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  • 1
    Publication Date: 2024-02-29
    Description: In dieser Abschrift der Bergordnung wurden zur besseren Übersicht noch einmal die 23 Paragrafen der Kremnitzer Bergordnung von 1492 aufgeführt. Im Jahr 1504 wurden drei Paragrafen hinzugefügt. Im Jahr 1537 erließ Oberkammergrafen Bernhard Behem weitere 21 Paragrafen. Der Bergmeister wurde hier zur obersten Amtsperson im Revier erklärt und entsprechend vereidigt. Beschrieben wurden ausführlich seine Rechte und Pflichten.
    Description: source
    Keywords: Slowakei ; Ungarn ; Kremnitz/Kremnica ; Silberbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 20
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  • 2
    Publication Date: 2024-02-21
    Description: Diese Bergordnung, erlassen im Jahr 1520, wiederholt die 103 Paragrafen der Annaberger Bergordnung aus dem Jahr 1509 sowie die dort aufgeführten Eide. Zusätzlich wurden ihr weitere 32 Paragrafen hinzugefügt, die in der Zeit zwischen 1510 und 1519 erlassen wurden. Mit dem Druck der neuen Bergordnung wollte man den Text der alten Bergordnung und die inzwischen erlassenen Paragrafen in einem Buch zusammenfassen. Obwohl auch in den neuen Paragrafen immer wieder Bezug auf Annaberg genommen wurde, war es aber schon in der Einleitung deutlich, dass diese Bergordnung für die gesamte Grafschaft Sachsen Gültigkeit hatte. Ausgenommen, waren auch hier die Bergwerke in Freiberg.
    Description: source
    Keywords: Herzog Georg von Sachsen ; Annaberg ; Freiberg ; Dresden ; Sachsen ; Silberbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 47
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  • 3
    Publication Date: 2024-02-07
    Description: Diese Bergordnung für Schemnitz/Banská Štiavnica wurde im Jahr 1513 veröffentlicht. Sie wiederholt die Bergordnung von Schemnitz aus dem Jahr 1466. Danach werden neun weitere Artikel hinzugefügt. Sie präzisieren die Rechte der einzelnen Gruben beim Anschaaren von zwei Gängen und das Prozedere der Vermessung dieser Gänge.
    Description: source
    Keywords: König Bela IV. von Ungarn ; König Vladislav II. von Böhmen und Ungarn ; Slowakei ; Ungarn ; Schemnitz/Banská Štiavnica ; Silberbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 11
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  • 4
    Publication Date: 2024-01-04
    Description: Um das Jahr 1540 erließen die Herren zu Franckenstein und die Herren von Heusenstamm eine Bergordnung für die Bergwerke in Espa im Taunus. Als Vorlage für diese Bergordnung diente eine Abschrift der Bergordnung der Grafen von Hohnstein vom 3. Februar 1528 für die Bergwerke in der Grafschaft Lauterberg. Es wurden aber nicht alle Paragrafen übernommen. Es fehlen eine Abschlusserklärung mit den Anwendungsbestimmungen sowie ein Datum zum Erlass dieser Bergordnung. Wahrscheinlich handelt es sich bei dieser Bergordnung um einen unveröffentlichten Entwurf. Eine weitere Bergordnung für dieses Gebiet ist aber nicht bekannt.
    Description: source
    Keywords: Herren zu Frankenstein ; Herren zu Heusenstamm ; Espa (Langgöns) ; Silberbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 21
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  • 5
    Publication Date: 2024-01-11
    Description: Im Jahr 1529 erließ Herzog Georg von Sachsen eine neue Bergordnung für die Bergwerke in Freiberg. Im Gegensatz zum Erzgebirge, wo die 1509 erlassene Annaberger Bergordnung allgemeine Gültigkeit erlangt hatte, beharrte der Rat zu Freiberg auf ein in Teilen eigenständiges Bergrecht für die Stadt. Die Freiberger Bergordnung wurde vom Rat zu Freiberg gemeinsam mit den Gewerken im Beisein von Herzog Georg erstellt. In den 38 Artikeln wurde im Wesentlichen der Inhalt der Annaberger Bergordnung wiederholt. Neu für Freiberg war die Abrechnung und Austeilung sowie Veranschlagung der Zubuße in einem festgesetzten Zeitraum. Im Gegensatz zur Abrechnung in vier Quartalen, wie es im Erzgebirge seit 1476 Vorschrift war, erfolgte diese in Freiberg zu drei Terminen im Jahr. Weiterhin wurde darauf verwiesen, dass die Freiberger Bergbeamten die Eide analog der Annaberger Bergordnung leisten sollten.
    Description: source
    Keywords: Herzog Georg von Sachsen ; Freiberg ; Annaberg ; Silberbergbau ; Sachsen ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 11
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  • 6
    Publication Date: 2024-04-25
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Mercury is the smallest and innermost planet of our solar system and has a dipole‐dominated internal magnetic field that is relatively weak, very axisymmetric and significantly offset toward north. Through the interaction with the solar wind, a magnetosphere is created. Compared to the magnetosphere of Earth, Mercury's magnetosphere is smaller and more dynamic. To understand the magnetospheric structures and processes we use in situ MESSENGER data to develop further a semi‐empiric model of the magnetospheric magnetic field, which can explain the observations and help to improve the mission planning for the BepiColombo mission en‐route to Mercury. We present this semi‐empiric KTH22‐model, a modular model to calculate the magnetic field inside the Hermean magnetosphere. Korth et al. (2015, 〈ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1002/2015JA021022"〉https://doi.org/10.1002/2015JA021022〈/ext-link〉, 2017, 〈ext-link ext-link-type="uri" xlink:href="https://doi.org/10.1002/2017gl074699"〉https://doi.org/10.1002/2017gl074699〈/ext-link〉) published a model, which is the basis for the KTH22‐model. In this new version, the representation of the neutral sheet current magnetic field is more realistic, because it is now based on observations rather than ad‐hoc assumptions. Furthermore, a new module is added to depict the eastward ring shaped current magnetic field. These enhancements offer the possibility to improve the main field determination. In addition, analyzing the magnetic field residuals allows us to investigate the field‐aligned currents and their possible dependencies on external drivers. We see increasing currents under more disturbed conditions inside the magnetosphere, but no clear dependence on the z‐component of the interplanetary magnetic field nor on the magnetosheath plasma 〈italic〉β〈/italic〉.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We present a revised model of Mercury's magnetospheric magnetic field〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The model now includes an eastward ring shaped current and the neutral sheet current is calculated more precisely with Biot Savart's law〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The strength of the field‐aligned currents increases with higher magnetic activity〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: German Ministerium für Wirtschaft und Klimaschutz and the German Zentrum für Luft‐ und Raumfahrt
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: ESA Research Fellowship
    Keywords: ddc:523 ; Mercury ; magnetosphere ; field‐aligned currents ; modeling ; neutral sheet current ; planetary dipole moment
    Language: English
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  • 7
    Publication Date: 2024-04-25
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Recent observations and modeling increasingly reveal the key role of cold pools in organizing the convective cloud field. Several methods for detecting cold pools in simulations exist, but are usually based on buoyancy fields and fall short of reliably identifying the active gust front. The current cold pool (CP) detection and tracking algorithm (CoolDeTA), aims to identify cold pools and follow them in time, thereby distinguishing their active gust fronts and the “offspring” rain cells generated nearby. To accomplish these tasks, CoolDeTA utilizes a combination of thermodynamic and dynamical variables and examines the spatial and temporal relationships between cold pools and rain events. We demonstrate that CoolDeTA can reconstruct CP family trees. Using CoolDeTA we can contrast radiative convective equilibrium (RCE) and diurnal cycle CP dynamics, as well as cases with vertical wind shear and without. We show that the results obtained are consistent with a conceptual model where CP triggering of children rain cells follows a simple birth rate, proportional to a CP's gust front length. The proportionality factor depends on the ambient atmospheric stability and is lower for RCE, in line with marginal stability as traditionally ascribed to the moist adiabat. In the diurnal case, where ambient stability is lower, the birth rate thus becomes substantially higher, in line with periodic insolation forcing—resulting in essentially run‐away mesoscale excitations generated by a single parent rain cell and its CP.〈/p〉
    Description: Plain Language Summary: Cold pools are cooled air masses below thunderstorm clouds, produced when rain evaporates underneath such clouds. Cold pools are important, as they produce strong gusts and have been associated with clumping of rain cells, whereby heavy rainfall over relatively small areas could be generated—with implications for flooding. The current work describes a method that helps identify such cold pools in computer simulation data. In contrast to earlier methods, we here show that the interaction between a CP and its surroundings can be reconstructed by the method. We show that this identification works under a range of contexts, such as when horizontal wind is applied in the simulations or when the surface temperature is not constant—as might often be the case over a land surface. The identification reveals interesting dynamical effects, such as that in some cases, cold pools can kick‐start a form of chain reaction, by which “rain cell children” of it give rise to additional cold pools that again produce children, and so forth. The dynamics revealed is in line with expectations of widespread, so‐called mesoscale convective systems over land, whereas over an ocean surface the dynamics is much less explosive.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Our CoolDeTA algorithm reliably detects and tracks cold pools and their causal chains〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉We propose a simple conceptual model which reproduces the cascade‐like mesoscale cold pool dynamics identified by CoolDeTA〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉CoolDeTA opens for new studies into the dynamics of convective self‐organization through cold pools〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Villum Fonden http://dx.doi.org/10.13039/100008398
    Description: European Research Council http://dx.doi.org/10.13039/501100000781
    Description: Novo Nordisk Foundation Interdisciplinary Synergy Program
    Description: Scientific Steering Committee
    Description: https://doi.org/10.5281/zenodo.6513224
    Description: https://github.com/Shakiro7/coldPool-detection-and-tracking
    Description: https://doi.org/10.5281/zenodo.10115957
    Description: https://doi.org/10.7717/peerj.453
    Keywords: ddc:551.6 ; cold pools ; detection ; tracking ; cloud resolving simulation ; convective organization
    Language: English
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  • 8
    Publication Date: 2024-04-25
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The seasonal deposition and sublimation of CO〈sub〉2〈/sub〉 constitute a major element in the Martian volatile cycle. Here, we propose to use the shadow variations of the ice blocks at the foot of the steep scarps of the North Polar Layered Deposits (NPLD) to infer the vertical evolution of the seasonal deposits. We conduct an experiment at a steep scarp centered at (85.0°N, 151.5°E). We assume that no snowfall remains on top of the selected ice blocks, the frost ice layer is homogeneous around the ice blocks and their surroundings, and no significant moating is present. We show that the average thickness of the seasonal deposits due to snowfalls in Mars Year 31 is 0.97 ± 0.13 m at Ls = 350.7° in late winter. The large depth measured makes us wonder if snowfalls are more frequent and violent than previously thought. Meanwhile, we show that the average frost thickness in Mars Year 31 reaches 0.64 ± 0.18 m at Ls = 350.7° in late winter. Combined, the total thickness of the seasonal cover in Mars Year 31 reaches 1.63 ± 0.22 m at Ls = 350.7° in late winter, continuously decreases to 0.45 ± 0.06 m at Ls = 42.8° in middle spring and 0.06 ± 0.05 m at Ls = 69.6° in late spring. These estimates are up to 0.8 m lower than the existing Mars Orbiter Laser Altimeter results during the spring. Meanwhile, we observe that snow in the very early spring of Mars Year 36 can be 0.36 ± 0.13 m thicker than that in Mars Year 31. This study demonstrates the dynamics of the Martian climate and emphasizes the importance of its long‐term monitoring.〈/p〉
