ALBERT

Description: Albedo – the reflectivity of a surface - is an important component in the energy budget, impacting the local to global climate. Data from nadir-viewing satellites can be combined with bidirectional reflectance distribution function (BRDF) data from multi-angular observation platforms to achieve realistic albedo values that acknowledge anisotropy. In my thesis, I evaluated how the land surface albedo varied on spatial and temporal scales during the snow-free period on Disko Island, Greenland. I examined how the albedo differed among the vegetation classes. Concerning the methodology, I assessed how the combination of MODIS BRDF data with Landsat 8 (L8) or Sentinel-2 (S2) influenced the albedo. The study area was located at the southern tip of Disko Island (69.27 °N, -53.47 °E) in West Greenland and covered a wetland and a range of tundra vegetation. I analysed automatic weather station (AWS) data from 2013 to 2022 and conducted mobile albedo measurements in August and September 2022 to examine the temporal and spatial variability. For the period from June to September 2022, I derived the L8 and S2 based albedo with inclusion of MODIS BRDF and narrow to broadband conversion and analysed their variability with regard to vegetation classes. In the snow-free period, the albedo increased from a monthly mean of 0.16 in June to 0.19 in September in the AWS data. The mobile measurements ranged from 〈 0.10 above bare soil and water to 〉 0.23 above areas dominated by lichen, Salix glauca or Equisetum arvense. The satellite-based albedo revealed temporally variable, significant correlations to normalised difference vegetation and moisture indices that reached values 〉 0.5 in the fen and wet heath class on several days. The albedo of shrubs was not notably smaller than other vegetation types but partly 0.01-0.05 above them in both the mobile measurements and the satellite-derived albedo. This finding challenges the assumption that shrubification causes climate forcing in all circumstances. The albedo of L8 and S2 differed to each other and the local data (root-mean-square error 0.04-0.14). The BRDF correction increased the albedo by 0.01 on average compared to nadir reflectance. L8 was better in reproducing the expected temporal and spatial variability of albedo than S2, which displayed less variability. S2 seemed to be more sensitive to atmospheric effects of haze and clouds influencing albedo. Thus, L8 seemed more suitable to calculate albedo in the study area. Though there were some methodological limitations, this thesis highlights aspects that should be considered when analysing albedo or jointly using L8 and S2 in high latitude regions.

Description: The origin, transport pathway, and spatial variability of total organic carbon (OC) in the western Himalayan glaciers are poorly understood compared to those of black carbon (BC) and dust, but it is critically important to evaluate the climatic role of OC in the region. By applying the distribution of OC activation energy; 14C activity; and radiogenic isotopes of 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb in glacial debris and atmospheric particulate matter (PM10 size fraction), we demonstrate that 98.3 ± 1.6 and 1.7 ± 1.6% of OC in western Himalayan glaciers are derived from biomass and petrogenic sources, respectively. The δ13C and N/C composition indicates that the biomass is a complex mixture of C3 vegetation and autochthonous photoautotrophic input modified by heterotrophic microbial activity. The data set reveals that the studied western Himalayan glacier has negligible contributions from fossil-fuel-derived particles, which contrasts to the central and eastern Himalayan glaciers that have significant contributions from fossil fuel sources. We show that this spatial variability of OC sources relates to regional differences in air mass transport pathways and precipitation regimes over the Himalaya. Moreover, our observation suggests that biomass-derived carbon could be the only primary driver of carbon-induced glacier melting in the western Himalaya.

Description: Fluoride contamination in groundwater is a worldwide phenomenon. Excess fluoride in drinking water causes serious health risks, and as a result, fluoride contamination of water resources is a global concern. In this study, an attempt has been made to provide the distribution of fluoride and related non-carcinogenic health hazards to local individual groups (males, females, and children separately) in the fluoride endemic region of Patiala, Punjab located in the Northern Indo-Gangetic Plain (IGP). The study shows that the dissolved groundwater fluoride concentration ranged between 1.5 and 9.2 mg/L with ∼98% of the sampling locations having fluoride levels higher than the permissible limit. Samples collected from deeper aquifers (〉284 m bgl) showed ∼27% more fluoride contamination compared to those collected from 〈284 m bgl. Maximum incidence of elevated fluoride concentrations was observed in the eastern part of the study area in-sync with groundwater movement. The hazard quotient of fluoride (HQFluoride) calculated to assess the non-carcinogenic health risk was higher than the unitary value in all individual groups suggesting a prevalence of distressful fluorosis and chronic health risk. Results show that the children are the most vulnerable to fluoride toxicity followed by males and females. Our results are consistent with the recent trends in an increase in dental, skeletal fluorosis, and liver functional damage problems reported in children and adults of the studied region. The study area, therefore, needs the urgent attention of policymakers and government agencies to implement proper water management and cost-effective fluoride remedial measures to reduce the current and future chronic health risks associated with high fluoride intake.

Description: Die Bestimmung der Temperaturverteilung in der Erdkruste und im oberen Erdmantel ist von großer Bedeutung für die Behandlung geotektonischer Probleme. In dieser Arbeit wird die Temperaturverteilung längs eines Profils in Süditalien untersucht, das vom Südadriatischen Meer durch Kalabrien zum Tyrrhenischen Meer verläuft. Grundlage für diese Untersuchung bilden eine Anzahl publizierter Wärmeflußwerte und ein refraktionsseismisches Profil. Längs des ausgewählten geothermischen Profils sind die Temperatur-Tiefen-Funktionen für zwei Modelle der Wärmeproduktionsverteilung, Schichten- und Exponential-Modell , für den stationären Zustand berechnet worden.

Description: The determination of temperature distribution in the earth's crust and upper mantle is of great importance for geotectonic problems. The temperature distribution is discussed along a profile in southern Italy, which runs from the Adriatic to the Tyrrhenian Seas. This study is based on published heat flow values and seismic refraction data. The temperature-depth-functions are calculated for layer and exponential models for the heat production assuming a stationary state.

Description: thesis

Description: DFG, SUB Göttingen

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"〉Vegetation classification is an essential prerequisite for understanding vegetation‐water relations at a range of spatial scales. However, in site‐specific applications, such classifications were mostly based on a single Unmanned Aerial Vehicle (UAV) flight, which can be challenging in grasslands and/or herbaceous‐dominated systems, as those communities are small in size and highly mixed. Here, we conducted monthly UAV flights for two years in a riparian wetland in Germany, with acquired imagery used for vegetation classification on a monthly basis under different strategies (with or without auxiliary information from other flights) to increase understanding in ecohydrology. The results show that multi‐flight‐based classification outperformed single‐flight‐based classification due to the higher classification accuracy. Moreover, improved sensitivity of temporal changes in community distribution highlights the benefits of multi‐flight‐based classification ‐ providing a more comprehensive picture of community evolution. From reference to the monthly community distribution, we argue that a combination of two or three flights in early‐ and late‐summer is enough to achieve comparable results to monthly flights, while mid‐summer would be a better timing in case only one flight is scheduled. With such detailed vegetation mapping, we further interpreted the complex spatio‐temporal heterogeneity in NDVI and explored the dominant areas and developmental progress of each community. Impacts from management (mowing events) were also evaluated based on the different responses between communities in two years. Finally, we explored how such vegetation mapping could help understand landscape ecohydrology, and found that the spatio‐temporal distribution of minimal soil moisture was related to NDVI peaks of local community, while grass distribution was explained by both topography and low moisture conditions. Such bi‐directional relationships proved that apart from contributing to an evidence base for wetland management, multi‐flight UAV vegetation mapping could also provide fundamental insights into the ecohydrology of wetlands.〈/p〉

Description: Chinese Scholarship Council (CSC)

Description: Einstein Foundation Berlin and Berlin University Alliance

Description: Leverhulme Trust http://dx.doi.org/10.13039/501100000275

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"〉To evaluate how the presence of pseudotachylytes affects the strength of crustal rocks, deformed pseudotachylytes and their relationship with pristine pseudotachylytes at the base of the Silvretta nappe are analyzed. Pseudotachylytes formed associated with high‐stress crystal plasticity (〈italic〉σ〈/italic〉〈sub〉〈italic〉d〈/italic〉〈/sub〉 > 400 MPa), as indicated by twinned amphiboles in gneisses. Mylonitic quartz clasts enclosed within deformed pseudotachylytes and mylonitic vein‐quartz, hosting folded pseudotachylyte injection veins, reflect creep at lower stresses (ca. 100 MPa) after seismic rupturing. Deformed pseudotachylytes can be crosscut by pristine pseudotachylytes, indicating a second, independent stage of coseismic rupturing after creep. The evidence of dynamic dislocation creep of quartz and the presence of stilpnomelane and epidote associated with all fault rocks indicate similar ambient greenschist facies conditions during all deformation stages. Whereas the intermediate stage of creep is interpreted to represent deformation at large distance to the propagating thrust tip, the pristine pseudotachylytes represent the last stage of rupturing eventually leading to nappe decoupling from its basement. Gneiss clasts in an ultramylonitic matrix (i.e., deformed pseudotachylyte) reveal that pseudotachylytes have a lower strength during creep in relation to the hosting gneisses. In contrast, during coseismic high‐stress crystal plasticity, the coarse gneisses accumulate a higher amount of strain. This strength‐relationship explains that only those rocks rupture, which have not been previously deformed before. The study demonstrates the importance of different strengths of crustal rocks at specific stress‐ and strain‐rate conditions in dependence on the distance to the propagating fault tip.〈/p〉

Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Ultramylonites (deformed pseudotachylytes) and mylonites represent creep at large distance to the propagating thrust tip〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Pristine pseudotachylytes represent final deformation at the tip of the propagating thrust fault associated with nappe decoupling〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Pseudotachylytes are weak during aseismic creep and strong during coseismic high‐stress plasticity〈/p〉〈/list-item〉 〈/list〉 〈/p〉

Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Description: https://doi.org/10.17632/xhh2ktks9g.4

Description: https://nano.oxinst.com/products/aztec/

Description: https://www.horiba.com/aut/scientific/products/detail/action/show/Product/labspec-6-spectroscopy-suite-software-1843/

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"〉There have been a number of theories proposed concerning the loss of relativistic electrons from the radiation belts. However, direct observations of loss were not possible on a number of previous missions due to the large field of view of the instruments and often high‐altitude orbits of satellites that did not allow researchers to isolate the precipitating electrons from the stably trapped. We use measurements from the ELFIN‐L suit of instruments flown on Lomonosov spacecraft at LEO orbit, which allows us to distinguish stably trapped from the drift loss cone electrons. The sun‐synchronous orbit of Lomonosov allows us to quantify scattering that occurred into the loss cone on the dawn‐side and the dusk‐side magnetosphere. The loss at MeV energies is observed predominantly on the dawn‐side, consistent with the loss induced by the chorus waves. The companion data publication provides processed measurements.〈/p〉

Description: Plain Language Summary: There have been a number of models proposed concerning the loss of relativistic electrons from radiation belts. However, the direct observations of loss have been missing, as for most of the previous missions; the large aperture telescopes could not isolate the precipitating electrons from being stably trapped. In this study, we use measurements from ELFIN‐L on Lomonosov that allow for such separation and allow us to distinguish stably trapped from precipitating particles. We can also identify the particles that will be lost within one drift around the Earth, the so‐called drift loss cone. For understanding the loss processes and differentiating between them, it's crucially important to quantify where in local magnetic time these electrons will be scattered into the drift loss cone. Measurements from the ELFIN‐L instrument show that the loss at MeV energies is observed predominantly on the dawn side, consistent with the loss induced by the so‐called chorus plasma waves.〈/p〉

Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉ELFIN‐L measurements allow comparing scattering into the loss cone on the dawn and dusk side〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Processed Level‐3 measurements are provided in the data publication〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Most of the relativistic electrons are scattered into the drift loss cone on the dawn side〈/p〉〈/list-item〉 〈/list〉 〈/p〉

Description: National Science Foundation

Description: Russian University Satellite Mission

Description: Helmholtz Association

Description: European Union's Horizon 2020 Research and Innovation Program

Description: https://doi.org/10.5880/GFZ.2.7.2023.002

Description: https://doi.org/10.5880/GFZ.2.7.2023.003

Description: https://doi.org/10.5880/GFZ.2.7.2023.004

Description: https://doi.org/10.5880/GFZ.2.7.2023.005

Description: https://doi.org/10.5880/GFZ.2.7.2023.006

Description: https://doi.org/10.5880/GFZ.2.7.2023.007

Description: https://www.ncei.noaa.gov/data/poes-metop-space-environment-monitor/access/l1b/v01r00/

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

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

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

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〉

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

Description: Geophysikalische Sensoren wie Erdgezeitengravimeter und Bohrlochneigungsmesser gehören zu den empfindlichsten mechanischen Meßgeräten, die gebaut werden. Sie zeichnen sich durch große Dynamik bei gleichzeitig extremer Breitbandigkeit aus. Vor allem diesen beiden Aspekten kann bei der konventionellen analogen Registrierung nicht immer Rechnung getragen werden. Deshalb wird mit dieser Arbeit die Einführung eines digitalen Registriersystems für diese Sensoren beschrieben, das moderne Konzepte der digitalen Datenerfassung und -Verarbeitung einsetzt. Bei zwei aktuellen Projekten in Skandinavien werden drei Askania Bohrlochneigungsmesser und ein LaCoste & Romberg Erdgezeitengravimeter betrieben. Bei der Installation in Norwegen geht es mit dem Einsatz von zwei Neigungsmessern um die Registrierung von Auflastsignalen durch einen Stausee und in Finnland soll mit der 3 Komponentenstation das gesamte Spektrum der Krustendynamik von Eigenschwingungen des Erdkörpers bis zu rezenten Deformationen auf gezeichnet werden. Es wird zunächst der Aufbau der Bohrlochneigungsmesser beschrieben und diskutiert, welche Signale in welchem Frequenzbereich gemessen werden können. Für die Vorbereitung dieser Arbeit wurden Modellrechnungen durchgeführt um über das tatsächliche Übertragungsverhalten im Bereich der Eigenperiode des Pendels mit und ohne Fesselung Auskunft zu erhalten. Die Überholung der Bohrlochneigungsmesser mit dem Ersatz des empfindlichen Original Vorverstärkers bilden den Abschluß der Pendelbeschreibung. Die Grundlagen des Meßprinzips der LaCoste & Romberg Gravimeter werden beschrieben und der analoge Eigenschwingungsfilter des Gravimeters untersucht. Für einen breitbandigen Datenkanal stellt sich bei einer Auflösung der Eigenschwingungssignale mit 72dB die Forderung nach einer Gesamtdynamik von 130dB. Bei der Darstellung der Grundlagen der digitalen Datenerfassung wird der Schwerpunkt auf die Beschreibung des Abtasttheorems gelegt und das Prinzip des Oversampling beschrieben. Die Umsetzung dieser Theorie in ein digitales Registriersystem mit einer Dynamik von 130dB bei einer Frequenzauflösung von .02 Hertz und dessen Einsatz im Gelände werden vorgestellt. Dabei wurde eine flexible Lösung gefunden, die sich ohne Probleme als Einkanalstation beim Gravimeter, oder als Mehrkanalsystem mit den Neigungsmessern konfigurieren läßt. Darüber hinaus werden zusätzliche Kanäle für meteorologischen Meßdaten bereitgestellt. Kurze Registrierbeispiele geben einen Eindruck von der Qualität der Rohdaten, und die Berechnung einiger Rauschspektren bestätigt, dass die geforderte Auflösung erreicht werden konnte. Beim Gravimeter konnten im Bereich von 102 bis 104 Sekunden

