A5080539087- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Bacteriophages and microbial interactions
- Evolution and Genetic Dynamics
- Protist diversity and phylogeny
- Plant Virus Research Studies
- Methane Hydrates and Related Phenomena
- Genomics and Phylogenetic Studies
- Marine Biology and Ecology Research
- Marine and fisheries research
- Arctic and Antarctic ice dynamics
- Mathematical and Theoretical Epidemiology and Ecology Models
- Geological Studies and Exploration
- Isotope Analysis in Ecology
- RNA and protein synthesis mechanisms
- Animal Virus Infections Studies
- Microbial Metabolic Engineering and Bioproduction
- Bacterial Genetics and Biotechnology
- Oceanographic and Atmospheric Processes
- Food Industry and Aquatic Biology
- Delphi Technique in Research
- Plant and animal studies
- Genetic diversity and population structure
- Evolutionary Game Theory and Cooperation
- Atmospheric and Environmental Gas Dynamics
University of Bergen
2016-2025
Institute for Marine and Antarctic Studies
2016
UiT The Arctic University of Norway
2011
Abstract. The traditional view of the planktonic food web describes consumption inorganic nutrients by photoautotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at foundation most models used to explore biogeochemical cycling, functioning biological pump, impact climate change these processes. We suggest an alternative new paradigm, sees bulk base this...
Arranging organisms into functional groups aids ecological research by grouping (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzooplankton”. However, there is a growing recognition the importance mixotrophy euphotic aquatic systems, where many often combine modes nutrition. Such do not align traditional dichotomy phytoplankton...
Significance This work presents the first detailed analysis to authors’ knowledge of how species-level diversity is a property emerging from competitive and defensive abilities at organism level in microbial system where diversity-generating mechanism strain-specific viral lysis. The theoretical constitutes general case treatment important special question what properties may make SAR11, subphylum within Alphaproteobacteria, so dominant pelagic environment. resulting conceptual framework...
This first comprehensive analysis of the global biogeography marine protistan plankton with acquired phototrophy shows these mixotrophic organisms to be ubiquitous and abundant; however, their differs markedly between different functional groups. These mixotrophs, lacking a constitutive capacity for photosynthesis (i.e. non-constitutive NCMs), acquire phototrophic potential through either integration prey-plastids or endosymbiotic associations photosynthetic microbes. Analysis field data...
Abstract The blooming cosmopolitan coccolithophore Emiliania huxleyi and its viruses (EhVs) are a model for density-dependent virulent dynamics. EhVs commonly exhibit rapid viral reproduction drive host death in high-density laboratory cultures mesocosms that simulate blooms. Here we show this system exhibits physiology-dependent temperate dynamics at environmentally relevant E. densities rather than dynamics, with switching from long-term non-lethal phase healthy hosts to lethal lytic stage...
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...
By adding a generic description of cost resistance (COR) to the existing 'killing-the-winner' model, we show how this expands model's explanatory power include rank-abundance relationships in host population. The model can predict counter-intuitive relationship previously suggested literature, where abundant viruses are associated with rare hosts and vice versa. explains observed dominance slow-growing prokaryotes as result successful defence strategies, rather than dormancy lacking...
The effects of viruses on marine microbial communities are myriad. high biodiversity and their complex interactions with diverse hosts makes it a challenge to link modeling work experimental work. In various trophic groups, trait-based approaches have helped simplify this complexity, as traits describe organism properties in terms taxon-transcending units, allowing for easier identification generic, underlying principles. By predicting large-scale biogeography different plankton functional...
Trophic mechanisms that can generate biodiversity in food webs include bottom-up (growth rate regulating) and top-down (biomass factors. The control has traditionally been analyzed using the concepts of "Keystone Predation" (KP) "Killing-the-Winner" (KtW), predominately occuring discussions macro- micro-biological ecology, respectively. Here we combine classical diamond-shaped web structure frequently discussed KP analyses KtW concept by introducing a defense strategist capable partial...
