity of the EOD Operation.
    Type: Software , NonPeerReviewed
    Format: archive
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  • 151
    Publication Date: 2024-02-12
    Description: Highlights: • Change in sea urchin species composition from RBC and NRBC habitats. • Sand coverage is an important factor that influences the sea urchin species composition. • The relationship between sea urchins and their habitat is species-specific. Sea urchins are important components of marine ecosystems and can act as bioindicators, reflecting the health of reefs. The spatial patterns of sea urchins are largely shaped by the type of habitat. In Hong Kong, coral communities are divided into two distinct types: reef -building coral habitats and non -reef -building coral habitats. In summer 2020, a qualitative survey was conducted using SCUBA at 56 sites across eastern and western waters, recording a total of 11 species from 6 families of sea urchins. Out of these 56 sites, 14 were selected for a quantitative survey to investigate the relationship between sea urchin assemblages and the two types of coral habitat. We found that the species composition of sea urchins differed significantly between the two habitats, and the presence of sand was a critical factor influencing the species composition of sea urchins. Sand coverage had a positive effect on Salmasic sphaeroides abundance but a negative effect on the abundance of Diadema setosum and Heliocidaris crassispina. The distribution of sea urchins across different degrees of sand coverage may be associated with food availability or species -specific adaptive behaviour, likely due to niche preferences.
    Type: Article , PeerReviewed
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  • 152
    Publication Date: 2024-02-12
    Description: Highlights • East Asian climate evolution was dependent on the latitude of the proto-Tibetan Plateau in the deep past; • Global warming induced wetting at mid-latitude East Asian in the mid-Cretaceous; • The proto-Tibetan Plateau uplift led to drying in the subtropical East Asian in the mid-Cretaceous. Abstract Sedimentary records indicate that subtropical and mid-latitude East Asia exhibited considerable drying and wetting, respectively, during the mid-Cretaceous, which is considered to be relevant to much higher atmospheric carbon dioxide (pCO2) concentrations and/or proto-Tibetan Plateau (proto-TP) uplift. In order to explore and compare their roles on the East Asian climate evolution, we conducted simulations of the mid-Cretaceous climate system with different atmospheric pCO2 levels and varying topographies. The results show that both factors had significant influences on the East Asian climate. As the increase in atmospheric pCO2 levels from ∼560–1120 ppmv to ∼1120–2240 ppmv, the precipitation increases considerably over mid-latitude East Asia, but only small changes in the subtropical portion of East Asia occur. Simultaneously, the effects of the proto-TP uplift are opposite to those of global warming trend during that period. Generally, it leads to a precipitation decrease over subtropical East Asia, but rather minor changes over mid-latitude East Asia. These changes are qualitatively consistent with the deduction based on the geological records, but the magnitudes of the modeled precipitation changes are relatively smaller. Therefore, we can conclude that the subtropical East Asian drying during the mid-Cretaceous can be partly explained by the proto-TP uplift, while the mid-latitude East Asian wetting was partly due to global warming. However, additional factor(s) also played a significant role in the East Asian climate evolution during the mid-Cretaceous.
    Type: Article , PeerReviewed
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  • 153
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    GEOMAR Helmholtz Centre for Ocean Research
    Publication Date: 2024-02-12
    Description: Catania (09.02.24) – Catania (22.02.24), MIDES - Measuring and Imaging Deformation of Etna’s Submerged unstable flank
    Type: Report , NonPeerReviewed
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  • 154
    Publication Date: 2024-02-12
    Description: Carbon dioxide removal (CDR) – the creation, enhancement, and upscaling of carbon sinks – has become a pillar of national and corporate commitments towards Net Zero emissions, as well as pathways towards realizing the Paris Agreement's ambitious temperature targets. In this perspective, we explore CDR as an emerging issue of Earth System Governance (ESG). We draw on the results of a workshop at the 2022 Earth System Governance conference that mapped a range of actors, activities, and issues relevant to carbon removal, and refined them into research questions spanning four intersecting areas: modeling and systems assessment, societal appraisal, policy, and innovation and industry. We filter these questions through the five lenses of the ESG framework and highlight several key ‘cross-cutting’ issues that could form the basis of an integrated ESG research agenda on CDR.
    Type: Article , PeerReviewed
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  • 155
    Publication Date: 2024-02-12
    Description: Highlights • Cu complexation was measured for the first time in the Fram Strait region. • Cu-binding ligand concentrations and binding strength varied longitudinally in the Fram Strait. • More than 99 % of dCu was organically complexed by strong ligands. • On the Greenland shelf the Transpolar Drift and the coastal processes were the main sources of Cu ligands. Abstract The Fram Strait represents the major gateway of Arctic Ocean waters towards the Nordic Seas and North Atlantic Ocean and is a key region to study the impact of climate change on biogeochemical cycles. In the region, information about trace metal speciation, such as copper, is scarce. This manuscript presents the concentrations and conditional stability constants of copper-binding ligands (LCu and log KcondCu2+L) in the water column of Fram Strait and the Greenland shelf (GEOTRACES cruise GN05). Cu-binding ligands were analysed by Competitive Ligand Exchange-Adsorptive Cathodic Stripping Voltammetry (CLE-ACSV) using salicylaldoxime (SA) as competitive ligand. Based on water masses and the hydrodynamic influences, three provinces were considered (coast, shelf, and Fram Strait) and differences were observed between regions and water masses. The strongest variability was observed in surface waters, with increasing LCu concentrations (mean values: Fram Strait = 2.6 ± 1.0 nM; shelf = 5.2 ± 1.3 nM; coast = 6.4 ± 0.8 nM) and decreasing log KcondCu2+L values (mean values: Fram Strait = 15.7 ± 0.3; shelf = 15.2 ± 0.3; coast = 14.8 ± 0.3) towards the west. The surface LCu concentrations obtained above the Greenland shelf indicate a supply from the coastal environment to the Polar Surface Water (PSW) which is an addition to the ligand exported from the central Arctic to Fram Strait. The significant differences (in terms of LCu and log KcondCu2+L) between shelf and coastal samples were explained considering the processes which modify ligand concentrations and binding strengths, such as biological activity in sea-ice, phytoplankton bloom in surface waters, bacterial degradation, and meltwater discharge from 79NG glacier terminus. Overall, the ligand concentration exceeded those of dissolved Cu (dCu) and kept the free copper (Cu2+) concentrations at femtomolar levels (0.13–21.13 fM). This indicates that Cu2+ toxicity limits were not reached and dCu levels were stabilized in surface waters by organic complexes, which favoured its transport to the Nordic Seas and North Atlantic Ocean and the development of microorganism.
    Type: Article , PeerReviewed
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  • 156
    Publication Date: 2024-02-12
    Description: Weather causes extremes in photovoltaic and wind power production. Here we present a comprehensive climatology of anomalies in photovoltaic and wind power production associated with weather patterns in Europe considering the 2019 and potential 2050 installations, and hourly to ten-day events. To that end, we performed kilometer-scale numerical simulations of hourly power production for 23 years and paired the output with a weather classification which allows a detailed assessment of weather-driven spatio-temporal production anomalies. Our results highlight the dependency of low-power production events on the installed capacities and the event duration. South-shifted Westerlies (Anticyclonic South-Easterlies) are associated with the lowest hourly (ten-day) extremes for the 2050 (both) installations. Regional power production anomalies can differ from the ones in the European mean. Our findings suggest that weather patterns can serve as indicators for expected photovoltaic and wind power production anomalies and may be useful for early warnings in the energy sector.
    Type: Article , PeerReviewed
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  • 157
    Publication Date: 2024-02-12
    Description: The southeastern tropical Atlantic hosts a coastal upwelling system characterized by high biological productivity. Three subregions can be distinguished based on differences in the physical climate: the tropical Angolan and the northern and southern Benguela upwelling systems (tAUS, nBUS, sBUS). The tAUS, which is remotely forced via equatorial and coastal trapped waves, can be characterized as a mixing-driven system, where the wind forcing plays only a secondary role. The nBUS and sBUS are both forced by alongshore winds and offshore cyclonic wind stress curl. While the nBUS is a permanent upwelling system, the sBUS is impacted by the seasonal cycle of alongshore winds. Interannual variability in the region is dominated by Benguela Niños and Niñas that are warm and cold events observed every few years in the tAUS and nBUS. Decadal and multidecadal variations are reported for sea surface temperature and salinity, stratification and subsurface oxygen. Future climate warming is likely associated with a southward shift of the South Atlantic wind system. While the mixing-driven tAUS will most likely be affected by warming and increasing stratification, the nBUS and sBUS will be mostly affected by wind changes with increasing winds in the sBUS and weakening winds in the northern nBUS.
