34 Works

Ku- and Ka-band polarimetric radar backscatter of Arctic sea ice between October 2019 and September 2020 - VERSION 2.0

Julienne Stroeve, Vishnu Nandan, Rasmus Tonboe, Stefan Hendricks, Robert Ricker & Gunnar Spreen
This data set provides processed Ku- and Ka-band fully-polarimetric backscatter and derived polarimetric parameters from hourly scans, acquired using the KuKa radar, during Legs 1, 2, 4 and 5 of the 2019-2020 MOSAiC International Arctic Drift Expedition. Scans were acquired during winter (Legs 1 and 2), advanced melt (Leg 4) and freeze-up (Leg 5) seasons, from various Remote Sensing (RS) sites, located in the MOSAiC ice floe. The first deployment of the KuKa radar was...

Deposition of Subglacial Lake Sediments underneath the Laurentide Ice Sheet? – Sediment Cores from Lake Melville, Canada, provide first Evidence

Sophie Kowalski, Christian Ohlendorf, Jens Matthiessen & Andrea Catalina Gebhardt
Lake Melville is a fjord-type lake located in Labrador, Eastern Canada, as part of the Hamilton Inlet System. It is significantly characterised by its eastern connection to the Labrador Sea through a shallow sill at the entrance to the Rigolet Narrows. In contrast, the western part of the lake receives freshwater input from several major rivers. Previous studies assumed that Lake Melville was fully excavated by the Laurentide Ice Sheet (LIS) during the last glacial....

Redox conditions during deserpentinization in western Elba Island, Italy.

Malte Kalter & Wolfgang Bach
The observation of oxidized arc melts has led to a discussion about the redox conditions during the dehydration reactions of serpentinites in subduction zones. The discussed range of oxygen fugacities (fO2) between+5 and -2 log units relatively to the QFM buffer allows sulfur to be present either as oxidized or reduced species. This work investigates the development of the fO2 with serpentines form the western part of the island Elba in Italy. We compared observations...

First evidence from Lake Melville, Canada: Subglacial lake sediments underneath the Laurentide Ice Sheet?

Sophie Kowalski , Christian Ohlendorf , Andrea Catalina Gebhardt & Jens Matthiessen
The fjord-type Lake Melville is located in Labrador, Eastern Canada, as part of the Hamilton Inlet System. It is mainly characterised by riverine freshwater influx into its western end and intrusion of saline water from the Labrador Sea through the shallow Rigolet Narrows. Previous studies assumed that the retreating Laurentide Ice Sheet (LIS) caused the deposition of a typical glacial sediment sequence when its margin reached Lake Melville between 10,000 to 8,000 years ago (King,...

No warming in the eastern Gulf of Mexico since 1845 recorded by a Siderastrea siderea coral from Cuba

Marie Harbott , Henry C. Wu , Henning Kuhnert , Simone Kasemann , Anette Meixner , Carlos Jimenez , Patricia González-Díaz & Tim Rixen
Changes in the surface ocean pH and temperature caused by the uptake of anthropogenic CO2 are posing a threat to calcifying marine organisms. Recent studies have observed significant impacts on coral reef ecosystems with impaired carbonate skeletal growth and decreased calcification due to acidifying oceans. The current coverage of observations for the northwestern Cuban coastal waters provides an incomplete picture of natural climate variability over interannual to interdecadal timescales, showing the need for high resolution...

In-situ silicon isotopes in mantle wedge serpentinites - a new proxy for slab dehydration reactions

Sonja Geilert , Elmar Albers , Daniel A. Frick , Christian T. Hansen & Friedhelm von Blanckenburg
The Mariana forearc provides a unique natural laboratory to study slab dehydration in an active subduction zone by its deep-rooted mud volcanism. To test if mantle wedge serpentinites would record the source fluid composition and thus the dehydration reactions in the slab, we investigated silicon (Si) isotopic compositions (δ30Si) in serpentine veins by in-situ femtosecond laser ablation ICP mass spectrometry. Our samples were recovered during IODP Expedition 366 and originate from three mud volcanoes that...

