Kai Waldemar Finster

• PhD
• Professor at Aarhus University

Any life on Mars has to contest with harsh ionising radiation conditions, a lack of bioavailable liquid water, and the oxidising effects of the Martian regolith. The latter is in part due to ˙OH production during wind-driven saltation leading to triboelectric charging and formation of radicals on newly exposed surfaces, mediated by the high Fe²⁺ le...

The accelerated warming of the Arctic manifests in sea ice loss and melting glaciers, significantly altering the dynamics of marine biota. This disruption in marine ecosystems can lead to an increased emission of biological ice-nucleating particles (INPs) from the ocean into the atmosphere. Once airborne, these INPs induce cloud droplet freezing, t...

Aerosols, including biological aerosols, exert a significant influence on cloud formation, influencing the global climate through their effects on radiative balance and precipitation. The Arctic region features persistent mixed-phase clouds, which are impacted by ice nucleating particles (INPs) that modulate the phase transitions within clouds, aff...

Aerosols, including biological aerosols, exert a significant influence on cloud formation, influencing the global climate through their effects on radiative balance and precipitation. The Arctic region features persistent mixed-phase clouds, which are impacted by ice nucleating particles (INPs) that modulate the phase transitions within clouds, aff...

Astrobiology, the interdisciplinary study of life beyond Earth, finds itself in an unusual position. Unlike other scientific disciplines, which define themselves by the objects they study, astrobiology is a science in search of its primary subject. Life beyond Earth remains a hypothesis, unverified by direct evidence yet compelling in its plausibil...

Is there anybody out there?" hedder en af sangene på Pink Floyds fantastiske album "The Wall", som udkom i 1979. "Er der nogen/noget derude?" er et af menneskehedens store spørgsmål og temaet for mange science fiction-bøger og-film. Hvis der er nogen/noget derude, hvordan ser de/det så ud, og hvordan kan vi komme i kontakt med det? Og skulle det ly...

The accelerated warming of the Arctic manifests in sea ice loss and melting glaciers, significantly altering the dynamics of marine biota. This disruption in marine ecosystems can lead to the emission of biological ice nucleating particles (INPs) from the ocean into the atmosphere. Once airborne, these INPs induce cloud droplet freezing, thereby af...

Background Sex is a significant epidemiological factor in the incidence of respiratory disease. However, the role of sex in indoor bacterial exposure remains largely unexplored. Objective Our objective was to investigate the association between indoor bacterial exposure and lung function and airway inflammation, focusing on sex-specific difference...

Ice nucleation particles play a crucial role in atmospheric processes; for example, they can trigger ice formation in clouds and thus influence their lifetime and optical properties. The quantification and characterization of these particles require reliable and precise measurement techniques. In this publication, we present a novel droplet freezin...

Ice nucleation particles play a crucial role in atmospheric processes e.g., they can trigger ice formation in clouds and thus influence their lifetime and optical properties. The quantification and characterisation of these particles require reliable and precise measurement techniques. In this study, we present a novel droplet freezing instrument t...

Since the Viking Labeled Release experiments were carried out on Mars in the 1970s, it has been evident that the martian surface regolith has a strong oxidizing capacity that can convert organic compounds into CO2 and probably water. While H2O2 was suggested originally for being the oxidizing agent responsible for the outcome of the Viking experime...

Airborne bacteria and endotoxin may affect asthma and allergies. However, there is limited understanding of the environmental determinants that influence them. This study investigated the airborne microbiomes in the homes of 1038 participants from five cities in Northern Europe: Aarhus, Bergen, Reykjavik, Tartu, and Uppsala. Airborne dust particles...

Background Sulfate-reducing bacteria (SRB) drive the ocean sulfur and carbon cycling. They constitute a diverse phylogenetic and physiological group and are widely distributed in anoxic marine environments. From a physiological viewpoint, SRB’s can be categorized as complete or incomplete oxidizers, meaning that they either oxidize their carbon sub...