    Type: Book chapter , NonPeerReviewed , info:eu-repo/semantics/bookPart
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  • 158
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    GEOMAR
    Publication Date: 2024-02-13
    Description: RV MARIA S. MERIAN MSM126 “Jellyweb Madeira” 9. Februar – 4. März 2024 1. Wochenbericht (9.-11. Februar, 2024)
    Type: Report , NonPeerReviewed
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  • 159
    Publication Date: 2024-02-13
    Description: Ethiopia is highly vulnerable to climate change, the impacts of which can be felt across different sectors. In particular forests are threatened by rising temperatures, shifting precipitation patterns and extreme weather events. Human activities like deforestation and land-use change further exacerbate climate impacts, increasing the risk of wildfires and reducing the potential of forests for carbon sequestration. However, forests and trees are of major importance for ecosystems and local communities, providing plant and animal habitat, protection against soil erosion, provision of sufficient water resources, wood for fuel and construction, and various non-timber products. In addition, climate change is increasingly impacting water resources through prolonged and more frequent droughts, leading to water scarcity, crop failures and food insecurity for millions of people in Ethiopia. At the same time, erratic and heavy precipitation events lead to increased instances of flooding and soil erosion, further compromising water availability and quality. In a similar way, soils are impacted by climate change, with temperature increases and shifting precipitation patterns leading to soil degradation and reduced soil fertility, making it harder for smallholder farmers to pursue agriculture as a livelihood. Forests and trees are particularly threatened by climate change. At the same time, they are key in both climate change mitigation and adaptation efforts. Against this background, this policy brief discusses the potential of forests and trees in addressing climate change, specifically looking at natural forest regeneration as a mitigation strategy and at agroforestry as an adaptation strategy, highlighting the unique potential of forests and trees to achieve a dual benefit for climate action. Although these strategies are considered in greater detail, it should be noted that there is no single best mitigation or adaptation strategy, but rather different mutually complementing strategies. Mitigation describes efforts to reduce greenhouse gas emissions as well as measures to enhance greenhouse gas sinks. Forest and tree-based mitigation options can be classified as efforts to maintain the remaining forest cover (reduce deforestation and degradation), and measures to increase forest cover (natural regeneration and reforestation) (Nabuurs et al., 2007). We briefly describe each strategy but focus on natural regeneration later on.
    Language: English
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  • 160
    Publication Date: 2024-02-13
    Description: Agricultural sustainability faces challenges in the changing climate, particularly for rain-fed systems like those in Ethiopia. This study examines the combined impacts of climate change and soil acidity on future crop potential, focusing on Ethiopia as a case study. The EcoCrop crop suitability model was parameterized and run for four key food crops in Ethiopia (teff, maize, barley and common wheat), under current and mid-century climate conditions. To assess the impacts of soil acidification on crop suitability, a simulation study was conducted by lowering the soil pH values by 0.5, 1.0 and 1.5 and re-running the suitability model, comparing the changes in the area suitable for each crop. Our evaluation of the model, by comparing the modeled suitable areas with reference data, indicated that there was a good fit for all the four crops. Using default soil pH values, we project that there will be no significant changes in the suitability of maize, barley and wheat and an increase in the suitability of teff by the mid-century, as influenced by projected increases in rainfall in the country. Our results demonstrate a direct relationship between the lowering of soil pH and increasing losses in the area suitable for all crops, but especially for teff, barley and wheat. We conclude that soil acidification can have a strong impact on crop suitability in Ethiopia under climate change, and precautionary measures to avoid soil acidification should be a key element in the design of climate change adaptation strategies.
    Language: English
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  • 161
    Publication Date: 2024-02-12
    Description: Abstract
    Description: Crystallographic Information File (CIF) of the magnesium phosphate mineral struvite collected by single-crystal X-Ray diffraction.  The magnesium phosphate mineral struvite (MgNH4PO4·6H2O) is of interest for the recovery of phosphorus from wastewaters and for use as a fertilizer in agriculture, yet its structure is still debated. The structure of synthetic single crystals of struvite was characterized through refinement of a single-crystal X-ray diffraction pattern acquired at 100 K. The crystal structure was processed into a crystallographic information file (CIF), which is an internationally used data format used by crystallographers, mineralogists and chemists, containing all relevant information about the structure of a specific crystalline phase (Hall et al.: International Tables for Crystallography (2006). Vol. G, ch. 2.2, pp. 20-36). Detailed description and experimental outline of the structural determination is found in Volkmann et al. (2024), DOI: https://doi.org/10.31223/X5KQ4F
    Keywords: Struvite ; Crystal structure ; Mineral ; Phosphate ; EARTH SCIENCE 〉 SOLID EARTH 〉 ROCKS/MINERALS/CRYSTALS 〉 SEDIMENTARY ROCKS 〉 SEDIMENTARY ROCK PHYSICAL/OPTICAL PROPERTIES
    Type: Dataset , Dataset
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  • 162
    Publication Date: 2024-02-12
    Description: Abstract
    Description: In near-Earth space, a large population of high-energy electrons are trapped by Earth’s magnetic field. These energetic electrons are trapped in the regions called Earth’s ring current and radiation belts. They are very dynamic and show a very strong dependence on solar wind and geomagnetic conditions. These energetic electrons can be dangerous to satellites in the near-Earth space. Therefore, it is very important to understand the mechanisms which drive the dynamics of these energetic electrons. Wave-particle interaction is one of the most important mechanisms. Among the waves that can be encountered by the energetic electrons when they move around our Earth, whistler mode chorus waves can cause both acceleration and the loss of energetic electrons in the Earth's radiation belts and ring current. Using more than 5 years of wave measurements from NASA’s Van Allen Probe mission, Wang et al (2019) developed chorus wave models which depend on magnetic local time (MLT), Magnetic Latitude (MLat), L-shell, and geomagnetic condition index Kp. To quantify the effect of chorus waves on energetic electrons, we calculated the bounce-averaged quasi-linear diffusion coefficients using the chorus wave model developed by Wang et al (2019) and extended to higher latitudes according to Wang and Shprits (2019). Using these diffusion coefficients, we calculated the lifetime of the electrons with an energy range from 1 keV to 2 MeV. In each MLT, we calculate the lifetime for each energy and L-shell using two different methods according to Shprits et al (2007) and Albert and Shprits (2009). We make the calculated electron lifetime database available here. Please notice that the chorus wave model by Wang et al (2019) is valid when Kp 〈= 6. If the user wants to use this lifetime database for Kp 〉6, please be careful and contact the authors.
    Keywords: Earth's radiation belt; ring current; electron precipitation; electron lifetime ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 PLASMA WAVES ; EARTH SCIENCE SERVICES 〉 MODELS 〉 SOLAR-ATMOSPHERE/SPACE-WEATHER MODELS
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  • 163
    Publication Date: 2024-02-14
    Description: The increasing global demand for seafood, coupled with the limitations of current fish stocks and aquaculture practices, requires the development of sustainable aquaculture solutions. In this context, this study explores the potential of a novel cage technology - Flow2Vortex - for the cultivation of jellyfish, a low-trophic-level organism with increasing market demand. The unique cage design creates a laminar and circular water flow, providing optimal conditions for cultivating fragile planktonic species. Indoor experiments demonstrated the successful growth of jellyfish in the cage, with growth rates of up to 11.6% per day. In addition, field tests in open waters confirmed the cage's ability to maintain a diffuse and controlled flow inside, even under strong external currents. The cage also maintained significantly higher zooplankton concentrations than the surrounding environment, offering a consistent food source for the cultivated jellyfish. These findings highlight the potential of the Flow2Vortex cage for scalable indoor and outdoor cultivation of low-trophic-level organisms, such as jellyfish, contributing to the diversification and sustainability of aquaculture practices.
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  • 164
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    GFZ Data Services
    Publication Date: 2024-02-14
    Description: Abstract
    Description: This database contains a compilation of published zircon geochronology, chemistry and isotope data. The database was created through automated web scraping of the Figshare data repository. Data included U-Pb and Pb-Pb dating, Lu-Hf isotopes, trace element and rare earth element chemistry and isotopes. Where available, metadata on the analytical method, lithology, sample description and sampling coordinates are included. All analyses include a citation and doi link to the original data hosted on Figshare. See metadata table for descriptions of table headers. See associated manuscript for web scraping code.