Nutrition Transition in Europe: East-West Dimensions in the Last 30 Years-A Narrative Review

Klara G Dokova, Rouzha Z Pancheva, Natalya V Usheva, Galina A Haralanova, Silviya P Nikolova, Todorka I Kostadinova, Caue Egea Rodrigues, Jessica Radcliffe, Anne-Kathrin Illner & Krasimira Aleksandrova
The current review aims to summarize published research on nutrition transition patterns (depicting changes in dietary consumption) in European populations over the last three decades (1990-2020), with a focus on East-West regional comparisons. Pubmed and Google-Scholar databases were searched for articles providing information on repeated dietary intakes in populations living in countries across Europe, published between January 1990 and July 2021. From the identified 18,031 articles, 62 were found eligible for review (17 from Eastern...

Biologic agents mediating matter-flow inside the porous igneous oceanic crust, Vesteris Seamount, Greenland Sea

Hinrich Schmid-Beurmann, Magnus Ivarsson, Wolfgang Bach, Wolf-Achim Kahl & Jörn Peckmann
Microorganisms within the lithosphere are biologic agents settling in niches inside the terrestrial and oceanic crust, populating the extreme environments of the deep biosphere. The fossil record of the permeable igneous oceanic crust, constructed out of primitive extrusive rock, opens a window into Earth’s early evolution and serves as an analogue for life in extraterrestrial worlds. In 2019, samples of highly porous basanites of Vesteris Seamount in the Greenland Sea were retrieved during a cruise...

Compositions of hydrothermal vent fluids as a guide to subseafloor mineralization processes

Wolfgang Bach & Alexander Diehl
Studying active hydrothermal systems in the deep-sea provides unique opportunities for furthering our understanding of how polymetallic seafloor massive sulfide accumulations form. The possibility of sampling the ore-forming fluids that are emitted through sulfide-sulfate chimneys is particularly powerful. The use of gas-tight samplers in collecting hydrothermal vent fluids facilitates measurements of the contents of dissolved gases and metals and allows for accurate reconstructions of in situ pH and redox conditions. Metal transport in seafloor hydrothermal...

Shallow-marine carbonate cementation in Holocene segments of the calcifying green alga Halimeda

Thomas Mann , André Wizemann , Marleen Stuhr , Yannis Kappelamann , Alexander Janßen , Jamaluddin Jompa & Hildegard Westphal
Early-diagenetic cementation of tropical carbonates results from the combination of numerous physico-chemical and biological processes. In the marine phreatic environment it represents an essential mechanism for the development and stabilization of carbonate platforms. However, many early-diagenetic cements that developed in the marine phreatic environment are likely to become obliterated during later stages of meteoric or burial diagenesis. In this contribution, a petrographic microfacies analysis of Holocene Halimeda segments collected on a coral island in the...

The impact of increasing temperature on microbial lipid distributions in the Nankai Trough subduction zone, IODP Exp. 370

Florence Schubotz , Inga Hölscher , Julius Sebastian Lipp , Yuki Morono , Fumio Inagaki , Verena B. Heuer & Kai-Uwe Hinrichs
Site C0023 in the Nankai Through subduction zone was established in 2016 to investigate the temperature limits of deep subsurface life. Here, we report on the detection of intact polar lipids and their degradation products in sediments recovered from this site where temperatures reach values close to the known limit of life of ca. 120°C at the bottom of the core at 1170 m. Lipid biomarkers characteristic for sedimentary methanogens and unclassified heterotrophic archaea were...

Unexpected high amounts of H2 produced during serpentinization at magma-poor rifted margins

Elmar Albers , Wolfgang Bach , Marta Pérez-Gussinyé , Catherine McCammon & Thomas Frederichs
At magma-poor rifted margins, serpentinization of lherzolitic mantle rocks releases molecular hydrogen (H2) that supports chemosynthesis-based deep life. Until now, however, H2 fluxes in these systems remain largely unquantified. To help closing this knowledge gap we investigated serpentinization and H2 production using drill core samples from the West Iberia margin (Ocean Drilling Program Leg 103, Hole 637A). The mostly lherzolitic samples are strongly serpentinized, consist of serpentine with little magnetite, and are generally brucite-free. Serpentine...