Description: Geophysical sensors like earth tide gravity meters and borehole tilt meters belong to the group of most sensitive mechanical devices, being available today. Their main features include wide dynamic range and extreme broadband resolution. These aspects are not always taken into consideration when dealing with analogue recording systems. Therefore, this work introduces a digital recording system for the above mentioned sensors which includes the modern concept of data acquisition and data processing. Within the scope of two projects being carried out in Scandinavia, three Askania borehole tilt meters and one LaCoste & Romberg earth tide gravity meter have been put into operation. In Norway two tilt meters are recording the loading signal of a reservoir. In Finland, a three component station is recording the whole spectrum of crusta dynamics, ranging from free mode signals of the earth to active crustal deformation. After the mechanical construction of the tilt meter has been discussed and the expected signal- and frequency range evaluated, model calculations are presented in order to determine the true transfer property of the pendulum around its natural resonance frequency. The introduction of an improved preamplifier stage for the borehole tilt meter then terminates the chapter on tilt meters. In the following the principle of operation of the LaCoste & Romberg gravity meter and the analogue free mode filter are being discussed in detail. For a broadband data stream dissolving the free mode signal at 72dB, the total dynamic range requires 130dB. For a broader understanding the basics of digital data acquisition, the sampling theorem and what is called oversampling are discussed in more detail. Furthermore, a digital recording system with a dynamic range of 130dB (at a frequency resolution of .02Hz) and its performance under field conditions is described. In conclusion, the configuration of the system as single channel station (gravity meter) or multichannel station (tilt meter) is demonstrated. In addition to the already existing data channels other channels are available to include meteorological data. Finally, a few original recordings are presented to demonstrate the quality of the raw data sets. The computation of the noise spectra shows, it was possible to achieve the necessary resolution. The noise amplitudes of the gravity meter at the range of 102 - 104 seconds were less than 2 ngal/√Hz and about 10 ngal/√Hz for the pendula.

Description: thesis

Description: DFG, SUB Göttingen

Description: Die Toskana ist die stärkste geothermische Anomalie auf dem europäischen Kontinent. In dieser Anomalie finden sich zahlreiche lokale geothermische Felder mit hoher Enthalpie, wie z.B. das Feld von Travale. In diesem geothermischen Feld, das im Era-Graben liegt, wurden in den Jahren 1980/81 elektromagnetische Messungen durchgeführt. Es war das Ziel der Untersuchungen, die Quelle und die Ursache dieser teilweise bekannten Anomalie zu finden. Hierzu sollte die Verteilung der elektrischen Leitfähigkeit in der Erdkruste bis in Tiefen der Kruste-Mantel-Grenze mit den Methoden der Magnetotellurik und Erdmagnetischen Tiefensondierung untersucht werden. Parallel dazu wurde die geothermische Anomalie von Travale mit einer Vielzahl weiterer elektromagnetischer, seismischer und geochemischer Methoden untersucht. Das Ziel, die geothermische Anomalie in der Erdkruste zu lokalisieren, war nicht einfach zu erreichen. Deshalb war es notwendig, ein Modell der Anomalie zu erarbeiten, aus dem die Lokalität folgen sollte. Vor angegangene elektromagnetische Untersuchungen (HAAK & SCHWARZ 1981) hatten gezeigt, daß nahezu das gesamte Gebiet der Toskana als eine Anomalie der elektrischen Leitfähigkeit anzusehen ist: Gutleitende Deckschichten, mit bis zu 10 km Mächtigkeit, werden von einem hochohmigen Basement unterlagert. An einigen Meßorten deutet sich der Übergangsbereich Kruste / Mantel - in einer Tiefe zwischen 20 und 30 km - durch eine Zone hoher Leitfähigkeit an. Dieser Bereich zeichnet sich durch Lamellen hoher und extrem niedriger seismischer Wellengeschwindigkeiten aus. Petrologisch kann dieses durch eine Wechsellagerung von basischem und saurem Material gedeutet werden. Die zeitlichen Variationen des elektrischen und magnetischen Feldes wurden im geothermischen Feld von Travale in einem breiten Periodenbereich von 6 - 10.000 s registriert. Die Meßorte liegen überwiegend auf zwei Profilen, eines verläuft parallel zum Era-Graben aus der Anomalie heraus nach NW, das zweite schneidet die Anomalie senkrecht zum Graben. Der Meßpunktabstand war mit einigen hundert Metern bis zu mehreren Kilometern sehr dicht, um möglichst alle lateralen Variationen der scheinbaren spezifischen Widerstände beobachten zu können. Es zeigte sich, daß die lateralen Variationen der spezifischen Widerstände im Gebiet von Travale sehr groß waren. Bis zu Perioden von 50-100 s ist der Era-Graben die dominierende zweidimensionale Leitfähigkeitsstruktur. Die gemessenen scheinbaren spezifischen Widerstände sind bei längeren Perioden durch dreidimensionale Leitfähigkeitsstrukturen verzerrt. Die scheinbaren elektrischen Widerstände sind innerhalb der geothermischen Anomalie mit Werten bis zu 50 Qm äußerst klein, während sie nördlich des geothermischen Feldes auf 100-300 Qm ansteigen, um dann etwa 7 km NW der Anomalie wieder deutlich abzufallen. Selbst in der tieferen Kruste werden keine höheren Widerstände angetroffen. Die integrierte Leitfähigkeit weist das geothermische Feld ebenso als eine Anomalie der elektrischen Leitfähigkeit aus, während nördlich davon die "hochohmige Barriere" bestätigt wurde. Aus den Ergebnissen der Seismik und Magnetotellurik wurde ein Modell für die geothermische Anomalie von Travale und die Toskana abgeleitet, das sich in drei Stockwerke gliedert: - Das unterste Stockwerk, die Übergangszone zwischen Oberem Mantel und Unterkruste in 20-30 km Tiefe ist die Quelle auf steigender heißer Gase und Flüssigkeiten. Die Temperatur beträgt etwa 700° C. - Das mittlere Stockwerk ist von tief reichenden, vertikalen Störungen durchsetzt, die einen konvektiven Wärmetransport durch die hydrothermalen Phasen in das oberste Stockwerk erlauben. Im Gebiet von Travale hat sich durch längs- und zum Era-Graben querstreichende Störungen eine ausgeprägte Schwächezone in der Kruste gebildet, die einen besonders intensiven Wärmetransport zuläßt. Der Temperaturgradient wird mit 15° C/km angenommen. - Das oberste Stockwerk besteht aus Sedimenten und kristallinen Formationen, die im wesentlichen von horizontalen Abscherungs- und Störungsflächen durchzogen sind, in denen hydrothermale Phasen zirkulieren. Innerhalb der Basements hat sich so ein zweites Reservoir ausgebildet, welches das bekannte geothermische Reservoir in den Karbonaten in Tiefen von 1-2 km durch ein ausgeprägtes Bruchsystem speist. Die Temperatur ist in 4 km Tiefe mit 400° C sehr hoch. Die augenblicklich geförderten heißen Gase und Wässer sind meteorologischen Ursprungs und werden an der Oberkante des toskanischen Basements aufgeheizt. Aus tektonischer Sicht besteht das oberste Stockwerk aus allochthonen Decken, die während der Orogenese über die Toskana hinweggeschoben wurden. Dieser tektonischen Kompressionsphase folgte eine Phase starker lateraler Dehnungen, die bis heute andauern. Das System von Grabenbrüchen und tiefgreifenden Verwerfungen ist Ausdruck dieser Dehnungstektonik. Die damit verbundenen Störungszonen tragen zu einer Entwässerung und Entgasung der tiefen Erdkruste bei und lassen die hydrothermalen Phasen in das oberste Stockwerk aufs teigen. In ausgeprägte Schwächezonen, die die gesamte Kruste durchziehen und die durch undurchlässige Schichten nach oben abgeschlossen werden, kann sich so ein geothermisches Reservoir ausbilden.

Description: Tuscany is the strongest geothermal anomaly in continental Europe. Numerous local high enthalpy geothermal fields are to be found within this anomaly, e.g. the Travale field. Electromagnetic soundings have been carried out in this geothermal field, which lies in the Era-Graben, in the years 1980 and 1981. The aim of this study was to find the origin as well as the cause of this partly known anomaly, using the methods of magnetotelluric- and geomagnetic depth soundings to study the distribution of electrical conductivity in the earth's crust downwards to the crust/mantle boundary, at least. Parallel to this study the geothermel anomaly of Travale has been studied with the help of various other methods, including electromagnetic, seismic and geochemical surveys. To localize the geothermal anomaly in the earth's crust was not an easy task. Therefore it seemed to be necessary to develop a model of the anomaly, first, and then to localize it. Earlier electromagnetic investigations (HAAK & SCHWARZ 1981) have shown, that nearly the whole area of Tuscany corresponds to an electrical conductivity anomaly: A well conducting cover, reaching down to 10 km depth is underlain by a high resistive basement. At some places within the geothermal anomaly a zone of high conductivity has been found at the depth of the crust/mantle-boundary (between 20 and 30 km) . Seismic refraction measurements are indicating a wide transition zone between the crust und upper mantle, displayed by alternating high- und extreme low-velocity layers. The time-varying electric- and magnetic fields have been recorded in the Travale area in a broad period range from 6-10.000 s, mainly on two profiles, the one parallel, the other perpendicular to the Era-Graben. The stations have been very close to each other, spacings varied between some hundreds of meters and a few kilometers, to study lateral variations of apparent resistivities within the Graben. In deed, lateral variations of apparent resistivities have been very large in the Travale area. Up to 50-100 s the Era-Graben is the dominating 2D-structure, but for longer periods of investigation the three-dimensionality of the electrical conductivity structure has to be considered. The apparent resistivities inside the geothermal anomaly are extremely low, reaching not more than 50 Gm, even in the lower crust, whereas going up to 100-300 firn north of the geothermal field. Further to NW apparent resistivities are coming down again to 5-5o Gm. Total conductance as well indicates the geothermal field as a local conductivity anomaly, whereas more to the north the poorly conducting "barrier" has been confirmed. Based on the results of the magnetotelluic soundings and those of the seismic survey a geothermal model for the anomaly of Travale as well as for Tuscany has been developed. The crust is built up by 3 stories: - The lowermost story of the transition from the mantle to the crust at 20-30 km depth has to be regarded as the origin of hot gases and fluids. Temperature amounts to 700° C. - The central story is more or less fractured vertically so that pathways allow convective transport of heat by means of hydrothermal fluids to the upper story. In the Travale area a weak crustal zone of faults crossing over has developed, allowing the transport of heat to be very intensive. The temperature gradient is assumed to reach not more than 15° C/km. - The uppermost story consists of sediments and more or less horizontally fractured crystalline formations, filled with hot, circulating fluids. Within the basement a second reservoir has evolved, which feeds the known geothermal reservoir in the carbonate series at 1-2 km depth through fractures and cracks in the top of the basement. The temperature of about 400° C in 4 km depth is extremely high. The actually exploited hot gases and fluids are of meterological origin and heated up at the top of the basement. From the tectonic point of view, the uppermost story consists of allochthonous nappes shifted across Tuscany during orogenesis. This compressive tectonic deformation was followed by strong dilatational forces, which are still active in the whole crust, expressed by the features of graben structures and deep reaching faults. This process gives volatiles and water generated by dehydration in the deep crust the chance to rise to the uppermost story. A basement fractured at the top and an impermeable cover in the uppermost layer will then favour the development of a geothermal reservoir.