    Description: Other
    Description: The DIGIS geochemical data repository is a research data repository in the Earth Sciences domain with a specific focus on geochemical data. It is hosted at GFZ Data Services through a collaboration between the Digital Geochemical Data Infrastructure (DIGIS) for GEOROC 2.0 (https://digis.geo.uni-goettingen.de) and the GFZ German Research Centre for Geosciences. The repository archives, publishes and makes accessible user-contributed, peer-reviewed research data that fall within the scope of the GEOROC database. Compilations of previously published data are also made available on the GEOROC website (https://georoc.eu) as Expert Datasets.
    Keywords: data compilation ; zircon geochronology ; geochemistry data ; isotope data ; GEOROC Expert Dataset ; zircon ; magmatic ; detrital ; U-Pb age ; Pb-Pb age ; Lu-Hf isotopes ; trace elements ; rare earth elements ; adakite ; amphibolite ; andesite ; anorthosite ; aplite ; arenite ; ash ; basalt ; basaltic andesite ; basaltic trachyandesite ; bentonite ; biotitite ; charnockite ; conglomerate ; dacite ; diamictite ; diorite ; dolerite ; dunite ; gabbro ; granite ; granodiorite ; granulite ; greenschist ; greywacke ; hornblendite ; kersantite ; kimberlite ; lamprophyre ; leucogranite ; lherzolite ; limestone ; migmatite ; monzodiorite ; monzogranite ; monzonite ; norite ; orthogneiss ; paragneiss ; pegmatite ; pelite ; psammite ; pumice ; pyroxenite ; quartzite ; radiolarite ; rhyodacite ; rhyolite ; rodingite ; sandstone ; schist ; serpentinite ; shale ; siltstone ; spessartite ; syenite ; syenogranite ; tonalite ; trachyandesite ; trachydacite ; trachyte ; trondhjemite ; tuff ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES 〉 ISOTOPE MEASUREMENTS ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES 〉 ISOTOPE RATIOS ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES 〉 ISOTOPES ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES 〉 ISOTOPIC AGE ; EARTH SCIENCE 〉 SOLID EARTH 〉 ROCKS/MINERALS/CRYSTALS 〉 MINERALS 〉 MINERAL AGE DETERMINATIONS
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  • 165
    Publication Date: 2024-02-15
    Description: Die Energiewende sorgt für einen Paradigmenwechsel von einem grundlastbasierten zu einem flexiblen Stromsystem. Die zentralen Treiber für den zunehmenden Flexibilitätsbedarf sind die Stromerzeugung durch Wind und Sonne sowie die weiterhin bestehende unflexible Stromnachfrage, die gedeckt werden muss. Die vorliegende Studie analysiert, wie im Zeitverlauf bis zum Jahr 2045 der Flexibilitätsbedarf zunimmt und wie die Betriebsweisen der verschiedenen Technologien sich anpassen können. In der Studie wird auf das Energiesystemmodell REMod zurückgegriffen, mit dem eine Analyse über die intersektorale Flexibilität bis zum Jahr 2045 möglich ist. Für kurzfristige Flexibilität können in dieser Betrachtung zum Beispiel Batterien sowie Stromimporte und -exporte eingesetzt werden. Durch die Sektorenkopplung kann bei der Wärmebereitstellung in Gebäuden ebenfalls ein erheblich angepasstes Lastmanagement erfolgen. Ein höherer Anteil an Flexibilität kann jedoch durch Stromaufnahme in Elektrolyseanlagen und die Nutzung von Power-to-X-Kraftstoffen erfolgen. So können während längerer Dunkelflauten flexible Backup-Gasturbinen eingesetzt werden, um die Versorgungssicherheit zu gewährleisten. Um die notwendige Integration der Flexibilitäts-Technologien in den verschiedenen Märkten (insbesondere Strommarkt) und Sektoren voranzutreiben, müssen technische Voraussetzung, Marktregeln sowie Regulatorik in Bezug auf Bau und Betrieb so angepasst werden, dass die Technologien ihr Flexibilitätspotential bestmöglich ausspielen können.
    Language: German
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  • 166
    Publication Date: 2024-02-15
    Description: Mit steigendem Anteil fluktuierender Erneuerbarer Energien im Stromsystem steigt auch der Bedarf an steuerbaren Kapazitäten, die Stromangebot und -nachfrage ausgleichen können, so genannte Flexibilitätstechnologien. In dieser Analyse wird der Nutzen von zehn verschiedenen Technologien, die Flexibilität bereitstellen können, für das deutsche Stromsystem im Jahr 2030 ermittelt. Die Nutzenanalyse macht deutlich, dass die Verschiebung von großen Energiemengen über einen längeren Zeitraum (saisonaler Ausgleich) den höchsten spezifischen Nutzen erreicht. Eine Schlüsseltechnologie für das Jahr 2030 sind daher Langzeitspeicher mit großen Speichervolumen, zum Beispiel in Form von Wasserstoff-Kavernenspeichern. Das Fehlen einer hierfür geeigneten Technologie würde zu hohen Effizienzverlusten führen. Die zweite Schlüsseltechnologie ist die steuerbare Leistung von Power-to-Heat1 in Wärmenetzen der allgemeinen Versorgung, die für den täglichen Ausgleich zwischen Nachfrage und erneuerbarer Erzeugung eingesetzt wird. Hier können allerdings auch andere nachfrageseitige Flexibilitäten eine ähnliche Funktion für das Stromsystem übernehmen. Die Analyse zeigt auch, dass die Erschließung der hier betrachteten Flexibilitätstechnologien, zum Beispiel durch den Abbau von regulatorischen Hemmnissen, bis zum Jahr 2030 für das Stromsystem von hoher Relevanz ist. Auch über die angenommenen Potentialgrenzen hinaus bieten insbesondere nachfrageseitige Flexibilitätstechnologien noch einen positiven Nutzen. Eine technologieoffene, marktbasierte Lösung zur Einbindung dieser Flexibilitäten könnte die unterschiedlichen Charakteristika, Nutzenniveaus sowie sich ändernde Rahmenbedingungen effizient berücksichtigen.
