A5050166381- Arctic and Antarctic ice dynamics
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Marine and coastal ecosystems
- X-ray Spectroscopy and Fluorescence Analysis
- Catalysis and Oxidation Reactions
- Corporate Governance and Management
- Transition Metal Oxide Nanomaterials
- Climate change and permafrost
- Digital Innovation in Industries
- Electron and X-Ray Spectroscopy Techniques
- Ga2O3 and related materials
- Cryospheric studies and observations
- Isotope Analysis in Ecology
- Advanced X-ray Imaging Techniques
- Catalytic Processes in Materials Science
- Polar Research and Ecology
- Nuclear Physics and Applications
- Ocean Acidification Effects and Responses
- Quantum Dots Synthesis And Properties
- Machine Learning in Materials Science
- Chalcogenide Semiconductor Thin Films
- Environmental DNA in Biodiversity Studies
- Marine animal studies overview
- Liquid Crystal Research Advancements
University of Bergen
2016-2025
SLAC National Accelerator Laboratory
2017-2023
Stanford Synchrotron Radiation Lightsource
2017-2023
University of Wuppertal
2011-2022
Menlo School
2021-2022
Heinrich Heine University Düsseldorf
2022
Stanford University
1938-2017
University of Münster
2010-2012
University of Bayreuth
2002-2005
University of Augsburg
1995-1997
The quick-EXAFS (QEXAFS) method adds time resolution to X-ray absorption spectroscopy (XAS) and allows dynamic structural changes be followed. A completely new QEXAFS setup consisting of monochromator, detectors data acquisition system is presented, as installed at the SuperXAS bending-magnet beamline Swiss Light Source (Paul Scherrer Institute, Switzerland). monochromator uses Si(111) Si(311) channel-cut crystals mounted on one crystal stage, remote exchange an energy range from 4.0 keV 32...
Flowering is an important agronomic trait that often depends on the integration of photoperiod, vernalization, gibberellin and/or autonomous signaling pathways by regulatory proteins such as FLOWERING LOCUS T (FT), a member phosphatidylethanolamine-binding protein (PEBP) family. Six PEBP family control flowering in model plant Arabidopsis thaliana, and their functions are well established, but variation number structural diversity PEBPs different species means precise must be determined...
Increasing temperatures, with pronounced effects at high latitudes, have raised questions about potential changes in species composition, as well possible increased importance of small-celled phytoplankton marine systems. In this study, we mapped out one the smallest and globally most widespread primary producers, picocyanobacterium Synechococcus, within Atlantic inflow to Arctic Ocean. contrast general understanding that Synechococcus is almost absent polar oceans due low encountered...
The rapid melt of snow and sea ice during the Arctic summer provides a significant source low-salinity meltwater to surface ocean on local scale. accumulation this on, under, around floes can result in relatively thin layers upper ocean. Due small-scale nature these upper-ocean features, typically order 1 m thick or less, they are rarely detected by standard methods, but nevertheless pervasive critically important summer. Observations Multidisciplinary drifting Observatory for Study Climate...
The decrease in Arctic sea-ice extent and thickness as a result of global warming will impact the timing, duration, magnitude composition phytoplankton production with cascading effects on marine food-webs biogeochemical cycles. Here, we elucidate environmental drivers shaping composition, abundance, biomass, trophic state vertical flux protists (unicellular eukaryotes), including phytoplankton, Barents Sea late August 2018 2019. two years were characterized by contrasting conditions. In...
Low-salinity meltwater from Arctic sea ice and its snow cover accumulates creates under-ice layers below ice. These can result in the formation of new layers, or false bottoms, at interface this low-salinity colder seawater. As part Multidisciplinary drifting Observatory for Study Climate (MOSAiC), we used a combination coring, temperature profiles thermistor strings underwater multibeam sonar surveys with remotely operated vehicle (ROV) to study areal coverage temporal evolution bottoms...
The structure of iron and copper sites during the selective catalytic reduction (SCR) NOx by NH3 related reactions (NH3 adsorption/oxidation, NO oxidation) has been elucidated spatially- time-resolved X-ray absorption spectroscopy (XAS) along catalyst bed over Fe-containing BEA ZSM-5 zeolites as well Cu-SAPO-34 silicoaluminophosphate. Strong gradients Fe Cu oxidation state are present for processes involving less pronounced oxidation, whereas in containing feed resembles that a exposed to...
As the global climate changes, higher latitudes are seen to be warming significantly faster. It is likely that Arctic biome will experience considerable shifts in ice melt season length, leading changes photoirradiance and freshwater inputs marine environment. The exchange of nutrients between surface deep waters their cycling throughout water column driven by seasonal change. impacts, however, current transition period on biodiversity Ocean its activity not yet known. To determine variation...
The methanation of CO2 within the power-to-gas concept was investigated under fluctuating reaction conditions to gather detailed insight into structural dynamics catalyst. A 10 wt % Ni/Al2O3 catalyst with uniform 3.7 nm metal particles and a dispersion 21% suitable investigate changes also in surface-sensitive way prepared characterized detail. Operando quick-scanning X-ray absorption spectroscopy (XAS/QEXAFS) studies were performed analyze influence 30 s 300 H2 interruptions during presence...
One of the most abundant archaeal groups on earth is Thaumarchaeota. They are recognized as major contributors to marine ammonia oxidation, a crucial step in biogeochemical cycling nitrogen. Their universal success attributed high genomic flexibility and niche adaptability. Based differences gene coding for monooxygenase subunit A (amoA), two different ecotypes with distinct distribution patterns water column have been identified. We used high-throughput sequencing 16S rRNA genes combined...
