A5003302071- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Microbial Community Ecology and Physiology
- Ocean Acidification Effects and Responses
- Oceanographic and Atmospheric Processes
- Wastewater Treatment and Nitrogen Removal
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Atmospheric and Environmental Gas Dynamics
- Marine Bivalve and Aquaculture Studies
- Microbial Fuel Cells and Bioremediation
- Protist diversity and phylogeny
- Geology and Paleoclimatology Research
- Coastal and Marine Management
- Global Energy and Sustainability Research
- Hydrocarbon exploration and reservoir analysis
- Aerospace Engineering and Energy Systems
- Geophysics and Gravity Measurements
- Geochemistry and Geologic Mapping
- Metalloenzymes and iron-sulfur proteins
- CO2 Sequestration and Geologic Interactions
- Genomics and Phylogenetic Studies
- Marine and fisheries research
- Legume Nitrogen Fixing Symbiosis
- Algal biology and biofuel production
University of Southern Denmark
2016-2025
GEOMAR Helmholtz Centre for Ocean Research Kiel
2015-2021
The Open University
2019
Kiel University
2010-2018
Abstract. The recent finding that microbial ammonia oxidation in the ocean is performed by archaea to a greater extent than bacteria has drastically changed view on oceanic nitrification. numerical dominance of archaeal ammonia-oxidizers (AOA) over their bacterial counterparts (AOB) large parts leads hypothesis AOA rather AOB could be key organisms for production strong greenhouse gas nitrous oxide (N2O) occurs as by-product Very recently, enrichment cultures marine ammonia-oxidizing have...
Plastics and other artificial materials pose new risks to health of the ocean. Anthropogenic debris travels across large distances is ubiquitous in water on shorelines, yet, observations its sources, composition, pathways distributions ocean are very sparse inaccurate. Total amounts plastics man-made shore, temporal trends these under exponentially increasing production, as well degradation processes, vertical fluxes time scales largely unknown. Present circulation models not able accurately...
In Eastern Boundary Upwelling Systems nutrient-rich waters are transported to the ocean surface, fuelling high photoautotrophic primary production. Subsequent heterotrophic decomposition of produced biomass increases oxygen-depletion at intermediate water depths, which can result in formation oxygen minimum zones (OMZ). OMZs sporadically accumulate hydrogen sulfide (H2S), is toxic most multicellular organisms and has been implicated massive fish kills. During a cruise OMZ off Peru January...
Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of marine microbial biodiversity and function world's oceans. It is simultaneous global mega-sequencing campaign aiming generate largest standardized data set in single day. This will be achievable only through coordinated efforts an Consortium, supportive partnerships networks between sites. commentary outlines establishment, aims Consortium...
Abstract. Ocean alkalinity enhancement (OAE) is an emerging strategy that aims to mitigate climate change by increasing the of seawater. This approach involves ocean enhance its capacity absorb and store carbon dioxide (CO2) from atmosphere. chapter presents overview technical aspects associated with full range OAE methods being pursued discusses implications for undertaking research on these approaches. Various have been developed implement OAE, including direct injection alkaline liquid...
Oxygen minimum zones are major sites of fixed nitrogen loss in the ocean. Recent studies have highlighted importance anaerobic ammonium oxidation, anammox, pelagic removal. Sources for anammox reaction, however, remain controversial, as heterotrophic denitrification and alternative pathways organic matter remineralization cannot account requirements reported rates. Here, we explore significance microaerobic respiration a source during degradation oxygen-deficient waters off Namibia Peru....
Members of the gammaproteobacterial clade SUP05 couple water column sulfide oxidation to nitrate reduction in sulfidic oxygen minimum zones (OMZs). Their abundance offshore OMZ waters devoid detectable has led suggestion that local sulfate fuels SUP05-mediated a so-called "cryptic sulfur cycle". We examined distribution and metabolic capacity Peru Upwelling waters, using combination oceanographic, molecular, biogeochemical single-cell techniques. A single species, U Thioglobus perditus, was...
Abstract. Despite the worldwide occurrence of marine hypoxic regions, benthic nitrogen (N) cycling within these areas is poorly understood and it generally assumed that represent zones intense fixed N loss from system. Sulfate reduction can be an important process for organic matter degradation in sediments beneath waters many sulfate-reducing bacteria (SRB) have genetic potential to fix molecular (N2). Therefore, SRB may supply systems, countering some lost via microbial processes, such as...