    Language: German
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  • 167
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    GEOMAR Helmholtz Centre for Ocean Research
    Publication Date: 2024-02-19
    Description: Catania (09.02.24) – Catania (22.02.24), MIDES - Measuring and Imaging Deformation of Etna’s Submerged unstable flank
    Type: Report , NonPeerReviewed
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  • 168
    Publication Date: 2024
    Description: 〈p〉〈em〉The COVID-19 pandemic has underscored the necessity for digital infrastructure and accessibility, particularly in the education sector. This paper investigates the benefits and effectiveness of utilizing Green Cloud Computing (GCC) techniques for the dissemination of educational library data in remote regions of India during this critical period. The GCC model, known for its energy efficiency and reduced environmental impact, is proposed as a robust, scalable, and eco-friendly solution for providing remote educational access. The research utilizes a mixed-methods approach, incorporating both quantitative assessments of data reach and usage, and qualitative surveys to understand user experiences. The study reveals that GCC techniques can significantly improve educational resource distribution, thereby mitigating the educational disparities further exacerbated by the pandemic. These findings reinforce the potential of GCC techniques as a sustainable and inclusive technology in reshaping the educational landscape in remote regions.〈/em〉〈/p〉
    Print ISSN: 2321-421X
    Electronic ISSN: 2230-7990
    Topics: Geography , Geosciences
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  • 169
    Publication Date: 2024
    Description: 〈p〉〈em〉One of the most crucial global issues of our era is climate change, whose consequences are presently being felt all over the world. As climate change keeps on forgoing, it's important that governments, organizations, and businesses take visionary actions for adapting and protecting themselves from calamities.〈/em〉〈em〉 This paper summarizes the application of Remote Sensing (RS) and 〈/em〉〈em〉Geographic Information System (〈/em〉〈em〉GIS) in observing impact of climate change on drought, soil moisture, land degradation, food security, EHIs’ characterization and blue carbon science and review of AI based climate solutions. The〈/em〉〈em〉 〈/em〉〈em〉integration of advanced machine learning algorithms,〈/em〉〈em〉 〈/em〉〈em〉real-time data analysis, and other cutting-edge technologies could lead to even more effective climate change〈/em〉〈em〉 〈/em〉〈em〉adaptation strategies. AI-activated climate change adaptation strategies have the prospective to significantly〈/em〉〈em〉 〈/em〉〈em〉improve the resilience of infrastructure communities, and businesses to the changing climate.〈/em〉〈strong〉〈/strong〉〈/p〉
    Print ISSN: 2321-421X
    Electronic ISSN: 2230-7990
    Topics: Geography , Geosciences
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  • 170
  • 171
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  • 173
    Publication Date: 2024-02-22
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 174
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    GEOMAR
    Publication Date: 2024-02-22
    Description: RV MARIA S. MERIAN MSM126 “Jellyweb Madeira” 9. Februar – 4. März 2024 2.Wochenbericht (12. – 18. Februar 2024)
    Type: Report , NonPeerReviewed
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  • 175
    Publication Date: 2024-02-22
    Description: Highlights • More diverse non-native taxa generally include more economically costly species. • Chordates, nematodes and pathogens are among significantly over-represented taxa. • Monetary cost magnitude links positively to numbers of costly invasive species. • Costs are biased towards a few ‘hyper-costly’ invasive species groups. • Future invasion rates will continue to harbour new economically costly species. Abstract A dominant syndrome of the Anthropocene is the rapid worldwide spread of invasive species with devastating environmental and socio-economic impacts. However, the dynamics underlying the impacts of biological invasions remain contested. A hypothesis posits that the richness of impactful invasive species increases proportionally with the richness of non-native species more generally. A competing hypothesis suggests that certain species features disproportionately enhance the chances of non-native species becoming impactful, causing invasive species to arise disproportionately relative to the numbers of non-native species. We test whether invasive species with reported monetary costs reflect global numbers of established non-native species among phyla, classes, and families. Our results reveal that numbers of invasive species with economic costs largely reflect non-native species richness among taxa (i.e., in 96 % of families). However, a few costly taxa were over- and under-represented, and their composition differed among environments and regions. Chordates, nematodes, and pathogenic groups tended to be the most over-represented phyla with reported monetary costs, with mammals, insects, fungi, roundworms, and medically-important microorganisms being over-represented classes. Numbers of costly invasive species increased significantly with non-native richness per taxon, while monetary cost magnitudes at the family level were also significantly related to costly invasive species richness. Costs were biased towards a few ‘hyper-costly’ taxa (such as termites, mosquitoes, cats, weevils, rodents, ants, and asters). Ordination analysis revealed significant dissimilarity between non-native and costly invasive taxon assemblages. These results highlight taxonomic groups which harbour disproportionately high numbers of costly invasive species and monetary cost magnitudes. Collectively, our findings support prevention of arrival and containment of spread of non-native species as a whole through effective strategies for mitigation of the rapidly amplifying impacts of invasive species. Yet, the hyper- costly taxa identified here should receive greater focus from managers to reduce impacts of current invasive species.
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  • 176
    Publication Date: 2024-02-22
    Description: The coastal ocean contributes to regulating atmospheric greenhouse gas concentrations by taking up carbon dioxide (CO2) and releasing nitrous oxide (N2O) and methane (CH4). In this second phase of the Regional Carbon Cycle Assessment and Processes (RECCAP2), we quantify global coastal ocean fluxes of CO2, N2O and CH4 using an ensemble of global gap-filled observation-based products and ocean biogeochemical models. The global coastal ocean is a net sink of CO2 in both observational products and models, but the magnitude of the median net global coastal uptake is similar to 60% larger in models (-0.72 vs. -0.44 PgC year-1, 1998-2018, coastal ocean extending to 300 km offshore or 1,000 m isobath with area of 77 million km2). We attribute most of this model-product difference to the seasonality in sea surface CO2 partial pressure at mid- and high-latitudes, where models simulate stronger winter CO2 uptake. The coastal ocean CO2 sink has increased in the past decades but the available time-resolving observation-based products and models show large discrepancies in the magnitude of this increase. The global coastal ocean is a major source of N2O (+0.70 PgCO2-e year-1 in observational product and +0.54 PgCO2-e year-1 in model median) and CH4 (+0.21 PgCO2-e year-1 in observational product), which offsets a substantial proportion of the coastal CO2 uptake in the net radiative balance (30%-60% in CO2-equivalents), highlighting the importance of considering the three greenhouse gases when examining the influence of the coastal ocean on climate. The coastal ocean regulates greenhouse gases. It acts as a sink of carbon dioxide (CO2) but also releases nitrous oxide (N2O) and methane (CH4) into the atmosphere. This synthesis contributes to the second phase of the Regional Carbon Cycle Assessment and Processes (RECCAP2) and provides a comprehensive view of the coastal air-sea fluxes of these three greenhouse gases at the global scale. We use a multi-faceted approach combining gap-filled observation-based products and ocean biogeochemical models. We show that the global coastal ocean is a net sink of CO2 in both observational products and models, but the coastal uptake of CO2 is similar to 60% larger in models than in observation-based products due to model-product differences in seasonality. The coastal CO2 sink is strengthening but the magnitude of this strengthening is poorly constrained. We also find that the coastal emissions of N2O and CH4 counteract a substantial part of the effect of coastal CO2 uptake in the atmospheric radiative balance (by 30%-60% in CO2-equivalents), highlighting the need to consider these three gases together to understand the influence of the coastal ocean on climate. We synthesize air-sea fluxes of CO2, nitrous oxide and methane in the global coastal ocean using observation-based products and ocean models The coastal ocean CO2 sink is 60% larger in ocean models than in observation-based products due to systematic differences in seasonality Coastal nitrous oxide and methane emissions offset 30%-60% of the CO2 coastal uptake in the net radiative balance
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  • 177
    Publication Date: 2024
    Description: 〈p〉〈em〉Urban transportation systems face significant challenges due to rapid population growth and development. This study delves into the enhancement of road safety in Navi Mumbai by employing Geographic Information System (GIS) and Remote Sensing (RS) techniques. The escalating rate of vehicular accidents in Navi Mumbai presents a pressing concern. This research investigates accident data and traffic patterns, identifying vulnerable areas prone to accidents and congestion. By conducting spatial analysis using GIS and RS, the study aims to uncover accident hotspots and traffic congestion zones, offering insights into underlying road safety issues. The research methodology involves a multi-stage process. Initial data collection from various sources, including police reports, live traffic data, and satellite imagery, forms the foundation. Geographic coordinates extracted and processed through GIS applications aid in plotting accident locations and creating density maps. Additionally, on-site investigations at strategically chosen locations provide invaluable insights into local conditions, traffic patterns, and contributing factors to congestion and accidents. The findings are presenting tailored solutions for each area, ranging from optimized traffic signal timings to infrastructural improvements. The findings of this study present actionable insights aimed at improving road safety and traffic management in Navi Mumbai. Recommendations encompassing signal optimizations, infrastructure enhancements, and community engagement strategies offer a holistic approach to mitigate traffic congestion and reduce accidents. The collaborative effort with relevant authorities, as highlighted in the study, serves as a crucial step towards implementing these recommendations for meaningful change. This research not only identifies critical areas for intervention but also serves as a model for leveraging GIS and RS techniques to enhance the road safety in urban areas, paving the way for safer and efficient transportation networks in the future.〈/em〉〈/p〉
    Print ISSN: 2321-421X
    Electronic ISSN: 2230-7990
    Topics: Geography , Geosciences
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  • 178
    Publication Date: 2024-02-23
    Description: Shimmy dynamics of a dual-wheel nose landing gear system with torsional freeplay under stochastic lateral wind disturbances is studied. Dynamic characteristics of the deterministic case are numerically analysed, especially the shimmy of the landing gear through bifurcation analysis. Meanwhile, the influences of the freeplay nonlinearity on shimmy behaviours are examined in detail. We found that the freeplay leads to an enlargement of the shimmy area and an enhancement of the shimmy characteristics compared to the case without freeplay. Furthermore, impacts of stochastic lateral wind disturbances on the shimmy of the landing gear system are estimated via time history and recurrence plots. We find that the stochastic excitation enhances shimmy of the lateral bending direction. More interestingly, the stochastic excitation strengthens the effect of the freeplay nonlinearity, which causes random intermittent large-amplitude oscillations in the torsional direction. Our results show that the interaction between the freeplay nonlinearity and the random load induces a significant reduction in the critical shimmy velocity, which has an adverse impact on the stability of the nose landing gear of an aircraft. This work will provide an insightful guidance for the design of landing gear parameters in engineering practice.
    Language: English
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  • 179
    Publication Date: 2024-02-22
    Description: This is the data repository to reproduce the scenario analysis of the paper "Complementary roles of direct and indirect electrification in pathways to a renewables-dominated European energy system".
