Publications by authors named "Lise Ovreas"

Article Synopsis
  • A diverse range of microbes live around hydrothermal vents on the seafloor, thriving in harsh conditions like high pressure, extreme temperatures, and total darkness.
  • Researchers studied three aerobic strains of Planctomycetota isolated from deep-sea iron-rich deposits in the Arctic and Pacific Oceans.
  • The genomic analysis showed that these deep-sea strains do not significantly differ from their surface-dwelling relatives, indicating a non-extreme genomic makeup despite their extreme habitat.
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The microbial diversity associated with terrestrial groundwater seepage through permafrost soils is tightly coupled to the geochemistry of these fluids. Terrestrial alkaline methane seeps from Lagoon Pingo, Central Spitsbergen (78°N) in Norway, with methane-saturated and oxygen-limited groundwater discharge providing a potential habitat for methanotrophy. Here, we report on the microbial community's comparative analyses and distribution patterns at two sites close to Lagoon Pingo's methane emission source.

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This study aimed to understand the antibiotic resistance prevalence among Enterococcus spp. from raw and treated sewage in Bergen city, Norway. In total, 517 Enterococcus spp.

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The Barents Sea is a transition zone between the Atlantic and the Arctic Ocean. The ecosystem in this region is highly variable, and a seasonal baseline of biological factors is needed to monitor the effects of global warming. In this study, we report the results from the investigations of the bacterial and archaeal community in late winter, spring, summer, and early winter along a transect through the northern Barents Sea into the Arctic Ocean east of Svalbard using 16S rRNA metabarcoding.

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Why are some groups of bacteria more diverse than others? We hypothesize that the metabolic energy available to a bacterial functional group (a biogeochemical group or 'guild') has a role in such a group's taxonomic diversity. We tested this hypothesis by looking at the metacommunity diversity of functional groups in multiple biomes. We observed a positive correlation between estimates of a functional group's diversity and their metabolic energy yield.

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Under very cold conditions, delicate ice-crystal structures called frost flowers emerge on the surface of newly formed sea ice. These understudied, ephemeral structures include saline brine, organic material, inorganic nutrients, and bacterial and archaeal communities in their brine channels. Hitherto, only a few frost flowers have been studied during spring and these have been reported to be dominated by Rhizobia or members of the SAR11 clade.

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The aim of this study was to understand the prevalence of antibiotic resistance in Klebsiella pneumoniae present in the population in Bergen city, Norway using city-scale sewage-based surveillance, as well as the potential spread of K. pneumoniae into the marine environment through treated sewage. From a total of 30 sewage samples collected from five different sewage treatment plants (STPs), 563 presumptive K.

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The Arctic is warming 2-3 times faster than the global average, leading to a decrease in Arctic sea ice extent, thickness, and associated changes in sea ice structure. These changes impact sea ice habitat properties and the ice-associated ecosystems. Sea-ice algal blooms provide various algal-derived carbon sources for the bacterial and archaeal communities within the sea ice.

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Methylotrophic bacteria (non-methanotrophic methanol oxidizers) consuming reduced carbon compounds containing no carbon-carbon bonds as their sole carbon and energy source have been found in a great variety of environments. Here, we report a unique moderately thermophilic methanol-oxidising bacterium (strain LS7-MT) that grows optimally at 55 °C (with a growth range spanning 30 to 60 °C). The pure isolate was recovered from a methane-utilizing mixed culture enrichment from an alkaline thermal spring in the Ethiopia Rift Valley, and utilized methanol, methylamine, glucose and a variety of multi-carbon compounds.

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Meromictic lakes are permanently stratified lakes that display steep gradients in salinity, oxygen and sulphur compounds tightly linked to bacterial community structure and diversity. Lake Sælenvannet is a meromictic lake located south of Bergen, Norway. The 26 m deep lake is connected to the open sea and permanently stratified into two layers separated by a chemocline.

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Permafrost underlies a large portion of the land in the Northern Hemisphere. It is proposed to be an extreme habitat and home for cold-adaptive microbial communities. Upon thaw permafrost is predicted to exacerbate increasing global temperature trend, where awakening microbes decompose millennia old carbon stocks.

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Aerobic moderately thermophilic and thermophilic methane-oxidizing bacteria make a substantial contribution in the control of global warming through biological reduction of methane emissions and have a unique capability of utilizing methane as their sole carbon and energy source. Here, we report a novel moderately thermophilic -like Type Ib methanotroph recovered from an alkaline thermal spring (55.4 °C and pH 8.