The land-to-ocean flux of organic carbon is increasing in glacierized regions response to temperatures the Arctic (Hood et al., 2015). In order understand ecosystem metabolism input it essential determine bioavailability different sources system. We quantified bacterial turnover a high fjord system (Young Sound, NE Greenland) during ice-free period (July-October 2014) and assessed quality quantity 3 major sources; 1) local phytoplankton production 2) runoff from land-terminating glaciers...
Abstract. Particulate (POM) and dissolved (DOM) organic matter in the ocean are important components of Earth's biogeochemical cycle. The two a constant state dynamic change as result physical biochemical processes; however, they mostly treated distinct entities, separated operationally by filter. We studied seasonal transition DOM POM pools their drivers sub-Arctic fjord means monthly environmental sampling performing experiments at selected time points. For experiments, surface water (5 m)...
Abstract The Multidisciplinary Observatory for Study of the Arctic Climate (MOSAiC) expedition consisted a year-long drifting survey Central Ocean. ecosystems component MOSAiC included sampling molecular data, with metagenomes collected from diverse range environments. generation metagenome-assembled-genomes (MAGs) are starting point genome-resolved analyses. This dataset presents catalogue MAGs recovered set 73 samples MOSAiC, including 2407 prokaryotic and 56 eukaryotic MAGs, as well...
The projected transition of the central Arctic Ocean (CAO) into a warmer, seasonally ice-free ocean requires more knowledge this environment to predict changes in structure and dynamics its ecosystems. We aimed compare state underlying processes Nansen Basin Amundsen ecosystems observed August–September 2021 assess impacts Atlantic Water inflow fresher Transpolar Drift waters, respectively, on these basins differed features sea ice, hydrography, chemical biological compositions. near-slope...
Summary Thawing permafrost can stimulate microbial activity, leading to faster decomposition of formerly preserved organic matter and CO 2 release. Detailed knowledge about the vertical distribution responsible community that is changing with increasing soil depth limited. In this study, we determined composition from cores sampled in a high Arctic heath at Svalbard, Norway; spanning active layer (AL) into (PL). A special aim has been on identifying recently thawed soil, transition zone...
Copper chalcogenide nanocrystals find applications in photovoltaic inks, bio labels, and thermoelectric materials. We reveal insights the nucleation growth during synthesis of anisotropic Cu
Although bacteria are commonly co-occurring in microalgal cultivation and production systems, little is known about their community structure how it might be affected by specific groups or growth conditions. A better understanding the underlying factors that determine of bacterial populations not only important for optimizing processes, but also context product quality when algal biomass to used future food feed. We analyzed composition associated with nine strains stock culture, maintained...
Climate change related alterations in the Arctic have influences on marine ecosystems, particular phytoplankton bloom dynamics. Since blooms are main provider of carbon sources to microbial loop, bacterial and archaeal community affected by changes as well. Warmer water less sea ice can lead an earlier onset consequently also dynamics throughout summers. Here, we compared composition during three summers (2018, 2019, 2021) along a transect from Barents Sea Ocean north Svalbard. We used 16S...
In human monocytes, lipoperoxides were increased 3‐fold at 2 h, 6‐fold 5 h and 7.5‐fold 12 after hemozoin phagocytosis. 4‐Hydroxynonenal (HNE) was also increased, reaching 40 nmol/10 10 cells (approximate intracellular concentration [AIE] 8 μM), 230 (AIE 46 μM) 79 16 h. A moderate increase in HNE, approx. 20 4 observed phagocytosis of anti‐D IgG‐opsonized erythrocytes. HNE unfed controls 1 during the whole incubation period. An amount protein kinase C (PKC)/HNE adduct demonstrated...
The warming of the Arctic causes increased riverine discharge, coastal erosion, and thawing permafrost. Together, this is leading to an wash out terrestrial dissolved organic matter (tDOM) into ecosystems. This tDOM may be anticipated affect both carbon nutrient flow in microbial food web community composition, but there are few studies detailing marine We tested effects on bacterial composition net-growth by extracting DOM from active layer permafrost soil adding aged concentrate a natural...
The design and capabilities of a novel Quick scanning Extended X-ray Absorption Fine Structure (QEXAFS) monochromator are presented. oscillatory movement the crystal stage is realized by means unique open-loop driving scheme operating direct drive torque motor. entire mechanics installed inside goniometer located on atmospheric side vacuum chamber. This allows remote adjustment oscillation frequency spectral range, giving complete control QEXAFS measurements. It also features real...
Sea ice ridges are one of the most under-sampled and poorly understood components Arctic sea system. Yet, play a crucial role in mass balance have been identified as ecological hotspots for ice-associated flora fauna Arctic. To better understand ridges, we drilled sampled two different first-year (FYI) June–July 2020 during Multidisciplinary drifting Observatory Study Climate (MOSAiC). Ice cores were cut into 5 cm sections, melted, then analyzed salinity oxygen (δ18O) isotope composition....
Despite the lack of local anthropogenic mercury sources, methylated (MeHg) concentrations in Arctic biota are higher than from lower latitudes. The main entry route occurs during bioconcentration seawater monomethylmercury (MMHg) into phytoplankton. known seasonal changes biological activity region, little is about cycling total (THg) and MeHg Ocean. Here, we report THg sampled northwestern Barents Sea water column late winter spring. In upper 500 m, significantly spring (0.64 ± 0.09 pmol...