A5080260035- Marine and coastal ecosystems
- Wastewater Treatment and Nitrogen Removal
- Microbial Community Ecology and Physiology
- Marine Biology and Ecology Research
- Marine Bivalve and Aquaculture Studies
- Freshwater macroinvertebrate diversity and ecology
- Aquatic Invertebrate Ecology and Behavior
- Fish Ecology and Management Studies
- Soil and Water Nutrient Dynamics
- Protist diversity and phylogeny
- Diatoms and Algae Research
- Microbial Fuel Cells and Bioremediation
- Ocean Acidification Effects and Responses
- Gastroesophageal reflux and treatments
- Analytical Chemistry and Sensors
- Aquatic Ecosystems and Phytoplankton Dynamics
- Isotope Analysis in Ecology
- Marine Biology and Environmental Chemistry
- Physiological and biochemical adaptations
- Methane Hydrates and Related Phenomena
- Marine and coastal plant biology
- Marine and fisheries research
- Water Quality Monitoring and Analysis
- Environmental DNA in Biodiversity Studies
- Marine and environmental studies
University of Southern Denmark
2014-2024
Max Planck Institute for Marine Microbiology
2006-2022
Max Planck Society
2002-2014
Nordisk Fond for Miljø og Udvikling
2014
Aarhus University
2006-2013
Max Planck Institute for Evolutionary Biology
2005-2006
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2006
University of Cologne
2001
Current sampling of genomic sequence data from eukaryotes is relatively poor, biased, and inadequate to address important questions about their biology, evolution, ecology; this Community Page describes a resource 700 transcriptomes marine microbial help understand role in the world's oceans.
Significance Evidence whether the recently discovered denitrification-dependent methane oxidation (nitrate/nitrite-dependent anaerobic oxidation, n-damo) represents a major sink or an insignificant side aspect in global cycle is scarce. High-resolution microprofiles measured intact sediment cores close to situ conditions, anoxic incubations of sediments, and quantification responsible microorganisms with molecular techniques proved n-damo be Lake Constance, one best-studied freshwater lakes....
Diatoms survive in dark, anoxic sediment layers for months to decades. Our investigation reveals a correlation between the dark survival potential of marine diatoms and their ability accumulate NO 3 − intracellularly. Axenic strains benthic pelagic that stored 11–274 mM cells survived 6–28 wk. After sudden shifts conditions, diatom Amphora coffeaeformis consumed 84–87% its intracellular pool within 1 d. A stable-isotope labeling experiment proved 15 consumption was accompanied by production...
Abstract. Invertebrate animals that live at the bottom of aquatic ecosystems (i.e., benthic macrofauna) are important mediators between nutrients in water column and microbes benthos. The presence macrofauna stimulates microbial nutrient dynamics through different types animal–microbe interactions, which potentially affect trophic status ecosystems. This review contrasts three interactions benthos ecosystems: (i) ecosystem engineering, (ii) grazing, (iii) symbiosis. Their specific...
There is ample evidence that tube‐dwelling invertebrates such as chironomids significantly alter multiple important ecosystem functions, particularly in shallow lakes. Chironomids pump large water volumes, and associated suspended dissolved substances, through the sediment thereby compete with pelagic filter feeders for particulate organic matter. This can exert a high grazing pressure on phytoplankton, microorganisms, perhaps small zooplankton thus strengthen benthic‐pelagic coupling....
Zero-discharge marine aquaculture systems are an environmentally friendly alternative to conventional aquaculture. In these systems, water is purified and recycled via microbial biofilters. Here, quantitative data on nitrifier community structure of a trickling filter biofilm associated with recirculating system presented. Repeated rounds the full-cycle rRNA approach were necessary optimize DNA extraction probe set for FISH obtain reliable comprehensive picture ammonia-oxidizing community....
Summary Nitrification was investigated in a model freshwater sediment by the combined use of microsensors and fluorescence situ hybridization with rRNA‐targeted oligonucleotide probes. In nitrification activity restricted mainly to upper 2 mm coincided maximum abundance nitrifying bacteria, i.e. 1.5 × 10 7 cells cm −3 for ammonia‐oxidizing Beta‐proteobacteria (AOB) 8.6 Nitrospira ‐like nitrite‐oxidizing bacteria (NOB). Cell numbers AOB decreased more rapidly depth than NOB. For first time,...
A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate present in environment. The emission ascribed denitrification by ingested bacteria anoxic animal gut, and exceptionally high N(2)O-to-N(2) production ratio suggested delayed induction last step denitrification. Filter- deposit-feeding species showed highest rates predators lowest, probably reflecting different amounts denitrifying diet. We estimate that is quantitatively important...
In the world's oceans, even relatively low oxygen (O2) levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here we show that sinking diatom aggregates can host at ambient O2 well above hypoxic threshold. Aggregates were produced from ubiquitous Skeletonema marinoi and natural community of seawater. Microsensor profiling through center revealed internal...
Abstract Identifying and quantifying nitrogen pools is essential for understanding the cycle in aquatic ecosystems. The ubiquitous diatoms represent an overlooked nitrate pool as they can accumulate intracellularly utilize it assimilation, dissipation of excess photosynthetic energy, Dissimilatory Nitrate Reduction to Ammonium (DNRA). Here, we document global co-occurrence intracellular phototrophic microbial communities freshwater ( n = 69), coastal 44), open marine 4) habitats. Diatom...