Description: thesis

Description: DFG, SUB Göttingen

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"〉In this contribution we report the first systematic study of zircon U‐Pb geochronology and δ〈sup〉18〈/sup〉O‐〈italic〉ε〈/italic〉Hf〈sub〉(〈italic〉t〈/italic〉)〈/sub〉 isotope geochemistry from 10 islands of the hot‐spot related Galapagos Archipelago. The data extracted from the zircons allow them to be grouped into three types: (a) young zircons (0–∼4 Ma) with 〈italic〉ε〈/italic〉Hf〈sub〉(〈italic〉t〈/italic〉)〈/sub〉 (∼5–13) and δ〈sup〉18〈/sup〉O (∼4–7) isotopic mantle signature with crystallization ages dating the islands, (b) zircons with 〈italic〉ε〈/italic〉Hf〈sub〉(〈italic〉t〈/italic〉)〈/sub〉 (∼5–13) and δ〈sup〉18〈/sup〉O (∼5–7) isotopic mantle signature (∼4–164 Ma) which are interpreted to date the time of plume activity below the islands (∼164 Ma is the minimum time of impingement of the plume below the lithosphere), and (c) very old zircons (∼213–3,000 Ma) with mostly continental (but also juvenile) 〈italic〉ε〈/italic〉Hf〈sub〉(〈italic〉t〈/italic〉)〈/sub〉 (∼−28–8) and δ〈sup〉18〈/sup〉O (∼5–11) isotopic values documenting potential contamination from a number of sources. The first two types with similar isotopic mantle signature define what we call the Galápagos Plume Array (GPA). Given lithospheric plate motion, this result implies that GPA zircon predating the Galápagos lithosphere (i.e., >14–164 Ma) formed and were stored at sublithospheric depths for extended periods of time. In order to explain these observations, we performed 2D and 3D thermo‐mechanical numerical experiments of plume‐lithosphere interaction which show that dynamic plume activity gives rise to complex asthenospheric flow patterns and results in distinct long‐lasting mantle domains beneath a moving lithosphere. This demonstrates that it is physically plausible that old plume‐derived zircons survive at asthenospheric depths below ocean islands.〈/p〉

Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Our data define the Galápagos Plume Array defined by mantle 〈italic〉ε〈/italic〉Hf〈sub〉(〈italic〉t〈/italic〉)〈/sub〉 and δ18O values in the range ∼0–164 Ma〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉This finding allows dating back plume activity to, at least, early Middle Jurassic (∼164 Ma)〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Numerical experiments confirm it is plausible that old Plume‐derived zircons survive in the asthenosphere for extended periods of time〈/p〉〈/list-item〉 〈/list〉 〈/p〉

Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Description: Ministerio de Asuntos Económicos y Transformación Digital, Gobierno de España http://dx.doi.org/10.13039/501100010198

Description: Ministerio de Ciencia e Innovación http://dx.doi.org/10.13039/501100004837

Description: European Research Council http://dx.doi.org/10.13039/501100000781

Description: https://doi.org/10.5281/zenodo.7047729

Description: https://doi.org/10.5281/zenodo.6967187

Description: research

Description: research

Description: research

Description: research

Description: research

Description: Previous field studies in the Southern Ocean (SO) indicated an increased occurrence and dominance of cryptophytes over diatoms due to climate change. To gain a better mechanistic understanding of how the two ecologically important SO phytoplankton groups cope with ocean acidification (OA) and iron (Fe) availability, we chose two common representatives of Antarctic waters, the cryptophyte Geminigera cryophila and the diatom Pseudo-nitzschia subcurvata. Both species were grown at 2°C under different pCO2 (400 vs. 900 μatm) and Fe (0.6 vs. 1.2 nM) conditions. For P. subcurvata, an additional high pCO2 level was applied (1400 μatm). At ambient pCO2 under low Fe supply, growth of G. cryophila almost stopped while it remained unaffected in P. subcurvata. Under high Fe conditions, OA was not beneficial for P. subcurvata, but stimulated growth and carbon production of G. cryophila. Under low Fe supply, P. subcurvata coped much better with OA than the cryptophyte, but invested more energy into photoacclimation. Our study reveals that Fe limitation was detrimental for the growth of G. cryophila and suppressed the positive OA effect. The diatom was efficient in coping with low Fe, but was stressed by OA while both factors together strongly impacted its growth. The distinct physiological response of both species to OA and Fe limitation explains their occurrence in the field. Based on our results, Fe availability is an important modulator of OA effects on SO phytoplankton, with different implications on the occurrence of cryptophytes and diatoms in the future.

Description: The SUMup database is a compilation of surface mass balance (SMB), subsurface temperature and density measurements from the Greenland and Antarctic ice sheets. This 2023 release contains 4 490 442 data points: 1 778 540 SMB measurements, 2 706 413 density measurements and 5 489 subsurface temperature measurements. This is respectively 1 477 132, 420 825 and 4 715 additional observations of SMB, density and temperature compared to the 2022 release. This new release provides not only snow accumulation on ice sheets, like its predecessors, but all types of SMB measurements, including from ablation areas. On the other hand, snow depth on sea ice is discontinued, but can still be found in the previous releases. The data files are provided in both CSV and NetCDF format and contain, for each measurement, the following metadata: latitude, longitude, elevation, timestamp, method, reference of the data source and, when applicable, the name of the measurement group it belongs to (core name for SMB, profile name for density, station name for temperature). Data users are encouraged to cite all the original data sources that are being used. Issues about this release as well as suggestions of datasets to be added in next releases can be done on a dedicated user forum: https://github.com/SUMup-database/SUMup-data-suggestion/issues. Example scripts to use the SUMup 2023 files are made available on our script repository: https://github.com/SUMup-database/SUMup-example-scripts.

Description: The SUMup database is a compilation of surface mass balance (SMB), subsurface temperature and density measurements from the Greenland and Antarctic ice sheets. This 2023 release contains 4 490 442 data points: 1 778 540 SMB measurements, 2 706 413 density measurements and 5 489 subsurface temperature measurements. This is respectively 1 477 132, 420 825 and 4 715 additional observations of SMB, density and temperature compared to the 2022 release. This new release provides not only snow accumulation on ice sheets, like its predecessors, but all types of SMB measurements, including from ablation areas. On the other hand, snow depth on sea ice is discontinued, but can still be found in the previous releases. The data files are provided in both CSV and NetCDF format and contain, for each measurement, the following metadata: latitude, longitude, elevation, timestamp, method, reference of the data source and, when applicable, the name of the measurement group it belongs to (core name for SMB, profile name for density, station name for temperature). Data users are encouraged to cite all the original data sources that are being used. Issues about this release as well as suggestions of datasets to be added in next releases can be done on a dedicated user forum: https://github.com/SUMup-database/SUMup-data-suggestion/issues. Example scripts to use the SUMup 2023 files are made available on our script repository: https://github.com/SUMup-database/SUMup-example-scripts.

Description: Palaeoenvironmental records from permafrost sequences complemented by infrared stimulated luminescence (IRSL) and 230Th/U dates from Bol'shoy Lyakhovsky Island (73°20′N, 141°30′E) document the environmental history in the region for at least the past 200 ka. Pollen spectra and insect fauna indicate that relatively wet grasssedge tundra habitats dominated during an interstadial c. 200-170 ka BP. Summers were rather warm and wet, while stable isotopes reflect severe winter conditions. The pollen spectra reflect sparser grass-sedge vegetation during a Taz (Late Saalian) stage, c. 170-130 ka BP, with environmental conditions much more severe compared with the previous interstadial. Open Poaceae and Artemisia plant associations dominated vegetation at the beginning of the Kazantsevo (Eemian) c. 130 ka BP. Some shrubs (Alnus fruticosa, Salix, Betula nana) grew in more protected and wetter places as well. The climate was relatively warm during this time, resulting in the melting of Saalian ice wedges. Later, during the interglacial optimum, shrub tundra with Alnus fruticosa and Betula nana s.l. dominated vegetation. Climate was relatively wet and warm. Quantitative pollen-based climate reconstruction suggests that mean July temperatures were 4-5°C higher than the present during the optimum of the Eemian, while late Eemian records indicate significant climate deterioration. © 2004 Taylor & Francis.

Description: 〈jats:p〉Diatoms captivate both biologists and engineers with their remarkable mechanical properties and lightweight design principles inherent in their shells. Recent studies have indicated that diatom frustules possess optimized shapes that align with vibrational modes, suggesting an inherent adaptation to vibratory loads. The mode shape adaptation method is known to significantly alter eigenfrequencies of 1D and 2D structures to prevent undesired vibration amplitudes. Leveraging this insight, the diatom-inspired approach to deform structures according to mode shapes was extended to different complex 3D structures, demonstrating a significant enhancement in eigenfrequencies with distinct mode shapes. Through extensive parameter studies, frequency increases exceeding 200% were obtained, showcasing the method’s effectiveness. In the second study part, the studied method was integrated into a user-friendly, low-code software facilitating swift and automated structural adjustments for eigenfrequency optimization. The created software tools, encompassing various components, were successfully tested on the example structures demonstrating the versatility and practicality of implementing biomimetic strategies in engineering designs. Thus, the present investigation does not only highlight the noteworthiness of the structural adaptation method inspired by diatoms in maximizing eigenfrequencies, but also originate software tools permitting different users to easily apply the method to distinct structures that have to be optimized, e.g., lightweight structures in the mobility or aerospace industry that are susceptible toward vibrations.〈/jats:p〉

Description: A trend towards earlier sea-ice melt is detected in many ice-covered regions in the Arctic. The timing of the melt onset has a strong impact on the sea-ice energy budget. Melt onset changes the radiative properties of the ice due to increasing snow wetness and meltwater. So far, satellite passive microwave data are used to detect the melt onset. We analyzed transmitted radiation spectra as collected underneath drifting sea-ice using a remotely operated vehicle during the ARTofMELT expedition in the Fram Strait in spring 2023. We colocated those spectra with measurements of snow depth, sea ice and surface topography, chlorophyll-a concentration in the water column, and with aerial images. This combined dataset enables us to track down possible subsurface pathways and accumulation pools of meltwater. Areas of low snow load and depressed surface topography are characterized by higher transmitted radiation compared to areas with a thick snow cover. Those areas overlapped with areas that showed the first signs of surface melt. Chlorophyll-a concentrations varied only slightly in magnitude and did not match with the heterogeneous pattern of snow depth and ice topography. Here we discuss how to disentangle the influences of chlorophyll a and the subsurface meltwater on the spectral shape of transmitted radiation. We propose that upon successful disentanglement, the spectra can be used as an indicator for subsurface melting. Our study suggests that sea-ice melting starts subsurface and that measurements of transmitted solar radiation spectra could be used to identify the melt onset prior to surface melting. This can provide an interesting complementary information on melt occurrence and on the location of the water in the snowpack in addition to satellite passive microwave data.

Description: A trend towards earlier sea-ice melt is detected in many ice-covered regions in the Arctic. The timing of the melt onset has a strong impact on the sea-ice energy budget. Melt onset changes the radiative properties of the ice due to increasing snow wetness and meltwater. So far, satellite passive microwave data are used to detect the melt onset. We analyzed transmitted radiation spectra as collected underneath drifting sea-ice using a remotely operated vehicle during the ARTofMELT expedition in the Fram Strait in spring 2023. We colocated those spectra with measurements of snow depth, sea ice and surface topography, chlorophyll-a concentration in the water column, and with aerial images. This combined dataset enables us to track down possible subsurface pathways and accumulation pools of meltwater. Areas of low snow load and depressed surface topography are characterized by higher transmitted radiation compared to areas with a thick snow cover. Those areas overlapped with areas that showed the first signs of surface melt. Chlorophyll-a concentrations varied only slightly in magnitude and did not match with the heterogeneous pattern of snow depth and ice topography. Here we discuss how to disentangle the influences of chlorophyll a and the subsurface meltwater on the spectral shape of transmitted radiation. We propose that upon successful disentanglement, the spectra can be used as an indicator for subsurface melting. Our study suggests that sea-ice melting starts subsurface and that measurements of transmitted solar radiation spectra could be used to identify the melt onset prior to surface melting. This can provide an interesting complementary information on melt occurrence and on the location of the water in the snowpack in addition to satellite passive microwave data.

Description: The paralytic shellfish toxin (PST) profiles of Gymnodinium catenatum Graham have been reported for several strains from the Pacific coast of Mexico cultured under different laboratory conditions, as well as from natural populations. Up to 15 saxitoxin analogues occurred and the quantity of each toxin depended on the growth phase and culture conditions. Previous analysis of toxin profiles of G. catenatum isolated from Mexico have been based on post-column oxidation liquid chromatography with fluorescence detection (LC-FLD), a method prone to artefacts and non-specificity, leading to misinterpretation of toxin composition. We describe, for the first time, the complete toxin profile for several G. catenatum strains from diverse locations of the Pacific coast of Mexico. The new results confirmed previous reports on the dominance of the less potent sulfocarbamoyl toxins (C1/2); significant differences, however, in the composition (e.g., absence of saxitoxin, gonyautoxin 2/3 and neosaxitoxin) were revealed in our confirmatory analysis. The LC-MS/MS analyses also indicated at least seven putative benzoyl toxin analogues and provided support for their existence. This new toxin profile shows a high similarity (〉 80%) to the profiles reported from several regions around the world, suggesting low genetic variability among global populations.

Description: Coastal upwelling, driven by alongshore winds and characterized by cold sea surface temperatures and high upper-ocean nutrient content, is an important physical process sustaining some of the oceans’ most productive ecosystems. To fully understand the ocean properties in eastern boundary upwelling systems, it is important to consider the depth of the source waters being upwelled, as it affects both the SST and the transport of nutrients toward the surface. Here, we construct an upwelling source depth distribution for parcels at the surface in the upwelling zone. We do so using passive tracers forced at the domain boundary for every model depth level to quantify their contributions to the upwelled waters. We test the dependence of this distribution on the strength of the wind stress and stratification using high-resolution regional ocean simulations of an idealized coastal upwelling system. We also present an efficient method for estimating the mean upwelling source depth. Furthermore, we show that the standard deviation of the upwelling source depth distribution increases with increasing wind stress and decreases with increasing stratification. These results can be applied to better understand and predict how coastal upwelling sites and their surface properties have and will change in past and future climates.

Description: The genus Amphidinium Clap. & J. Lachm. comprises a high diversity of planktonic and benthic (epiphytic and sand-dwelling) dinoflagellates from marine and freshwater ecosystems. High morphological plasticity and vaguely defined genus characteristics (e.g., a small epicone size) have complicated the clear delineation of species boundaries. Although six Amphidinium morphospecies have been reported from Mexican coastal waters, species identifications are uncertain and not generally supported by molecular phylogenetic data. In this study, seven isolates of Amphidinium from diverse benthic coastal locations on the NE Pacific, Gulf of California, and southern Gulf of Mexico were subjected to critical morphological analysis using photonic and scanning electron microscopy. The phylogenetic reconstruction was based on nuclear-encoded, partial large-subunit (LSU) rDNA and internal transcribed spacer I and II (ITS1 and ITS2) sequences. The revised phylogenetic analysis was consistent with the traditional subdivision of the genus Amphidinium into two sister groups: Herdmanii and Operculatum clades. This study provided the first confirmed records of A. theodorei and A. massartii from coastal waters of Mexico. The molecular phylogenetic evidence indicated that the morphologically described A. cf. carterae from Baja California was in fact more closely allied with A. eilatiensis sequences. A few Amphidinium species are known to form toxigenic (i.e., fish-killing) harmful algal blooms worldwide, and therefore knowledge on species diversity and biogeography is critical in developing effective strategies for evaluating the potential emerging threat in Mexican coastal waters.