Arctic permafrost soils store substantial reserves of organic matter (OM) from which microbial transformation contributes significantly to greenhouse gas emissions of CH4 and CO2. However, many younger sediments exposed by glacier retreat and sea level change in fjord landscapes lack significant organic carbon resources, so their capacity to promot...

The Arctic is a hot spot for climate change with potentially large consequences on a global scale. Aerosols, including bioaerosols, are important players in regulating the heat balance through direct interaction with sunlight and indirectly, through inducing cloud formation. Airborne bacteria are the major bioaerosols with some species producing th...

Microbially-produced ice nucleating proteins (INpro) are unique molecular structures with the highest known catalytic efficiency for ice formation. Airborne microorganisms utilize these proteins to enhance their survival by reducing their atmospheric residence times. INpro also have critical environmental effects including impacts on the atmospheri...

Living on a farm has been linked to a lower risk of immunoregulatory disorders, such as asthma, allergy, and inflammatory bowel disease. It is hypothesized that a decrease in the diversity and composition of indoor microbial communities is a sensible explanation for the upsurge in immunoregulatory diseases, with airborne bacteria contributing to th...

Experiments in quartz ampoules that simulate the saltation of quartz grains in a methane atmosphere show that the solid phase acquires a reddish color, reminiscent of the color observed on Triton, Pluto, and Charon. Reflection spectroscopy of the coated grains show a wide, continuous absorption spectrum peaking at near-UV wavelengths, in line with...

The iconic Viking Landers that landed on Mars in 1976 demonstrated that the Martian surface is an extreme place, dominated by high UV fluxes and regolith chemistry capable of oxidizing organic molecules. From follow-on missions , we have learned that Mars was much warmer and wetter in its early history, and even some areas of Mars (such as crater l...

Microbially-produced ice nucleating proteins (INpro) are unique molecular structures with the highest known catalytic efficiency for ice formation. Their critical role in rain formation and frost damage of crops together with their diverse commercial applications warrant an in-depth understanding of their inherent ice nucleation mechanism. We used...

Grundstoffet silicium ligner kulstof på fl ere måder, og det har fået forskere til at spekulere over, om liv på fjerne planeter kunne vaere baseret på silicium i stedet for kulstof som her på Jorden. Hvorfor det i praksis ikke kan lade sig gøre, får vi forklaringen på her. Om forfatterne Kai Finster er kandidat i biologi fra Aarhus Universitet og h...

A quartz ampoule with quartz grains is mechanically activated in a dry Earth-like atmosphere with 0.5 % of one of the major greenhouse gases CO2, CH4, and N2O. The grains rub against each other and the walls of the ampoule during activation, leading to triboelectric charging and erosion. IR spectroscopy shows the greenhouse gases disappear during a...

Transport of microbes in the atmosphere allows them to spread and to colonize new habitats. To survive the harsh environmental conditions encountered in the atmosphere, these microorganisms have to possess properties that allow them to resist atmospheric stress. We combined physiological experiments and genome analysis of Pseudomonas syringae strai...

Numerous studies have demonstrated that tardigrades in a resting state (tun state) are very resistant to exceptional stress levels in comparison with the resistance observed in multicellular organisms in general. The types of stress include desiccation and radiation, which are also relevant in astrobiological research, and therefore, tardigrades ar...

As humans explore and settle in space, they will need to mine elements to support industries such as manufacturing and construction. In preparation for the establishment of permanent human settlements across the Solar System, we conducted the ESA BioRock experiment on board the International Space Station to investigate whether biological mining co...

A previous cultivation-independent investigation of the microbial community structure of natural oil and asphalt seeps in the Kurdistan Region of Iraq (KRI) revealed the dominance of uncultured bacterial taxa belonging to the phyla Deferribacterota and Coprothermobacterota and the orders Thermodesulfobacteriales, Thermales, and Burkholderiales. Her...

Ice-nucleation active (INA) bacteria can promote the growth of ice more effectively than any other known material. Using specialized ice-nucleating proteins (INPs), they obtain nutrients from plants by inducing frost damage and, when airborne in the atmosphere, they drive ice nucleation within clouds, which may affect global precipitation patterns....