    Description: Plain Language Summary: Like Earth, Mars also has seasons. Up to one third of the atmospheric CO〈sub〉2〈/sub〉 annually exchanges with the polar surface through seasonal deposition/sublimation processes. Deposition can be either atmospheric precipitation as snowfall or direct surface condensation as frost. At the steep scarps of the North Polar Layered Deposits (NPLD), fractured ice fragments can detach and fall to form ice blocks. We propose to use variations in the shadows of these ice blocks, observed in the High Resolution Imaging Science Experiment images, to infer the thickness evolution of the seasonal deposits. We make reasonable assumptions about the distribution of snowfall and frost around the ice blocks and their surroundings, which allow us to separately measure the thickness of snowfall and frost. Meanwhile, we introduce a novel approach that allows us to estimate the thickness of the seasonal deposits during late winter and early spring when image quality is insufficient. This approach also enables us to peer into the interannual thickness variations of snowfall. We carry out a successful experiment at a scarp centered at (85.0°N, 151.5°E). The obtained thickness measurements demonstrate the dynamics of the Martian volatile cycling and can be used to constrain the Martian climate models.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We propose to examine the shadow variations of the ice blocks at the Martian polar region to infer the thickness of the seasonal deposits〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Maximum thickness of the seasonal deposits at the study scarp in MY31 is 1.63 ± 0.22 m to which snowfalls contribute 0.97 ± 0.13 m〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Seasonal deposits at the study scarp are up to 0.8 m shallower than previous measurements during spring〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: HX, LML, and PJG
    Description: https://doi.org/10.17189/1520303
    Description: https://doi.org/10.17632/5yy475dbry.1
    Description: https://doi.org/10.17632/x953mzxxvv.1
    Description: https://doi.org/10.17189/1520101
    Description: http://www.msss.com/moc_gallery/2001
    Keywords: ddc:523 ; Mars ; seasonal polar caps ; thickness ; ice blocks ; HiRISE ; CO2
    Language: English
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  • 9
    Publication Date: 2024-04-25
    Description: 〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉〈italic〉INSIGHT〈/italic〉 is a Python‐based software tool for processing and reducing 2D grazing‐incidence wide‐ and small‐angle X‐ray scattering (GIWAXS/GISAXS) data. It offers the geometric transformation of the 2D GIWAXS/GISAXS detector image to reciprocal space, including vectorized and parallelized pixel‐wise intensity correction calculations. An explicit focus on efficient data management and batch processing enables full control of large time‐resolved synchrotron and laboratory data sets for a detailed analysis of kinetic GIWAXS/GISAXS studies of thin films. It processes data acquired with arbitrarily rotated detectors and performs vertical, horizontal, azimuthal and radial cuts in reciprocal space. It further allows crystallographic indexing and GIWAXS pattern simulation, and provides various plotting and export functionalities. Customized scripting offers a one‐step solution to reduce, process, analyze and export findings of large 〈italic〉in situ〈/italic〉 and 〈italic〉operando〈/italic〉 data sets.〈/p〉
    Keywords: ddc:548 ; grazing‐incidence X‐ray scattering ; time‐resolved studies ; in situ studies ; operando studies ; computer programs
    Language: English
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  • 10
    Publication Date: 2024-04-25
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Dansgaard‐Oeschger (D‐O) climate variability during the last glaciation was first evidenced in ice cores and marine sediments, and is also recorded in various terrestrial paleoclimate archives in Europe. The relative synchronicity across Greenland, the North Atlantic and Europe implies a tight and fast coupling between those regions, most probably effectuated by an atmospheric transmission mechanism. In this study, we investigated the atmospheric changes during Greenland interstadial (GI) and stadial (GS) phases based on regional climate model simulations using two specific periods, GI‐10 and GS‐9 both around 40 ka, as boundary conditions. Our simulations accurately capture the changes in temperature and precipitation as reconstructed by the available proxy data. Moreover, the simulations depict an intensified and southward shifted eddy‐driven jet during the stadial period. Ultimately, this affects the near‐surface circulation toward more southwesterly and cyclonic flow in western Europe during the stadial period, explaining much of the seasonal climate variability recorded by the proxy data, including oxygen isotopes, at the considered proxy sites.〈/p〉
    Description: Plain Language Summary: The climate during the last ice age varied between colder and warmer periods on timescales ranging from hundreds to thousands of years. This variability was first detected in Greenland ice cores and marine sediment cores of the North Atlantic, as well as in continental geological records in Europe. The variation between the colder and warmer periods occur mostly simultaneously in Greenland and in Europe, which is why the atmosphere is assumed to have an important role in transferring the climate signals. We simulated two different periods of the last ice age, one colder and one warmer around 40,000 years ago, using a regional climate model. The aim was to study how the climate and atmospheric circulation changed during these two periods. We find the eddy‐driven jet over the North Atlantic intensified and shifted southward during the colder period. The jet influences the near‐surface atmospheric circulation and leads to more southwesterly and cyclonic flow in western Europe. Oxygen isotope variations observed in western European paleoclimate records may be partly explained by different, more southern moisture sources on top of changes in seasonal temperatures.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Simulated temperatures agree with proxy data; precipitation is biased but GI‐10 versus GS‐9 differences are well captured〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The stadial winter jet stream is intensified and shifted southward, consistent with dominant southwesterly/cyclonic flow in western Europe〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Oxygen isotope signal changes at western European proxy sites may be explained not only by temperature but also by varying moisture sources〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: NRDIO
    Description: AXA Research Fund http://dx.doi.org/10.13039/501100001961
    Description: https://doi.org/10.5065/1dfh-6p97
    Keywords: ddc:551.6 ; Dansgaard‐Oeschger cycle ; regional atmospheric dynamics ; regional climate modeling ; continental paleoclimate proxy ; Europe
    Language: English
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  • 11
    Publication Date: 2024-01-18
    Description: Die Bergordnung für Schemnitz/Banská Štiavnica wurde im Jahr 1466 als Anhang zum Stadtrecht im Stadtbuch (1432 begonnen) niedergeschrieben. Von den 59 Paragrafen waren nur die Paragrafen 42 bis 59 für das das Bergrecht relevant. Die Entstehungszeit der Bergordnung geht auf die Regierungszeit König Béla IV. (1235-1270) zurück. Nach der Einleitung durch König Béla IV. beschreiben die Geschworenen der Stadt die Verleihung von Gruben, die Rechte und Pflichten beim Betrieb der Bergwerke, das Stollenrecht und die Vermessung der Gruben. Im Gegensatz zu späteren Bergordnungen wurden hier nicht aufgetretene Fehlentwicklungen geregelt, sondern bereits klare gesetzliche Regelungen für den Bergbau vorgegeben.
    Description: source
    Keywords: König Béla IV. von Ungarn ; Slowakei ; Ungarn ; Schemnitz/Banská Štiavnica ; Iglau/Jihlava ; Silberbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 9
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  • 12
    Publication Date: 2024-01-28
    Description: Diese im Jahr 1536 neu verfasste Bergordnung für Freiberg, erlassen von Herzog Georg von Sachsen wiederholt die 38 Artikel der Bergordnung von 1529. Zwischen 1530 und 1536 wird sie um vier weitere Artikel, unterteilt in 24 Absätze und einen Nachsatz, erweitert. Aus den angefügten Artikeln geht hervor, das die Bergordnung von 1529 nur widerwillig umgesetzt wurde. Die alte Bergordnung wird präzisiert, ein Hüttenraiter eingeführt und der Freiberger Rat mit Nachdruck aufgefordert die Durchsetzung der Bergordnung streng zu befolgen.
    Description: source
    Keywords: Herzog Georg von Sachsen ; Freiberg ; Annaberg ; Silberbergbau ; Sachsen ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 16
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  • 13
    Publication Date: 2024-03-22
    Description: Obwohl die Wettiner das Gebiet um Berggießhübel und Gottleuba schon 1405 übernommen haben, wurde erst 1516 eine Bergordnung für den dortigen Eisenerzbergbau erlassen. In den vier Paragrafen geht es um Zustand der Bergwerke, das ordentliche Vermessen der Gruben und die Zahlung des Zehnten. Weiterhin soll der offensichtlich dauerhafte Streit zwischen den Gewerken und den Hammermeistern um Menge und Qualität des Eisensteins beendet werden.
    Description: source
    Keywords: Herzog Georg von Sachsen ; Freiberg ; Pirna ; Berggießhübel ; Bad Gottleuba ; Eger/Cheb ; Sachsen ; Eisenerzbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
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  • 14
    Publication Date: 2024-04-03
    Description: In der Bohrung Moosburg 4 wurden die Nichtkarbonate (HCl-Unlösliches; 45 Proben) der Karbonatgesteine vom Malm Alpha (Unteres Oxfordium) bis zum Malm Zeta (Oberes Tithonium) röntgendiffraktometrisch untersucht. Ziel war es, die bestehende lithostratigraphische Untergliederung genauer mineralogisch und tonmineralogisch zu untermauern, um diese in Malm-Bohrungen des Molasse-Untergrundes besser belegen zu können. Die Kombination von mineralogischen und tonmineralogischen röntgenographischen Untersuchungen der Nichtkarbonate ermöglichen es, unter Bezug zum Gamma-Log der Bohrung Moosburg SC4 eine Untergliederung in neun Einheiten (I – IX) zu definieren. Diese entspricht vom Malm Alpha bis Malm Zeta 3 weitgehend der lithostratigraphischen Unterteilung, wie sie von Meyer (1994) dokumentiert wird. Die von Meyer (1994) vorgenommene Positionierung des Malm Zeta 4-5 und die der als Purbeck definierten Schichtfolge müssen dagegen revidiert werden. Die Malm/ Purbeck-Grenze ist um 99 m ins Hangende zu legen. Damit entspricht der dort im Malm analysierte Bereich dem Untertithon und dem Obertithon. Karbonatgesteine des Purbeck wurden in der vorliegenden Studie nicht untersucht. Die Zuordnung der Einheiten I-VI zu den lithostratigraphischen Einheiten von Meyer (1994) ist gut. Es ist nur der obere Teil der Bohrung Moosburg 4 als Unteres und als Oberes Tithon neu zu definieren. Allgemein kann festgestellt werden, dass eine lithostratigraphische Untergliederung des Malm auf der Basis mineralogisch/tonmineralogischer Analysen der Nichtkarbonate erstellt werden kann. Diese Methode kann daher auch in neuen Bohrungen im Molassebecken zur Untergliederung der oberjurassischen Schichtfolge erfolgreich angewendet werden.
    Description: research
    Keywords: Ober-Jura ; Tonmineral-Stratigraphie ; Mineralostratigraphie
    Language: German
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  • 15
    Publication Date: 2024-04-03
    Description: Bergordnung für St. Joachimsthal, vom 2. August 1518. Basis dieser Bergordnung bildet die Bergordnungen für St. Annaberg vom 5. Februar 1509. Die 103 Paragraphen der Annaberger Bergordnung wurden fast wortwörtlich übernommen. Es wurde der gesamte Bergwerksbetrieb, die Arbeit der Schmelzhütten und das Gericht in St. Joachimsthal geregelt. Auch die Eide der Bergbeamten wurden übernommen. In weiteren drei Paragraphen wurden die Entlohnung der Bergleute sowie die Lohnfortzahlung und das Arztgeld nach Arbeitsunfällen aufgeführt.