Abstract. Oxygen-deficient zones (ODZs) are major sites of net natural nitrous oxide (N2O) production and emissions. In order to understand changes in the magnitude N2O response global change, knowledge on individual contributions microbial pathways (nitrification denitrification) their regulation is needed. ODZ coastal area off Peru, sensitivity oxygen organic matter was investigated using 15N tracer experiments combination with quantitative PCR (qPCR) microarray analysis total active...
Abstract. Marine diazotrophs convert dinitrogen (N2) gas into bioavailable nitrogen (N), supporting life in the global ocean. In 2012, first version of oceanic diazotroph database (version 1) was published. Here, we present an updated 2), significantly increasing number situ diazotrophic measurements from 13 565 to 55 286. Data points for N2 fixation rates, cell abundance, and nifH gene copy abundance have increased by 184 %, 86 809 respectively. Version 2 includes two new data sheets...
The air–sea exchange and oceanic cycling of greenhouse gases (GHG), including carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), monoxide (CO), nitrogen oxides (NOx = NO + NO2), are fundamental in controlling the evolution Earth’s atmospheric chemistry climate. Significant advances have been made over last 10 years understanding, instrumentation methods, as well deciphering production consumption pathways GHG upper ocean (including surface subsurface down to approximately 1000 m)....
Abstract. The eastern tropical North Atlantic (ETNA) features a mesopelagic oxygen minimum zone (OMZ) at approximately 300–600 m depth. Here, concentrations rarely fall below 40 µmol O2 kg−1, but are expected to decline under future projections of global warming. recent discovery mesoscale eddies that harbour shallow suboxic (< 5 kg−1) OMZ just the mixed layer could serve identify zooplankton groups may be negatively or positively affected by ongoing ocean deoxygenation. In spring 2014,...
Abstract. The temporal evolution of the physical and biogeochemical structure an oxygen-depleted anticyclonic modewater eddy is investigated over a 2-month period using high-resolution glider ship data. A weakly stratified core (squared buoyancy frequency N2 ∼ 0.1 × 10−4 s−2) at shallow depth identified with horizontal extent about 70 km bounded by maxima in N2. upper maximum (3–5 coincides mixed layer base lower (0.4 found 200 m centre. shows constant slope temperature/salinity (T∕S)...
Abstract. Benthic microbial methanogenesis is a known source of methane in marine systems. In most sediments, the majority located below sulfate-reducing zone, as sulfate reducers outcompete methanogens for major substrates hydrogen and acetate. The coexistence reduction has been shown before possible through usage noncompetitive by such methanol or methylated amines. However, knowledge about magnitude, seasonality, environmental controls this production sparse. present study, presence...
Microbially induced corrosion of metallic iron (Fe0)-containing structures is an environmental and economic hazard. Methanogens are abundant in low-sulfide environments yet their specific role Fe0 poorly understood. In this study, Sporomusa Methanosarcina dominated enrichments from Baltic Sea methanogenic sediments that were established with as the sole electron donor CO2 acceptor. The Baltic-Sporomusa was phylogenetically affiliated to electroactive acetogen S. silvacetica. adjusted rapidly...
Abstract. The Bay of Bengal (BoB) has long stood as a biogeochemical enigma, with subsurface waters containing extremely low, but persistent, concentrations oxygen in the nanomolar range which – for some, yet unconstrained, reason are prevented from becoming anoxic. One this may be low productivity BoB due to nutrient limitation and resulting lack respiration organic material at intermediate waters. Thus, parameters determining primary production key understanding what prevents developing...
Abstract. Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by nutrient-rich deep waters and high incident light at sea surface. However, biotic abiotic factors can modify surface related biogeochemical processes. Determining these important because EBUS considered hotspots climate change, reliable predictions their future functioning requires understanding mechanisms driving cycles therein. In...
Microbe-mineral interactions, such as mineral substrate utilization and aggregate formation, have played a key role in the cycling of elements through Earth evolution. In water, soils, sediment biogeochemistry modulates microbial community composition formation over spatial temporal scales. Plastic is new material that now widespread environment. Both associations with plastic comprise Plastisphere , which influences fate plastic. This study focuses on how biogeochemical environment defines...