Microorganisms are employed to mine economically important elements from rocks, including the rare earth elements (REEs), used in electronic industries and alloy production. We carried out a mining experiment on the International Space Station to test hypotheses on the bioleaching of REEs from basaltic rock in microgravity and simulated Mars and Ea...

Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experimen...

Statement: This article presents a method for the first-ever quantification of O 2 respiration rate in the tardigrades Richtersius coronifer and Macrobiotus macrocalix using micro-respirometry. Journal of Experimental Biology • Accepted manuscript http://jeb.biologists.org/lookup/ Abstract: Studies of tardigrade biology have been severely limited b...

Ice-nucleation active (INA) bacteria can promote the growth of ice more effectively than any other known material. Utilizing specialized ice-nucleating proteins (INPros), they obtain nutrients from plants by inducing frost damage and, when airborne in the atmosphere, they drive ice nucleation within clouds and may affect global precipitation patter...

To identify hydrocarbon-degrading microorganisms contributing to the formation of heavy oil we investigated the microbial community composition in different types of crude oils from oil-production facilities and in crude oil and asphalt from different natural seeps from the Kurdistan Region of Iraq (KRI). Crude oils from five out of six production...

[This corrects the article DOI: 10.3389/fmicb.2018.03086.].

A sulfide-oxidizing microorganism, Desulfurivibrio alkaliphilus (DA), generates a consistent enrichment of sulfur-34 (34 S) in the produced sulfate of +12.5 per mil or greater. This observation challenges the general consensus that the microbial oxidation of sulfide does not result in large 34 S enrichments and suggests that sedimentary sulfides an...

Laboratory experiments show that sand grain saltation in a Mars-like environment can result in the ionization of argon. This suggests that saltation can be a mechanism for the destruction of methane (CH4) on Mars given the ionization energy of argon is higher than the energy required to ionize methane to a reactive cation. The ionization energy is...

Airborne dispersal of microorganisms influences their biogeography, gene flow, atmospheric processes, human health and transmission of pathogens that affect humans, plants and animals. The extent of their impact depends essentially on cell-survival rates during the process of aerosolization. A central factor for cell-survival is water availability...

The genera Methanospirillum and Methanosaeta contain species of anaerobic archaea that grow and divide within proteinaceous tubular sheaths that protect them from environmental stressors. The sheaths of Methanosaeta thermophila PT are composed of the 60.9 kDa major sheath protein MspA. In this study we show that sheaths purified from Methanospirill...

Numerous studies have demonstrated that the martian surface environment is hostile to life because of its rough radiation climate and the reactive chemistry of the regolith. Physical processes such as erosion and transport of mineral particles by wind-driven saltation have hitherto not been considered as a life hazard. We report a series of experim...

The Exo-Life Finder (ELF) will be an optical system with the resolving power of a ≥20m telescope optimized for characterizing exoplanets and detecting exolife. It will allow for direct detection of Earth-size planets in commonly-considered water-based habitable zones (WHZ) of nearby stars and for generic exolife studies. Here we discuss capabilitie...

Airborne bacterial communities are subject to conditions ill-suited to microbial activity and growth. In spite of this, air is an important transfer medium for bacteria, with the bacteria in indoor air having potentially major consequences for the health of a building’s occupants. A major example is the decreased diversity and altered composition o...

Methane (CH 4) is one of the most abundant greenhouse gases in the atmosphere and identification of its sources and sinks is crucial for the reliability of climate model outputs. Although CH 4 production and consumption rates have been reported from a broad spectrum of environments, data obtained from glacier forefields are restricted to a few loca...

Methane (CH4) is one of the most abundant greenhouse gases in the atmosphere and identification of its sources and sinks is crucial for the reliability of climate model outputs. Although CH4 production and consumption rates have been reported from a broad spectrum of environments, data obtained from glacier forefields are restricted to a few locati...