    Description: source
    Keywords: Graf Stefan Schlick zu Passaun ; Konradsgrün ; Joachimsthal/Jáchymov ; Annaberg ; Marienberg ; Schneeberg ; Silberbergbau ; Böhmen ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 39
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  • 16
    Publication Date: 2024-04-03
    Description: Tiefgreifende Hangbewegungen stellen neben Muren und Lawinen, welche durch Faktoren wie Extremniederschlagsereignisse und Unterschneidungsvorgänge entstehen, eine akute Gefahr für die Bevölkerung und die Infrastruktur im alpinen Raum dar (Moser 2013). Talzuschübe, oder auch DSGSD für Deep-seated Gravitational Slope Deformation (Crosta et al. 2013), sind großflächige und tiefgreifende Hangbewegungen im alpinen Raum. Im Rahmen dieser Untersuchungen erfolgte eine ingenieurgeologische Aufnahme des Dürnbachtals bei Neukirchen am Großvenediger mit der Erstellung von Hangprofilen und der Aufnahme des Trennflächengefüges. Weiter wurde der Einfluss der beidseitigen Talzuschübe auf den Wildbach und das Murereignis nach einem Starkniederschlagsereignis am 28.07.2022 analysiert. Zuletzt wurde eine Abschätzung des Gefahrenpotentials des Dürnbachs für den Ort Neukirchen am Großvenediger erstellt.
    Description: research
    Keywords: Talzuschub ; counterscarps ; Massenbewegung ; Murgang ; Starkniederschlag ; Salzburger Land ; Österreich
    Language: German
    Type: doc-type:article
    Format: 41
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  • 17
    Publication Date: 2024-04-19
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Heavy‐mineral suites are used widely in sandstone provenance and are key when connecting source and sink. When characterizing provenance related signatures, it is essential to understand the different factors that may influence a particular heavy‐mineral assemblage for example, chemical weathering or diagenetic processes. Hydrodynamics, causing size‐density sorting, exert major control on the distribution of heavy minerals. Here, we highlight the effect of grain‐size inheritance, essentially the absence of certain grain sizes within a specific heavy‐mineral species, on two distinct types of sediments. Modern deposits from a high‐energy beach in NW Denmark give an analog for heavily reworked sediment, primarily controlled by hydrodynamic processes. In contrast, three Palaeogene turbidite successions in the Eastern Alps were sampled, presenting a more complex history that includes diagenesis. All samples were processed for their heavy‐mineral compositions using Raman spectroscopy, and several techniques applied to determine the effect of grain‐size inheritance. Results show that (a) even within the hydrodynamically well‐sorted beach and placer deposits, evidence of grain‐size inheritance is apparent, and (b) turbidites of variable heavy‐mineral composition show strong effects of grain‐size inheritance for several mineral species. Moreover, considerable intersample contrasts within single turbidite beds are observed. We enforce the importance of understanding grain‐size inheritance, as well as other processes effecting size‐density relations in clastic sediment that go well beyond purely hydrodynamic control of intrasample heavy‐mineral variability.〈/p〉
    Description: Plain Language Summary: Heavy minerals are commonly found within sediments and sedimentary rocks and can tell us from which source regions the sediment may have originated. However, it is important to understand that the type, size, and abundance of particular heavy minerals can change depending on factors such as environmental conditions. The size, shape, and density of the heavy minerals also limits when and where they will settle and/or stay. A lack of big or small grains of a particular heavy mineral in the source rocks dictates the size of the minerals deposited; this is known as grain‐size inheritance. Using both ancient and modern sediment, we are looking for traces of grain‐size inheritance. Surprisingly, in all samples investigated we noted effects of grain‐size inheritance, for different heavy‐mineral types. The modern beach sediments, as expected, show more impact of hydraulic processes, but inherited grain sizes are still apparent. Within the ancient examples, grain‐size inheritance is more obvious, with further variations even observed between samples collected from the same area. Having identified this control on grain size, we can highlight the importance of understanding this effect when analyzing clastic sediments.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Understanding factors that can modify a heavy‐mineral assemblage is fundamental in provenance analysis〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Heavy minerals of two distinct sedimentary environments were analyzed and compared to their “ideal” hydrodynamically sorted compositions〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Several heavy‐mineral species of modern and ancient settings were identified to be influenced by grain‐size inheritance from the source〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: https://doi.org/10.25625/MVUIJQ
    Keywords: ddc:552.5 ; heavy minerals ; provenance ; grain‐size inheritance ; hydrodynamics ; diagenesis
    Language: English
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  • 18
    Publication Date: 2024-04-19
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The Ismenius Lacus region of Mars has a diverse geological history, and we present the first high‐resolution map of Deuteronilus Cavus (36.2°N; 14.0°E, ∼120 km diameter) in the fretted terrain south of the dichotomy boundary. Strong evidence suggests a volcanic origin of the regional plains, based on the ∼50 m thick volcanic bed underlying 180–300 m of sublimation residue associated with Amazonian plateau glaciation. Pervasive external volcanic flooding, internal erosional modification, and enlargement of a pre‐existing crater by up to 175%–200% resulted in the cavus' present shape. The phyllosilicates detected within Deuteronilus Cavus could be primary materials associated with the surficial aqueous activity, subsurface alteration products excavated by impacts, or a combination of both. We observe branching fluvial channels that are more recent than the traditional valley networks and may be related to fretted terrain resurfacing during the waning period of a high‐obliquity glaciation phase. This is consistent with our interpretation of the ∼600 m thick lobate and lineated deposits, which are remnants of receding glaciers. The glacial ice, protected by a 15–20 m insulating layer of debris cover, is of significant interest for future landing missions because of its potential to preserve biological and climatological signatures, to provide a critical test of Amazonian plateau glaciation, and to be used for in situ resource utilization. With our detailed geological mapping, we improved our understanding of the geological evolution and climatic conditions in the enigmatic fretted terrain near the dichotomy boundary.〈/p〉
    Description: Plain Language Summary: The ∼120 km long Deuteronilus Cavus was initiated by an impact event. The resulting impact crater was modified by glacial erosional and fluvial processes, leading to the enlargement of 175%–200% of the pre‐existing crater. In addition, we find strong evidence for recent glaciation (〈1 Ga) that left 180–300 m of sublimation residue on the plateau superimposed on a ∼50 m thick volcanic bed, suggesting a volcanic origin of the regional plains. During the waning period of a high‐glacial phase, the meltwater ponded on the surface of the cavus, altered surface rocks to produce phyllosilicates, formed channels (now observed as inverted sinuous ridges), and locally distributed branched fluvial channels that are more recent than the traditional valley networks. Glacial landforms still contain up to 600 m of remnant ice from the retreating glaciers at the end of the last glacial period. The relatively pure ice, protected by a 15–20 m insulating layer of debris cover, is critical for future landing missions because of its potential to preserve biological and climatological signatures and to be used for in situ resource utilization. Overall, this research enhances our understanding of the geological evolution and climatic history of Mars.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We have produced the first high‐resolution map of Deuteronilus Cavus in the fretted terrain south of the Martian dichotomy boundary〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The region records a complex erosional and depositional history, including fluvial and glacial processes in the Amazonian period〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉This study provides a framework for exploration of high‐obliquity mid‐latitude plateau glaciation〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsches Zentrum für Luft‐ und Raumfahrt http://dx.doi.org/10.13039/501100002946
    Description: https://doi.org/10.5281/zenodo.8205276
    Description: https://doi.org/10.17189/1520332
    Description: https://doi.org/10.17189/1520266
    Description: https://doi.org/10.17189/1520303
    Description: https://doi.org/10.5270/esa-pm8ptbq
    Keywords: ddc:523 ; Mars ; Deuteronilus Cavus ; geological mapping ; glaciation
    Language: English
    Type: doc-type:article
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  • 19
    Publication Date: 2024-04-20
    Description: Im Zusammenhang mit der Neuordnung der Bergverwaltung fand auch in Berggießhübel eine Besichtigung der Bergwerke statt. Aufgrund der festgestellten Unregelmäßigkeiten wurde eine neue Bergordnung erlassen. In 11 Paragrafen wurde eine ordentliche Rechnungslegung festgelegt, die Hammerherren zur pünktlichen Bezahlung des Eisensteins aufgefordert und eine strenge Kontrolle der Arbeitszeit angeordnet. Weiterhin erhielten Gewerken eine Steuererleichterung beim Stollnvortrieb.
    Description: source
    Keywords: Herzog Moritz von Sachsen ; Dresden ; Pirna ; Berggießhübel ; Gottleuba ; Sachsen ; Eisenerzbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 7
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  • 20
    Publication Date: 2024-05-11
    Description: Diese Bergordnung wurde am 5. Januar 1517 von Maximilian I., Römisch deutscher Kaiser und König sowie Erzherzog von Österreich, für die Bergwerke in Österreich, der Steiermark, Kärnten und Krain erlassen. Die mit 271 Paragrafen sehr umfangreiche Bergordnung basiert auf dem Bergrecht von Iglau und der Bergordnung für Schwaz von 1490. Sie ist in acht Abschnitte gegliedert. Geregelt werden alle den Bergbau betreffende Maßnahmen. Angefangen über die Festlegung der Grubenmaße, die Rechte und Pflichten der Bergbeamten, Bergleute, Schmiede und Schmelzer, die Arbeitszeiten und Bezahlung, die Holzrechte bis hin zur Führung von Gerichtsprozessen über Streitigkeiten und deren Kosten.