Description: Mexican studies on marine benthic dinoflagellates (MBD) began in 1942 from the offshore region of Oaxaca, based on water column samples. Subsequently, in ten Mexican maritime states, both epibenthos and plankton samples have been collected, species have been cultured, and field and laboratory studies have been carried out. Goals: The objective of this contribution is to review the studies on MBD in Mexican waters for current status and future risk assessment. Methods: Available literature on MBD from Mexico published from 1942 to 2022 was analyzed. Results: A review of the studies on MBD is presented herein, subdivided into four sections: (1) taxonomic diversity (morphological and molecular), (2) benthic phycotoxin vectors and toxigenicity, (3) toxicity and (4) species interactions. A map of the location of field populations of MBD and a reference list of taxonomic and ecological studies on MBD in Mexico is provided. A taxonomic list of ca. 60 species, mainly of Prorocentrum, followed in number by Amphidinium, Gambierdiscus, Ostreopsis, Coolia, and Sinophysis is presented. This list is accompanied by scanning electron microscopic images of 15 species. Knowledge of the toxigenicity of MBD is scarce, hence a reference table of known toxigenic species in Mexico and their respective associated syndromes is included. Conclusions: Studies on MBD in Mexico have slowly increased, probably due to the availability of a greater number of cultured strains, as well as to more extensive international collaborations. Confirmed links between benthic harmful algal bloom species and events associated with the etiology of toxic syndromes are rarely known in Mexico.

Description: Harmful algal blooms (HABs) have significant impacts on food safety and security through contamination or mass mortalities of aquatic organisms. Indeed, if not properly controlled, aquatic products contaminated with HAB biotoxins are responsible for potentially deadly foodborne diseases and when rapidly growing, HAB consequences include reduced dissolved oxygen in the ocean, dead zones, and mass mortalities of aquatic organisms. Improving HAB forecasting is an opportunity to develop early warning systems for HAB events such as food contamination, mass mortalities, or foodborne diseases. Surveillance systems have been developed to monitor HABs in many countries; however, the lead-time or the type of data (i.e. identification at the Species-level, determination of toxicity) may not be sufficient to take effective action for food safety management measures or other reasons, such as transfer of aquaculture products to other areas. Having early warning systems could help mitigate the impact of HABs and reduce the occurrence of HAB events. In this regard, FAO took the lead in the development of a Joint FAO-IOC-IAEA Technical Guidance for the Implementation of Early Warning Systems for HABs. The document will guide competent authorities and relevant institutions involved in consumer protection or environmental monitoring to implement early warning systems for HABs present in their areas (marine and brackish waters), specifically for those affecting food safety or food security (benthic HABs, fish-killing HABs, pelagic toxic HABs, and cyanobacteria HABs).

Description: As society's reliance on software systems escalates over time, so too does the cost of failure of these systems. Meanwhile, the complexity of software systems, as well as of their designs, is also ever-increasing, influenced by the proliferation of new tools and technologies to address intended societal needs. The traditional response to this complexity in software engineering and software architecture has been to apply rationalistic approaches to software design through methods and tools for capturing design rationale and evaluating various design options against a set of criteria. However, research from other fields demonstrates that intuition may also hold benefits for making complex design decisions. All humans, including software designers, use intuition and rationality in varying combinations. The aim of this article is to provide a comprehensive overview of what is known and unknown from existing research regarding the use and performance consequences of using intuition and rationality in software design decision-making. To this end, a systematic literature review has been conducted, with an initial sample of 3909 unique publications and a final sample of 26 primary studies. We present an overview of existing research, based on the literature concerning intuition and rationality use in software design decision-making and propose a research agenda with 14 questions that should encourage researchers to fill identified research gaps. This research agenda emphasizes what should be investigated to be able to develop support for the application of the two cognitive processes in software design decision-making.

Description: Die Grundstoffindustrie ist ein wichtiger Pfeiler des Wohlstands in Deutschland, sie garantiert Wertschöpfung und sorgt für über 550.000 hochwertige Arbeitsplätze. Um diese für die deutsche Wirtschaft wichtigen Branchen zu erhalten, müssen jetzt die Schlüsseltechnologien für eine CO2-arme Grundstoffproduktion entwickelt und für den großtechnischen Einsatz skaliert werden. Die vorliegende Analyse ist als Ergänzung zu der Studie "Klimaneutrale Industrie: Schlüsseltechnologien und Politikoptionen für Stahl, Chemie und Zement" gedacht. Die 13 in der erwähnten Studie vorgestellten Schlüsseltechnologien werden hier für die technisch interessierten Leserinnen und Leser eingehender beschrieben und diskutiert. Diese Publikation dient als Aufschlag für eine Diskussion über Technologieoptionen und Strategien für eine klimaneutrale Industrie. Alle Daten und Annahmen in dieser Analyse wurden mit Unternehmen und Branchenverbänden intensiv besprochen. Die quantitativen Aussagen sind trotzdem als vorläufig zu betrachten, da sich viele Technologien noch in einer frühen Entwicklungsphase befinden und Abschätzungen über Kosten mit großen Unsicherheiten verbunden sind.

Description: Die Grundstoffindustrie ist ein Pfeiler des Wohlstands in Deutschland, sie garantiert Wertschöpfung und sorgt für über 550.000 hochwertige Arbeitsplätze. Im Ausland steht Made in Germany für höchste Qualität und Innovationsdynamik. Aber: Trotz Effizienz­steigerungen sind die Emissionen der Industrie in den letzten Jahren nicht gefallen und durch die nationalen und internationalen Klimaschutzziele steigt der Druck. Die zentrale Frage lautet daher: Wie kann die Grundstoffindustrie in Deutschland bis spätestens 2050 klimaneutral werden - und gleichzeitig ihre starke Stellung im internationalen Wettbewerbs­umfeld behalten? Agora Energiewende und das Wuppertal Institut haben im Rahmen dieses Projekts in zahlreichen Workshops mit Industrie, Verbänden, Gewerkschaften, Ministerien und der Zivilgesellschaft die Zukunft für eine klimaneutrale Industrie diskutiert und einen Lösungsraum aus technologischen Optionen und politischen Rahmenbedingungen skizziert. In den Workshops wurde deutlich: Die Industrie steht in den Startlöchern, die Herausforderung Klimaschutz offensiv anzugehen. Die fehlenden Rahmenbedingungen und der bisher unzureichende Gestaltungswille der Politik, innovative Instrumente umzusetzen, hindern sie jedoch voranzugehen. Es ist höchste Zeit, dass sich das ändert. Denn jede neue Industrieanlage muss klimasicher sein - schließlich hat sie eine Laufzeit bis weit über das Jahr 2050 hinaus. Diese Publikation soll einen Beitrag dazu leisten, richtungssicher investieren zu können.

Description: A complete mitochondrial genome of Great Knot (Calidris tenuirostris), MK992912, was published by He and colleagues in 2020. Here we show that this mitogenome is actually a chimera containing DNA fragments of both C. tenuirostris (15,567 bp, 92.8%) and Pacific Golden Plover (Pluvialis fulva, 1208 bp, 7.2%). Detecting such errors is possible before publication if each sequenced fragment is separately analyzed phylogenetically before assembling the fragments into a single mitogenome. This mitogenome has been re-used in at least four phylogenies. The error is documented to avoid the perpetuation of erroneous sequence information in the literature.

Description: Background: The genus Clavicornaltica Scherer 1974 consists of very small, soil-dwelling flea beetles in South, Southeast and East Asia. Due to their diminutive size and morphological similarities, very little is known about their ecology and taxonomical diversity. It is likely that further studies will reveal this genus to be much more speciose than the 30 species currently recognised. New information: A new species of Clavicornaltica from Brunei Darussalam is described, C. mataikanensis Otani et al., sp. nov. This is the second species of this genus recorded from Ulu Temburong National Park.

Description: 1. The interruption of plant-pollinator interactions may threaten global plant diversity, food security and ecosystem stability. Recent reports of strong declines in both insects and plants point to insect decline as a driver of plant decline. However, it is still unknown whether these trends are related as plants often produce seeds without the need for insect pollinators, and to what extent insect-pollinated plants have declined in relation to plants not pollinated by insects. 2. In this study, we hypothesise that natural plant communities have shifted away from insect-pollination. We combined 365,768 vegetation plots from 1930 to 2017 in the Netherlands and plant traits to assess the changes in occurrences of plants pollinated by different modes. Furthermore, we included key drivers in plant decline—specifically nitrogen, moisture and habitat types—as interaction factors to explore the persistence of the observed changes under different environmental conditions. 3. The proportion of insect-pollinated plants has declined while that of wind-pollinated plants has increased over the last 87 years. This proportional change reflects an absolute decrease in the number of insect-pollinated species and an increase in the number of wind-pollinated species. 4. Synthesis and applications. This study implies that Dutch landscapes are losing insect-pollinated plant species, which is likely due, at least in part, to the decline in pollination services. Our results of quantifying the decline in insect-pollinated plants support the necessity and urgency of taking conservation initiatives. Several management strategies and policy recommendations could be applied to alleviate the decline of insect-pollinated plants and ensure crop safety. For example, conserving natural environments by reducing nitrogen deposition may support local plants and insect pollinators. Additionally, there is a particular need for focused efforts to protect natural grasslands, as these areas harbour many insect-pollinated plants, which have experienced declines. Finally, monitoring and assessing the state of both pollinators and (insect-pollinated) plants is needed to assess the progress of conservation measures. While recognising the interdependence of pollinators and pollinated plants, it is crucial to extend efforts beyond pollinator conservation alone to effectively safeguard insect- pollinated plants and ensure crop safety.

Description: The genus Calonectria includes many important plant pathogens with a wide global distribution. In order to better understand the reproductive biology of these fungi, we characterised the structure of the mating type locus and flanking genes using the genome sequences for seven Calonectria species. Primers to amplify the mating type genes in other species were also developed. PCR amplification of the mating type genes and multi-gene phylogenetic analyses were used to investigate the mating strategies and evolution of mating type in a collection of 70 Calonectria species residing in 10 Calonectria species complexes. Results showed that the organisation of the MAT locus and flanking genes is conserved. In heterothallic species, a novel MAT gene, MAT1-2-12 was identified in the MAT1-2 idiomorph; the MAT1-1 idiomorph, in most cases, contained the MAT1-1-3 gene. Neither MAT1-1-3 nor MAT1-2-12 was found in homothallic Calonectria (Ca.) hongkongensis, Ca. lateralis, Ca. pseudoturangicola and Ca. turangicola. Four different homothallic MAT locus gene arrangements were observed. Ancestral state reconstruction analysis provided evidence that the homothallic state was basal in Calonectria and this evolved from a heterothallic ancestor.

Description: New records of notoaturine water mites (Aturidae: Notoaturinae) from New Zealand are presented. Five new species are described: Evidaturus longiscutatus n. sp., Kritaturus (Kritaturus) longipalpis n. sp., Planaturus simpsonensis n. sp., Tryssaturus longwood n. sp. and Zelandalbia thibaulti n. sp. The males are described for the first time for Planaturus pileatus Smit, 2017 and Zelandalbia cf. hopkinsi Imamura, 1978 and the females are described for the first time for Kritaturus (Kritaturus) sornus Cook, 1983, Paratryssaturus zodelus Cook, 1983 and Taintaturus accidens Cook, 1983.

Description: The red turpentine beetle (RTB; Dendroctonus valens) is a bark beetle that is native to Central and North America. This insect is well-known to live in association with a large number of Ophiostomatalean fungi. The beetle is considered a minor pest in its native range, but has killed millions of indigenous pine trees in China after its appearance in that country in the late 1990s. In order to increase the base of knowledge regarding the RTB and its symbionts, surveys of the beetle’s fungal associates were initially undertaken in China, and in a subsequent study in its native range in NorthAmerica.Atotal of 30 Ophiostomatalean species that included several undescribed taxa, were identified in these surveys. In the present study, seven of the undescribed taxa collected during the surveys were further characterised based on their morphological characteristics and multi-gene phylogenies. We proceeded to describe five of these as novel Leptographium spp. and two as new species of Ophiostoma. Four of the Leptographium spp. resided in the G. galeiformis-species complex, while one formed part of the L. olivaceumspecies complex. One Ophiostoma sp. was a member of the O. ips-species complex, while the only new species from China was closely related to O. floccosum. Two of the previously undescribed taxa from North America were shown to be congeneric with L. terebrantis, implying that this species was most often isolated in association with the RTB in North America. The undescribed taxon from North America was identified as O. ips, and like L. terebrantis, this species was also not recognized during the initial North American survey. Resolving the identities of these taxa provides essential baseline information to better understand the movement of fungal pathogens with this beetle. This then enhances our ability to accurately assess and predict the risks of invasions by these and related fungi.

Description: The ongoing biodiversity crisis, driven by factors such as land-use change and global warming, emphasizes the need for effective ecological monitoring methods. Acoustic monitoring of biodiversity has emerged as an important monitoring tool. Detecting human voices in soundscape monitoring projects is useful both for analyzing human disturbance and for privacy filtering. Despite significant strides in deep learning in recent years, the deployment of large neural networks on compact devices poses challenges due to memory and latency constraints. Our approach focuses on leveraging knowledge distillation techniques to design efficient, lightweight student models for speech detection in bioacoustics. In particular, we employed the MobileNetV3-Small-Pi model to create compact yet effective student architectures to compare against the larger EcoVADteacher model, a well-regarded voice detection architecture in eco-acoustic monitoring. The comparative analysis included examining various configurations of the MobileNetV3-Small-Pi-derived student models to identify optimal performance. Additionally, a thorough evaluation of different distillation techniques was conducted to ascertain the most effective method for model selection. Our findings revealed that the distilled models exhibited comparable performance to the EcoVAD teacher model, indicating a promising approach to overcoming computational barriers for real-time ecological monitoring.

Description: Strains with a yeast-like appearance were frequently collected in two surveys on the biodiversity of fungi in Germany, either associated with necroses in wood of Prunus trees in orchards in Saxony, Lower Saxony and Baden-Württemberg or captured in spore traps mounted on grapevine shoots in a vineyard in Rhineland-Palatinate. The morphology of the strains was reminiscent of the genus Collophorina: all strains produced aseptate conidia on integrated conidiogenous cells directly on hyphae, on discrete phialides, adelophialides and by microcyclic conidiation, while in some strains additionally endoconidia or conidia in conidiomata were observed. Blastn searches with the ITS region placed the strains in the Leotiomycetes close to Collophorina spp. Analyses based on morphological and multi-locus sequence data (LSU, ITS, EF-1α, GAPDH) revealed that the 152 isolates from wood of Prunus spp. belong to five species including C. paarla, C. africana and three new species. A further ten isolates from spore traps belonged to seven new species, of which one was isolated from Prunus wood as well. However, a comparison with both LSU and ITS sequence data of these collophorina-like species with reference sequences from further Leotiomycetes revealed the genus Collophorina to be polyphyletic and the strains to pertain to several genera within the Phacidiales. Collophorina paarla and C. euphorbiae are transferred to the newly erected genera Pallidophorina and Ramoconidiophora, respectively. The new genera Capturomyces, Variabilispora and Vexillomyces are erected to accommodate five new species isolated from spore traps. In total nine species were recognised as new to science and described as Collophorina badensis, C. germanica, C. neorubra, Capturomyces funiculosus, Ca. luteus, Tympanis inflata, Variabilispora flava, Vexillomyces palatinus and V. verruculosus.