The Arctic is undergoing dramatic climatic changes that cause profound transformations in its terrestrial ecosystems and consequently in the microbial communities that inhabit them. The assembly of these communities is affected by aeolian deposition. However, the abundance, diversity, sources, and activity of airborne microorganisms in the Arctic a...

Ice nucleation active bacteria have attracted particular attention due to their unique ability to produce specific ice nucleation proteins (INpros), which are the most efficient ice nuclei known as they induce nucleation at temperatures close to 0°C. Our model bacterium Pseudomonas syringae strain R10.79 produced INpros containing 67 tandem repeats...

Strain S3-2T, isolated from sediment of a frozen freshwater pond, shares 99% 16S rRNA gene sequence identity with strains of the genus Janthinobacterium. Strain S3-2T is a facultative anaerobe that lacks the ability to produce violacein but shows antibiotic resistance, psychrotolerance, incomplete denitrification, and fermentation. The draft genome...

The habitability of Mars is determined by the physical and chemical environment. The effect of low water availability, temperature, low atmospheric pressure and strong UV radiation has been extensively studied in relation to the survival of microorganisms. In addition to these stress factors, it was recently found that silicates exposed to simulate...

Figure S1. Growth curves for P. putida, B. subtilis and D. radiodurans. The cultures were incubated in 30 ml of 20% LB media and 80% PBS for P. putida and 30 ml of 20% NB media and 80% for B. subtilis and D. radiodurans in 100 ml Erlenmeyer flasks on a shaker running at 120 rpm at 21°C. The flasks were fused with test tubes so that we could direct...

The results of the Labeled Release and the Gas Exchange experiments conducted on Mars by the Viking Landers show that compounds in the Martian soil can cause oxidation of organics and a release of oxygen in the presence of water. Several sources have been proposed for the oxidizing compounds, but none has been validated in situ and the cause of the...

Bacterial ice-nucleating particles (INP) have the ability to facilitate ice nucleation from super-cooled cloud droplets at temperatures just below the melting point. Bacterial INP have been detected in cloud water, precipitation, and dry air, hence they may have an impact on weather and climate. In modeling studies, the potential impact of bacteria...

The study of airborne bacteria relies on a sampling strategy that preserves their integrity and in situ physiological state, e.g. viability, cultivability, metabolic activity, and ice-nucleation activity. As ambient air harbours low concentrations of bacteria, an effective bioaerosol sampler should have a high sampling efficiency and a high airflow...

In this paper, we describe the development of an International Space Station experiment, BioRock. The purpose of this experiment is to investigate biofilm formation and microbe–mineral interactions in space. The latter research has application in areas as diverse as regolith amelioration and extraterrestrial mining. We describe the design of a prot...

This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus. Instead, the genome contains all of the genes...

A new kind of solid-gas chemical reactions has been investigated using solid-state powder 2H, 13C, and 29Si NMR and EPR spectroscopies. These studies involve reactions between a silicate created Si free-radical intermediate and a few ordinary gases such as isotopically 2H-, 13C-, and 17O-enriched methane (13CH4 and CD4), carbon dioxide (13CO2), hyd...

Abstract The increasing number of missions to Mars also increases the risk of forward contamination. Consequently there is a need for effective protocols to ensure efficient protection of the Martian environment against terrestrial microbiota. Despite the fact of constructing sophisticated clean rooms for spacecraft assembly a 100 % avoidance of co...

Bacterial ice-nucleating particles (INP) are present in the atmosphere and efficient in heterogeneous ice-nucleation at temperatures up to -2 °C in mixed-phase clouds. However, due to their low emission rates, their climatic impact was considered insignificant in previous modeling studies. In view of uncertainties about the actual atmospheric emiss...

Microbial communities in the glacier forefield of Styggedalsbreen, Norway, were investigated along a chronosequence from newly exposed soil to vegetated soils using next-generation sequencing of the 16S rRNA gene. In order to monitor the short-term effect of temperature on community successions along the soil gradient, the soil samples were incubat...