    Description: source
    Keywords: Maximilian I. ; Österreich ; Steiermark ; Kärnten ; Krain ; Friesach ; Frohnleiten ; Glödnitz ; Meislding ; Obervellach ; Rottenmann ; Schladming ; Schrems ; Seckau ; St. Paul bei Hornburg ; St. Veit an der Glan ; Villach ; Waitschach ; Windisch Bleiberg ; Zeiring ; Zeltschach ; Schwaz ; Iglau/Jihlava ; Silberbergbau ; Bergordnung
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 49
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  • 21
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Mineral dust is one of the most abundant atmospheric aerosol species and has various far‐reaching effects on the climate system and adverse impacts on air quality. Satellite observations can provide spatio‐temporal information on dust emission and transport pathways. However, satellite observations of dust plumes are frequently obscured by clouds. We use a method based on established, machine‐learning‐based image in‐painting techniques to restore the spatial extent of dust plumes for the first time. We train an artificial neural net (ANN) on modern reanalysis data paired with satellite‐derived cloud masks. The trained ANN is applied to cloud‐masked, gray‐scaled images, which were derived from false color images indicating elevated dust plumes in bright magenta. The images were obtained from the Spinning Enhanced Visible and Infrared Imager instrument onboard the Meteosat Second Generation satellite. We find up to 15% of summertime observations in West Africa and 10% of summertime observations in Nubia by satellite images miss dust plumes due to cloud cover. We use the new dust‐plume data to demonstrate a novel approach for validating spatial patterns of the operational forecasts provided by the World Meteorological Organization Dust Regional Center in Barcelona. The comparison elucidates often similar dust plume patterns in the forecasts and the satellite‐based reconstruction, but once trained, the reconstruction is computationally inexpensive. Our proposed reconstruction provides a new opportunity for validating dust aerosol transport in numerical weather models and Earth system models. It can be adapted to other aerosol species and trace gases.〈/p〉
    Description: Plain Language Summary: Most dust and sand particles in the atmosphere originate from North Africa. Since ground‐based observations of dust plumes in North Africa are sparse, investigations often rely on satellite observations. Dust plumes are frequently obscured by clouds, making it difficult to study the full extent. We use machine‐learning methods to restore information about the extent of dust plumes beneath clouds in 2021 and 2022 at 9, 12, and 15 UTC. We use the reconstructed dust patterns to demonstrate a new way to validate the dust forecast ensemble provided by the World Meteorological Organization Dust Regional Center in Barcelona, Spain. Our proposed method is computationally inexpensive and provides new opportunities for assessing the quality of dust transport simulations. The method can be transferred to reconstruct other aerosol and trace gas plumes.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We present the first fast reconstruction of cloud‐obscured Saharan dust plumes through novel machine learning applied to satellite images〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The reconstruction algorithm utilizes partial convolutions to restore cloud‐induced gaps in gray‐scaled Meteosat Second Generation‐Spinning Enhanced Visible and Infrared Imager Dust RGB images〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉World Meteorological Organization dust forecasts for North Africa mostly agree with the satellite‐based reconstruction of the dust plume extent〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: GEOMAR Helmholtz Centre for Ocean Research Kiel
    Description: University of Cologne
    Description: https://doi.org/10.5281/zenodo.6475858
    Description: https://github.com/tobihose/Masterarbeit
    Description: https://dust.aemet.es/
    Description: https://ads.atmosphere.copernicus.eu/cdsapp#!/dataset/cams-global-reanalysis-eac4?tab=overview
    Description: https://navigator.eumetsat.int/product/EO:EUM:DAT:MSG:DUST
    Description: https://navigator.eumetsat.int/product/EO:EUM:DAT:MSG:CLM
    Description: https://doi.org/10.5067/KLICLTZ8EM9D
    Description: https://disc.gsfc.nasa.gov/datasets?project=MERRA-2
    Description: https://doi.org/10.5067/MODIS/MOD08_D3.061
    Description: https://doi.org/10.5067/MODIS/MYD08_D3.061
    Description: https://doi.org/10.5281/ZENODO.8278518
    Keywords: ddc:551.5 ; mineral dust ; North Africa ; MSG SEVIRI ; machine learning ; cloud removal ; satellite remote sensing
    Language: English
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  • 22
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Regardless of the steady increase of computing power during the last decades, numerical models in a 3D spherical shell are only used in specific setups to investigate the thermochemical convection in planetary interiors, while 2D geometries are typically favored in most exploratory studies involving a broad range of parameters. The 2D cylindrical and the more recent 2D spherical annulus geometries are predominantly used in this context, but the extent to how well they reproduce the 3D spherical shell results in comparison to each other and in which setup has not yet been extensively investigated. Here we performed a thorough and systematic study in order to assess which 2D geometry reproduces best the 3D spherical shell. In a first set of models, we investigated the effects of the geometry on thermal convection in steady‐state setups while varying a broad range of parameters. Additional thermal evolution models of three terrestrial bodies, namely Mercury, the Moon, and Mars, which have different interior structures, were used to compare the 2D and 3D geometries. Our investigations show that the 2D spherical annulus geometry provides results closer to models in a 3D spherical shell compared to the 2D cylindrical geometry. Our study indicates where acceptable differences can be expected when using a 2D instead of a 3D geometry and where to be cautious when interpreting the results.〈/p〉
    Description: Plain Language Summary: In geodynamic modeling, numerical models are used in order to investigate how the interior of a terrestrial planet evolves from the earliest stage, after the planetary formation, up to present day. Often, the mathematical equations that are used to model the physical processes in the interior of rocky planets are discretized and solved using geometric meshes. The most commonly applied geometries are the 3D spherical shell, the 2D cylinder, and the 2D spherical annulus. While being the most accurate and realistic, the 3D geometry is expensive in terms of computing power and time of execution. On the other hand, 2D geometries provide a reduced accuracy but are computationally faster. Here we perform an extensive comparison between 2D and 3D geometries in scenarios of increasing complexity. The 2D spherical annulus geometry shows much closer results to the 3D spherical shell when compared to the 2D cylinder and should be given preference in 2D modeling studies.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Interior dynamics models using the 2D spherical annulus geometry match the results of a 3D spherical shell better than the 2D cylinder〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The difference between 2D and 3D geometries decreases when models are heated from below by the core and from within by radioactive elements〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The 2D spherical annulus shows negligible differences to 3D for the thermal evolution of Mercury and the Moon, and acceptable values for Mars〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Ministry of Science, Research and the Arts Baden‐Württemberg
    Description: Federal Ministry of Education and Research
    Description: https://doi.org/10.5281/zenodo.8047757
    Keywords: ddc:523 ; mantle convection ; thermal evolution ; spherical annulus ; Mars ; Moon ; Mercury
    Language: English
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  • 23
    Publication Date: 2024-05-21
    Description: Das Deutsche Iglauer Bergrecht liegt in drei Varianten vor, die von Adolf Zycha entsprechend mit I, II und III bezeichnet wurden. Es entstand im 13. und 14. Jahrhundert. Die Abschriften Adolf Zychas beruhen auf Originalakten aus dem Ratsarchiv Freiberg und dem Stadtarchiv Iglau. In ihm wurden analog zu den Iglauer Bergrechten A und B die rechtlichen Regelungen für den Bergbau im Königreich Böhmen und der Markgrafschaft Mähren niedergeschriebenen. In der Variante II wurden zwei Paragrafen hinzugefügt und in der Variante III vierzehn Paragrafen. Elf Paragrafen der Variante III beinhalten Stadtrecht.
    Description: source
    Keywords: Böhmen ; Mähren ; Iglau/Jihlava ; Freiberg ; Silberbergbau ; Bergrecht
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 24
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  • 24
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉NASA's Juno mission delivered gravity data of exceptional quality. They indicate that the zonal winds, which rule the dynamics of Jupiter's cloud deck, must slow down significantly beyond a depth of about 3,000 km. Since the underlying inversion is highly non‐unique additional constraints on the flow properties at depth are required. These could potentially be provided by the magnetic field and its Secular Variation (SV) over time. However, the role of these zonal winds in Jupiter's magnetic field dynamics is little understood. Here we use numerical simulations to explore the impact of the zonal winds on the dynamo field produced at depth. We find that the main effect is an attenuation of the non‐axisymmetric field, which can be quantified by a modified magnetic Reynolds number Rm that combines flow amplitude and electrical conductivity profile. Values below Rm = 3 are required to retain a pronounced non‐axisymmetric feature like the Great Blue Spot (GBS), which seems characteristic for Jupiter's magnetic field. This allows for winds reaching as deep as 3,400 km. A SV pattern similar to the observation can only be found in some of our models. Its amplitude reflects the degree of cancellation between advection and diffusion rather than the zonal wind velocity at any depth. It is therefore not straightforward to make inferences on the deep structure of cloud‐level winds based on Jupiter's SV.〈/p〉
    Description: Plain Language Summary: The dynamics in Jupiter's cloud layer is dominated by eastward and westward directed wind jets that circumvent the planet and reach velocities of up to 150 m per second. For the first time, NASA's Juno mission could measure the tiny gravity changes caused by these winds. The data show that the winds reach down to a depth of about 3,000 km, roughly 4% of Jupiter's radius. However, the interpretation is difficult and several alternative wind profiles have been suggested. In this paper we use numerical simulations to explore how these winds would affect Jupiter's magnetic field, which has also been measured with high precision by Juno. The field shows a strong inward‐directed local patch just south of the equator, called the GBS. The impact of the winds on the magnetic field rapidly increases with depth because of the increase in the electrical conductivity. Our simulations show that winds reaching deeper than about 3,400 km would practically wipe out the GBS. This confirms that they have to remain shallower. Juno also observed an east‐ward drift of the GBS. While some of our simulations also show an east‐ward drift it is typically much too slow.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We study the magnetic field variations caused by Jupiter's deep‐reaching surface winds for various flow and electrical conductivity models〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Zonal winds reaching deeper than 3,400 km would yield a very axisymmetric surface field and are thus unrealistic〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉It seems questionable that Jupiter's secular variation carries any useful information on the zonal winds〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266
    Description: https://doi.org/10.17617/3.CNVRWD
    Keywords: ddc:523 ; Jupiter ; magnetic field ; atmospheric dynamics ; zonal winds
    Language: English
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  • 25
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The microphysical structure of the lunar regolith provides information on the geologic history of the Moon. We used remote sensing measurements of thermal emission and a thermophysical model to determine the microphysical properties of the lunar regolith. We expand upon previous investigations by developing a microphysical thermal model, which more directly simulates regolith properties, such as grain size and volume filling factor. The modeled temperatures are matched with surface temperatures measured by the Diviner Lunar Radiometer Experiment on board the Lunar Reconnaissance Orbiter. The maria and highlands are investigated separately and characterized in the model by a difference in albedo and grain density. We find similar regolith temperatures for both terrains, which can be well described by similar volume filling factor profiles and mean grain sizes obtained from returned Apollo samples. We also investigate a significantly lower thermal conductivity for highlands, which formally also gives a very good solution, but in a parameter range that is well outside the Apollo data. We then study the latitudinal dependence of regolith properties up to ±80° latitude. When assuming constant regolith properties, we find that a variation of the solar incidence‐dependent albedo can reduce the initially observed latitudinal gradient between model and Diviner measurements significantly. A better match between measurements and model can be achieved by a variation in intrinsic regolith properties with a decrease in bulk density with increasing latitude. We find that a variation in grain size alone cannot explain the Diviner measurements at higher latitudes.〈/p〉
    Description: Plain Language Summary: The Moon is covered by a layer of fine grained material called regolith. To extract information about the regolith, such as grain size or stratification, we used data from the Diviner instrument on board the Lunar Reconnaissance Orbiter. Diviner measures the surface temperature of the regolith for each location on the Moon and all times during day and night. To derive regolith properties, we developed a model and varied its model parameters until the simulated surface temperatures matched the measured ones. We applied the model up to a latitude of 80° and find as the best solution a decrease in regolith packing density with increasing latitude. We also find that a variation of regolith grain size alone cannot explain the measurements. These predictions are valuable for planning future missions targeting higher latitudes and can be compared with future in situ measurements and returned samples. However, the fraction of sunlight that actually heats the regolith is quite unknown, especially at high latitudes. A variation of this fraction can explain the measured surface temperatures reasonably well even without a variation of the regolith properties with latitude.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We developed a microphysical thermal model accounting for regolith grain size and volume filling factor〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉The best match between model and Lunar Reconnaissance Orbiter/Diviner data was achieved with a decrease in bulk density between 30° and 80° latitude〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉We also found a reasonable agreement between observed and modeled surface temperatures when varying the solar incidence dependent albedo〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: LRO project