Description: Species of Diaporthe (syn. Phomopsis) are important endophytes, saprobes and pathogens, infecting a wide range of plants and resulting in important crop diseases. However, the species occurring on pear remain largely unresolved. In this study, a total of 453 Diaporthe isolates were obtained from branches of Pyrus plants (including P. bretschneideri, P. communis, P. pyrifolia and P. ussuriensis collected from 12 provinces in China) showing shoot canker symptoms. Phylogenetic analyses based on five loci (ITS, TEF, CAL, HIS, and TUB) coupled with morphology of 113 representative isolates revealed that 19 Diaporthe species were isolated, representing 13 known species (including D. caryae, D. cercidis, D. citrichinensis, D. eres, D. fusicola, D. ganjae, D. hongkongensis, D. padina, D. pescicola, D. sojae, D. taoicola, D. unshiuensis and D. velutina) and six new species described here as D. acuta, D. chongqingensis, D. fulvicolor, D. parvae, D. spinosa and D. zaobaisu. Although Koch’s postulates confirmed all species to be pathogenic, a high degree of variation in aggressiveness was observed. Moreover, these species have a high diversity, plasticity, and prevalence related to the geographical location and pear species involved.

Description: Gymnosporangium species (Pucciniaceae, Pucciniales, Basidiomycota) are the causal agents of cedarapple rust diseases, which can lead to significant economic losses to apple cultivars. Currently, the genus contains 17 described species that alternate between spermogonial/aecial stages on Malus species and telial stages on Juniperus or Chamaecyparis species, although these have yet to receive a modern systematic treatment. Furthermore, prior studies have shown that Gymnosporangium does not belong to the Pucciniaceae sensu stricto (s.str.), nor is it allied to any currently defined rust family. In this study we examine the phylogenetic placement of the genus Gymnosporangium. We also delineate interspecific boundaries of the Gymnosporangium species on Malus based on phylogenies inferred from concatenated data of rDNA SSU, ITS and LSU and the holomorphic morphology of the entire life cycle. Based on these results, we propose a new family, Gymnosporangiaceae, to accommodate the genus Gymnosporangium, and recognize 22 Gymnosporangium species parasitic on Malus species, of which G. lachrymiforme, G. shennongjiaense, G. spinulosum, G. tiankengense and G. kanas are new. Typification of G. asiaticum, G. fenzelianum, G. juniperi-virginianae, G. libocedri, G. nelsonii, G. nidus-avis and G. yamadae are proposed to stabilize the use of names. Morphological and molecular data from type materials of 14 Gymnosporangium species are provided. Finally, morphological characteristics, host alternation and geographical distribution data are provided for each Gymnosporangium species on Malus.

Description: Trunk disease fungal pathogens reduce olive production globally by causing cankers, dieback, and other decline-related symptoms on olive trees. Very few fungi have been reported in association with olive dieback and decline in South Africa. Many of the fungal species reported from symptomatic olive trees in other countries have broad host ranges and are known to occur on other woody host plants in the Western Cape province, the main olive production region of South Africa. This survey investigated the diversity of fungi and symptoms associated with olive dieback and decline in South Africa. Isolations were made from internal wood symptoms of 145 European and 42 wild olive trees sampled in 10 and 9 districts, respectively. A total of 99 taxa were identified among 440 fungal isolates using combinations of morphological and molecular techniques. A new species of Pseudophaeomoniella, P. globosa, had the highest incidence, being recovered from 42.8 % of European and 54.8 % of wild olive samples. This species was recovered from 9 of the 10 districts where European olive trees were sampled and from all districts where wild olive trees were sampled. Members of the Phaeomoniellales (mainly P. globosa) were the most prevalent fungi in five of the seven symptom types considered, the only exceptions being twig dieback, where members of the Botryosphaeriaceae were more common, and soft/white rot where only Basidiomycota were recovered. Several of the species identified are known as pathogens of olives or other woody crops either in South Africa or elsewhere in the world, including species of Neofusicoccum, Phaeoacremonium, and Pleurostoma richardsiae. However, 81 of the 99 taxa identified have not previously been recorded on olive trees and have unknown interactions with this host. These taxa include one new genus and several putative new species, of which four are formally described as Celerioriella umnquma sp. nov., Pseudophaeomoniella globosa sp. nov., Vredendaliella oleae gen. & sp. nov., and Xenocylindrosporium margaritarum sp. nov.

Description: Specimens of Nectria spp. and Nectriella rufofusca were obtained from the fungarium of Pier Andrea Saccardo, and investigated via a morphological and molecular approach based on MiSeq technology. ITS1 and ITS2 sequences were successfully obtained from 24 specimens identified as ‘Nectria’ sensu Saccardo (including 20 types) and from the type specimen of Nectriella rufofusca. For Nectria ambigua, N. radians and N. tjibodensis only the ITS1 sequence was recovered. On the basis of morphological and molecular analyses new nomenclatural combinations for Nectria albofimbriata, N. ambigua, N. ambigua var. pallens, N. granuligera, N. peziza subsp. reyesiana, N. radians, N. squamuligera, N. tjibodensis and new synonymies for N. congesta, N. flageoletiana, N. phyllostachydis, N. sordescens and N. tjibodensis var. crebrior are proposed. Furthermore, the current classification is confirmed for Nectria coronata, N. cyanostoma, N. dolichospora, N. illudens, N. leucotricha, N. mantuana, N. raripila and Nectriella rufofusca. This is the first time that these more than 100-yr-old specimens are subjected to molecular analysis, thereby providing important new DNA sequence data authentic for these names.

Description: Members of the genus Cytospora are often reported as endophytes, saprobes or phytopathogens, primarily causing canker diseases of woody host plants. They occur on a wide range of hosts and have a worldwide distribution. Although several species have in the past been reported from China, the vast majority are not known from culture or DNA phylogeny. The primary aim of the present study was thus to clarify the taxonomy and phylogeny of a large collection of Cytospora species associated with diverse hosts in China. Cytospora spp. were collected in northeast, northwest, north and southwest China, indicating that the cold and dry environments favour these fungi. In this paper, we provide an assessment of 52 Cytospora spp. in China, focussing on 40 species represented by 88 isolates from 28 host genera. Based on a combination of morphology and a six-locus phylogeny (ITS, LSU, act1, rpb2, tef1-α and tub2), 13 new species and one new combination are introduced. The majority of the species investigated here appear to be host-specific, although further collections and pathogenicity studies will be required to confirm this conclusion.

Description: Bees are important actors in terrestrial ecosystems and are recognised for their prominent role as pollinators. In the Iberian Peninsula, approximately 1,100 bee species are known, with nearly 100 of these species being endemic to the Peninsula. A reference collection of DNA barcodes, based on morphologically identified bee specimens, representing 514 Iberian species, was constructed. The "InBIO Barcoding Initiative Database: DNA Barcodes of Iberian bees" dataset contains records of 1,059 sequenced specimens. The species of this dataset correspond to about 47% of Iberian bee species diversity and 21% of endemic species diversity. For peninsular Portugal only, the corresponding coverage is 71% and 50%. Specimens were collected between 2014 and 2022 and are deposited in the research collection of Thomas Wood (Naturalis Biodiversity Center, The Netherlands), in the FLOWer Lab collection at the University of Coimbra (Portugal), in the Andreia Penado collection at the Natural History and Science Museum of the University of Porto (MHNC-UP) (Portugal) and in the InBIO Barcoding Initiative (IBI) reference collection (Vairão, Portugal).

Description: Plantation-grown Eucalyptus (Myrtaceae) and other trees residing in the Myrtales have been widely planted in southern China. These fungal pathogens include species of Cryphonectriaceae that are well-known to cause stem and branch canker disease on Myrtales trees. During recent disease surveys in southern China, sporocarps with typical characteristics of Cryphonectriaceae were observed on the surfaces of cankers on the stems and branches of Myrtales trees. In this study, a total of 164 Cryphonectriaceae isolates were identified based on comparisons of DNA sequences of the partial conserved nuclear large subunit (LSU) ribosomal DNA, internal transcribed spacer (ITS) regions including the 5.8S gene of the ribosomal DNA operon, two regions of the β-tubulin (tub2/tub1) gene, and the translation elongation factor 1-alpha (tef1) gene region, as well as their morphological characteristics. The results showed that eight species reside in four genera of Cryphonectriaceae occurring on the genera Eucalyptus, Melastoma (Melastomataceae), Psidium (Myrtaceae), Syzygium (Myrtaceae), and Terminalia (Combretaceae) in Myrtales. These fungal species include Chrysoporthe deuterocubensis, Celoporthe syzygii, Cel. eucalypti, Cel. guangdongensis, Cel. cerciana, a new genus and two new species, as well as one new species of Aurifilum. These new taxa are hereby described as Parvosmorbus gen. nov., Par. eucalypti sp. nov., Par. guangdongensis sp. nov., and Aurifilum terminali sp. nov. Pathogenicity tests showed that the eight species of Cryphonectriaceae are pathogenic to two Eucalyptus hybrid seedlings, Melastoma sanguineum branches, and Psidium guajava and Syzygium jambos seedlings. The overall data showed that Chr. deuterocubensis is the most aggressive, followed by Par. eucalypti. Significant differences in tolerance were observed between the two tested Eucalyptus hybrid genotypes, suggesting that disease-tolerant genotypes can be selected for disease management in the Eucalyptus industry.

Description: Reef cores are a powerful tool for investigating temporal changes in reef communities. Radiometric dating facilitates the determination of vertical accretion rates, which has allowed for examination of local-regional controlling factors, such as subsidence and sea level changes. Coral reefs must grow at sufcient rates to keep up with sea level rise, or risk ‘drowning.’ As sea level is expected to rise signifcantly in the next 100 years and beyond, it is important to understand whether reefs will be able to survive. Historical records of reef accretion rates extracted from cores provide valuable insights into extrinsic controlling factors of reef growth and are instrumental in helping predict if future reefs can accrete at rates needed to overcome predicted sea level changes. While extensive research exists at local and regional scales, limited attention has been given to identifying global patterns and drivers. To address this, we present “RADReef”: A global dataset of dated Holocene reef cores. RADReef serves as a foundation for further research on past, present and future reef accretion.

Description: The possibility that the Amazon forest system could soon reach a tipping point, inducing large-scale collapse, has raised global concern. For 65 million years, Amazonian forests remained relatively resilient to climatic variability. Now, the region is increasingly exposed to unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central and remote parts of the system. Long existing feedbacks between the forest and environmental conditions are being replaced by novel feedbacks that modify ecosystem resilience, increasing the risk of critical transition. Here we analyse existing evidence for five major drivers of water stress on Amazonian forests, as well as potential critical thresholds of those drivers that, if crossed, could trigger local, regional or even biome-wide forest collapse. By combining spatial information on various disturbances, we estimate that by 2050, 10% to 47% of Amazonian forests will be exposed to compounding disturbances that may trigger unexpected ecosystem transitions and potentially exacerbate regional climate change. Using examples of disturbed forests across the Amazon, we identify the three most plausible ecosystem trajectories, involving diferent feedbacks and environmental conditions. We discuss how the inherent complexity of the Amazon adds uncertainty about future dynamics, but also reveals opportunities for action. Keeping the Amazon forest resilient in the Anthropocene will depend on a combination of local eforts to end deforestation and degradation and to expand restoration, with global eforts to stop greenhouse gas emissions.

Description: Novel species of fungi described in this study include those from various countries as follows: Australia, Austroboletus asper on soil, Cylindromonium alloxyli on leaves of Alloxylon pinnatum, Davidhawksworthia quintiniae on leaves of Quintinia sieberi, Exophiala prostantherae on leaves of Prostanthera sp., Lactifluus lactiglaucus on soil, Linteromyces quintiniae (incl. Linteromyces gen. nov.) on leaves of Quintinia sieberi, Lophotrichus medusoides from stem tissue of Citrus garrawayi, Mycena pulchra on soil, Neocalonectria tristaniopsidis (incl. Neocalonectria gen. nov.) and Xyladictyochaeta tristaniopsidis on leaves of Tristaniopsis collina, Parasarocladium tasmanniae on leaves of Tasmannia insipida, Phytophthora aquae-cooljarloo from pond water, Serendipita whamiae as endophyte from roots of Eriochilus cucullatus, Veloboletus limbatus (incl. Veloboletus gen. nov.) on soil. Austria, Cortinarius glaucoelotus on soil. Bulgaria, Suhomyces rilaensis from the gut of Bolitophagus interruptus found on a Polyporus sp. Canada, Cantharellus betularum among leaf litter of Betula, Penicillium saanichii from house dust. Chile, Circinella lampensis on soil, Exophiala embothrii from rhizosphere of Embothrium coccineum. China, Colletotrichum cycadis on leaves of Cycas revoluta. Croatia, Phialocephala melitaea on fallen branch of Pinus halepensis. Czech Republic, Geoglossum jirinae on soil, Pyrenochaetopsis rajhradensis from dead wood of Buxus sempervirens. Dominican Republic, Amanita domingensis on litter of deciduous wood, Melanoleuca dominicana on forest litter. France, Crinipellis nigrolamellata (Martinique) on leaves of Pisonia fragrans, Talaromyces pulveris from bore dust of Xestobium rufovillosum infesting floorboards. French Guiana, Hypoxylon hepaticolor on dead corticated branch. Great Britain, Inocybe ionolepis on soil. India, Cortinarius indopurpurascens among leaf litter of Quercus leucotrichophora. Iran, Pseudopyricularia javanii on infected leaves of Cyperus sp., Xenomonodictys iranica (incl. Xenomonodictys gen. nov.) on wood of Fagus orientalis. Italy, Penicillium vallebormidaense from compost. Namibia, Alternaria mirabibensis on plant litter, Curvularia moringae and Moringomyces phantasmae (incl. Moringomyces gen. nov.) on leaves and flowers of Moringa ovalifolia, Gobabebomyces vachelliae (incl. Gobabebomyces gen. nov.) on leaves of Vachellia erioloba, Preussia procaviae on dung of Procavia capensis. Pakistan, Russula shawarensis from soil on forest floor. Russia, Cyberlindnera dauci from Daucus carota. South Africa, Acremonium behniae on leaves of Behnia reticulata, Dothiora aloidendri and Hantamomyces aloidendri (incl. Hantamomyces gen. nov.) on leaves of Aloidendron dichotomum, Endoconidioma euphorbiae on leaves of Euphorbia mauritanica, Eucasphaeria proteae on leaves of Protea neriifolia, Exophiala mali from inner fruit tissue of Malus sp., Graminopassalora geissorhizae on leaves of Geissorhiza splendidissima, Neocamarosporium leipoldtiae on leaves of Leipoldtia schultzii, Neocladosporium osteospermi on leaf spots of Osteospermum moniliferum, Neometulocladosporiella seifertii on leaves of Combretum caffrum, Paramyrothecium pituitipietianum on stems of Grielum humifusum, Phytopythium paucipapillatum from roots of Vitis sp., Stemphylium carpobroti and Verrucocladosporium carpobroti on leaves of Carpobrotus quadrifolius, Suttonomyces cephalophylli on leaves of Cephalophyllum pilansii. Sweden, Coprinopsis rubra on cow dung, Elaphomyces nemoreus from deciduous woodlands. Spain, Polyscytalum pini-canariensis on needles of Pinus canariensis, Pseudosubramaniomyces septatus from stream sediment, Tuber lusitanicum on soil under Quercus suber. Thailand, Tolypocladium flavonigrum on Elaphomyces sp. USA, Chaetothyrina spondiadis on fruits of Spondias mombin, Gymnascella minnisii from bat guano, Juncomyces patwiniorum on culms of Juncus effusus, Moelleriella puertoricoensis on scale insect, Neodothiora populina (incl. Neodothiora gen. nov.) on stem cankers of Populus tremuloides, Pseudogymnoascus palmeri from cave sediment. Vietnam, Cyphellophora vietnamensis on leaf litter, Tylopilus subotsuensis on soil in montane evergreen broadleaf forest. Morphological and culture characteristics are supported by DNA barcodes.