TCCON data from Orléans (FR), Release GGG2020.R0

T. Warneke, C. Petri, J. Notholt & M. Buschmann
The Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier Transform Spectrometers that record direct solar absorption spectra of the atmosphere in the near-infrared. From these spectra, accurate and precise column-averaged abundances of atmospheric constituents including CO2, CH4, N2O, HF, CO, H2O, and HDO, are retrieved. This is the GGG2020 data release of observations from the TCCON station at Orleans, France

The impact of variable Fe concentrations on Fe-binding ligands, dissolved organics and microbial communities in hydrothermal plumes – an experimental study

Christian Tobias Hansen, Charlotte Kleint , Stefanie Böhnke , Lukas Klose , Nicole Adam , Katharina Sass, Mirjam Perner , Thorsten Dittmar & Andrea Koschinsky
Iron (Fe) plays an important role in aquatic environments as an essential, often biolimiting micronutrient but at very high concentrations can potentially be toxic. Consequently, microbes have evolved capabilities to influence Fe bioavailability through production of organic molecules, so called ligands, which can enhance iron bioavailability or be used for detoxification mechanisms. Hydrothermal vents represent a major source of Fe to the oceans and host specialized microbes that are likely capable of influencing Fe speciation...

Data from: Proteomic fingerprinting enables quantitative biodiversity assessments of species and ontogenetic stages in Calanus congeners (Copepoda, Crustacea) from the Arctic Ocean

Sven Rossel, Patricia Kaiser, Maya Bode-Dalby, Jasmin Renz, Holger Auel, Wilhelm Hagen & Pedro Martínez Arbizu
Species identification is pivotal in biodiversity assessments, and proteomic fingerprinting by MALDI-TOF mass spectrometry has already been shown to reliably identify calanoid copepods to species level. However, MALDI-TOF data may contain more information beyond mere species identification. In this study, we investigated different ontogenetic stages (copepodids C1-C6 females) of three co-occurring Calanus species from the Arctic Fram Strait, which cannot be identified to species level based on morphological characters alone. Differentiation of the three species...

Nutrition Transition in Europe: East-West Dimensions in the Last 30 Years-A Narrative Review

Klara G Dokova, Rouzha Z Pancheva, Natalya V Usheva, Galina A Haralanova, Silviya P Nikolova, Todorka I Kostadinova, Caue Egea Rodrigues, Jessica Radcliffe, Anne-Kathrin Illner & Krasimira Aleksandrova
The current review aims to summarize published research on nutrition transition patterns (depicting changes in dietary consumption) in European populations over the last three decades (1990-2020), with a focus on East-West regional comparisons. Pubmed and Google-Scholar databases were searched for articles providing information on repeated dietary intakes in populations living in countries across Europe, published between January 1990 and July 2021. From the identified 18,031 articles, 62 were found eligible for review (17 from Eastern...

Microplastics alter feeding strategies of a coral reef organism

Marlena Joppien, Hildegard Westphal, Marleen Stuhr & Steve Doo
Increasing marine microplastic pollution has detrimentally impacted organismal physiology and ecosystem functioning. While previous studies document negative effects of microplastics on coral reef animals, the potential responses of organisms such as Large Benthic Foraminifera (LBF) are largely unknown. Here, we document the impact of microplastics on heterotrophic feeding behavior of LBF. Specimens of Amphistegina gibbosa were incubated in three experimental treatments: (1) Artemia sp. nauplii only; (2) pristine microplastic particles only; (3) choice of nauplii...

No short-term effect of sinking microplastics on heterotrophy or sediment clearing in the tropical coral Stylophora pistillata

Sonia Bejarano, Anna Feuring, Valeska Diemel, Mattia Ghilardi & Tilmann Harder
Investigations of encounters between corals and microplastics have, to date, used particle concentrations that are several orders of magnitude above environmentally relevant levels. Here we investigate whether concentrations closer to values reported in tropical coral reefs affect sediment shedding and heterotrophy in reef-building corals. We show that single-pulse microplastic deposition elicits significantly more coral polyp retraction than comparable amounts of calcareous sediments. When deposited separately from sediments, microplastics remain longer on corals than sediments, through...

Monitoring of Methane Emissions at Southern Hydrate Ridge using Deep-Sea Cabled Observatory

Yann Marcon , Deborah Kelley , Blair Thornton , Dana Manalang & Gerhard Bohrmann
Natural methane gas release from the seafloor is a widespread phenomenon that occurs at cold seeps along most continental margins. Since their discovery in the early 1980s, seeps have been the focus of intensive research, partly aimed at refining the global carbon budget. However, deep-sea research is challenging and expensive and, to date, few programs have successfully monitored the variability of methane gas release over several weeks or more. Long-term monitoring is necessary to study...

