A5008559028- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Geology and Paleoclimatology Research
- Geochemistry and Elemental Analysis
- Marine and environmental studies
- Paleontology and Stratigraphy of Fossils
- Geological Studies and Exploration
- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Geochemistry and Geologic Mapping
- Atmospheric and Environmental Gas Dynamics
- Marine Biology and Ecology Research
- Polar Research and Ecology
- Geological formations and processes
- Mine drainage and remediation techniques
- Geological Modeling and Analysis
- Isotope Analysis in Ecology
- Geological and Geophysical Studies
- Geomagnetism and Paleomagnetism Studies
- Hydraulic Fracturing and Reservoir Analysis
- Cryospheric studies and observations
- Landslides and related hazards
- Geotechnical and Geomechanical Engineering
- Heavy metals in environment
- Groundwater and Isotope Geochemistry
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2014-2024
University of Bremen
2017-2024
Leibniz Centre for Tropical Marine Research
2021-2022
University of Cologne
2011-2017
International Ocean Discovery Program
2017
Shikoku (Japan)
2017
Abstract Here, we present results from sediments collected in the Argentine Basin, a non‐steady state depositional marine system characterized by abundant oxidized iron within methane‐rich layers due to sediment reworking followed rapid deposition. Our comprehensive inorganic data set shows that reduction these sulfate and sulfide‐depleted is best explained microbially mediated process—implicating anaerobic oxidation of methane coupled (Fe‐ AOM ) as most likely major mechanism. Although...
The interplay between sediment deposition patterns, organic matter type and the quantity quality of reactive mineral phases determines accumulation, speciation isotope composition pore water solid phase sulfur constituents in marine sediments. Here, we present geochemistry siliciclastic sediments from two sites along Argentine continental slope—a system characterized by dynamic reworking, which result non-steady state conditions. investigated have different depositional histories but common...
Deep, hot, and more alive than we thought Marine sediments represent a massive microbial ecosystem, but still do not fully understand what factors shape limit life underneath the seafloor. Analyzing samples from subduction zone off coast of Japan, Heuer et al. found that life, in particular bacterial vegetative cells, decreases as depth temperature increases down to ∼600 meters below seafloor, corresponding temperatures ∼70°C. Below this limit, endospores are common—a remnant, potential...
The flux of methane, a potent greenhouse gas, from the seabed is largely controlled by anaerobic oxidation methane (AOM) coupled to sulfate reduction (S-AOM) in transition (SMT). S-AOM estimated oxidize 90 % produced marine sediments and governed consortium methanotrophic archaea (ANME) reducing bacteria. An additional sink, i.e., iron oxide AOM (Fe-AOM), has been suggested be active methanic zone sediments. Geochemical signatures below SMT such as high dissolved iron, low undetectable...
The Cretaceous period (∼145–65 m.y. ago) was characterized by intervals of enhanced organic carbon burial associated with increased primary production under greenhouse conditions. global consequences these perturbations, oceanic anoxic events (OAEs), lasted up to 1 m.y., but short-term nutrient and climatic controls on widespread anoxia are poorly understood. Here, we present a high-resolution reconstruction redox cycling as recorded in subtropical shelf sediments from Tarfaya, Morocco,...
Assessing frequency and extent of mass movement at continental margins is crucial to evaluate risks for offshore constructions coastal areas.A multidisciplinary approach including geophysical, sedimentological, geotechnical, geochemical methods was applied investigate multistage transport deposits (MTDs) off Uruguay, on top which no surficial hemipelagic drape detected based echosounder data.Nonsteady state pore water conditions are evidenced by a distinct gradient change in the...
Research Article| August 01, 2013 A slump in the trench: Tracking impact of 2011 Tohoku-Oki earthquake M. Strasser; Strasser 1Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092 Switzerland Search for other works by this author on: GSW Google Scholar Kölling; Kölling 2MARUM—Center Marine Environmental Sciences, University Bremen, Leobener Strasse, 28359 Germany C. dos Santos Ferreira; Ferreira H.G. Fink; Fink T. Fujiwara; Fujiwara 3Japan Agency Marine-Earth Science and Technology...
Marine permeable sediments are important sites for organic matter turnover in the coastal ocean. However, little is known about their role trapping dissolved (DOM). Here, we examined DOM abundance and molecular compositions (9804 formulas identified) subtidal along a near- to offshore gradient German North Sea. With salinity increasing from 30.1 34.6 PSU, composition bottom water shifts relatively higher abundances of aromatic compounds more highly unsaturated compounds. In bulk sediment,...
Iron (Fe) fluxes from reducing sediments and subglacial environments are potential sources of bioavailable Fe into the Southern Ocean. Stable isotopes (δ56Fe) considered a proxy for reaction pathways, but respective data scarce cycling in complex natural is not understood sufficiently to constrain δ56Fe "endmembers" different types sediments, environmental conditions, biogeochemical processes. We present pore waters sequentially extracted sedimentary phases two contrasting sites Potter Cove...