Sulfur and oxygen isotope fractionation of elemental sulfur disproportionation at anaerobic haloalkaline conditions were evaluated for the first time. Isotope enrichment factors of the strains Desulfurivibrio alkaliphilus and Dethiobacter alkaliphilus growing at pH 9 or 10 were −0.9 ‰ to −1 ‰ for sulfide (34ϵ), +3.6 ‰ to +4.7 ‰ for sulfate (34ϵ), a...

De.sul.fu.ro.mu' sa . L. pref. de from; L. n. sulfur sulfur; M.L. n. musa banana; M.L. fem. n. Desulfuromusa a banana‐shaped bacterium that reduces sulfur. Proteobacteria / Deltaproteobacteria / Desulfuromonales / Desulfuromonaceae / Desulfuromusa Slightly curved or rod‐shaped cells 0.4–0.8 × 1–6 μm . Motile by means of a single, subpolarly inserte...

De.sul.fo.spi' ra . L. pref. de from; L. n. sulfur sulfur; Gr. n. spira a coil; M.L. fem. n. Desulfospira a sulfate‐reducing coil. Desulfobacterota / Desulfobacteria / Desulfobacterales / Desulfobacteraceae / Desulfospira Curved, often spirilloid cells 0.7–0.8 × 1–2 μm . Nonmotile. Gram negative. Endospores not formed. Anaerobic, having a respirato...

Archaea are renowned for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes that are extremely resistant to chemical and thermal denaturation and resist proteolysis by common proteases. Here we employ amyloid-specific conformation ant...

Inspired by the recent demonstration of polarized reflected light being detectable from exoplanetary atmospheres [1,2], we aim at identifying spectro-polarimetric biosignatures that were resulting from biological polarization, e.g., selective light absorption or scattering by biogenic molecules.

Crude oils from the Kurdistan region of Iraq (KRI) are typically of high density and viscosity and have low API gravity values. Crude oil with these characteristics is termed heavy oil. The formation of heavy oil is often the result of biodegradation, because microorganisms will preferentially degrade light over the heavy, less viscous and denser,...

Some bacteria have the unique capacity of synthesising ice-nucleation-active (INA) proteins and exposing them at their outer membrane surface. As INA bacteria enter the atmosphere, they may impact the formation of clouds and precipitation. We studied members of airborne bacterial communities for their capacity to catalyse ice formation and we repor...

Bacillus azotoformans MEV2011, isolated from soil, is a microaerotolerant obligate denitrifier, which can also produce N2 by co-denitrification. Oxygen is consumed but not growth-supportive. The draft genome has a size of 4.7 Mb and contains key genes for both denitrification and dissimilatory nitrate reduction to ammonium. Electronic supplementar...

Introduction: Recently methane (CH 4) has been ob-served in the Martian atmosphere from a satellite orbit-ing the planet [1] as well as from Earth based tele-scopes [2]. A significant feature of methane concentra-tions is that they show a substantial time and spatial variation. Detailed recent snapshots measurements by MSL have shown that the conce...

Iron-reducing bacteria switch to sulfur reduction as their main energy source in alkaline environments [Also see Report by Flynn et al. ]

A k t u e l N a t u r v i d e n s k a b | 2 | 2 0 0 1 ■ Når natten falder på, forla-der den lille blaeksprutte Euprymna scolopes sit skjulested og går på jagt ved Hawaiis klippekyster. Dens silhuet, som er tydelig i månelyset, vil kunne gøre den til et let bytte for sine mange fjender, som ligger på lur i huler og spraekker. Blaek-sprutten har dog...

A k t u e l N a t u r v i d e n s k a b | 3 | 2 0 0 0 21-06-00 10.16 n De fleste forbinder forgaering med fremstillingen af ethanol (sprit) udfra sukkerstoffer un-der iltfrie forhold. Forgaeringen er kendetegnet ved, at sukker-molekylet både undergår oxida-tion og reduktion. Der dannes derved to produkter, hvoraf det ene, spritten, er mere reducere...