    Language: English
    Type: info:eu-repo/semantics/workingPaper
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  • 180
    Publication Date: 2024-02-22
    Description: A new resilient distributed secondary control for AC microgrids is studied based on event-triggered mechanisms and trust-reputation evaluation methods. When distributed generators (DGs) in a microgrid are subject to attacks, their transmitted state information would be tampered and thus affect the dynamics of normal generators. In order to isolate possible attacks, two types of trust evaluation metrics with different attack indices and time scales are designed, by which the performance of neighboring DGs can be assessed for specific practical demands. Based on the trust values of each neighbor, a reputation-propagation method is introduced at triggered time instants to determine whether a DG is under attack by comprehensively incorporating the opinion of mutual neighbors. The dynamic updating law of the communication edge weights is utilized with the derived reputation values. Based on this, a distributed Zeno-free event-triggered control protocols for voltage/frequency restoration and active power sharing are proposed. Sufficient conditions for picking proper control parameters are given in the main theorem. Lastly, the simulations are conducted in MATLAB/SimPowerSystems for several scenarios to validate the effectiveness of the proposed algorithms.
    Language: English
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  • 181
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    In:  The Journal of Development Studies
    Publication Date: 2024-02-22
    Description: This paper analyses poverty dynamics and checks for the existence of poverty traps among refugee and host communities living close to each other in Uganda. Although some non-linearities emerge in asset dynamics, there is convergence towards one stable equilibrium for the whole sample that suggests the existence of a structural poverty trap. However, households are quite heterogeneous: when analysing refugees and hosts separately, refugees converge to a lower own-group equilibrium than hosts. The household size and education are asset growth enablers for both communities. Noticeably, access to land, past history and social cohesion are also significant correlates of refugees’ asset dynamics. From a policy perspective, structural poverty traps are bad news, because standard anti-poverty interventions would not unlock the trap. Our results stress the need of more structural approaches aimed at promoting economic growth in the whole area where refugee and host communities live, targeting both communities.
    Language: English
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  • 182
    Publication Date: 2024-02-22
    Description: Die schnelle und umfassende Emissionsminderung in der Energie- und Kreislaufwirtschaft ist der Schlüssel für die Begrenzung der Erderwärmung auf unter 2 °C. In Deutschland werden entsprechende Politiken seit den 1990er-Jahren verfolgt, allerdings erst in jüngster Vergangenheit mit dem notwendigen Nachdruck und der notwendigen Orientierung hin zu mehr Marktmechanismen. Wesentliche Handlungsfelder sind Energieeinsparung und erhöhte Energieeffizienz, Umstieg auf erneuerbare Energien, Bepreisung von Klimagasen sowie eine Reduzierung und Schließung der Stoffkreisläufe. In allen Handlungsfeldern sind Grundlagen geschaffen, es bleibt jedoch der Großteil des Weges noch zu gehen, um Klimaneutralität zu erreichen. Für einen schnellen Fortschritt spielen neben der Überwindung der technischen, ökonomischen und organisatorischen Herausforderungen auch Verteilungsfragen und die Einbettung in internationale Maßnahmen eine zunehmende Rolle.
    Language: German
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  • 183
    Publication Date: 2024-02-22
    Description: Recent research on environmental inequality has extended its focus from ongoing pollution to legacy pollution by examining the geography of industrial brownfields, defined as non-productive, contaminated land. This article is the first extensive brownfield analysis for a European country from an environmental inequality perspective, exploiting the political momentum in France where brownfield restoration has become a national priority. We combine data on over 7200 industrial brownfields from the 2022 geodatabase ‘Cartofriches’ with socio-economic variables at the municipality level. We demonstrate that communities with higher percentages of foreign-born and unemployed persons are disproportionately more likely to be located in proximity to brownfields. The social gradient increases significantly in communities that host more than two brownfields. There is an inverted U-shaped relationship with income, with a turning point at approximately 25,600 annually. These findings are robust across urban and rural areas, though with regional differences. Our analysis provides entry points for restorative environmental justice considerations and has important implications for Europe's just transition and cohesion policies.
    Language: English
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  • 184
    Publication Date: 2024-02-22
    Description: Precipitation is essential for food production in Sub-Saharan Africa, where more than 80 % of agriculture is rainfed. Although ∼40 % of precipitation in certain regions is recycled moisture from Africa's tropical rainforest, there needs to be more knowledge about how this moisture supports the continent's agriculture. In this study, we quantify all moisture sources for agrarian precipitation (African agricultural precipitationshed), the estimates of African rainforest's moisture contribution to agricultural precipitation, and the evaporation from agricultural land across the continent. Applying a moisture tracking model (UTRACK) and a dynamic global vegetation model (LPJmL), we find that the Congo rainforest (〉60 % tree cover) is a crucial moisture source for many agricultural regions. Although most of the rainforest acreage is in the DRC, many neighboring nations rely significantly on rainforest moisture for their rainfed agriculture, and even in remote places, rainforest moisture accounts for ∼10–20 % of agricultural water use. Given continuous deforestation and climate change, which impact rainforest areas and resilience, more robust governance for conserving the Congo rainforest is necessary to ensure future food production across multiple Sub-Saharan African countries.
    Language: English
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  • 185
    Publication Date: 2024-02-22
    Description: Renewable electricity can facilitate climate change mitigation in the buildings, industry and transport sector via direct electrification or indirect electrification, that is, converting electricity to hydrogen-based fuels. While direct electrification is generally energy efficient, indirect electrification can partially build upon existing applications and infrastructure. However, their roles and relative importance have not been well researched in mitigation scenarios. Here, we derive plausible ranges for both strategies based on EU climate neutrality scenarios using the REMIND model. We find that by 2050 direct electrification is the dominant strategy with an electricity share of 42%–60% in final energy, while indirect electrification is necessary in hard-to-electrify sectors and contributes a share of 9%–26%. Our analysis highlights that policy makers should respect the distinct sectoral roles of both strategies by fostering an end-use transformation towards direct electrification while prioritizing hydrogen and synthetic fuels for applications where they are indispensable.
    Language: English
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  • 186
    Publication Date: 2024-02-23
    Description: Highlights: • Ca. 418 ka Pauzhetka tephra from South Kamchatka was found in 11 marine sediment cores. • New major and trace element analyses allow identification of tephra glasses. • K/Ti and K/Fe maxima mark the Pauzhetka tephra presence in marine sediments. • The tephra occurs at Marine Isotope Stages 12 to 11c and below the Bermuda excursion. • The revised ash dispersal covers vast areas in the NW Pacific and Okhotsk Sea. Abstract: The distal Pauzhetka tephra, formed by a large caldera-forming volcanic eruption in South Kamchatka, has been identified in eleven recently recovered marine sediment cores based on major and trace element compositions of tephra glass. Ten SO264 cores form a transect along the Emperor Seamount Chain (ESC) in the Northwest (NW) Pacific between ∼50.3° and ∼45°N, 800–1200 km southeast of the Pauzhetka caldera. One additional core LV28-41-4 was retrieved in the Okhotsk Sea, ∼600 km west of the caldera. The Pauzhetka tephra glass shards have a characteristic medium-K rhyolite composition and trace element content compatible with the rear-arc position of the source volcano that ensures their identification. In the NW Pacific SO264 cores, the tephra is preserved as layers in cores 33, 47, 49, 53, 55, 56 and 62, as a lens in core 45, and as cryptotephra in cores 57 and 66. It forms a cryptotephra in the Okhotsk Sea core LV28-41-4. Distinctively high XRF-retrieved K/Ti and K/Fe ratios compared to those for the host sediments help identify the Pauzhetka tephra. According to our refined stable oxygen isotope (δ18O)- and magneto-stratigraphy of two studied and two reference cores, the Pauzhetka tephra occurs within a local δ18O maximum during a transition from marine isotope stage 12 to 11c (Termination V) and below a paleointensity minimum referred to as the Bermuda excursion, at ca. 418 ka. Using the tephra age as an isochron, we show that average linear sedimentation rates decrease southward along a transect of the SO264 cores, except in core 55. It partially reflects an intensification of mid-depth currents causing winnowing, erosion or non-deposition along the ESC over the past 418 kyr. An increased linear sedimentation rate in core 55, recovered from the southern leeward side of the Minnetonka Seamount, appears to record the pelagic accumulation protected from the mid-depth current influence. Our findings expand the former ash dispersal area farther southeast in the NW Pacific and southwest in the Okhotsk Sea. The new data on the tephra thickness supports the axis direction of the fallout zone southeast of the Pauzhetka caldera. Our results suggest the Pauzhetka tephra as a key middle Pleistocene isochron for the stratigraphy and correlation of the NW Pacific and Okhotsk Sea sediments.