Description: This data set includes grain size analyses and SST reconstructions from core AXC1432 in Nørre Skjoldungensund, SE-Greenland. Furthermore it contains water temperatures calculated from mesurements from https://www.ICES.dk and from the HadISST dataset. Heat transport via ocean currents can affect the melting of marine-terminating glaciers in Greenland. Studying past changes of marine-terminating glaciers allows assessing the regional sensitivity of the Greenland Ice Sheet (GrIS) to ocean temperature changes in the context of a warming ocean. Here, we present a high-resolution multi-proxy marine sediment core study from Skjoldungen Fjord, close to the marine-terminating Thrym Glacier. Grain-size data is obtained to reconstruct the calving activity of Thrym Glacier, sortable silt is used as a proxy for fjord water circulation and sea surface temperatures (SSTs) are reconstructed from alkenone paleothermometry (Uk'37). Measurements of 210Pb, 137Cs and 14C indicate that the core covers the past 220 years (1796 CE to 2013 CE). Comparisons with modelled SST data (HadISST) and instrumental temperatures (ICES) suggest that the SST proxy record reflects temperature variability of the surface waters over the shelf and that alkenones are advected into the fjord. Additionally, average temperatures and the amplitude of fluctuations are influenced by alkenones advected from upstream the Irminger Current. We find that the SST record compares well with other alkenone-based reconstructions from SE-Greenland, and thus features regional shelf water variability. The calving activity as well as the terminus position of Thrym Glacier did not seem to respond to the SST variability. Limited ice-ocean interactions owing to the specific setting of the glacier would explain this. Instead, the fjord circulation may have been influenced by enhanced meltwater production as well as to larger scale changes in the AMOC.

Description: Few studies have focused on past hydroclimatic changes in the tropical coastal regions of eastern South America compared to the core South American Monsoon System (SAMS) domain. We suggest that unlike the core monsoon region, the densely populated coastal zone of eastern Brazil (which is the focus of this study) may not adhere to the typical mechanism of precession has a dominant driver of precipitation changes. This study presents sediment color reflectance, benthic foraminifera stable isotope, X-ray fluorescence (XRF), and lipid biomarker data generated from piston core M125-73-3. Core M125‐73‐3 is 1,249 cm long and was retrieved from off the coast of eastern Brazil (14°10.608′S, 38°21.178′W) from a water depth of 2106.9 m in April 2016 during RV METEOR cruise M125. Our multiproxy reconstruction has a temporal span of ~850 kyr and represents the longest continuous record of South American climate variability to date.

Description: The evolution of the South Asian monsoon (SAM) is not well-constrained prior to the Pleistocene, primarily due to a lack of recovered marine sediment archives. This study presents geochemical data from Site NGHP-01-01A in the eastern Arabian Sea from the Oligocene to Early Miocene (~32–20 Ma) to reconstruct the oceanographic evolution of this region through this interval. Analyses consist of planktic and benthic foraminiferal oxygen and carbon isotopes, and planktic foraminiferal trace elements (Mg/Ca and Mn/Ca), as well as seawater d18O (d18Osw) and Mg/Ca-derived temperatures. Along with XRF-derived elemental analysis, these reveal the Oligocene–Miocene transition (~23.7–22.7 Ma) to be a key initiation/intensification of the proto-SAM system, with the development of an intense oxygen minimum zone and monsoonal atmospheric circulation.

Description: This dataset includes planktic foraminifera (Globigerinoides ruber sensu-stricto) stable oxygen isotope and Mg/Ca data from IODP Expedition 353, Sites U1446 and U1448 across Marine Isotope Stage 5 (140-70 ka). Additionally, included is a time-series of annual change in precipitation as emulated by PaleoPGEM across 6 large-scale low-latitude regions throughout Marine Isotope Stage 5 (140-70 Ka).

Description: We compiled modern and fossil relative abundance of coccolithophore species Florisphaera profunda from published and unpublished datasets, along with ocean environmental variable data from satellite remote sensing and physical measurements. The database includes relative abundances of F. profunda in sediment trap (n = 26) and core-top (n = 1258), and sediment core samples (n = 104). Downcore data covers the Last Glacial Maximum (n = 94, 24-19 ka) or the Mid-to-Late Holocene (n = 77, 〈6 ka). This database allows studying modern and past biogeography of F. profunda as a response to changing ocean and climate conditions, “Quantitative reconstruction of primary productivity in low latitudes during the last glacial maximum and the mid-to-late Holocene from a global Florisphaera. profunda calibration dataset” (Hernández-Almeida et al., 2018).

Description: This dataset presents the XRF core-scanning record from International Ocean Discovery Program (IODP) Site U1478 off the Limpopo River mouth (Mozambique Channel, SW Indian Ocean) spanning the past c. 4 Ma. Site U1478 was drilled in the northernmost Natal Valley, on the Inharrime Terrace (25°49.26′ S; 34°46.16′ E) at a water depth of 488 m below sea level. The XRF core scanning of the ~257-m-long splice for Site U1478 was carried out using an Itrax Core Scanner at Lamont-Doherty Earth Observatory Core Repository, Columbia University (USA). In total, 239 sections (archive halves) were scanned at a voltage of 30 kV and a tube current of 55 mA using a Cr tube and employing an exposure time of 2 seconds. Measurement spacing was set at 2 mm, with downcore and crosscore slit sizes set at 2 mm and 2 cm, respectively. The individual element counts were normalized using the ratio of raw total counts of a given element to the total counts of all processed elements for the respective measurement position. To eliminate non-linear matrix effects and constant-sum constraints, log ratios were applied on the elemental ratios. The age model of Site U1478 is based on cyclostratigraphic analysis of the XRF-based log(Ti/Ca) record and its tuning to ice-volume, precession and eccentricity cycles.

Description: Seven different labs XRF scanned the same seven marine sediment sections. Additionally, four labs XRF scanned pellets that had known compositions determined by ICP-ES and ICP-MS. These datasets contain the XRF scanning results of the seven sediment section and four pellets. The seven 1.5 m core sections of marine sediment core used in this study were drilled during Integrated Ocean Drilling Program (IODP) Expedition 346 at Site U1424 in the Japan Basin (40°11.39'N, 138°13.90'E, 2808 m water depth) and Site U1425 on the Yamato Rise (39°29.43' N, 134°26.55' E, 1909 m water depth). The sections selected (Hole U1424C Sections 1H4, 2H5, 3H5 and Hole U1425C Sections 2H3, 2H4, and 2H6, and 3H6) cover a range of sediment compositions. U-channels extracted continuous marine sediment approximately 1 cm thick from the center of each split core section. One lab scanned sections from different holes at the same sites (U1424A, U1425B, and U1425D) that were stratigraphically aligned with the sections listed above. Over the course of four years (2014 to 2017), the set of seven u-channels was shipped around the world to seven labs with XRF scanners including, in no particular order, the Kochi Core Center at Kochi University (Japan), IODP Core Repository at Texas A&M University (U.S.A.), Nanjing Normal University (China), Rosenstiel School of Marine and Atmospheric Science at the University of Miami (U.S.A.), ETH Zurich (Switzerland), Woods Hole Oceanographic Institution (U.S.A.), and the Royal Netherlands Institute of Sea Research (The Netherlands). We intentionally do not identify which lab generated which scans, as many of the variables (e.g., X-ray tube aging, detector aging, and/or dehydration of the core material) could affect any instrument at various times or be exacerbated during the transit between labs. Instead, we label the XRF scans #1-#7 in the order in which they were scanned. The lead investigators overseeing the XRF scanning in these labs were shipboard participants on IODP Expedition 346 and are among the authors of this paper. The only instructions to each lab were "to XRF scan the seven sediment sections at 1mm or 2mm resolution using the approach and elements typical for paleoceanographic research performed in your lab." To emulate variations in the XRF results that have been previously published, these simple guidelines were intentionally broad and general to determine the degree of intercomparability between the labs amongst all the different settings and nuances of XRF scanning. The labs used various types and different generations of XRF scanning instruments (4 Avaatech Core Scanners, 2 ITRAX Core Scanners, and 1 Geotek Core Scanning Logger) with different X-ray sources (Rhodium, Molybdenum). Three of the labs scanned the cores at two or three excitation energies (e.g., 10 kV, 30 kV, and 50 kV). Each lab reported a different suite of elements, but all included Ca, Fe, K, Mn, Si, Sr, Ti, and Zr. Six labs also reported Al, Br, Cr, Cu, Ni, Pb, Rb, S, and Zn and five labs reported and Ba, Cl, Ga, Mo, V, and Y. In addition to the seven core sediment sections, we freeze-dried and powdered four discrete samples that were pressed into disc-shaped pellets about 2 cm in diameter from nearby Core MD01-2407 on the Oki Ridge (37°04'N, 134°42'E, 932m water depth). The four samples have a similar matrix to the seven sediment sections scanned in this study. The four samples from Core MD01-2407 covered a range of sediment types (calcareous, siliceous, light-, and dark-colored; Kido et al., 2007) that span the dynamic range of at least Fe and Ca element cps scanned for this study. A set of four pellets was sent to four of the seven labs (1 ITRAX and 3 Avaatech) involved in the study to be scanned using the same instrument parameters they used on the sediment sections. Three labs used the same instrument and parameters used for the sediment section, but the fourth lab replaced the X-ray tube in between scanning the pellets and sediment sections. The major and trace element concentrations of the pellets were also analyzed by inductively coupled plasma (ICP)-optical emission spectrometry (OES) and ICP-mass spectrometry (MS) in the Analytical Geochemistry Facilities at Boston University, Boston, MA, USA. The ICP analyses had ~2% precision and a standard reference material analyzed as an unknown alongside the samples was accurate within precision.

Description: The early Eocene epoch was characterized by extreme global warmth, which in terrestrial settings was characterized by an expansion of near-tropical vegetation belts into the high latitudes. During the middle to late Eocene, global cooling caused the retreat of tropical vegetation to lower latitudes. In high-latitude settings, near-tropical vegetation was replaced by temperate floras. This floral change has recently been traced as far south as Antarctica, where along the Wilkes Land margin paratropical forests thrived during the early Eocene and temperate Nothofagus forests developed during the middle Eocene. Here we provide both qualitative and quantitative palynological data for this floral turnover based on a sporomorph record recovered at Integrated Ocean Drilling Program (IODP) Site U1356 off the Wilkes Land margin. Following the nearest living relative concept and based on a comparison with modern vegetation types, we examine the structure and diversity patterns of the Eocene vegetation along the Wilkes Land margin. Our results indicate that the early Eocene forests along the Wilkes Land margin were characterized by a diverse canopy composed of plants that today occur in tropical settings; their richness pattern was similar to that of present-day forests from New Caledonia. The middle Eocene forests were characterized by a canopy dominated by Nothofagus and exhibited richness patterns similar to modern Nothofagus forests from New Zealand.

Description: Neodymium isotopes are becoming widely used as a palaeoceanographic tool for reconstructing the source and flow direction of water masses. A new method using planktonic foraminifera which have not been chemically cleaned has proven to be a promising means of avoiding contamination of the deep ocean palaeoceanographic signal by detrital material. However, the exact mechanism by which the Nd isotope signal from bottom waters becomes associated with planktonic foraminifera, the spatial distribution of rare earth element (REE) concentrations within the shell, and the possible mobility of REE ions during changing redox conditions, have not been fully investigated. Here we present REE concentration and Nd isotope data from mixed species of planktonic foraminifera taken from plankton tows, sediment traps and a sediment core from the NW Atlantic. We used multiple geochemical techniques to evaluate how, where and when REEs become associated with planktonic foraminifera as they settle through the water column, reside at the surface and are buried in the sediment. Analyses of foraminifera shells from plankton tows and sediment traps between 200 and 2938 m water depth indicate that only ~20% of their associated Nd is biogenically incorporated into the calcite structure. The remaining 80% is associated with authigenic metal oxides and organic matter, which form in the water column, and remain extraneous to the carbonate structure. Remineralisation of these organic and authigenic phases releases ions back into solution and creates new binding sites, allowing the Nd isotope ratio to undergo partial equilibration with the ambient seawater, as the foraminifera fall through the water column. Analyses of fossil foraminifera shells from sediment cores show that their REE concentrations increase by up to 10-fold at the sediment-water interface, and acquire an isotopic signature of bottom water. Adsorption and complexation of REE3+ ions between the inner layers of calcite contributes significantly to elevated REE concentrations in foraminifera. The most likely source of REE ions at this stage of enrichment is from bottom waters and from the remineralisation of oxide phases which are in chemical equilibrium with the bottom waters. As planktonic foraminifera are buried below the sediment-water interface redox-sensitive ion concentrations are adjusted within the shells depending on the pore-water oxygen concentration. The concentration of ions which are passively redox sensitive, such as REE3+ ions, is also controlled to some extent by this process. We infer that (a) the Nd isotope signature of bottom water is preserved in planktonic foraminifera and (b) that it relies on the limited mobility of particle reactive REE3+ ions, aided in some environments by micron-scale precipitation of MnCO3. This study indicates that there may be sedimentary environments under which the bottom water Nd isotope signature is not preserved by planktonic foraminifera. Tests to validate other core sites must be carried out before downcore records can be used to interpret palaeoceanographic changes.