    Description: https://doi.org/10.17189/WJ0S-W188
    Description: https://doi.org/10.5281/zenodo.8433837
    Description: https://doi.org/10.5281/zenodo.10781188
    Keywords: ddc:523 ; Moon ; regolith ; Diviner ; thermal modeling ; lunar
    Language: English
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  • 26
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The Ries impact structure (Germany) contains well‐preserved ejecta deposits consisting of melt‐free lithic breccia (Bunte Breccia) overlain by suevite. To test their emplacement conditions, we investigated the magnetic properties and microstructures of 26 polymict breccia clasts and a stratigraphic profile from the clasts into the suevite at the Aumühle quarry. Remanent magnetization directions of the Bunte Breccia clasts fall into two groups: those whose directions mostly lie parallel to the reversed field during impact carried mostly by magnetite, and those whose directions vary widely among each clast carried by titanohematite. Basement clasts containing titanohematite acquired a chemical remanent magnetization (CRM) during the ejection process and then rotated during turbulent deposition. Clasts of sedimentary rocks grew magnetite after turbulent deposition, with CRM directions lying parallel to the paleofield. Suevite holds a thermal remanent magnetization carried by magnetite, except for ∼12 cm from the contact with the Bunte Breccia, where hematite concentrations increase due to hydrothermal alteration. These observations lead us to propose a three‐stage model of (a) turbulent deposition of the melt‐free breccia with clast rotation 〈580°C, (b) deposition of the overlying suevite, which acted as a semi‐permeable barrier that confined hot (〈300°C) oxidizing fluids to the permeable breccia zone, and (c) prolonged hydrothermal activity producing further alteration which ended before the next geomagnetic reversal. Basement outcrops have significantly different magnetic properties than the Bunte Breccia basement clasts with similar lithology. Two basement blocks situated near the inner ring may have been thermally overprinted up to 550°C.〈/p〉
    Description: Plain Language Summary: The 26‐km‐diameter, ∼15‐million‐year‐old Ries meteorite impact structure in southern Germany is characterized by well‐preserved ejecta deposits expelled from the crater within seconds after the impact. These deposits consist of two main layers: melt‐free, lithic breccia (Bunte Breccia), overlain by melt‐bearing breccia (suevite). To understand the formation conditions of the ejecta deposits, we performed paleomagnetic and rock magnetic measurements and microstructural experiments on clasts within Bunte Breccia and on the overlying suevite at the Aumühle quarry. We found that clasts derived from crystalline basement materials experienced high pressures during the impact. These clasts had randomly oriented magnetization directions carried by titanohematite. In contrast, clasts derived from sedimentary rocks experienced only low pressures and had coherent magnetization directions oriented parallel to the reversed field during the impact that are carried by magnetite. Our findings can be interpreted by a three‐stage model that explains the thermal and structural formation of impact ejecta at the Ries impact structure.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Randomly oriented paleomagnetic directions in basement clasts in ejecta deposits suggest turbulent emplacement〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Bunte Breccia was chemically altered and locally heated by the overlying suevite, resulting in hydrothermal activity up to 300°C〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Basement rocks near the inner ring may have experienced temperatures up to 550°C from cratering〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: https://earthref.org/MagIC/19984
    Keywords: ddc:622.153 ; Paleomagnetism ; remanent magnetization ; chemical remanence ; impact crater ; impact ejecta ; hydrothermal activity
    Language: English
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  • 27
    Publication Date: 2024-05-23
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉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 〈italic〉M〈/italic〉〈sub〉〈italic〉W〈/italic〉〈/sub〉 ≥ 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, for example, rupture on conjugate faults, bilateral propagation, and dynamic triggering by a P wave. For megathrust earthquakes, ruptures encircling asperities were frequently observed, with downdip, updip, and balanced patterns. Although there is a preference for short‐period emissions to emanate from central and downdip parts of the megathrust, emissions updip of the main asperity are more frequent than suggested by earlier results.〈/p〉
    Description: Plain Language Summary: Back‐projection is an earthquake imaging method based on seismic waveforms recorded remotely at a group of seismometers (seismic array). Here, we develop a new approach to combine backprojections from multiple arrays and seismic waveforms and use it to derive a catalog of large earthquake rupture histories from 2010 to 2022, providing a map view of the high‐frequency radiation emitted along the fault. The method automatically estimates the earthquake rupture length, speed, directivity, and aspect ratio. Based on these estimates, we obtained scaling relations between the earthquake magnitude and rupture length that agree with classical relationships. We identified strike‐slip earthquakes propagating at supershear, that is, faster than the shear wave speed, the usual limit for self‐sustaining rupture propagation. We observed complex rupture behaviors, for example, multiple faults activated, bilateral ruptures, and triggering of the main phase of a rupture by a primary (P) wave from the earliest part of the rupture. For subduction earthquakes, high‐frequency emissions were often observed, forming a ring around the fault interface patches (asperities) where the main slip occurs. There was a preference for high‐frequency radiation to emanate from central and deeper parts of the subducting plate interface, but shallower emissions were more frequent than expected from previous literature.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉We provide a complete catalog of high‐frequency rupture histories for 〈italic〉M〈/italic〉 ≥ 7.5 events 2010–2022〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉We develop a semi‐automatic method for estimating rupture length, speed, directivity, and aspect ratio〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Both encircling ruptures and emissions updip of slip asperities common in megathrust earthquakes〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: National Agency for Research and Development (ANID)
    Description: https://doi.org/10.5880/GFZ.2.4.2024.001
    Keywords: ddc:551.22 ; back‐projection ; megathrust earthquakes ; complex ruptures ; supershear ruptures ; scaling relations ; earthquake rupture catalog
    Language: English
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  • 28
    Publication Date: 2024-05-30
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Mass transfer across the crust‐mantle boundary is a fundamental process governing planetary differentiation, the evolution of geochemical reservoirs and ore formation, controlled by physicochemical conditions at the crust‐mantle interface. In situ trace‐element, clinopyroxene 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr and garnet Fe〈sup〉3+〈/sup〉/ΣFe of kimberlite‐borne eclogite xenoliths from the deep (∼50 km) crust‐mantle transition below the ca. 1.2–1.0 Ga Namaqua‐Natal Fold Belt (southwestern Kaapvaal craton margin) were determined to elucidate their origin and evolution, and to constrain the oxygen fugacity of this pivotal but largely inaccessible environment. Based on a garnet source signature (NMORB‐normalized Er/Lu > 1) in pristine “gabbroic” eclogites with pronounced positive Eu, Sr, and Pb anomalies, the suite is interpreted as originating as plagioclase‐rich cumulates in oceanic crust from melts generated beneath mature oceanic lithosphere, subsequently subducted during the Namaqua‐Natal orogeny. Enriched eclogites have higher measured 〈sup〉87〈/sup〉Sr/〈sup〉86〈/sup〉Sr in clinopyroxene (up to 0.7054) than gabbroic ones (up to 0.7036), and show increasing bulk‐rock Li, Be and Pb abundances with increasing δ〈sup〉18〈/sup〉O in clinopyroxene, and muted Eu‐Sr‐Pb anomalies. These systematics suggest interaction with a siliceous fluid sourced from seawater‐altered oceanic sediment in a subduction mélange setting. Garnet Fe〈sup〉3+〈/sup〉/ΣFe in deep crustal eclogites is extremely low (0.01–0.04, ±0.01 1〈italic〉σ〈/italic〉), as inherited from the plagioclase‐rich cumulate protolith, and owing to preferred partitioning into clinopyroxene at low temperatures (∼815–1000°C). Average maximum oxygen fugacities (∆logƒO〈sub〉2〈/sub〉(FMQ) = −3.1 ± 1.0 to −0.5 ± 0.7 relative to the Fayalite‐Magnetite‐Quartz buffer) are higher than in deeper‐seated on‐craton eclogite xenoliths, but mostly below sulfate stability, limiting the role of S〈sup〉6+〈/sup〉 species in oxidizing the mantle wedge.〈/p〉
    Description: Plain Language Summary: Subduction zones represent the main interface between Earth's surface and its deep interior. Metamorphic reactions during subduction cause fluid or melt loss from seawater‐altered oceanic crust and sediment, which enriches the overlying mantle, and possibly oxidizes it. This would explain why the mantle sources of subduction zone magmas appear to be more oxidized than in other tectonic settings. However, the details of the mass transfer in this deep environment are difficult to constrain because it is inaccessible. Using rare deep‐seated magmas (kimberlites) as probes of a ca. 1.2 billion year old southern African subduction zone, we investigated eclogite fragments that originated as subducted oceanic crust and were much later plucked from the wallrocks by the ascending magma. These eclogites show elemental and isotopic signatures of interaction with subducted sediments, pointing to mingling processes similar to those observed in modern subduction zones. We also estimated their oxygen fugacity, a measure of the chemical potential of oxygen. We find that sulfur, which has been implicated in mantle oxidation, would have only been stable in these rocks in its reduced form, making even seawater‐altered eclogites sinks rather than sources of oxygen, with implications for the transfer of sulfur‐loving metals across the mantle‐to‐crust‐boundary.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Eclogite xenoliths sampling deep crust‐mantle transition below Namaqua‐Natal Fold Belt have plagioclase‐rich oceanic protoliths〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Enriched xenoliths show signatures of interaction with siliceous, subducted sediment‐derived fluids under shallow fore‐arc conditions〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Fe〈sup〉3+〈/sup〉‐based eclogite oxybarometry with oxygen fugacities below sulfate stability limits the role of S〈sup〉6+〈/sup〉 species in mantle wedge oxidation〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: Deutsche Forschungsgemeinschaft
    Description: https://doi.org/10.60520/IEDA/113077
    Keywords: ddc:552.4 ; kimberlite‐borne eclogite xenoliths ; crust‐mantle transition ; subduction zone processes ; redox budget ; metallogeny ; mantle wedge oxidation
    Language: English
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  • 29
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    Landesamt für Geologie und Bergbau Rheinland-Pfalz
    Publication Date: 2024-05-30
    Description: Ob Energiewende, die Gewinnung geothermischer Energie aus dem Boden, der Bau von unterirdischen Stromtrassen oder die Modellierung des Energiehaushalts der Erdoberfläche – die Kenntnisse der physikalisch-thermischen Eigenschaften des oberflächennahen Untergrundes sind von zentraler Bedeutung für zahlreiche Fragestellen der angewandten Bodenkunde. Böden als 3-Phasengemische aus Wasser, Luft und Festsubstanz können erhebliche Unterschiede und Differenzierungen bezüglich der thermischen Eigenschaften aufweisen. Neben dem Wasser- und Lufthaushalt sind Lagerungsdichte, Textur sowie die mineralogische Zusammensetzung entscheidende Einflussfaktoren. Auf Basis dieser Grundlagen wurden von verschiedenen Autoren Modellansätze entwickelt, um thermische Parameter bei unterschiedlichen Feuchtezuständen abzuleiten. Die meisten dieser Ansätze beruhen auf der Auswertung von repräsentativen Bodenproben, die ein möglichst breites Texturspektrum abbilden sollen. Die vorliegende Untersuchung verfolgt einen alternativen Ansatz. Durch Messungen im Routinebetrieb eines bodenphysikalischen Labors wurde ein umfangreicher Datensatz aufgebaut, der Auswertungen nach verschiedenen laboranalytischen sowie boden- und substratsystematischen Aspekten ermöglicht. Auf dieser breiten Datenbasis sollen die thermischen Eigenschaften von Böden bei definierten Randbedingungen noch genauer gefasst werden. Darüber hinaus sollen Grundlagen erarbeitet werden, die es ermöglichen, thermische Kennwerte über die Kenntnis einfacher Feldparameter möglichst präzise abzuschätzen.
    Description: research
    Keywords: ddc:631.436 ; Bodenphysik ; Wärmeleitfähigkeit ; Rheinland-Pfalz
    Language: German
    Type: doc-type:book , publishedVersion
    Format: 56
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  • 30
    Publication Date: 2024-06-07
    Description: Nach dem Streit um die Lieferung und den Besitz von Eisenstein zwischen Johannes, Abt des Klosters Grünhain, und Ernst II. von Schönburg, erließ Johannes mit Unterstützung von Kurfürst Johann Friedrich I. 1534 eine Bergordnung für den Eisensteinbergbau am Emmler und dem Hutstein.
    Description: source
    Keywords: Johannes Abt von Grünhain ; Kurfürst Johann Friedrich I. von Sachsen ; Ernst II. von Schönburg ; Kloster Grünhain ; Eisenerzbergbau
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 6
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  • 31
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    ARGE GMIT, Bonn
    Publication Date: 2024-06-19
    Description: Die Ausgabe der Geowissenschaftlichen Mitteilungen vom Juni 2024 enthält die Themenblöcke: GEOfokus: Die Ur-Ems – ein Fluss legt sich zurück -Vom Ende der Eiszeit zurück in die Zukunft-, GEOaktiv (Wirtschaft, Beruf, Forschung und Lehre), GEOlobby (Gesellschaften, Verbände, Institutionen), GEOreport (Geowissenschaftliche Öffentlichkeitsarbeit, Tagungsberichte, Ausstellungen, Exkursionen, Publikationen), GEOszene (Würdigungen, Nachrufe).