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  • 187
    Publication Date: 2024-02-23
    Description: Three boreholes drilled during the International Ocean Discovery Program (IODP) Expedition 396 have yielded unexpected findings of altered granitic rocks covered by basalt flows, interbedded sediments and glacial mud near the continent‐ocean transition of the mid‐Norwegian margin. U‐Pb and K‐Ar geochronological analyses were conducted on both protolithic and authigenically formed K‐bearing minerals to determine the age of granite crystallisation and subsequent alteration episodes. The granite's crystallisation age based on 104 zircons is 56.3 ± 0.2 Ma, and subsequent exhumation along with alteration/weathering events took place between 54.7 ± 1 and 37.1 ± 1 Ma. This intrusion represents the youngest granite discovered in Norway and intruded at an extremely shallow crustal level before a rapid rift‐to‐drift transition. The shallow emplacement of granitic rock and its fast exhumation before and during the onset of volcanism holds significant implications for the syn‐ and post‐breakup tectonic evolution of volcanic margins.
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  • 188
    Publication Date: 2024-02-23
    Description: Predatory non-indigenous species (NIS) have profound impacts on global ecosystems, potentially leading to native prey extinction and reshaping community dynamics. Among mechanisms potentially mediating predator impacts and prey invasion success are predator preferences between native vs. non-indigenous prey, a topic still underexplored. Using functional response and prey preference experiments, this study focused on the predation by the non-indigenous Japanese brush-clawed shore crab, Hemigrapsus takanoi, between the native gammarid Gammarus duebeni and the analogous non-indigenous Gammarus tigrinus. Although H. takanoi showed subtle differences in its functional response type between the two prey species, its preferences across their environmental frequencies were not strongly influenced by the prey invasion scenario. The findings highlight the need for a comprehensive understanding of interactions in ecosystems with multiple NIS, offering fresh insights into complex feeding interactions within marine environments.
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  • 189
    Publication Date: 2024-02-23
    Description: The past ∼200 million years of Earth's geomagnetic field behavior have been recorded within oceanic basalts, many of which are only accessible via scientific ocean drilling. Obtaining the best possible paleomagnetic measurements from such valuable samples requires an a priori understanding of their magnetic mineralogies when choosing the most appropriate protocol for stepwise demagnetization experiments (either alternating field or thermal). Here, we present a quick, and non‐destructive method that utilizes the amplitude‐dependence of magnetic susceptibility to screen submarine basalts prior to choosing a demagnetization protocol, whenever conducting a pilot study or other detailed rock‐magnetic characterization is not possible. We demonstrate this method using samples acquired during International Ocean Discovery Program Expedition 391. Our approach is rooted in the observation that amplitude‐dependent magnetic susceptibility is observed in basalt samples whose dominant magnetic carrier is multidomain titanomagnetite (∼TM 60–65 , (Ti 0.60–0.65 Fe 0.35–0.40 )Fe 2 O 4 ). Samples with low Ti contents within titanomagnetite or samples that have experienced a high degree of oxidative weathering do not display appreciable amplitude dependence. Due to their low Curie temperatures, basalts that possess amplitude‐dependence should ideally be demagnetized either using alternating fields or via finely‐spaced thermal demagnetization heating steps below 300°C. Our screening method can enhance the success rate of paleomagnetic studies of oceanic basalt samples. Plain Language Summary Oceanic basalts are ideal recorders of the Earth's magnetic field. To decipher magnetic histories recorded in rocks, paleomagnetists need to isolate the magnetization directions and intensities within rocks by one of two possible methods. One method typically involves progressively heating the samples to high temperatures. The other method involves exposing samples to alternating magnetic fields with increasing peak field intensities. Both of these methods are ultimately destructive to the original magnetization preserved within rocks. However, without knowledge of a given rock's magnetic mineralogy, randomly choosing thermal or alternating field demagnetization methods may result in high failure rates. We developed a pre‐screening method to help decide which cleaning method will likely be more successful for a given sample based on low‐field magnetic susceptibility measurements. These measurements do not affect the original magnetic information recorded in a rock, thereby permitting subsequent paleomagnetic studies on the same sample. Our technique can be performed as rapidly as 2 min per sample, is non‐destructive, and does not require complicated sample preparation. Key Points Paleomagnetic studies utilize either alternating field or thermal demagnetization, but it is difficult to choose the best protocol a priori Amplitude‐dependence of magnetic susceptibility measurements permits preliminary magnetic mineralogy characterization in submarine basalts Rapid amplitude‐dependence measurements may aid in deciding upon the best demagnetization protocol for submarine basalt samples
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  • 190
    Publication Date: 2024-02-23
    Description: Marginal seas influenced by large rivers are characterized by complex hydrodynamic and organic matter cycling processes. However, the impacts of hydrodynamics on the composition and reactivity of particulate organic matter (POM) remain unclear. Here we conducted a comprehensive study on the bulk, molecular and biological properties of suspended POM in the Changjiang Estuary and adjacent area subjected to strong currents, eddies as well as typhoons during spring and autumn. D/L‐enantiomers of particulate amino acids (PAA) were analyzed to evaluate the bioreactivity of POM and quantify bacterial‐derived organic carbon. We found that POM bioavailability as indicated by carbon‐normalized yields of PAA (PAA‐C%) reflected the ecosystem productivity. Relatively high PAA‐C% values (20−35%) were observed in productive areas influenced by Changjiang River plume, cyclonic eddies and typhoons, likely related to the enhanced nutrient availability arising from hydrodynamic processes. In contrast, the oligotrophic Taiwan Warm Current‐influenced regions featured relatively low POM bioavailability (PAA‐C% 〈 10%) despite typhoons facilitating water mixing. The PAA‐C% values showed a significant positive correlation with extracellular enzyme activity, indicating that bioavailable POM can rapidly stimulate heterotrophic transformation. Hot spots of elevated bioavailable POM showed high contributions of bacterial organic carbon. A large portion (∼2/3) of bacterial organic carbon was present in the form of bacterial detritus, suggesting that patches of these biological hot spots represent important sites of carbon sequestration. Together, our findings indicate that fresh POM production is largely controlled by nutrient supply driven by hydrodynamic processes, with important implications for carbon sequestration in the dynamic ocean margins. Plain Language Summary Marginal seas are subject to complex hydrodynamic processes and play an important role in carbon sequestration. Disentangling the linkages between hydrodynamics and organic carbon reactivity and composition is crucial to understanding the regional carbon cycle. Here we collected suspended particulate organic matter (POM) in the Changjiang Estuary and adjacent coastal areas. Based on the biomarker D/L‐amino acids, we assessed the bioavailability of POM and quantified the organic carbon originating from bacteria. We found that high bioactivity of POM occurred in productive Changjiang River plume, cyclonic eddy, and typhoon influenced areas. These hydrodynamic processes appear to increase nutrient availability, therefore promoting phytoplankton growth. Bioavailable POM can rapidly stimulate heterotrophic activity and facilitate the transformation of algal‐derived organic carbon to bacterial detritus, thus contributing to carbon sequestration. Our findings suggest that the production of bioavailable POM is largely controlled by hydrodynamically driven nutrient supply. Key Points We use D/L‐amino acids to assess the bioreactivity and bacterial origins of particulate organic matter (POM) in the dynamic Changjiang Estuary and adjacent area High bioavailability of POM occurs in productive regions affected by Changjiang River plume, cyclonic eddies and typhoons Hot spots of bioavailable POM represent important sites for carbon sequestration
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  • 191
    Publication Date: 2024-02-23
    Description: Octocorals (Cnidaria: Anthozoa) have a global distribution and form benthic assemblages along the depth gradient, from shallow to deep waters. They often occur below SCUBA diving limits, where they can become dominant habitat builders and aggregate different taxa. During a cruise in February 2023, one octocoral specimen was collected at 1453 m depth at Kebrit Deep, in the northern Saudi Arabian Red Sea axis, an area with extremely high temperature and salinity profiles at depth. Morphological analysis coupled with DNA barcoding using two mitochondrial markers ( COI and mtMuts ), revealed that the coral belongs to Acanthogorgia , a genus of azooxanthellate octocorals known to occur from 3 to 2300 m depths in cold, temperate and tropical waters. In the Red Sea, the genus was previously only known from shallower waters. Hence, we report the deepest record of the genus Acanthogorgia from the warm and saline Red Sea basin. This finding provides novel insights on deep-water octocoral diversity in the Red Sea, a still scantily explored area of the world, while emphasizing the need for further explorations at depth.