ABSTRACT A lithotrophic freshwater Beggiatoa strain was enriched in O 2 -H S gradient tubes to investigate its ability oxidize sulfide with NO 3 − as an alternative electron acceptor. The contained different concentrations, and the chemotactic response of mats observed. effects sp. on vertical gradients , H S, pH, were determined microsensors. more that added agar, deeper filaments glided into anoxic agar layers, suggesting used at depths below depth penetrated. In presence formed thick...
Microbial denitrification is not considered important in human-associated microbial communities. Accordingly, metabolic investigations of the biofilm communities human dental plaque have focused on aerobic respiration and acid fermentation carbohydrates, even though it known that oral habitat constantly exposed to nitrate (NO3-) concentrations millimolar range houses bacteria can reduce this NO3- nitrite (NO2-). We show mediates nitric oxide (NO), nitrous (N2O), dinitrogen (N2) using...
'Candidatus Magnetobacterium bavaricum' is unusual among magnetotactic bacteria (MTB) in terms of cell size (8-10 µm long, 1.5-2 diameter), architecture, behaviour and its distinct phylogenetic position the deep-branching Nitrospira phylum. In present study, improved magnetic enrichment techniques permitted high-resolution scanning electron microscopy energy dispersive X-ray analysis, which revealed intracellular organization magnetosome chains. Sulfur globule accumulation cytoplasm point...
Emission of the greenhouse gas nitrous oxide (N2 O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2 O production by ingested denitrifying bacteria in anoxic gut animals. Our study marine molluscs now shows that also microbial biofilms on shell surfaces are important sites production. The Mytilus edulis, Littorina littorea Hinia reticulata contributed 18-94% total animal-associated emission. Nitrification denitrification were equally sources as revealed (15)...
Diatom-bacteria aggregates are key for the vertical transport of organic carbon in ocean. Sinking also represent pelagic microniches with intensified microbial activity, oxygen depletion center, and anaerobic nitrogen cycling. Since some aggregate-forming diatom species store nitrate intracellularly, we explored fate intracellular its availability metabolism within anoxic diatom-bacteria aggregates. The ubiquitous nitrate-storing Skeletonema marinoi was studied as both axenic cultures...
Abstract. The relative importance of two dissimilatory nitrate reduction pathways, denitrification (DEN) and to ammonium (DNRA), was investigated in intact sediment cores from five different coastal marine field sites (Dorum, Aarhus Bight, Mississippi Delta, Limfjord Janssand). vertical distribution DEN activity examined using the acetylene inhibition technique combined with N2O microsensor measurements, whereas NH4+ production via DNRA measured a recently developed gel probe-stable isotope...
Nitrification in shell biofilms and denitrification the gut of animal accounted for N(2)O emission by Dreissena polymorpha (Bivalvia), as shown gas chromatography gene expression analysis. The mussel's ammonium excretion was sufficient to sustain production thus potentially uncouples invertebrate from environmental N concentrations.
Thalassiosira weissflogii, an abundant, nitrate-storing, bloom-forming diatom in the world's oceans, can use its intracellular nitrate pool for dissimilatory reduction to ammonium (DNRA) after sudden shifts darkness and anoxia, most likely as a survival mechanism. T. weissflogii cells that stored 4 mM 15N-nitrate consumed 1.15 (±0.25) fmol NO3- cell-1 h-1 simultaneously produced 1.57 (±0.21) 15NH4+ during first 2 hours of dark/anoxic conditions. Ammonium from was excreted by cells,...
Summary The F e and N biogeochemical cycles play key roles in freshwater environments. We aimed to determine the spatial positioning interconnections of profundal lake sediments. gradients O 2 , NO 3 − NH 4 + pH E h e( II ) III were determined distribution microorganisms was assessed by most probable numbers quantitative polymerase chain reaction. redox zones could be divided into an oxic zone (0–8 mm), where microaerophiles ( G allionellaceae abundant at a depth 7 mm. This followed...
A wealth of microbial eukaryotes is adapted to life in oxygen-deficient marine environments. Evidence accumulating that some these survive anoxia by employing dissimilatory nitrate reduction, a strategy otherwise widespread prokaryotes. Here, we report on the anaerobic metabolism fungus Aspergillus terreus (isolate An-4) was obtained from sediment seasonal oxygen minimum zone Arabian Sea, globally important site oceanic nitrogen loss and nitrous oxide emission. Axenic incubations An-4...
A technique is presented for temporal characterization of the bioirrigation activity benthic macrofauna and quantitative estimation its effects on oxygen exchange between sediment overlying water. The based high resolution (15−30 s) imaging aided by a planar optode can be applied under laboratory field conditions, both freshwater marine. It allows direct observation complex 2D dynamics in around burrow while animal dwells undisturbed natural environment. conditions to which exposed easily...
The effect of sediment‐dwelling macrofauna on nitrifying bacteria was investigated by direct probing in their overlapping habitat, i.e., the upper few millimeters freshwater sediments. Microsensors (O 2 , NH 4 + NO 3 ‐ and diffusivity) were used at sediment surface inside animal burrows to record steady‐state dynamic distributions reactants, respectively. Short‐term changes metabolic activity (actual potential nitrification rates) long‐term abundance (fluorescence situ hybridization)...