Research Article| April 15, 2019 Naturally occurring, microbially induced smectite-to-illite reaction Jinwook Kim; Kim * 1Department of Earth System Sciences, Yonsei University, Seoul 03722, South Korea *E-mails: jinwook@yonsei.ac.kr; dongh@cugb.edu.cn Search for other works by this author on: GSW Google Scholar Hailiang Dong; Dong 2State Key Laboratory Biogeology and Environmental Geology, China University Geosciences, Beijing 100083, China3Department Geology Science, Miami Oxford, Ohio...
Abstract Elevated dissolved iron concentrations in the methanic zone are typical geochemical signatures of rapidly accumulating marine sediments. These sediments often characterized by co-burial oxides with recalcitrant aromatic organic matter terrigenous origin. Thus far, predicted to either impede degradation, aiding its preservation, or identified enhance carbon oxidation via direct electron transfer. Here, we investigated effect various oxide phases differing crystallinity (magnetite,...
Permeable sandy sediments cover 50-60 % of the global continental shelf and are important bioreactors that regulate organic matter (OM) turnover nutrient cycling in coastal ocean. In sands, dynamic porewater advection can cause rapid mass transfer variable redox conditions, thus affecting OM remineralization pathways, as well recycling iron phosphorus. this study, North Sea sands were incubated flow-through reactors (FTRs) to investigate biogeochemical processes under changing conditions. We...
The polar regions are the fastest warming places on earth. Accelerated glacial melting causes increased supply of nutrients such as metal oxides (i.e., iron and manganese oxides) into surrounding environment, marine sediments Potter Cove, King George Island/Isla 25 de Mayo (West Antarctic Peninsula). Microbial oxide reduction associated microbial communities poorly understood in sediments. Here, we investigated this process by geochemical measurements situ sediment pore water slurry...
Nature of sulfidization in shallow shelf sediments: Influence organoclastic sulfate reduction and anaerobic oxidation methane Anaerobic is an important biogeochemical process marine sediments responsible for consumption, significantly influencing the atmospheric budget, carbon cycle, sediment pore fluid chemistry. Sulfate-driven (SO42--AOM) (OSR) commonly lead to precipitation authigenic pyrite with characteristic sulfur isotopic compositions. In present study, we have investigated nature...
Abstract. The low δ56Fe values of dissolved iron liberated by microbial reduction are characteristic many shallow subsurface sediments and – if not significantly changed within the oxic sediment layer related benthic Fe fluxes into water column. Here, we decipher whether stable isotope signatures in pore respective solid-phase samples also useful for unraveling processes driving liberation deeper methanic sediments. We investigated fine-grained deposits Helgoland mud area, North Sea, where...
Magnetite (Fe3O4), a ubiquitous sedimentary iron mineral, is crucial for paleomagnetic records preservation. However, reactive ferric minerals, including magnetite, can undergo reduction in aquatic sediments above and within the sulfidic zone at Sulfate-Methane Transition Zone (SMTZ), resulting production of dissolved ferrous iron. Partial reoxidation reduced oxic-anoxic interface lead to authigenic magnetite precipitation. Yet, persistence behavior deeper methanic have remained poorly...
Numerous studies have provided compelling evidence that the Pacific Ocean has experienced substantial glacial/interglacial changes in bottom-water oxygenation associated with enhanced carbon dioxide storage glacial deep ocean. Under postulated low oxygen concentrations (O2bw), redox zonation, biogeochemical processes and element fluxes sediments must been distinctively different during last period (LGP) compared to current well-oxygenated conditions. In this study, we investigated six sites...
Colonization of newly ice-free areas by marine benthic organisms intensifies burial macroalgae detritus in Potter Cove coastal surface sediments (Western Antarctic Peninsula). Thus, fresh and labile macroalgal serves as primary organic matter (OM) source for microbial degradation. Here, we investigated the effects on post-depositional iron reduction using sediment incubations amended with pulverized OM source, acetate product degradation lepidocrocite reactive oxide to mimic situ conditions....
The area around the Antarctic Peninsula (AP) is facing rapid climatic and environmental changes, with so far unknown impacts on benthic microbial communities of continental shelves. In this study, we investigated impact contrasting sea ice cover community compositions in surface sediments from five stations along eastern shelf AP using 16S ribosomal RNA (rRNA) gene sequencing. Redox conditions long ice-free periods are characterized by a prevailing ferruginous zone, whereas comparatively...
Abstract. The burial of organic matter (OM) within fine-grained continental shelf sediments represents one the major long-term sinks carbon. We investigated key factors controlling carbon in Helgoland Mud Area (HMA), which most significant depocentre and organic-rich German Bight (SE North Sea). examined include sedimentation accumulation rates, sediment mixing grain size, total (TOC) content aerobic remineralisation rates. Highest rates up to ~4.5 mm yr-1 average TOC contents 2 wt% were...