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When it comes to the discovery and analysis of yet uncharted bacterial traits, pure cultures are essential as only these allow detailed morphological and physiological characterization as well as genetic manipulation. However, microbiologists are struggling to isolate and maintain the majority of bacterial strains, as mimicking their native environmental niches adequately can be a challenging task. Here, we report the diversity-driven cultivation, characterization and genome sequencing of 79 bacterial strains from all major taxonomic clades of the conspicuous bacterial phylum Planctomycetes.

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Permafrost contains one of the least known soil microbiomes, where microbial populations reside in an ice-locked environment. Here, 56 prokaryotic metagenome-assembled genome (MAG) sequences from 13 phyla are reported. These MAGs will provide information on metabolic pathways that could mediate biogeochemical cycles in Svalbard permafrost.

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Antimicrobials are naturally produced by microbes and therefore have always been present in their environment, as well as accompanying resistance mechanisms. The antibiotic resistance profile of environmental species is particularly relevant since genetic determinants of resistance can spread through horizontal gene transfer and reach clinically important species. The phylum Planctomycetes comprises Gram-negative bacteria characterised by unusual features and appear to be ubiquitously distributed.

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In food webs, interactions between competition and defence control the partitioning of limiting resources. As a result, simple models of these interactions contain links between biogeochemistry, diversity, food web structure and ecosystem function. Working at hierarchical levels, these mechanisms also produce self-similarity and therefore suggest how complexity can be generated from repeated application of simple underlying principles.

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Combining a minimum food web model with Arctic microbial community dynamics, we have suggested that top-down control by copepods can affect the food web down to bacterial consumption of organic carbon. Pursuing this hypothesis further, we used the minimum model to design and analyse a mesocosm experiment, studying the effect of high (+Z) and low (-Z) copepod density on resource allocation, along an organic-C addition gradient. In the Arctic, both effects are plausible due to changes in advection patterns (affecting copepods) and meltwater inputs (affecting carbon).

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Thawing permafrost can stimulate microbial activity, leading to faster decomposition of formerly preserved organic matter and CO release. Detailed knowledge about the vertical distribution of the responsible microbial community that is changing with increasing soil depth is limited. In this study, we determined the microbial community composition from cores sampled in a high Arctic heath at Svalbard, Norway; spanning from the active layer (AL) into the permafrost layer (PL).

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Here we present the genome of strain HV10-M2, a methanotroph isolated from Hardangervidda national park (Norway). This strain represents the second of the two validly published species genus with a sequenced genome. The other is HT12, which is the type strain of the species and the type species of the genus We present the genome of str.

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Here we show that a commercial blocking reagent (G2) based on modified eukaryotic DNA significantly improved DNA extraction efficiency. We subjected G2 to an inter-laboratory testing, where DNA was extracted from the same clay subsoil using the same batch of kits. The inter-laboratory extraction campaign revealed large variation among the participating laboratories, but the reagent increased the number of PCR-amplified16S rRNA genes recovered from biomass naturally present in the soils by one log unit.

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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 locations. We report the activities of methanotrophic communities and their diversity along a chronosequence in front of a sub-Arctic glacier using high-throughput sequencing and gas flux measurements.

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The microbial diversity associated with diffuse venting deep-sea hydrothermal deposits is tightly coupled to the geochemistry of the hydrothermal fluids. Previous 16S rRNA gene amplicon sequencing (metabarcoding) of marine iron-hydroxide deposits along the Arctic Mid Ocean Ridge, revealed the presence of diverse bacterial communities associated with these deposits (Storesund and Øvreås in Antonie van Leeuwenhoek 104:569-584, 2013). One of the most abundant and diverse phyla detected was the enigmatic Planctomycetes.

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One of the most abundant archaeal groups on Earth is the Thaumarchaeota. They are recognized as major contributors to marine ammonia oxidation, a crucial step in the biogeochemical cycling of nitrogen. Their universal success is attributed to a high genomic flexibility and niche adaptability.

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During the last decades, our knowledge about the activity of sponge-associated microorganisms and their contribution to biogeochemical cycling has gradually increased. Functional groups involved in carbon and nitrogen metabolism are well documented, whereas knowledge about microorganisms involved in the sulfur cycle is still limited. Both sulfate reduction and sulfide oxidation has been detected in the cold water sponge Geodia barretti from Korsfjord in Norway, and with specimens from this site, the present study aims to identify extant versus active sponge-associated microbiota with focus on sulfur metabolism.

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