    Description: DFG, SUB Göttingen
    Description: journal
    Keywords: ddc:550 ; GMIT
    Language: German
    Type: doc-type:book , publishedVersion
    Format: 136
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  • 32
    Publication Date: 2024-06-18
    Description: Trotz der am 2. August 1518 erlassenen Bergordnung kam es in den Folgejahren immer wieder zu Auseinandersetzungen zwischen den Bergleuten und den Bergbeamten. Hintergrund waren neben der wachsenden Korruption auch Betrug, Misswirtschaft und Machtmissbrauch der Bergbeamten, dem durch den rasant wachsenden Bergbau Tür und Tor geöffnet war. Mutmaßlich inspiriert durch die Bauernkriege kam es am 20. Mai 1525 zu einem Aufstand der Bergleuten in Joachimsthal. Nach der raschen Beilegung der Auseinandersetzung wurde zu der weiterhin gültigen Bergordnung vom 2. August 1518 eine Ergänzung mit 35 Artikeln erlassen.
    Description: source
    Keywords: Graf Stefan Schlick zu Passaun ; Alexander Burggraf von Leisnig ; Rudolf II. von Bünau ; Apel IV. Vitzthum ; Urban Osan ; Anton Römhelt ; Hans Hausmann ; Joachimsthal/Jáchymov ; Freiberg ; Annaberg ; Falkenau/Sokolow
    Language: German
    Type: doc-type:book , updatedVersion
    Format: 14
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  • 33
    Publication Date: 2023-11-21
    Description: The world's forests store large amounts of carbon (C), and growing forests can reduce atmospheric CO2 by storing C in their biomass. This has provided the impetus for world-wide tree planting initiatives to offset fossil-fuel emissions. However, forests interact with their environment in complex and multifaceted ways that must be considered for a balanced assessment of the value of planting trees. First, one needs to consider the potential reversibility of C sequestration in trees through either harvesting or tree death from natural factors. If carbon storage is only temporary, future temperatures will actually be higher than without tree plantings, but cumulative warming will be reduced, contributing both positively and negatively to future climate-change impacts. Alternatively, forests could be used for bioenergy or wood products to replace fossil-fuel use which would obviate the need to consider the possible reversibility of any benefits. Forests also affect the Earth's energy balance through either absorbing or reflecting incoming solar radiation. As forests generally absorb more incoming radiation than bare ground or grasslands, this constitutes an important warming effect that substantially reduces the benefit of C storage, especially in snow-covered regions. Forests also affect other local ecosystem services, such as conserving biodiversity, modifying water and nutrient cycles, and preventing erosion that could be either beneficial or harmful depending on specific circumstances. Considering all these factors, tree plantings may be beneficial or detrimental for mitigating climate-change impacts, but the range of possibilities makes generalisations difficult. Their net benefit depends on many factors that differ between specific circumstances. One can, therefore, neither uncritically endorse tree planting everywhere, nor condemn it as counter-productive. Our aim is to provide key information to enable appropriate assessments to be made under specific circumstances. We conclude our discussion by providing a step-by-step guide for assessing the merit of tree plantings under specific circumstances.
    Type: Article , PeerReviewed
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  • 34
    Publication Date: 2023-11-29
    Description: Seaweed farming contributes substantial amounts of organic carbon to the ocean, part of which can be locked for a long term in the ocean and perform the function of ocean carbon sequestration, and the other part can be converted into inorganic carbon through microbial mineralization and aerobic respiration, affecting the pCO2, pHT and dissolved oxygen of seawater. It is generally believed that seaweed farming will cause the seawater to become a sink of CO2 due to carbon fixation by macroalgal photosynthesis. However, little attention has been paid to the fact that seaweed farming environment may sometimes become a source rather than a sink of CO2. Here, through in-situ mesocosm cultivation experiments and eight field investigations covering different kelp growth stages in an intensive farming area in China, we found that compared with the surrounding seawater without kelps, the seawater at the fast-growth stage of kelp was a sink of CO2 (pCO2 decreased by 17−73 μatm), but became a source of CO2 at the aging stage of kelp (pCO2 increased by 20−37 μatm). Concurrently, seawater pHT experienced a transition from increase (by 0.02−0.08) to decline (by 0.03−0.04). In-situ mesocosm cultivation experiments showed that the positive environmental effects (i.e., pCO2 decrease and pHT increase) induced by kelps at the early growth stage could be offset within only 3 days at the late-growth and aging stages. The release of dissolved organic carbon by kelps at the late growth stage increased significantly, supporting the enhancement in microbial abundance and respiration, which was manifested by the remarkable decrease in seawater dissolved oxygen, ultimately leading to CO2 release exceeding photosynthetic CO2 absorption. This study suggests that mature farmed kelps should be harvested in time to best utilize their carbon sink function and environmental benefits, which has guiding significance for the rational management of seaweed farming.
    Type: Article , PeerReviewed
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  • 35
    Publication Date: 2023-12-06
    Description: Highlights: • Inhibitory potential of eelgrass microbiome against aquatic and fecal pathogens • Isolation of epiphytes and endophytes associated with eelgrass leaves and roots • Particularly leaf epibiotic bacteria exhibit significant antimicrobial activity. • Rich secondary metabolite composition by untargeted metabolomics • Potential involvement of eelgrass microbiome in seagrass ecosystem services Seagrass meadows provide crucial ecosystem services for coastal environments and were shown to reduce the abundance of waterborne pathogens linked to infections in humans and marine organisms in their vicinity. Among potential drivers, seagrass phenolics released into seawater have been linked to pathogen suppression, but the potential involvement of the seagrass microbiome has not been investigated. We hypothesized that the microbiome of the eelgrass Zostera marina, especially the leaf epiphytes that are at direct interface between the seagrass host and the surrounding seawater, inhibit waterborne pathogens thereby contributing to their removal. Using a culture-dependent approach, we isolated 88 bacteria and fungi associated with the surfaces and inner tissues of the eelgrass leaves (healthy and decaying) and the roots. We assessed the antibiotic activity of microbial extracts against a large panel of common aquatic, human (fecal) and plant pathogens, and mined the metabolome of the most active extracts. The healthy leaf epibiotic bacteria, particularly Streptomyces sp. strain 131, displayed broad-spectrum antibiotic activity superior to some control drugs. Gram-negative bacteria abundant on healthy leaf surfaces, and few endosphere-associated bacteria and fungi also displayed remarkable activities. UPLC-MS/MS-based untargeted metabolomics analyses showed rich specialized metabolite repertoires with low annotation rates, indicating the presence of many undescribed antimicrobials in the extracts. This study contributes to our understanding on microbial and chemical ecology of seagrasses, implying potential involvement of the seagrass microbiome in suppression of pathogens in seawater. Such effect is beneficial for the health of ocean and human, especially in the context of climate change that is expected to exacerbate all infectious diseases. It may also assist future seagrass conservation and management strategies.
    Type: Article , PeerReviewed
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  • 36
    Publication Date: 2023-12-18
    Description: Total alkalinity (TA) is an important variable of the ocean carbonate system. In coastal oceans, carbonate system dynamics are controlled by a range of processes including photosynthesis and respiration, calcification, mixing of water masses, continental inputs, temperature changes, and seasonal upwelling. Assessments of diel, seasonal and interannual variations in TA are required to understand the carbon cycle in coastal oceans. However, our understanding of these variations remains underdeveloped due to limitations in observational techniques. Autonomous TA measurements are therefore required. In this study, an in situ TA analyzer (ISA-TA) based on a single-point titration with spectrophotometric pH detection was deployed in Tong'an Bay, Xiamen, China, over a five-month period in 2021 to determine diel and seasonal TA variations. The TA observations were combined with an artificial neural network (ANN) model to construct TA prediction models for this area. This provided a simple method to investigate TA variations in this region and was applied to predict surface water TA between March and April 2021. The in situ TA observations showed that TA values in Tong'an Bay varied within a range from 1931 to 2294 μmol kg−1 over the study period, with low TA in late winter, early summer and late summer, and high TA in early winter. The TA variations in late summer and early winter were mainly controlled by mixing of water bodies. The diel variations of TA were greatly determined by tides, with a diel amplitude of 9 to 247 μmol kg−1. The ANN model used temperature, salinity, chlorophyll, and dissolved oxygen to estimate TA, with a root-mean-square error (RMSE) of ∼14 μmol kg−1, with salinity as the input variable with the greatest weight. The approach of combining ISA-TA observations with an ANN model can be extended to study the carbonate system in other coastal regions.
    Type: Article , PeerReviewed
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  • 37
    Publication Date: 2023-12-18
    Description: Cephalopods are well known for their cognitive capabilities and unique behavioural repertoires. Yet, certain life strategies and behaviours are still not fully understood. For instance, coastal octopuses have been documented (mainly through citizen science and TV documentaries) to occasionally leave the water and crawl in intertidal areas. Yet, there is a complete lack of knowledge on this behaviour's physiological and biochemical basis. Within this context, this study aimed to investigate, for the first time, physiological (routine and maximum metabolic rates and aerobic scope) and biochemical (i.e., antioxidant enzymes activities, heat shock protein and ubiquitin levels, DNA damage, lipid peroxidation) responses of the common octopus, Octopus vulgaris, to emersion. The octopuses’ physiological performance was determined by measuring metabolic rates in different emersion treatments and biochemical markers. The size-adjusted maximum metabolic rates (MMRadj) of octopuses exposed to 2:30 min of air exposure followed by re-immersion did not differ significantly from the MMRadj of the chased individuals (control group). Yet, most biochemical markers revealed no significant differences among the different emersion treatments. Our findings showed that O. vulgaris could tolerate exposure to short-term emersion periods due to an efficient antioxidant machinery and cellular repair mechanisms. Alongside, we argue that the use of atmospheric air through the mucus-covered gills and/or cutaneous respiration may also help octopus withstand emersion and crawling on land.
    Type: Article , PeerReviewed
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  • 38
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    GEOMAR
    Publication Date: 2024-01-04
    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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  • 39
    Publication Date: 2024-01-05
    Description: We investigate the drivers of global and regional changes in the potential for photovoltaic (PV) power production from the pre-industrial (1850) to present-day (1985-2014) and until the end of the century (2071-2100), based on output from the Coupled Model Intercomparison Project phase six (CMIP6). Our assessment separates regional contributions from changes in clouds, humidity, temperature, aerosols, and wind speed to the changes in PV power potentials for the first time. Present-day PV power potentials are adversely affected by anthropogenic aerosols compared to the pre-industrial, with a global decrease of the PV power potential by -1.3%. Our results highlight a globally averaged decrease in future PV power potentials primarily driven by temperature and humidity increases by -1.2% to more than -3.5%, depending on the scenario. Regionally different contributions of changes in clouds and aerosols cause heterogeneous spatial patterns in changes of PV potentials, with typically stronger (weaker) influences from clouds (aerosols) in SSP5-8.5 compared to SSP1-2.6. Our results imply that the uncertain response of clouds to warming and aerosol effects are hurdles in quantifying changes in the regional potentials for PV power production.
    Type: Article , PeerReviewed
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  • 40
    facet.materialart.
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    GEOMAR
    Publication Date: 2024-01-08
    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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  • 41
    Publication Date: 2024-01-07
    Description: The sustainability of southern Africa’s natural and managed marine and terrestrial ecosystems is threatened by overuse, mismanagement, population pressures, degradation, and climate change. Counteracting unsustainable development requires a deep understanding of earth system processes and how these are affected by ongoing and anticipated global changes. This information must be translated into practical policy and management interventions. Climate models project that the rate of terrestrial warming in southern Africa is above the global terrestrial average. Moreover, most of the region will become drier. Already there is evidence that climate change is disrupting ecosystem functioning and the provision of ecosystem services. This is likely to continue in the foreseeable future, but impacts can be partly mitigated through urgent implementation of appropriate policy and management interventions to enhance resilience and sustainability of the ecosystems. The recommendations presented in the previous chapters are informed by a deepened scientific understanding of the relevant earth system processes, but also identify research and knowledge gaps. Ongoing disciplinary research remains critical, but needs to be complemented with cross-disciplinary and transdisciplinary research that can integrate across temporal and spatial scales to give a fuller understanding of not only individual components of the complex earth-system, but how they interact.