Description: Few high-latitude terrestrial records document the timing and nature of the Cenozoic "Greenhouse" to "Icehouse" transition. Here we exploit the bulk geochemistry of marine siliciclastic sediments from drill cores on Antarctica's continental margin to extract a unique semiquantitative temperature and precipitation record for Eocene to mid-Miocene (~54-13 Ma). Alkaline elements are strongly enriched in the detrital mineral fraction in fine-grained siliciclastic marine sediments and only occur as trace metals in the biogenic fraction. Hence, terrestrial climofunctions similar to the chemical index of alteration (CIA) can be applied to the alkaline major element geochemistry of marine sediments on continental margins in order to reconstruct changes in precipitation and temperature. We validate this approach by comparison with published paleotemperature and precipitation records derived from fossil wood, leaves, and pollen and find remarkable agreement, despite uncertainties in the calibrations of the different proxies. A long-term cooling on the order of 〉=8°C is observed between the Early Eocene Climatic Optimum (~54-52 Ma) and the middle Miocene (~15-13 Ma) with the onset of transient cooling episodes in the middle Eocene at ~46-45 Ma. High-latitude stratigraphic records currently exhibit insufficient temporal resolution to reconstruct continental aridity and inferred ice-sheet development during the middle to late Eocene (~45-37 Ma). However, we find an abrupt aridification of East Antarctica near the Eocene-Oligocene transition (~34 Ma), which suggests that ice coverage influenced high-latitude atmospheric circulation patterns through albedo effects from the earliest Oligocene onward.

Description: The warmest global temperatures of the past 85 million years occurred during a prolonged greenhouse episode known as the Early Eocene Climatic Optimum (52-50 Ma). The Early Eocene Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica from 34 Ma onward. Whereas early studies attributed the Eocene transition from greenhouse to icehouse climates to the tectonic opening of Southern Ocean gateways, more recent investigations invoked a dominant role of declining atmospheric greenhouse gas concentrations (e.g., CO2). However, the scarcity of field data has prevented empirical evaluation of these hypotheses. We present marine microfossil and organic geochemical records spanning the early-to-middle Eocene transition fromthe Wilkes LandMargin, East Antarctica. Dinoflagellate biogeography and sea surface temperature paleothermometry reveal that the earliest throughflow of a westbound Antarctic Counter Current began ca. 49-50 Ma through a southern opening of the Tasmanian Gateway. This early opening occurs in conjunction with the simultaneous onset of regional surface water and continental cooling (2-4 °C), evidenced by biomarker- and pollen-based paleothermometry. We interpret that the westbound flowing current flow across the Tasmanian Gateway resulted in cooling of Antarctic surface waters and coasts, which was conveyed to global intermediate waters through invigorated deep convection in southern high latitudes. Although atmospheric CO2 forcing alone would provide a more uniform middle Eocene cooling, the opening of the Tasmanian Gateway better explains Southern Ocean surface water and global deep ocean cooling in the apparent absence of (sub-) equatorial cooling.

Description: The circum-Antarctic Southern Ocean is an important region for global marine food webs and carbon cycling because of sea-ice formation and its unique plankton ecosystem. However, the mechanisms underlying the installation of this distinct ecosystem and the geological timing of its development remain unknown. Here, we show, on the basis of fossil marine dinoflagellate cyst records, that a major restructuring of the Southern Ocean plankton ecosystem occurred abruptly and concomitant with the first major Antarctic glaciation in the earliest Oligocene (~33.6 million years ago). This turnover marks a regime shift in zooplankton-phytoplankton interactions and community structure, which indicates the appearance of eutrophic and seasonally productive environments on the Antarctic margin. We conclude that earliest Oligocene cooling, ice-sheet expansion, and subsequent sea-ice formation were important drivers of biotic evolution in the Southern Ocean.

Description: Atmospheric carbon dioxide concentrations and climate are regulated on geological timescales by the balance between carbon input from volcanic and metamorphic outgassing and its removal by weathering feedbacks; these feedbacks involve the erosion of silicate rocks and organic-carbon-bearing rocks. The integrated effect of these processes is reflected in the calcium carbonate compensation depth, which is the oceanic depth at which calcium carbonate is dissolved. Here we present a carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean. The carbonate compensation depth tracks long-term ocean cooling, deepening from 3.0-3.5 kilometres during the early Cenozoic (approximately 55 million years ago) to 4.6 kilometres at present, consistent with an overall Cenozoic increase in weathering. We find large superimposed fluctuations in carbonate compensation depth during the middle and late Eocene. Using Earth system models, we identify changes in weathering and the mode of organic-carbon delivery as two key processes to explain these large-scale Eocene fluctuations of the carbonate compensation depth.

Description: Fossil, facies, and isotope analyses of an early high-paleolatitude (55°S) section suggests a highly unstable East Antarctic Ice Sheet from 32 to 27 Myr. The waxing and waning of this ice sheet from 140% to 40% of its present volume caused sea level changes of ±25 m (ranging from -30 to +50 m) related to periodic glacial (100,000 to 200,000 years) and shorter interglacial events. The near-field Gippsland sea level (GSL) curve shares many similarities to the far-field New Jersey sea level (NJSL) estimates. However, there are possible resolution errors due to biochronology, taphonomy, and paleodepth estimates and the relative lack of lowstand deposits (in NJSL) that prevent detailed correlations with GSL. Nevertheless, the lateral variations in sea level between the GSL section and NJSL record that suggest ocean siphoning and antisiphoning may have propagated synchronous yet variable sea levels.

Description: There is much uncertainty surrounding the mechanisms that forced the abrupt climate fluctuations found in many palaeoclimate records during Marine Isotope Stage (MIS)-3. One of the processes thought to be involved in these events is the Atlantic Meridional Overturning Circulation (MOC), which exhibited large changes in its dominant mode throughout the last glacial period. Giant piston core MD95-2006 from the northeast Atlantic Ocean records a suite of palaeoceanographic proxies related to the activity of both surface and deep water masses through a period of MIS-3 when abrupt climate fluctuations were extremely pronounced. A two-stage progression of surface water warming during interstadial warm events is proposed, with initial warming related to the northward advection of a thin warm surface layer within the North Atlantic Current, which only extended into deeper surface layers as the interstadial progressed. Benthic foraminifera isotope data also show millennial-scale oscillations but of a different structure to the abrupt surface water changes. These changes are argued to partly be related to the influence of low-salinity deepwater brines. The influence of deepwater brines over the site of MD95-2006 reached a maximum at times of rapid warming of surface waters. This observation supports the suggestion that brine formation may have helped to destabilize the accumulation of warm, saline surface waters at low latitudes, helping to force the MOC into a warm mode of operation. The contribution of deepwater brines relative to other mechanisms proposed to alter the state of the MOC needs to be examined further in future studies.

Description: To gain insights into the mechanisms of abrupt climate change within interglacials, we have examined the characteristics and spatial extent of a prominent, climatically induced vegetation setback during the Holsteinian interglacial (Marine Isotope Stage 11c). Based on analyses of pollen and varves of lake sediments from Dethlingen (northern Germany), this climatic oscillation, here termed the "Older Holsteinian Oscillation" (OHO), lasted 220 years. It can be subdivided into a 90-year-long decline of temperate tree taxa associated with an expansion of Pinus and herbs, and a 130-year-long recovery phase marked by the expansion of Betula and Alnus, and the subsequent recovery of temperate trees. The climate-induced nature of the OHO is corroborated by changes in diatom assemblages and d18O measured on biogenic silica indicating an impact on the aquatic ecosystem of the Dethlingen paleolake. The OHO is widely documented in pollen records from Europe north of 50° latitude and is characterized by boreal climate conditions with cold winters from the British Isles to Poland, with a gradient of decreasing temperature and moisture availability, and increased continentality towards eastern Europe. This pattern points to a weakened influence of the westerlies and/or a stronger influence of the Siberian High. A comparison of the OHO with the 8.2 ka event of the Holocene reveals close similarities regarding the imprint on terrestrial ecosystems and the interglacial boundary conditions. Hence, in analogy to the 8.2 ka event, a transient, meltwater-induced slowdown of the North Atlantic Deep Water formation appears as a plausible trigger mechanism for the OHO. If correct, meltwater release into the North Atlantic may be a more common agent of abrupt climate change during interglacials than previously thought. We conclude that meltwater-induced climate setbacks during interglacials preferentially occurred when low rates of summer insolation increase during the preceding terminations facilitated the persistence of large-scale continental ice-sheets well into the interglacials.

Description: The Integrated Ocean Drilling Program Expedition 318 to the Wilkes Land margin of Antarctica recovered a sedimentary succession ranging in age from lower Eocene to the Holocene. Excellent stratigraphic control is key to understanding the timing of paleoceanographic events through critical climate intervals. Drill sites recovered the lower and middle Eocene, nearly the entire Oligocene, the Miocene from about 17 Ma, the entire Pliocene and much of the Pleistocene. The paleomagnetic properties are generally suitable for magnetostratigraphic interpretation, with well-behaved demagnetization diagrams, uniform distribution of declinations, and a clear separation into two inclination modes. Although the sequences were discontinuously recovered with many gaps due to coring, and there are hiatuses from sedimentary and tectonic processes, the magnetostratigraphic patterns are in general readily interpretable. Our interpretations are integrated with the diatom, radiolarian, calcareous nannofossils and dinoflagellate cyst (dinocyst) biostratigraphy. The magnetostratigraphy significantly improves the resolution of the chronostratigraphy, particularly in intervals with poor biostratigraphic control. However, Southern Ocean records with reliable magnetostratigraphies are notably scarce, and the data reported here provide an opportunity for improved calibration of the biostratigraphic records. In particular, we provide a rare magnetostratigraphic calibration for dinocyst biostratigraphy in the Paleogene and a substantially improved diatom calibration for the Pliocene. This paper presents the stratigraphic framework for future paleoceanographic proxy records which are being developed for the Wilkes Land margin cores. It further provides tight constraints on the duration of regional hiatuses inferred from seismic surveys of the region.

Description: To provide insights into the long-term evolution of aquatic ecosystems without human interference, we here evaluate a decadal- to centennial-scale-resolution diatom record spanning about 12 ka of the Holsteinian interglacial (Marine Isotope Stage 11c). Using a partially varved sediment core from the Dethlingen palaeolake (northern Germany), which has previously been studied for palynological and microfacies signals, we document the co-evolution of the aquatic and surrounding terrestrial environment. The diatom record is dominated by the genera Stephanodiscus, Aulacoseira, Ulnaria and Fragilaria. Based on the diatom assemblages and physical sediment properties, the evolution of the Dethlingen palaeolake can be subdivided into three major phases. During the oldest phase (lasting ~1900 varve years), the lake was ~10-15 m deep and characterized by anoxic bottom-water conditions and a high nutrient content. The following ~5600 years exhibited water depths 〉20 m, maximum diatom and Pediastrum productivity, and a peak in allochtonous nutrient input. During this phase, water-column mixing became more vigorous, resulting in a breakdown of anoxia. The youngest lake phase (~4000-5000 years) was characterized by decreasing water depth, turbulent water conditions and decreased nutrient loading. Based on our palaeolimnological data, we conclude that the evolution of the Dethlingen palaeolake during the Holsteinian interglacial responded closely to (i) changes within the catchment area (as documented by vegetation and sedimentation) related to the transition from closed forests growing on nutrient-rich soils (mesocratic forest phase) to open forests developing on poor soils (oligocratic forest phase), and (ii) short-term climate variability as reflected in centennial-scale climate perturbations.

Description: To unravel the climatic and environmental dynamics in the borderlands of the Aegean Sea during the early and middle Holocene, and notably for the interval of sapropel S1 (S1) formation, we have analysed terrestrial palynomorphs from a marine core in the northern Aegean Sea. The qualitative results were complemented by quantitative pollen-based climate reconstructions. A land-sea correlation was established based on pollen data and sediment lightness measurements from the same core, and previously published benthic foraminifer data from a nearby core. The borderlands of the Aegean Sea underwent a transition from an open vegetation to oak-dominated woodlands between ~10.4 and ~9.5 ka cal BP. A coeval increase in winter precipitation suggests that moisture availability was the main factor controlling Holocene reforestation. The ~50% higher winter precipitation during S1 formation relative to "pre-sapropelic" conditions suggests a strong contribution from the borderlands of the Aegean Sea to the freshwater surplus during S1 formation. The humid and mild winter conditions during S1 formation were repeatedly punctuated by short-term climatic events that caused a partial deforestation and a reorganisation within the broad-leaved arboreal vegetation. In the marine realm, these events are documented by improved benthic oxygenation. The strongest event represents the regional expression of the 8.2 ka cold event and led to an interruption in S1 formation. Except for the interval of S1 formation, the pollen-derived winter temperatures correlate with the smoothed GISP2 K+ series. They support the previously published, marine-based concept that the intensity of the Siberian High strongly controlled the winter climate in the Aegean region. During S1 formation in the Aegean Sea, however, climate conditions in the borderlands were more strongly affected by the monsoonally influenced climate system of the lower latitudes.

