A5034039583- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Aquatic Ecosystems and Phytoplankton Dynamics
- Algal biology and biofuel production
- Protist diversity and phylogeny
- Ocean Acidification Effects and Responses
- Marine Biology and Ecology Research
- Catalytic Processes in Materials Science
- Nematode management and characterization studies
- Wastewater Treatment and Nitrogen Removal
- Light effects on plants
- Photosynthetic Processes and Mechanisms
- Advanced Materials Characterization Techniques
- Diatoms and Algae Research
- Ion-surface interactions and analysis
- Metalloenzymes and iron-sulfur proteins
- Methane Hydrates and Related Phenomena
- Geochemistry and Elemental Analysis
- Carbon Dioxide Capture Technologies
- Water Quality and Pollution Assessment
- Radioactive element chemistry and processing
- Atmospheric chemistry and aerosols
- Legume Nitrogen Fixing Symbiosis
- Remote Sensing in Agriculture
- Chemical Reactions and Isotopes
Czech Academy of Sciences
2019-2024
Czech Academy of Sciences, Institute of Microbiology
2019-2024
Max Planck Institute for Marine Microbiology
2018-2021
University of Gothenburg
2017-2021
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2010-2014
Considering the important role of N2 fixation for primary productivity and CO2 sequestration, it is crucial to assess response diazotrophs ocean acidification. Previous studies on genus Trichodesmium suggested a strong sensitivity towards In view large functional diversity in fixers, objective this study was improve our knowledge responses other diazotrophs. To end, single-celled Cyanothece sp. two heterocystous species, Nodularia spumigena symbiotic Calothrix rhizosoleniae, were acclimated...
Abstract Gradients of oxygen (O2) and pH, as well small-scale fluxes carbon (C), nitrogen (N) O2 were investigated under different partial pressures dioxide (pCO2) in field-collected colonies the marine dinitrogen (N2)-fixing cyanobacterium Trichodesmium. Microsensor measurements indicated that cells within experienced large fluctuations O2, pH CO2 concentrations over a day–night cycle. varied with light intensity time day, yet exposed to supersaturated (up ~200%) throughout period anoxia...
To predict effects of climate change and possible feedbacks, it is crucial to understand the mechanisms behind CO 2 responses biogeochemically relevant phytoplankton species. Previous experiments on abundant N fixers Trichodesmium demonstrated strong responses, which were attributed an energy reallocation between its carbon (C) nitrogen (N) acquisition. Pursuing this hypothesis, we manipulated cellular budget by growing erythraeum IMS101 under different partial pressure ( pCO ) levels (180,...
Trichodesmium, the predominant marine diazotrophic cyanobacterium, concurrently performs nitrogen (N2) fixation and photosynthesis, latter of which produces oxygen (O2) that inhibits N2 fixation. Hopanoid lipids in Trichodesmium may play a role dynamically regulating membrane permeability to O2, potentially alleviating O2 stress on However, physiological impacts this dynamic are not well understood. We developed model showing modulating can enhance growth by over 50%. High (1.5*10-4...
Abstract Trichodesmium is an important dinitrogen (N2)-fixing cyanobacterium in marine ecosystems. Recent nucleic acid analyses indicate that colonies with their diverse epibionts support various nitrogen (N) transformations beyond N2 fixation. However, rates of these and concentration gradients N compounds remain largely unresolved. We combined isotope-tracer incubations, micro-profiling numeric modelling to explore carbon fixation, cycling processes as well oxygen, ammonium nitrate...
Diatom-diazotroph associations (DDAs) are symbioses where trichome-forming cyanobacteria support the host diatom with fixed nitrogen through dinitrogen (N2) fixation. It is inferred that growth of trichomes also supported by host, but mechanism has not been fully quantified. Here, we develop a coarse-grained, cellular model symbiosis between Hemiaulus and Richelia (one major DDAs), which shows carbon (C) transfer from enables faster N2 fixation rate trichomes. The predicts 5.5 times...
N2-fixing cyanobacteria mediate H2 fluxes through the opposing processes of evolution, which is a by-product N2 fixation reaction, and uptake, driven by uptake hydrogenases. Here, we used microelectrodes to characterize O2 dynamics in single natural colonies globally important fixer Trichodesmium collected from Gulf Eilat. We observed gradually changing over course day, including both net evolution as well large differences between individual colonies. Net was amended with light dark....
To predict effects of climate change on phytoplankton, it is crucial to understand how their mechanisms for carbon acquisition respond environmental conditions. Aiming shed light the responses extra- and intracellular inorganic C (Ci) fluxes, cyanobacterium Trichodesmium erythraeum IMS101 was grown with different nitrogen sources (N2 vs NO3–) pCO2 levels (380 1400 µatm). Cellular Ci fluxes were assessed by combining membrane inlet mass spectrometry (MIMS), 13C fractionation measurements,...