    Type: Book chapter , NonPeerReviewed
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  • 42
    Publication Date: 2024-01-07
    Description: The southern African subcontinent and its surrounding oceans accommodate globally unique ecoregions, characterized by exceptional biodiversity and endemism. This diversity is shaped by extended and steep physical gradients or environmental discontinuities found in both ocean and terrestrial biomes. The region’s biodiversity has historically been the basis of life for indigenous cultures and continues to support countless economic activities, many of them unsustainable, ranging from natural resource exploitation, an extensive fisheries industry and various forms of land use to nature-based tourism. Being at the continent’s southern tip, terrestrial species have limited opportunities for adaptive range shifts under climate change, while warming is occurring at an unprecedented rate. Marine climate change effects are complex, as warming may strengthen thermal stratification, while shifts in regional wind regimes influence ocean currents and the intensity of nutrient-enriching upwelling. The flora and fauna of marine and terrestrial southern African biomes are of vital importance for global biodiversity conservation and carbon sequestration. They thus deserve special attention in further research on the impacts of anthropogenic pressures including climate change. Excellent preconditions exist in the form of long-term data sets of high quality to support scientific advice for future sustainable management of these vulnerable biomes.
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  • 43
    Publication Date: 2024-01-11
    Description: Beryllium isotopes have emerged as a quantitative tracer of continental weathering, but accurate and precise determination of the cosmogenic 10 Be and stable 9 Be in seawater is challenging, because seawater contains high concentrations of matrix elements but extremely low concentrations of 9 Be and 10 Be. In this study, we develop a new, time‐efficient procedure for the simultaneous preconcentration of 9 Be and 10 Be from (coastal) seawater based on the iron co‐precipitation method. The concentrations of 9 Be, 10 Be, and the resulting 10 Be/ 9 Be ratio for Changjiang Estuary water derived from the new procedure agree well with those obtained from the conventional procedure requiring separate preconcentration for 9 Be and 10 Be determinations. By avoiding the separate preconcentration, our newly developed procedure contributes toward more time‐efficient handling of samples, less sample cross‐contamination, and a more reliable 10 Be/ 9 Be ratio. Prior to this, we validated the iron co‐precipitation method using artificial seawater and natural water samples from the Amazon Estuary regarding: (1) the “matrix effect” for Be analysis, (2) its extraction efficiency for pg g −1 levels Be in the presence and absence of organic matter, and (3) the data comparability with another preconcentration method. We calculated that for the determination of 9 Be and 10 Be in most open ocean seawater with typical 10 Be concentrations of 〉 500 atoms g −1 , good precisions (〈 5%) can be achieved using less than 3 liters of seawater compared to more than 20 liters routinely used previously. Even for coastal seawater with extremely low 10 Be concentration (e.g., 100 atoms g −1 ), we estimate a maximum amount of 10 liters to be adequate.
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  • 44
    Publication Date: 2024-01-12
    Description: Ice calved from the Antarctic and Greenland Ice Sheets or tidewater glaciers ultimately melts in the ocean contributing to sea-level rise. Icebergs have also been described as biological hotspots due to their potential roles as platforms for marine mammals and birds, and as micronutrient fertilizing agents. Icebergs may be especially important in the Southern Ocean where availability of the micronutrients iron and manganese extensively limits marine primary production. Whilst icebergs have long been described as a source of iron to the ocean, their nutrient signature is poorly constrained and it is unclear if there are regional differences. Here we show that 589 ice fragments collected from floating ice in contrasting regions spanning the Antarctic Peninsula, Greenland, and smaller tidewater systems in Svalbard, Patagonia and Iceland have similar characteristic (micro)nutrient signatures with limited or no significant differences between regions. Icebergs are a minor or negligible source of macronutrients to the ocean with low concentrations of NOx (NO3 + NO2, median 0.51 µM), PO4 (median 0.04 µM), and dissolved Si (dSi, median 0.02 µM). In contrast, icebergs deliver elevated concentrations of dissolved Fe (dFe; mean 82 nM, median 12 nM) and Mn (dMn; mean 26 nM, median 2.6 nM). A tight correlation between total dissolvable Fe and Mn (R2 = 0.95) and a Mn:Fe ratio of 0.024 suggested a lithogenic origin for the majority of sediment present in ice. Total dissolvable Fe and Mn retained a strong relationship with sediment load (both R2 = 0.43, p〈0.001), whereas weaker relationships were observed for dFe, dMn and dSi. Sediment load for Antarctic ice (median 9 mg L-1, n=144) was low compared to prior reported values for the Arctic. A particularly curious incidental finding was that melting samples of ice were observed to rapidly lose their sediment load, even when sediment layers were embedded within the ice and stored in the dark. Our results demonstrated that the nutrient signature of icebergs is consistent with an atmospheric source of NOx and PO4. Conversely, high Fe and Mn, and modest dSi concentrations, are associated with englacial sediment, which experiences limited biogeochemical processing prior to release into the ocean.
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  • 45
    Publication Date: 2024-01-12
    Description: Microbial carbonates are common components of Quaternary tropical coral reefs. Previous studies revealed that sulfate-reducing bacteria trigger microbial carbonate precipitation in supposedly cryptic reef environments. Here, using petrography, lipid biomarker analysis, and stable isotope data, we aim to understand the formation mechanism of microbial carbonate enclosed in deep fore reef limestones from Mayotte and Mohéli, Comoro Islands, which differ from other reefal microbial carbonates in that they contain less microbial carbonate and are dominated by numerous sponges. To discern sponge-derived lipids from lipids enclosed in microbial carbonate, lipid biomarker inventories of diverse sponges from the Mayotte and Mohéli reef systems were examined. Abundant peloidal, laminated, and clotted textures point to a microbial origin of the authigenic carbonates, which is supported by ample amounts of mono- O -alkyl glycerol monoethers (MAGEs) and terminally branched fatty acids; both groups of compounds are attributed to sulfate-reducing bacteria. Sponges revealed a greater variety of alkyl chains in MAGEs, including new, previously unknown, mid-chain monomethyl- and dimethyl-branched MAGEs, suggesting a diverse community of sulfate reducers different from the sulfate-reducers favoring microbialite formation. Aside from biomarkers specific for sulfate-reducing bacteria, lipids attributed to demosponges (i.e., demospongic acids) are also present in some of the sponges and the reefal carbonates. Fatty acids attributed to demosponges show a higher diversity and a higher proportion in microbial carbonate compared to sponge tissue. Such pattern reflects significant taphonomic bias associated with the preservation of demospongic acids, with preservation apparently favored by carbonate authigenesis.
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  • 46
    Publication Date: 2024-01-14
    Description: Marine methane hydrate is an ice-like substance that is stable in sediment around marine continental margins where water depths are greater than ~450–700 m. The release of methane due to melting of hydrates is considered to be a mechanism for past global carbon-cycle perturbations and could exacerbate ongoing anthropogenic climate change. Increases in bottom-water temperature at the landward limit of marine hydrate around continental margins, where vulnerable hydrate exists at or below the seabed, cause methane to vent into the ocean. However, this setting represents only ~3.5% of the global hydrate reservoir. The potential for methane from hydrate in deeper water to reach the atmosphere was considered negligible. Here we use three-dimensional (3D) seismic imagery to show that, on the Mauritanian margin, methane migrated at least 40 km below the base of the hydrate stability zone and vented through 23 pockmarks at the shelf break, probably during warmer Quaternary interglacials. We demonstrate that, under suitable circumstances, some of the 96.5% of methane bound in deeper water distal hydrates can reach the seafloor and vent into the ocean beyond the landward limit of marine hydrate. This reservoir should therefore be considered for estimating climate change-induced methane release during a warming world.
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  • 47
    Publication Date: 2024-01-14
    Description: Aim: Human activities have introduced numerous non-native species (NNS) worldwide. Understanding and predicting large-scale NNS establishment patterns remain fundamental scientific challenges. Here, we evaluate if NNS composition represents a proportional subset of the total species pool available to invade (i.e. total global biodiversity), or, conversely, certain taxa are disproportionately pre-disposed to establish in non-native areas. Location: Global. Time period: Present day. Major taxa studied: Global diversity. Methods: We compiled one of the most comprehensive global databases of NNS (36,822 established species) to determine if NNS diversity is a representative proportional subset of global biodiversity. Results: Our study revealed that, while NNS diversity mirrors global biodiversity to a certain extent, due to significant deviance from the null model it is not always a representative proportional subset of global biodiversity. The strength of global biodiversity as a predictor depended on the taxonomic scale, with successive lower taxonomic levels less predictive than the one above it. Consequently, on average, 58%, 42% and 28% of variability in NNS numbers were explained by global biodiversity for phylum, class and family respectively. Moreover, global biodiversity was a similarly strong explanatory variable for NNS diversity among regions, but not habitats (i.e. terrestrial, freshwater and marine), where it better predicted NNS diversity for terrestrial than for freshwater and marine habitats. Freshwater and marine habitats were also greatly understudied relative to invasions in the terrestrial habitats. Over-represented NNS relative to global biodiversity tended to be those intentionally introduced and/or ‘hitchhikers’ associated with deliberate introductions. Finally, randomness is likely an important factor in the establishment success of NNS. Main conclusions: Besides global biodiversity, other important explanatory variables for large-scale patterns of NNS diversity likely include propagule and colonization pressures, environmental similarity between native and non-native regions, biased selection of intentionally introduced species and disparate research efforts of habitats and taxa.
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  • 48
    Publication Date: 2024-01-14
    Description: Severe storm flooding poses a major hazard to the coasts of north‐western Europe. However, the long‐term recurrence patterns of extreme coastal flooding and their governing factors are poorly understood. Therefore, high‐resolution sedimentary records of past North Atlantic storm flooding are required. This multi‐proxy study reconstructs storm‐induced overwash processes from coastal lake sediments on the Shetland Islands using grain‐size and geochemical data, and the re‐analysis of historical data. The chronostratigraphy is based on Bayesian age–depth modelling using accelerator mass spectrometry 14 C and 137 Cs data. A high XRF‐based Si/Ti ratio and the unimodal grain‐size distribution link the sand layers to the beach and thus storm‐induced overwash events. Periods with more frequent storm flooding occurred 980–1050, 1150–1300, 1450–1550, 1820–1900 and 1950–2000 ce, which is largely consistent with a positive North Atlantic Oscillation mode. The Little Ice Age (1400–1850 ce ) shows a gap of major sand layers suggesting a southward shift of storm tracks and a seasonal variance with more storm floods in spring and autumn. Warmer phases shifted winter storm tracks towards the north‐east Atlantic, indicating a possible trend for future storm‐track changes and increased storm flooding in the northern North Sea region.
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  • 49
    Publication Date: 2024-01-14
    Description: The seafloor morphology reflects both past and on‐going sedimentary, oceanographic and tectonic processes. Vertical movement is one of the drivers responsible for reshaping the seafloor through forming steep flanks that decrease slope stability, favour landslides, change current paths, form minibasins and control the sediment deposition, distribution and geometry. Here, we make use of these interactions to derive vertical movements and constrain the active tectonic processes at the western termination of the upper Calabrian accretionary wedge from the integrated analysis of bathymetric, backscatter, surface attributes and high‐resolution reflection seismic data. Within this area, we identify two types of deformational features and mechanisms that affect the depositional, erosional and tectonic processes at different scales. These include the deviation of channels, landslide scars, mass transport deposits (MTDs), separated drifts, sediment waves, lineaments and offset seafloor structures. The first type (long‐wavelength uplift) is an uplifted 22‐km‐wide region, in which seismic onlap relationships and the dip of deep reflectors suggest long‐lasting but slow tectonic uplift affecting sedimentation, and the second type (short‐wavelength uplift) includes three narrow elongated structures and one circular dome encircling the first region of uplift. We interpret that the first type of uplift feature was caused by tectonic deformation, while the second type is interpreted as formed by the fast uplift, tilting and faulting of modern sediments caused by diapirism due to rapid sedimentation in response to the first tectonically driven uplift. The study provides insight into the complex interaction of tectonic and sedimentary processes in the upper Calabrian accretionary wedge.