Single-cell methods allow studying the activity of single bacterial cells, potentially shedding light on regulatory mechanisms involved in services like biochemical cycling. Bioorthogonal non-canonical amino acid tagging (BONCAT) is a promising method for natural communities, using methionine analogues L-azidohomoalanine (AHA) and L-homopropargylglycine (HPG) to track protein production cells. Both AHA HPG have been deemed non-toxic, but recent findings suggest that affects metabolism. In...
Abstract. The traditional view of the planktonic foodweb describes consumption inorganic nutrients by photo-autotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at foundation most models used to explore biogeochemical cycling, functioning biological pump, impact climate change these processes. We suggest an alternative paradigm, sees bulk base this...
Theoretical work has suggested an important role of lytic viruses in controlling the diversity their prokaryotic hosts. Yet, providing strong experimental or observational support (or refutation) for this proven evasive. Such models have usually assumed "host groups" to correspond "species" level, typically represented by 16S rDNA data. Recent model developments take into account resolution species strains with differences susceptibility viral attack. With as host groups, will explicit...
Factors controlling the community composition of marine heterotrophic prokaryotes include organic-C, mineral nutrients, predation, and viral lysis. Two mesocosm experiments, performed at an Arctic location bottom-up manipulated with had very different results in for both viruses. Previously, we showed how a simple mathematical model could reproduce food web level dynamics observed these mesocosms, demonstrating strong top-down control through predator chain from copepods via ciliates...
Abstract Interactions of bottom‐up factors such as the availability mineral and organic nutrients, top‐down like predation viral infection affect microbial communities pelagic food web. Hypothesis derived from previous experimental modeling work suggest some general mechanisms on how these may be linked call for an experiment to test interactions between (1) nitrogen source diatom cell size, (2) bacterial growth rate limitation by nutrients versus carbon, (3) enhanced decreased pressure...
Abstract. Recent meta-analyses suggest that microzooplankton biomass density scales linearly with phytoplankton density, suggesting a simple, general rule may underpin trophic structure in the global ocean. Here, we use set of highly simplified food web models, solved within circulation model, to examine core drivers linear predator–prey scaling. We parallel chain model which assumes grazers feed on distinct size classes and contrast this diamond allowing shared predation range classes....
Trophic interactions are highly complex and modern sequencing techniques reveal enormous biodiversity across multiple scales in marine microbial communities. Within the chemically physically relatively homogeneous pelagic environment, this calls for an explanation beyond spatial temporal heterogeneity. Based on observations of simple parasite-host predator-prey occurring at different trophic levels phylogenetic resolution, we present a theoretical perspective biodiversity, discussing...
Summary For more than 25 years, virus‐to‐bacteria ratios (VBR) have been measured and interpreted as indicators of the importance viruses in aquatic ecosystems, yet a generally accepted theory for understanding mechanisms controlling VBR is still lacking. Assuming that denominator (total bacterial abundance) primarily predator controlled, while viral lysis compensates host growth rates exceeding this grazing loss, numerator (viral reflects activity differences between prokaryotic hosts. then...
Antagonistic interactions between bacteriophage (phage) and its bacterial host drives the continual selection for resistance counter-defence. To date, much remains unknown about genomic evolution that occurs as part of underlying mechanisms. Such is case marine cyanobacteria Synechococcus viruses (cyanophages) infect them. Here, we monitored phage abundances, alongside changes to populations, in a 500-day (~55 generations) infection experiment sp. WH7803 T4-type cyanophage S-PM2d, run...
The main scientific goal of the Nansen Legacy JC2-2 cruise was to extend project’s research activities from northern Barents Sea shelf into central Arctic Ocean. Specifically, addressed objectives foci RF1, RF2 and RF3 by jointly collecting interdisciplinary samples data at five process (P) in-between NLEG stations extending northward previously northernmost station P7. We had a special focus on sea ice upper ocean as well connectivity mid deep water column underlying sediments in early...
Viruses play diverse and important roles in ecosystems. In recent years, trade-offs between host virus traits have gained increasing attention viral ecology evolution. However, microbial organism traits, population parameters particular, are challenging to monitor. Mathematical individual-based models useful tools for predicting virus-host dynamics. We developed an evolutionary model study ecological interactions evolution bacteria viruses, with emphasis on the impacts of competitive...