Summary To understand the role of micrometer‐scale oxygen (O 2 ) gradients in facilitating dinitrogen (N fixation, we characterized O dynamics microenvironment around free‐floating trichomes and colonies Trichodesmium erythraeum IMS 101. Diurnal spatial variability concentrations bulk medium, within colonies, along single cells were determined using optodes, microsensors model calculations. Carbon (C) N fixation as well evolution uptake under different analyzed by stable isotope incubations...
Abstract Low iron (Fe) and phosphorus (P) ocean regions are often home to the globally important N 2 ‐fixing cyanobacterium Trichodesmium spp., which physiologically adapted Fe/P co‐limitation. Given 's eminent ability capture particles common associations between Fe P in sediments aerosols, we hypothesized that mineral bio‐dissolution by spp. may enable them co‐acquire P. We present a new sensitive assay determine uptake from particles, utilizing 33 P‐labeled ferrihydrite. To validate...
Unicellular nitrogen fixing cyanobacteria (UCYN) are abundant members of phytoplankton communities in a wide range marine environments, including those with rapidly changing (N) concentrations. We hypothesized that differences N availability (N 2 vs. combined N) would cause UCYN to shift strategies intracellular and C allocation. used transmission electron microscopy nanoscale secondary ion mass spectrometry imaging track assimilation allocation 13 C-labeled CO 15 N-labeled or NO 3 at...
Abstract Colonies of the N 2 ‐fixing cyanobacterium Trichodesmium can harbor distinct chemical microenvironments that may assist colonies in acquiring mineral iron from dust. Here, we characterized O and pH gradients around by microsensor measurements on > 170 collected Gulf Eilat over ∼ months. concentrations values center single decreased dark due to respiration, reaching minimum 70 μ mol L −1 7.7, whereas light, increased photosynthesis, maximum 410 8.6. Addition dust bacteria...
Abstract The marine cyanobacterium Trichodesmium has the remarkable ability to interact with and utilize air‐borne dust as a nutrient source. However, may adversely affect through buoyancy loss exposure toxic metals. Our study explored effect of desert on mortality natural Red Sea puff‐shaped thiebautii . Sinking velocities individual colonies stay afloat increasing loads were studied in sedimentation chambers. Low up ∼400 ng per colony did not impact initial sinking velocity remained...
Stable isotope probing (SIP) combined with nano-scale secondary ion mass spectrometry (nanoSIMS) is a powerful approach to quantify assimilation rates of elements such as C and N into individual microbial cells. Here, we use mathematical modeling investigate how the derived rate estimates depend on model used describe substrate by cell during SIP incubation. We show that most commonly model, which based simplifying assumptions linearly increasing biomass cells over time no division, can...
Marine diazotrophs are a diverse group with key roles in biogeochemical fluxes linked to primary productivity. The unicellular, diazotrophic cyanobacterium Cyanothece is widely found coastal, subtropical oceans. We analyze the consequences of diazotrophy on growth efficiency, compared NO 3 – -supported , understand how cells cope N 2 -fixation when they also have face carbon limitation, which may transiently affect populations coastal environments or during blooms phytoplankton communities....
The productivity of the ocean is largely dependent on iron availability, and marine phytoplankton have evolved sophisticated mechanisms to cope with chronically low levels in vast regions open ocean. By analyzing metabarcoding data generated from Tara Oceans expedition, we determined how global distribution model chlorarachniophyte Bigelowiella natans varies across different concentrations. We performed a comprehensive proteomics analysis molecular underpinning adaptation B. scarcity report...
Abstract Photosynthesis and respiration cause distinct chemical microenvironments within cyanobacterial aggregates. Here, we used microsensors a diffusion–reaction model to characterize gradients in carbonate chemistry investigate how these are affected by ocean acidification Baltic vs. Pacific aggregates ( Nodularia Dolichospermum Trichodesmium ). Microsensor measurements of O 2 pH were performed under situ expected future p CO levels on collected the Sea. Under conditions, covered ranges...
Photosynthesis which harvests energy from the Sun, whether it occurs in prokaryotes or eukaryotes, is a key biological process that ultimately nourishes biosphere. The molecular efficiencies of photo-physical and physiological processes are intricately tied not only to photo-physics/enzymatic kinetics proteins involved, but also their spatial co-localization membrane microdomains cell compartments (e.g., membrane-less organelles). Similar heterogeneity function can be found between cells...
Abstract Colonies of the N2-fixing cyanobacterium Trichodesmium spp. constitute a consortium with multiple microorganisms that collectively exert ecosystem-level influence on marine carbon and nitrogen cycling, shunting newly fixed to low systems, exporting both deep sea. Here we identify seasonally recurrent association between puff colonies amoebae through two-year survey involving over 10 000 in Red Sea. This was most commonly found near-shore populations during spring. Microscopic...
The marine cyanobacterium Trichodesmium has a remarkable ability to interact with and utilize air-borne dust as nutrient source. However, may adversely affect through buoyancy loss exposure toxic metals. Our study explored the effect of desert on mortality natural Red Sea puff-shaped thiebautii . Sinking velocities individual colonies stay afloat increasing loads were studied in sedimentation chambers. Low up ~400 ng per colony did not impact initial sinking velocity remained chamber. Above...