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  • 50
    Publication Date: 2024-01-14
    Description: Methylmercury is a potent toxin threatening the global population mainly through the consumption of marine fish. Hydrothermal venting directly delivers natural mercury to the ocean, yet its global flux remains poorly constrained. To determine the extent to which anthropogenic inputs have increased oceanic mercury levels, it is crucial to estimate natural mercury levels. Here we combine observations of vent fluids, plume waters, seawater and rock samples to quantify the release of mercury from the Trans-Atlantic Geotraverse hydrothermal vent at the Mid-Atlantic Ridge. The majority (67–95%) of the mercury enriched in the vent fluids (4,966 ± 497 pmol l −1 ) is rapidly diluted to reach background seawater levels (0.80 pmol l −1 ). A small Hg fraction (2.6–10%) is scavenged to the Trans-Atlantic Geotraverse mound rocks. Scaling up our findings and previous work, we propose a mercury flux estimate of 1.5–64.7 t per year from mid-ocean ridges. This hydrothermal flux is small in comparison to anthropogenic inputs. This suggests that most of the mercury present in the ocean must be of anthropogenic origin and that the implementation of emissions reduction measures outlined in the Minamata Convention could effectively reduce mercury levels in the global ocean and subsequently in marine fish.
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  • 51
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    Unknown
    GEOMAR
    Publication Date: 2024-01-16
    Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024
    Type: Report , NonPeerReviewed
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  • 52
    Publication Date: 2024-01-17
    Description: In the boreal summer of 2021, the equatorial Atlantic experienced the strongest warm event, that is, Atlantic Niño, since the beginning of satellite observations in the 1970s. Such events have far‐reaching impacts on large‐scale wind patterns and rainfall over the surrounding continents. Yet, developing a paradigm of how Atlantic Niño interacts with the upper‐ocean currents and intraseasonal waves remains elusive. Here we show that the equatorial Kelvin wave associated with the onset of the 2021 Atlantic Niño modulated both the background flow and the eddy flux of the equatorial upper‐ocean circulation, causing an extremely weak and delayed tropical instability wave (TIW) season. TIW‐induced variations of sea surface temperature (SST), sea surface salinity, sea surface height, and eddy temperature advection were exceptionally weak during May to July, the climatological peak of TIW activity, but rebounded in August when higher than normal variability was observed. Moored velocity data at 23°W show that during the peak of the 2021 Atlantic Niño from June to August, the Equatorial Undercurrent was deeper and stronger than usual. An anomalously weak eddy momentum flux strongly suppressed barotropic energy conversion north of the equator from May to July, likely contributing to low TIW activity. Reduced baroclinic energy conversion also might have played a role, as the meridional gradient of SST was sharply reduced during the Atlantic Niño. Despite extremely weak TIW velocities, modest intraseasonal variability of chlorophyll‐a (Chl‐ a ) was observed during the Atlantic Niño, due to pronounced meridional Chl‐ a gradients that partly compensated for the weak TIWs. Plain Language Summary Every few years the eastern equatorial Atlantic Ocean is significantly warmer than usual during boreal summer. Such warm events are referred to as Atlantic Niño events, and share similarities with El Niño events in the Pacific. In 2021, the strongest Atlantic Niño in at least four decades was observed in the equatorial Atlantic. This study is the first that investigates the complex interaction between Atlantic Niño, tropical Atlantic upper‐ocean currents, and equatorial waves based on various observational data sets. We show that the developing 2021 Atlantic Niño weakened both the background flow and the variability of near‐surface currents in May, which in turn largely reduced the strength of intraseasonal (20–50 days) waves that are usually generated by instability of the upper‐ocean zonal currents. As a consequence, the cooling effect that these waves usually have north of the equator and the warming effect along the equator vanished from May to July 2021. Interestingly, variability of chlorophyll concentration was enhanced, suggesting that enhanced meridional chlorophyll gradients compensated for reduced wave activity. Key Points The developing 2021 Atlantic Niño led to weaker equatorial surface currents and reduced vertical shear of upper‐ocean horizontal velocity Strong reduction of the surface flow, eddy flux, and meridional temperature gradient in May caused extremely weak and delayed tropical instability wave (TIW) season Reduced meridional TIW advection contributed to sharpen the north equatorial Chl‐ a front resulting in modest intraseasonal Chl‐ a variability
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  • 53
    Publication Date: 2024-01-17
    Description: Phytoplankton primary productivity (PP) varies significantly over environmental gradients, particularly in physically‐dynamic systems such as estuaries and coastal seas. During summer, runoff peaks in the Changjiang River driving large environmental gradients in both the Changjiang estuary and adjacent East China Sea (ECS), likely driving significant variability in PP. As satellite models of PP often underperform in coastal waters, we aimed to develop a novel approach for assessing net PP variability in such a dynamic environment. Parallel in situ measurements of Fast Repetition Rate (FRR) fluorometry and carbon (C) uptake rates were conducted for the first time in this region during two summer cruises in 2019 and 2021. A series of 13 C‐incubations ( n = 31) were performed, with measured PP ranging from ∼6 to 1,700 mgC m −3 d −1 . Net PP values were significantly correlated with salinity ( r = 0.45), phytoplankton chlorophyll a (Chl‐ a , r = 0.88), Photosystem II (PSII) functional absorption cross‐section ( σ PSII , r = −0.76) and maximum PSII quantum yield ( F v / F m , r = 0.59). Stepwise regression analysis showed that Chl‐ a and σ PSII were the strongest predictors of net PP. A generalized additive model (GAM) was also used to estimate net PP considering nonlinear effects of Chl‐ a and σ PSII . We demonstrate that GAM outperforms linear modeling approaches in estimating net PP in this study, as evidenced by a lower root mean square error (∼140 vs. 250 mgC m −3 d −1 ). Our novel approach provides a valuable tool to examine carbon cycling dynamics in this important region. Plain Language Summary The East China Sea has a complex current system that creates a highly dynamic physical environment for phytoplankton, particularly during the summer months. Net primary productivity (PP) is highly variable in this region, yet characterizing these spatial patterns in PP is difficult due to the lack of a high‐resolution data collecting method. Therefore, a strong need exists for a quick and easily implemented method for monitoring PP in this dynamic system. Based on parallel measurements of phytoplankton biomass and photophysiology, we present a novel approach that allows us to rapidly and easily assess regional PP at a high resolution. The high data volume potentially afforded by our net PP estimation method could not only contribute to a better understanding of PP variations in such a dynamic environment, but also help fill the large gaps in field data needed for validating satellite‐based PP models. Key Points Parallel in situ measurements of net primary productivity (PP) and Fast Repetition Rate fluorometry were conducted in the Changjiang estuary Productivity was highest at stations with high Chl and low σ PSII , typically located along the Chiangjiang river plume front A generalized additive model was developed to estimate net PP, providing an approach for assessing regional C‐cycling dynamics
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  • 54
    Publication Date: 2024-01-17
    Description: Highlights • SPM concentration and organic fractions are analyzed in coastal-offshore gradients • Diagnostic model of SPM allows separating fresh, labile from less reactive PON • Analysis of PON fractions reveals a characteristic area, the transition zone • There, particle settling is enhanced, fostering their transport back to the coast, which controls the fate of organic matter • The transition zone is generally confined to water depths below 20 m Abstract Identifying the mechanisms that contribute to the variability of suspended particulate matter concentrations in coastal areas is important but difficult, especially due to the complexity of physical and biogeochemical interactions involved. Our study addresses this complexity and investigates changes in the horizontal spread and composition of particles, focusing on cross-coastal gradients in the southern North Sea and the English Channel. A semi-empirical model is applied on in situ data of SPM and its organic fraction to resolve the relationship between organic and inorganic suspended particles. The derived equations are applied onto remote sensing products of SPM concentration, which provide monthly synoptic maps of particulate organic matter concentrations (here, particulate organic nitrogen) at the surface together with their labile and less reactive fractions. Comparing these fractions of particulate organic matter reveals their characteristic features along the coastal-offshore gradient, with an area of increased settling rate for particles generally observed between 5 and 30 km from the coast. We identify this area as the transition zone between coastal and offshore waters with respect to particle dynamics. Presumably, in that area, the turbulence range and particle composition favor particle settling, while hydrodynamic processes tend to transport particles of the seabed back towards the coast. Bathymetry plays an important role in controlling the range of turbulent dissipation energy values in the water column, and we observe that the transition zone in the southern North Sea is generally confined to water depths below 20 m. Seasonal variations in suspended particle dynamics are linked to biological processes enhancing particle flocculation, which do not affect the location of the transition zone. We identify the criteria that allow a transition zone and discuss the cases where it is not observed in the domain. The impact of these particle dynamics on coastal carbon storage and export is discussed.
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  • 55
    Publication Date: 2024-01-19
    Description: The marine biological carbon pump (BCP) stores carbon in the ocean interior, isolating it from exchange with the atmosphere and thereby coregulating atmospheric carbon dioxide (CO 2 ). As the BCP commonly is equated with the flux of organic material to the ocean interior, termed “export flux,” a change in export flux is perceived to directly impact atmospheric CO 2 , and thus climate. Here, we recap how this perception contrasts with current understanding of the BCP, emphasizing the lack of a direct relationship between global export flux and atmospheric CO 2 . We argue for the use of the storage of carbon of biological origin in the ocean interior as a diagnostic that directly relates to atmospheric CO 2 , as a way forward to quantify the changes in the BCP in a changing climate. The diagnostic is conveniently applicable to both climate model data and increasingly available observational data. It can explain a seemingly paradoxical response under anthropogenic climate change: Despite a decrease in export flux, the BCP intensifies due to a longer reemergence time of biogenically stored carbon back to the ocean surface and thereby provides a negative feedback to increasing atmospheric CO 2 . This feedback is notably small compared with anthropogenic CO 2 emissions and other carbon‐climate feedbacks. In this Opinion paper, we advocate for a comprehensive view of the BCP's impact on atmospheric CO 2 , providing a prerequisite for assessing the effectiveness of marine CO 2 removal approaches that target marine biology.
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  • 56
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    GEOMAR
    Publication Date: 2024-01-24
    Description: RV Meteor M197 EMS-PS ('Eastern Mediterranean Sea - Process Study'), 30.12.2023 – 06.02.2024
    Type: Report , NonPeerReviewed
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  • 57
    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.
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  • 58
    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.
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  • 59
    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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  • 60
    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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  • 61
    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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  • 62
    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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  • 63
    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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  • 64
    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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  • 65
    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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  • 66
    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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  • 67
    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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  • 68
    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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  • 69
    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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  • 70
    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.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 71
    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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  • 72
    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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  • 73
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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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  • 74
    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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  • 75
    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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  • 76
    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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  • 77
    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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  • 78
  • 79
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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
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  • 80
    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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  • 81
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    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
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  • 82
    Publication Date: 2024-02-09
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  • 83
    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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  • 84
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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
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  • 85
    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.
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  • 86
    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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  • 87
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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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  • 88
    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.
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  • 89
    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.
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  • 90
    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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  • 91
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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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  • 92
    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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  • 93
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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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  • 94
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  • 97
    Publication Date: 2024-02-22
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 98
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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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  • 99
    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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  • 100
    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
    Type: Article , PeerReviewed
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