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  • 192
    Publication Date: 2024-02-23
    Description: Geodetic data in plate boundary zones reflect the accrual of tectonic strain and stress, which will ultimately be released in earthquakes, and so they can provide valuable insights into future seismic hazards. To incorporate geodetic measurements of contemporary deformation into the 2022 revision of the New Zealand National Seismic Hazard Model 2022 (NZ NSHM 2022), we derive a range of strain-rate models from published interseismic Global Navigation Satellite Systems velocities for New Zealand. We calculate the uncertainty in strain rate excluding strain from the Taupō rift–Havre trough and Hikurangi subduction zone, which are handled separately, and the corresponding moment rates. A high shear strain rate occurs along the Alpine fault and the North Island dextral fault belt, as well as the eastern coast of the North Island. Dilatation rates are primarily contractional in the South Island and less well constrained in the North Island. Total moment accumulation derived using Kostrov-type summation varies from 0.64 to 2.93×1019 N·m/yr depending on method and parameter choices. To account for both aleatory and epistemic uncertainty in the strain-rate results, we use four different methods for estimating strain rate and calculate various average models and uncertainty metrics. The maximum shear strain rate is similar across all methods, whereas the dilatation rate and overall strain rate style differ more significantly. Each method provides an estimate of its own uncertainty propagated from the data uncertainties, and variability between methods provides an additional estimate of epistemic uncertainty. Epistemic uncertainty in New Zealand tends to be higher than the aleatory uncertainty estimates provided by any single method, and epistemic uncertainty on dilatation rate exceeds the aleatory uncertainty nearly everywhere. These strain-rate models were provided to the NZ NSHM 2022 team and used to develop fault-slip deficit rate models and scaled seismicity rate models.
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  • 193
    Publication Date: 2024-02-23
    Description: Key Points: - Freshwater input has significantly contributed to the surface warming at the peak of the 1995 Benguela Niño - Anomalously high river discharge and precipitation increased stratification and reduced turbulent heat loss by creating barrier layers - Combination of high freshwater input and strong poleward surface current might play a role in temperature variability off Angola Benguela Nino events are characterized by strong warm sea surface temperature (SST) anomalies off the Angolan and Namibian coasts. In 1995, the strongest event in the satellite era took place, impacting fish availability in both Angolan and Namibian waters. In this study, we use direct observations, satellite data, and reanalysis products to investigate the impact that the up-until-now unnoticed mechanism of freshwater input from Congo River discharge (CRD) and precipitation had on the evolution of the 1995 Benguela Nino. In the onset phase of the event, anomalous rainfall in November/December 1994 at around 6 degrees S, combined with a high CRD, generated a low salinity plume. The plume was advected into the Angola-Namibia region in the following February/March 1995 by an anomalously strong poleward surface current generated by the relaxation of the southerly winds and shifts in the coastal wind stress curl. The presence of this low surface salinity anomaly of about -2 psu increased ocean stability by generating barrier layers, thereby reducing the turbulent heat loss, since turbulent mixing acted on a weak vertical temperature gradient. A mixed layer heat budget analysis demonstrates that southward advection of Angolan waters drove the warming at the onset, while reduced mixing played the main role at the event's peak. We conclude that a freshwater input contributed to the SST increase in this exceptionally strong event and suggest that this input can influence the SST variability in Angola-Namibia waters through a combination of high CRD, precipitation, and the presence of a strong poleward surface current. Benguela Nino events are characterized by excessive warming of the sea surface temperature off the Angolan and Namibian coasts. One of the strongest-ever recorded warm events dates back to 1995, impacting fish availability in both Angolan and Namibian waters. In our research, we investigate if freshwater from rain and from the Congo River could have impacted the evolution of this 1995 Benguela Nino. In the event's early stage, high precipitation and river discharge generated a low salinity pool at the Congo River mouth, which in February/March 1995 was taken to the south by an exceptionally strong surface current, generated by changes in wind strength and direction at the African coast. This low sea surface salinity in a shallow layer in the upper meters of the ocean increased the ocean's stability. As the stabilized waters diminished the usual mixing from the depths below which cools down the surface waters, it contributed to an increase in warming in the surface layer of the ocean. We conclude that the warming of the surface waters in the region was indeed influenced by the combination of high precipitation and high Congo River discharge with a strong surface current toward the south. Freshwater input has significantly contributed to the surface warming at the peak of the 1995 Benguela Nino Anomalously high river discharge and precipitation increased stratification and reduced turbulent heat loss by creating barrier layers Combination of high freshwater input and strong poleward surface current might play a role in temperature variability off Angola
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  • 194
    Publication Date: 2024-02-23
    Description: Iodine cycling in the ocean is closely linked to productivity, organic carbon export, and oxygenation. However, iodine sources and sinks at the seafloor are poorly constrained, which limits the applicability of iodine as a biogeochemical tracer. We present pore water and solid phase iodine data for sediment cores from the Peruvian continental margin, which cover a range of bottom water oxygen concentrations, organic carbon rain rates and sedimentation rates. By applying a numerical reaction‐transport model, we evaluate how these parameters determine benthic iodine fluxes and sedimentary iodine‐to‐organic carbon ratios (I:C org ) in the paleo‐record. Iodine is delivered to the sediment with organic material and released into the pore water as iodide (I − ) during early diagenesis. Under anoxic conditions in the bottom water, most of the iodine delivered is recycled, which can explain the presence of excess dissolved iodine in near‐shore anoxic seawater. According to our model, the benthic I − efflux in anoxic areas is mainly determined by the organic carbon rain rate. Under oxic conditions, pore water dissolved I − is oxidized and precipitated at the sediment surface. Much of the precipitated iodine re‐dissolves during early diagenesis and only a fraction is buried. Particulate iodine burial efficiency and I:C org burial ratios do increase with bottom water oxygen. However, multiple combinations of bottom water oxygen, organic carbon rain rate and sedimentation rate can lead to identical I:C org , which limits the utility of I:C org as a quantitative oxygenation proxy. Our findings may help to better constrain the ocean's iodine mass balance, both today and in the geological past. Key Points The impact of early diagenesis on benthic iodine fluxes and iodine burial was quantitatively evaluated using a reaction‐transport model Dissolved iodine anomalies in the water column are indicative of benthic efflux from anoxic sediments with high organic carbon turnover Not only bottom water oxygen but also organic carbon delivery and sedimentation rate determine sedimentary iodine‐to‐organic carbon ratios
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  • 195
    Publication Date: 2024-02-23
    Description: The understanding of silicate weathering and its role as a sink for atmospheric CO 2 is important to get a better insight into how the Earth shifts from warm to cool climates. The lithium isotope composition (δ 7 Li) of marine carbonates can be used as a proxy to track the past chemical weathering of silicates. A high‐resolution δ 7 Li record would be helpful to evaluate the role of silicate weathering during the late Cretaceous climate cooling. Here, we assess chalk as a potential archive for reconstructing Late Cretaceous seawater Li isotope composition by comparing Maastrichtian chalk from Northern Germany (Hemmoor, Kronsmoor) to a Quaternary coccolith ooze from the Manihiki Plateau (Pacific Ocean) as a lithological analog to modern conditions. We observe a negative offset of 3.9 ± 0.6‰ for the coccolith ooze relative to the modern seawater Li isotope composition (+31.1 ± 0.3‰; 2SE; n = 54), a value that falls in the range of published offsets for modern core‐top samples and for brachiopod calcite. Further, the negative offset between the Li isotope compositions of Manihiki coccolith ooze and modern planktonic foraminifera is 2.3 ± 0.6‰. Although chalk represents a diagenetically altered modification of pelagic nannofossil ooze, manifested by changes in the composition of trace elements, we observe a consistent offset of Li isotope data between Maastrichtian chalk and Maastrichtian planktonic foraminiferal data (−1.4 ± 0. 5‰) that lies within the uncertainty of modern values. We therefore suggest that chalk can be used as a reliable archive for δ 7 Li reconstructions. Key Points Chalk is a reliable archive for the Li isotope composition of seawater Coccolith ooze has a negative offset of 3.9 ± 0.6‰ from modern seawater for Li isotope ratios The estimated mean value for the late Maastrichtian seawater Li isotope composition is +27.5 ± 1.0‰
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  • 196
    Publication Date: 2024-02-23
    Description: Compositional variations of amphibole stratigraphically recovered from multiple eruptions at a given volcano have a great potential to archive long-term magmatic processes in its crustal plumbing system. Calcic amphibole is a ubiquitous yet chemically and texturally diverse mineral at Mount St. Helens (MSH), where it occurs in dacites and in co-magmatic enclaves throughout the Spirit Lake stage (last ~4000 years of eruptive history). It forms three populations with distinct geochemical trends in key major and trace elements, which are subdivided into a high-Al (11–14.5 wt% Al2O3), a medium-Al (10–12.5 wt% Al2O3), and a low-Al (7.5–10 wt% Al2O3) amphibole population. The oldest investigated tephra record (Smith Creek period, 3900–3300 years BP) yields a bimodal amphibole distribution in which lower-crustal, high-Al amphibole cores (crystallized dominantly from basaltic andesite to andesite melts) and upper-crustal, low-Al amphibole rims (crystallized from rhyolitic melt) document occasional recharge of a shallow silicic mush by a more mafic melt from a lower-crustal reservoir. The sudden appearance of medium-Al amphiboles enriched in incompatible trace elements in eruptive periods younger than 2900 years BP is associated with a change in reservoir conditions toward hotter and drier magmas, which indicates recharge of the shallow silicic reservoir by basaltic melt enriched in incompatible elements. Deep-crystallizing, high-Al amphibole, however, appears mostly unaffected by such incompatible-element-enriched basaltic recharge, suggesting that these basalts bypass the lower crustal reservoir. This could be the result of the eastward offset position of the lower crustal reservoir relative to the upper crustal storage zone underneath the MSH edifice. Amphibole has proven to be a sensitive geochemical archive for uncovering storage conditions of magmas at MSH. In agreement with geophysical observations, storage and differentiation have occurred in two main zones: an upper crustal and lower crustal reservoir (the lower one being chemically less evolved). The upper crustal silicic reservoir, offset to the west of the lower crustal reservoir, has captured compositionally unusual mafic recharge (drier, hotter, and enriched in incompatible trace elements in comparison to the typical parental magmas in the region), resulting in an increased chemical diversity of amphiboles and their carrier intermediate magmas, in the last ~3000 years of MSH’s volcanic record.