Description: To better understand the environmental variability during the Holsteinian interglacial, we have palynologically analyzed a new core from Dethlingen, northern Germany, at a decadal resolution. Our data provide insights into the vegetation dynamics and thus also climate variability during the meso- to telocratic forest phases of the interglacial. Temperate mixed forests dominated the regional landscape throughout the Holsteinian. However, changes in the forest composition during the younger stages of the interglacial suggest a climatic transition towards milder conditions in winter. The strong presence of boreal floral elements during the older stages of the Holsteinian interglacial suggests a high seasonality. In contrast, during the younger stages the development of sub-Atlantic and Atlantic floral elements suggests increasingly warm and humid climatic conditions. Peak warming during the younger stage of the Holsteinian is marked by the maximum pollen abundances of Buxus, Abies, and Quercus. Although the vegetation dynamics suggest a general warming trend throughout the Holsteinian interglacial, abrupt as well as gradual changes in the relative abundances of temperate plants indicate considerable climatic variability. In particular, two marked declines in temperate taxa leading to the transient development of boreal and sub-temperate forests indicate short-term climatic oscillations that occurred within full interglacial conditions. The palynological signatures of these two regressive phases in vegetation development differ with regard to the expansion of pioneer trees, the abundances and rates of change of temperate taxa, and the presence of frost-sensitive taxa. These differences point to different mechanisms responsible for the individual regressive phases. Assuming a correlation of the interglacial at Dethlingen with Marine Isotope Stage (MIS) 11, our data suggest that temperate forests prevailed in northern Germany during the younger parts of MIS 11c.

Description: The present study investigated the effect of elevated pCO2 on the development of early stages of the pelagic spawning marine fish Solea senegalensis, Diplodus sargus and Argyrosomus regius. Eggs and larvae were reared under control (pH 8.0, ,570 µatm) and two elevated pCO2 conditions (pH 7.8, ,1100 µatm; pH 7.6, ,1900 µatm) until mouth opening (3 days post-hatching). Egg size did not change with exposure to elevated pCO2, but hatching rate was significantly reduced under high pCO2 for all three species. Survival rate was not affected by exposure to increased pCO2, but growth rate was differently affected across species, with A. regius growing faster in the mid-level pCO2 treatment compared with control conditions. S. senegalensis and A. regius hatched with smaller yolk sacs under increased pCO2 but endogenous reserves of D. sargus were not affected. Otoliths were consistently larger under elevated pCO2 conditions for all the three species. Differences among egg batches and a significant interaction between batch and pCO2 suggest that other factors, such as egg quality, can influence the response to increased pCO2. Overall, the results support the occurrence of a species-specific response to pCO2, but highlight the need for cautious analysis of potential sensitivity of species from unreplicated observations.

Description: Millennial-scale oscillations are known to be important in the climatic evolution of the Atlantic basin, but which internal processes originates these oscillations are still uncertain. In this study, we investigated how the Greenland and Antarctic climates affect the SW Atlantic through basin-wide oceanographic features (such as the NADW formation and the Agulhas leakage). We reconstructed sea surface and subsurface temperatures (SST and subT) using three lipid-based biomarker proxies (UK'37, TEX86 and LDI indexes) from a sediment core (NAP 63-1) retrieved from the SW Atlantic slope (24.8°S, 44.3°W). This location permitted to evaluate the temperature oscillations of the Brazil Current without any terrigenous or upwelling-derived biases. Both TEX86-based and LDI-based estimates represent the mean annual SST, while the UK'37-based estimates represent the subT (around 30 m water depth). The periods with the most well-mixed water column were observed during intervals of cooling orbital trends due to the time required to transfer the surface cooling to the subsurface. The temperature reconstructions showed a general colder MIS 3 when compared to the MIS 4. They also showed evidence of a late response to the deglaciation, with its onset in the SW Atlantic occurring in the middle of the Last Glacial Maximum. Based on these reconstructions, the NAP 63-1 SST orbital-scale trend seems to be linked to the Antarctic climate, influenced by local insolation changes. These temperature records also presented a clear millennial periodicity around 8 kyr. On this timescale, the millennial oscillations in the SW Atlantic's SST are likely linked to the NADW formation.

Description: Holocene oceanographic conditions in Disko Bay, West Greenland were reconstructed from high-resolution diatom records derived from two marine sediment cores. A modern dataset composed of 35 dated surface sediment samples collected along the entire West Greenland coast accompanied by remote sensing data were used to develop a diatom transfer function to reconstruct April Sea Ice Concentration (SIC) supported by July Sea Surface Temperature (SST) in the area. Our quantitative reconstruction shows that oceanographic changes recorded throughout the last c. 11000 years reflect seasonal interplay between spring (April SIC) and summer (July SST) conditions. Our records show clear correlation with climate patterns identified from ice core data from GISP2 and Agassiz-Renland for the early to mid Holocene. The early Holocene deglaciation of western Greenland Ice Sheet was characterised in Disko Bay by initial strong centennial-scale fluctuations in April SIC with amplitude of over 40%, followed by high April SIC and July SST. These conditions correspond to a general warming of the climate in the Northern Hemisphere. A decrease in April SIC and July SST was recorded during the Holocene Thermal Optimum reflecting more stable spring-summer conditions in Disko Bay. During the late Holocene, high April SIC characterised the Medieval Climate Anomaly, while high July SST prevailed during the Little Ice Age, supporting previously identified anti-phase relationship between surface waters in West Greenland and climate in NW Europe. This anti-phase pattern might reflect seasonal variations in regional oceanographic conditions and large-scale fluctuations within the North Atlantic Oscillation and Atlantic Meridional Overturning Circulation.

Description: Astronomical tuning of sediment sequences requires both unambiguous cycle-pattern recognition in climate proxy records and astronomical solutions, and independent information about the phase relationship between these two. Here we present two different astronomically tuned age models for the Oligocene-Miocene Transition (OMT) from Integrated Ocean Drilling Program Site U1334 (equatorial Pacific Ocean) to assess the effect tuning has on astronomically calibrated ages and the geologic time scale. These alternative age models (from ~22 to ~24 Ma) are based on different tunings between proxy records and eccentricity: the first age model is based on an aligning CaCO3 weight (wt%) to Earth's orbital eccentricity, the second age model is based on a direct age calibration of benthic foraminiferal stable carbon isotope ratios (d13C) to eccentricity. To independently test which tuned age model and associated tuning assumptions is in best agreement with independent ages based on tectonic plate-pair spreading rates, we assign our tuned ages to the magnetostratigraphic reversals identified in deep-marine magnetic anomaly profiles. Subsequently, we compute tectonic plate-pair spreading rates based on the tuned ages. The resultant, alternative spreading rate histories indicate that the CaCO3 tuned age model is most consistent with a conservative assumption of constant, or linearly changing, spreading rates. The CaCO3 tuned age model thus provides robust ages and durations for polarity chrons C6Bn.1n-C6Cn.1r, which are not based on astronomical tuning in the latest iteration of the Geologic Time Scale. Furthermore, it provides independent evidence that the relatively large (several 10,000 years) time lags documented in the benthic foraminiferal isotope records relative to orbital eccentricity, constitute a real feature of the Oligocene-Miocene climate system and carbon cycle. The age constraints from Site U1334 thus provide independent evidence that the delayed responses of the Oligocene-Miocene climate-cryosphere system and carbon cycle resulted from highly nonlinear feedbacks to astronomical forcing.

Description: Palynological counts from IODP Leg 318 Hole U1356A, Cores 95R-11R, and the lithological facies as observed in Salabarnada et al., CP 2018. Reworked dinocysts (as by Bijl et al., JM 2018), in situ dioncysts, acritarchs and terrestrial palynomorphs, as well as dinocyst ecogroups.

Description: Paleohydrological data comprising pollen assemblages and leaf-wax hydrogen isotopes (δDwax) from paleolake sediments in the Qaidam Basin (China) provide evidence for a link between increased moisture availability on the Tibetan Plateau and global cooling during the Mid-Pleistocene Transition. Notably, they document the persistence of humid and cold conditions during Marine Isotope Stages 24–22 (936–866 ka) suggesting that boundary conditions favorable for extended glaciation on the Tibetan Plateau first developed at ~900 ka. Our δDwax results indicate a strong influence of proximal (monsoonal) moisture sources during that glacial, in agreement with the intensification of the inter-hemispheric moisture transport resulting from Antarctic ice-volume increase at ~900 ka. The consistency of our results with other marine and terrestrial climate datasets suggests that extended glaciation on the Tibetan Plateau may have initiated ~500 ka earlier than previously assumed, implying that mid-latitude ice sheets actively contributed to global cooling during the Mid-Pleistocene Transition.

Description: Detailed, stratigraphically well-constrained environmental reconstructions are available for Paleocene and Eocene strata at a range of sites in the southwest Pacific Ocean (New Zealand and East Tasman Plateau; ETP) and Integrated Ocean Discovery Program (IODP) Site U1356 in the south of the Australo-Antarctic Gulf (AAG). These reconstructions have revealed a large discrepancy between temperature proxy data and climate models in this region, suggesting a crucial error in model, proxy data or both. To resolve the origin of this discrepancy, detailed reconstructions are needed from both sides of the Tasmanian Gateway. Paleocene-Eocene sedimentary archives from the west of the Tasmanian Gateway have unfortunately remained scarce (only IODP Site U1356), and no well-dated successions are available for the northern sector of the AAG. Here we present new stratigraphic data for upper Paleocene and lower Eocene strata from the Otway Basin, southeast Australia, on the (north)west side of the Tasmanian Gateway. We analyzed sediments recovered from exploration drilling (Latrobe-1 drill core) and outcrop sampling (Point Margaret) and performed high-resolution carbon isotope geochemistry of bulk organic matter and dinoflagellate cyst (dinocyst) and pollen biostratigraphy on sediments from the regional lithostratigraphic units, including the Pebble Point Formation, Pember Mudstone and Dilwyn Formation. Pollen and dinocyst assemblages are assigned to previously established Australian pollen and dinocyst zonations and tied to available zonations for the SW Pacific. Based on our dinocyst stratigraphy and previously published planktic foraminifer biostratigraphy, the Pebble Point Formation at Point Margaret is dated to the latest Paleocene. The globally synchronous negative carbon isotope excursion that marks the Paleocene-Eocene boundary is identified within the top part of the Pember Mudstone in the Latrobe-1 borehole and at Point Margaret. However, the high abundances of the dinocyst Apectodinium prior to this negative carbon isotope excursion prohibit a direct correlation of this regional bio-event with the quasi-global Apectodinium acme at the Paleocene-Eocene Thermal Maximum (PETM; 56 Ma). Therefore, the first occurrence of the pollen species Spinizonocolpites prominatus and the dinocyst species Florentinia reichartii are here designated as regional markers for the PETM. In the Latrobe-1 drill core, dinocyst biostratigraphy further indicates that the early Eocene (~56-51 Ma) sediments are truncated by a ~10 Myr long hiatus overlain by middle Eocene (~40 Ma) strata. These sedimentary archives from southeast Australia may prove key in resolving the model-data discrepancy in this region, and the new stratigraphic data presented here allow for detailed comparisons between paleoclimate records on both sides of the Tasmanian Gateway.

Description: Expansions of coastal upwelling spots along the Brazilian coast were previously reported for Marine Isotope Stage (MIS) 5, but open questions remain regarding the climatic mechanisms and the periodicity of such changes. Based on two marine sediment cores, we provide evidence for multiple intensifications of the upwelling regime off the Southeast Brazilian margin (SBM) during several interglacials and highlight the major role of eccentricity as the responsible forcing. In addition, we show a two-step change in the upwelling regime across the Mid-Brunhes Event (MBE) and an increase in the amplitude of upwelling variability after this climatic transition. Our findings point to substantial modifications of the upwelling regions during several glacial-interglacial transitions that probably altered the regional marine productivity regime and the carbon budget.

Description: Nd isotope composition of weakly cleaned foraminifera in core tops close to ODP Site 1006. 12 Myr record of Nd isotopes measured in weakly cleaned foraminifera from ODP Site 1006. Record from 5.5 to 13.5 Myr of Nd isotopes measured in weakly cleaned foraminifera from ODP Site 1000. 12 Myr record of Nd and Sr isotopes measured in the detrital fraction from ODP Site 1006. Record from 5.5 to 13.5 Myr of Nd and Sr isotopes measured in the detrital fraction from ODP Site 1000.

Description: Here we present high-resolution (~500 years) grain-size, loss on ignition (LOI), and lithology records spanning the time interval ~2.74-2.07 Ma from the western Qaidam Basin, NE Tibetan Plateau that shows pronounced glacial-interglacial climate variability during the time interval.

Description: Census counts of marine microfossils in surface sediments represent an invaluable resource for paleoceanography and for the investigation of macroecological processes. A prerequisite for such applications is the provision of data syntheses for individual microfossil groups. Specific to such syntheses is the necessity of taxonomical harmonisation across the constituent datasets, coupled with dereplication of previous compilations. Both of these aspects require expert knowledge, but with increasing number of records involved in such syntheses, the application of expert knowledge via manual curation is not feasible. Here we present a synthesis of planktonic foraminifera census counts in surface sediment samples, which is taxonomically harmonised, dereplicated and treated for numerical and other inconsistencies. The data treatment is implemented as an objective and largely automated pipeline, allowing us to reduce the initial 6,984 records to 4,205 counts from unique sites and informative technical or true replicates. We provide the final product and document the procedure, which can be easily adopted for other microfossil data syntheses.

Description: There is growing interest in the scientific community in reconstructing the paleoceanography of the Southern Ocean during the Oligocene-Miocene because these time intervals experienced atmospheric CO2 concentrations with relevance to our future. However, it has remained notoriously difficult to put the sedimentary archives used in these efforts into a temporal framework. This is at least partially due to the fact that the bio-events recorded in organic-walled dinoflagellate cysts (dinocysts), which often represent the only microfossil group preserved, have not yet been calibrated to the international time scale. We here present dinocyst ranges from Oligocene-Miocene sediments drilled offshore the Wilkes Land continental margin, East Antarctica (Integrated Ocean Drilling Program (IODP) Hole U1356A). In addition, we apply statistical means to test a priori assumptions about whether the recorded taxa were deposited in situ or were reworked from older strata. Moreover, we describe two new dinocyst species, Selenopemphix brinkhuisii sp. nov. and Lejeunecysta adeliensis sp. nov., which are identified as important markers for regional stratigraphic analysis. Finally, we calibrate all identified dinocyst events to the international time scale using independent age control from calcareous nannoplankton and magnetostratigraphy from IODP Hole U1356A, and propose a provisional dinoflagellate cyst zonation scheme for the Oligocene-Miocene of the Southern Ocean.