16 Works

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...

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...

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...

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...

A 5.3-million-year history of monsoonal precipitation in northwestern Australia

Jan-Berend Willem Stuut , Patrick De Deckker , Mariem Saavedra-Pellitero , Franck Bassinot , Anna Joy Drury , Maureen Walczak & Kana Nagashima
NIOZ - Royal Netherlands Institute for Sea Research, and Utrecht University, Texel, the Netherlands (1); MARUM – Center for Marine Environmental Sciences, Bremen University, Bremen, Germany (2); Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, The Netherlands (3); ANU – Australian National University, Research School of Earth Sciences, Canberra, Australia (4); School of Geography, Earth and Environmental Sciences at University of Birmingham, Edgbaston Birmingham, United Kingdom (5); LSCE - Laboratoire des Sciences du...

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...

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...

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...

Similarities of the Scotia and Caribbean Plates: Implications for a common plate tectonic history?!

Burmeister Christian , Paul Wintersteller & Martin Meschede
The active volcanic arcs of the Scotia- and Caribbean Plate are two prominent features along the otherwise passive margins of the Atlantic Ocean, where subduction of oceanic crust is verifiable. Both arcs have been important oceanic gateways during their formation. Trapped between the large continental plates of North- and South America, as well as Antarctica, the significantly smaller oceanic plates show striking similarities in size, shape, plate margins and morphology, although formed at different times...

Volcanic structures and magmatic evolution of the Vesteris Seamount, Greenland Basin

Katharina Anna Unger Moreno, Janis Thal , Wolfgang Bach , Christoph Beier & Karsten Matthias Haase
The solitary intraplate volcano Vesteris Seamount is located in the Central Greenland Basin and rises around 3000 m above the seafloor with a total eruptive volume of ~500 km3. Newly acquired high-resolution bathymetry allows through backscatter data and raster terrain analysis to distinguish several volcanic structures. The Vesteris Seamount is a northeast to southwest elongated stellar-shaped seamount with an elongated, narrow summit radially surrounded by irregular volcanic ridges, separated by volcanic debris fans. Whole rock...

What factors control the development of moats and their associated contourite drifts?

Henriette Wilckens , Elda Miramontes , Tilmann Schwenk , Thomas Lüdmann , Christian Betzler , Javier Hernandez-Molina , Volkhard Spieß & Antonio Cattaneo
The interaction of sedimentary systems with oceanographic processes in deep-water environments is still not well understood, despite its importance for improving paleoreconstructions and for understanding source-to-sink sediment transport. The aim of this study is to improve our understanding of sediment deposits formed by the action of bottom currents (contourites), and specifically elongated depressions that are called ‘moats’. Moats are common incisions oriented alongslope formed by the main core of the current and are usually associated...

Unique islets in SE Asia: How Holocene climate and sea-level controlled growth of a coral reef island

Yannis Kappelmann, Hildegard Westphal, André Wizemann & Thomas Mann
Coral reef islands are unconsolidated landforms, composed of skeletal carbonate from surrounding reefs and related ecosystems. Facing the predicted rise of sea-level and a changing environment in the next decades, response of low-lying coral reef islands is of great scientific and public interest. To better estimate future behavior, it is necessary to know and classify the effects of past environmental changes on the sedimentary system. In SE Asia, sedimentological understanding of the development of these...

Registration Year

  • 2022
  • 2021

Resource Types

  • Text


  • University of Bremen
  • Leibniz Centre for Tropical Marine Research
  • Federal Institute for Geosciences and Natural Resources
  • Universität Hamburg, Hamburg, Germany
  • GEOMAR Helmholtz Centre for Ocean Research Kiel
  • Universität Bremen, Bremen, Germany
  • Japan Agency for Marine-Earth Science and Technology
  • //ror.org/00f7hpc57:affiliation affiliationIdentifier="https://ror.org/04ers2y35" affiliationIdentifierScheme="ROR" schemeURI="https://ror.org">Universität Bremen, Bremen, Germany
  • //ror.org/04g2vpn86:Royal Holloway University of London, Egham, Surrey, UK
  • Hasanuddin University