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  • 197
    Publication Date: 2024-02-26
    Description: This study investigates extreme wet and dry conditions over the humid tropics and their connections to the variability of the tropical ocean basins using observations and a multi-model ensemble of 24 state-of-the-art coupled climate models, for the 1930–2014 period. The extreme wet (dry) conditions are consistently linked to Central Pacific La Niña (Eastern Pacific El Niño), the weakest being the Congo basin, and homogeneous patterns of sea surface temperature (SST) variability in the tropical Indian Ocean. The Atlantic exhibits markedly varying configurations of SST anomalies, including the Atlantic Niño and pan-Atlantic decadal oscillation, with non-symmetrical patterns between the wet and dry conditions. The oceanic influences are associated with anomalous convection and diabatic heating partly related to variations in the strength of the Walker Circulation. The observed connection between the Amazon basin, as well as the Maritime continent, and the Indo-Pacific variability are better simulated than that of the Congo basin. The observed signs of the Pacific and Indian SST anomalies are reversed for the modelled Congo basin extreme conditions which are, instead, tied to the Atlantic Niño/Niña variability. This Atlantic–Congo basin connection is related to a too southerly location of the simulated inter-tropical convergence zone that is associated with warm SST biases over the Atlantic cold tongue. This study highlights important teleconnections and model improvements necessary for the skillful prediction of extreme precipitation over the humid tropics.
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  • 198
    Publication Date: 2024-02-26
    Description: Key Points: - North Atlantic biases are alleviated by an eddying nested ocean configuration embedded in a global climate model, FOCI-VIKING10 - It is indicated that reduction of the North Atlantic biases could improve the representation of NAO sub-decadal (8 years) variability - For detecting weak external imprints with limited computational resources, an ensemble with a coarse-resolution model is favorable Increasing the horizontal resolution of an ocean model is frequently seen as a way to reduce the model biases in the North Atlantic, but we are often limited by computational resources. Here, a two-way nested ocean model configuration (VIKING10) that consists of a high-resolution (1/10°) component and covers the northern North Atlantic, is embedded in a 1/2° ocean grid as part of the global chemistry-climate model, FOCI (called FOCI-VIKING10). This configuration yields a significantly improved path of the North Atlantic current (NAC), which here reduces the North Atlantic cold bias by ∼50%. Compared with the coarse-resolution, non-eddying model, the improved thermal state of upper ocean layers and surface heat fluxes in a historical simulation based on FOCI-VIKING10 are beneficial for simulating the subdecadal North Atlantic Oscillation (NAO) variability (i.e., a period of 8 years). A northward drift of the NAO-forced ocean thermal anomalies as seen in observations and the eddying FOCI-VIKING10, provide a lagged ocean feedback to the NAO via changes in the net surface heat flux, leading to the NAO periodicity of 8 years. This lagged feedback and the 8 years variability of the NAO cannot be captured by the non-eddying standard FOCI historical simulation. Furthermore, the argumentative responses of the North Atlantic to the 11-year solar cycle are re-examined in this study. The reported solar-induced NAO-like responses are confirmed in the 9-member ensemble mean based on FOCI but with low robustness among individual members. A lagged NAO-like response is only found in the nested eddying simulation but absent from the non-eddying reference simulation, suggesting North Atlantic biases importantly limit climate model capability to realistically solar imprints in North Atlantic climate.
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  • 199
    Publication Date: 2024-02-26
    Description: Abstract
    Description: To enhance the EU's economic autonomy, feasible options for local sourcing of critical raw materials that would allow for shorter supply routes along with ethical and responsible value chains are under contemplation. Social acceptance of mining in Europe is, however, low, and the establishment of new mining sites faces strong public opposition. Therefore, innovative solutions for the production of primary raw materials need to be developed. A new idea for raw material extraction is the extraction of essential elements from geothermal fluids. Deep geothermal fluids, increasingly used for energy production, often contain high concen-trations of dissolved ions and gases in commercially interesting concentrations. The EU-funded project CRM-geothermal aims to develop new technologies to extract these highly relevant elements, including helium, during geothermal production cycles. In this way, an environmentally friendly and socially acceptable exploration and exploitation method could be deployed. One aim of the CRM-geothermal project is to gain an overview of the actual quantities of critical raw materials in various geothermal fluids in Europe by taking and analyzing fluid samples. In Turkey for instance, classical high enthalpy (volcanic) systems exist, which are representative for many geothermal areas worldwide. The sites are located at the edges of tectonic plates and close to areas undergoing volcanic activity. The brines are mixed with seawater and circulate in the deeper crust. The data publication contains analyses results of three gas samples from Tuzla, two samples from Seferihisar geothermal power plant and one sample from the Dikili geothermal field in Turkey, taken in 2023 as part of the CRM-geothermal project.
    Type: Dataset , Dataset
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  • 200
    Publication Date: 2024-02-27
    Description: Highlights: • The interactions between vortices in a four-vortex flow field using a rotating water tank. • Driven by the strain field, non-ideal vortices stretch along the centerline, and manifest an asymmetric stretching pattern. • Non-ideal vortices disperse vorticity, accumulate filaments, and exhibit distinctive variations in anti-symmetric vorticity distribution, impacting respective merging efficiency. Abstract: Oceanic vortex merging is an important physical process for the vortex evolution and its impact on marine environment. However, limitation of the in-situ oceanic observational data of vortex merging inhabits its better understanding. This study investigates the interactions between non-ideal vortices in a four-vortex flow field in a rotating tank. We examine the merging stages of anticyclonic vortices, influenced by two other cyclonic vortices and their respective dynamical behaviors and quantify the effects of merging on vortex characteristics. The results indicate a strong shear flow between two counter-rotating vortices, which accelerates the motion of the anticyclonic vortex, while cyclonic ones exhibit greater stability. Subsequently, different stages of non-ideal vortex merging in a co-rotating framework are defined, primarily the encircling stage, rapid approaching stage, and merging vortex stage. In addition, we quantify and compare variations in morphological parameters and anti-symmetric vorticity distribution of non-ideal vortices across these stages. The stretching of vortices primarily occurs along the line connecting their centers due to the strain field exerted by neighboring vortices, resulting in an asymmetric stretching pattern in the interactions among non-ideal vortices. Furthermore, during the merging process, non-ideal vortices disperse vorticity outward and accumulate vortex filaments in the surrounding environment, leading to distinctive variations in anti-symmetric vorticity distribution, affecting their respective merging efficiency.
    Type: Article , PeerReviewed
    Format: text
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