Reconstructing past ice sheets and paleotopography using observations of past sea level and glacial geology

Evan James Gowan
During the Quaternary, large ice sheets repeatedly formed and retreated over continental North America and northern Europe, which in turn caused fluctuations in global sea level by up to 120 m. This caused substantial changes to the Earth's surface, changing the distribution of land, continental ice sheets, and ocean. I demonstrate a technique we use to reconstruct ice sheets and paleotopography, and its application for the past 800000 years. I show that with the use...

Rock-hosted life through time - Integrating biosignatures of ancient and modern hydrothermal systems

Florence Schubotz
Recent advances in analytical tools including more sensitive detection techniques have led to the discovery of microbial biosignatures in ultra-low biomass samples such as the oceanic lithosphere. Here, energy fluxes are low and microbial life has adapted to the slow cycling of sparsely available food and nutrient sources along cracks and fissures and the access to Earths chemical energy through water-rock interactions. Nevertheless, our understanding of the habitability of Earths lithosphere and potential connections to...

TCCON data from Nicosia (CY), Release GGG2020.R0

Christof Petri, Mihalis Vrekoussis, Constantina Rousogenous, Thorsten Warneke, Jean Sciare & Justus Notholt
The Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier Transform Spectrometers that record direct solar absorption spectra of the atmosphere in the near-infrared. From these spectra, accurate and precise column-averaged abundances of atmospheric constituents including CO2, CH4, N2O, HF, CO, H2O, and HDO, are retrieved. This is the GGG2020 data release of observations from the TCCON station at Nicosia (CY), The Cyprus Institute

Dynamic as always – Sedimentary evolution of a coral reef island from the Spermonde Archipelago, Indonesia

Yannis Kappelmann , Hildegard Westphal , Dominik Kneer , André Wizemann & Thomas Mann
Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstraße 6, Bremen, Germany(1);University of Bremen, Bibliothekstraße 1, Bremen, Germany(2);Bioplan GmbH, Strandstraße 32a, 18211 Ostseebad Nienhagen, Germany(3);Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, Hannover, Germany(4);The effects of changing climate and environmental conditions on coral reef islands have received a lot of attention, and the findings are discussed broadly. The low elevation of such islands above mean sea level and the largely unconsolidated sediment is exposing them to...

Antarctic sea ice reconstructions: pros and cons of highly branched isoprenoids as sea ice proxies

Nele Lamping , Wee Wei Khoo , Juliane Müller , Oliver Esper , Thomas Frederichs & Christian Haas
The reconstruction of past Antarctic sea ice coverage through the application of diatom assemblages is often hampered in near coastal environments due to silica dissolution effects. The more recently established approach of using highly branched isoprenoid biomarkers to identify past sea ice conditions seems a valid method to overcome this limitation and that may also provide insight into ice-shelf dynamics. Here, we evaluate the so-called PIPSO25 index applied to modern surface sediments from the Amundsen...

Asphalt formation at the seafloor of the Campeche-Sigsbee salt province, southern Gulf of Mexico

Gerhard Bohrmann , Miriam Römer , Chieh-Wei Hsu , Thomas Pape , Yann Marcon , Ian MacDonald & Paul Wintersteller
Hydrocarbon seepage is widespread distributed at the southern Gulf of Mexico. During several research cruises in 2003, 2006, and 2015 (SO174, M67/, and M114) we used multidisciplinary approaches, including multi-beam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits occur at numerous knolls and ridges in water depths from...

Registration Year

  • 2022
    34

Resource Types

  • Text
    24
  • Dataset
    10

Affiliations

  • University of Bremen
    26
  • Leibniz Centre for Tropical Marine Research
    6
  • Federal Institute for Geosciences and Natural Resources
    4
  • 4
  • Institute of Environmental Physics, University of Bremen, Bremen (DE)
    4
  • 4
  • GEOMAR Helmholtz Centre for Ocean Research Kiel
    3
  • Alfred Wegener Institute for Polar and Marine Research
    3
  • California Institute of Technology, Pasadena, CA (US)
    3
  • Universität Hamburg
    2