UNIVERSITY OF BERGEN

Department of
Biological Sciences

PhD Student, MSc
Anita Stene Løtvedt

I am an applied mathematician who is especially interested in environmental and dynamical modelling, as well as sensitivity analysis. My PhD project The Effect of Water Column Dynamics on the Microbial Food Web and Transfer to Higher Trophic Levels is a part of the project How can fisheries contribute to a more sustainable future?.

The Effect of Water Column Dynamics on the Microbial Food Web and Transfer to Higher Trophic Levels

As a PhD candidate, I will take part in developing a depth resolved Minimum Model (see Thingstad et al. 2007; Thingstad 2020), that can be utilized to analyse the effect of water column dynamics on the microbial food web and transfer to higher trophic levels (e.g., fish).

Methods of global sensitivity analysis (see Saltelli et al. 2010; Pianosi et al. 2018) will be applied on key model output, with the aim of analysing the effects of water column dynamics on the microbial food web and transfer to higher trophic levels, whilst accounting for uncertainties in the model.

The model simulations will also be confronted with observations from two contrasting environments: The Baltic Sea, which is a murky environment due to high supplies of dissolved organic matter (see Andersson et al. 2018) and the Red Sea which is a highly transparent environment (see Calleja et al. 2018).

References

A. Andersson, S. Brugel, J. Paczkowska, O.F. Rowe, D. Figueroa, S. Kratzer, C. Legrand. 2018.
Influence of allochtonous dissolved organic matter on pelagic basal production in a northerly estuary
Estuarine, Coastal and Shelf Science. 204: 225-235.
Maria L. Calleja, Mohd I. Ansari, Anders &oslahs;stad, Luis Silva, Stein Kaartvedt, Xabier Irigoien, Xosé Anxelu G. Morán. 2018.
The Mesopelagic Scattering Layer: A Hotspot for Heterotrophic Prokaryotes in the Red Sea Twilight Zone
Frontiers in Marine Science. 5: 1-9.
Francesca Pianosi, Thorsten Wagener. 2018.
Distribution-based sensitivity analysis from a generic input-output sample
Environmental Modelling & Software. 108: 197-207.
Andrea Saltelli, Paola Annoni. 2010.
How to avoid a perfunctory sensitivity analysis
Environmental Modelling & Software. 25: 1508-1517.
T. Frede Thingstad, Harry Havskum, Ulla Li Zweifel, Elisa Berdalet, M. Montserrat Sala, Francesc Peters, Miquel Alcaraz, Renate Scharek, Maite Perez, Stéphan Jacque, Gro Anita Fonnes Flaten, John R. Dolan, Celia Marrasé, Fereidoun Rassoulzadegan, Åke Hagstrøm, Daniel Vaulot. 2007.
Ability of a minimum microbial food web model to reproduce response patterns observed in mesocosms manipulated with N and P, glucose and Si
Journal of Marine Systems. 64: 15-34.
T. Frede Thingstad. 2020.
How trophic cascades and photic zone nutrient content interact to generate basin-scale differences in the microbial food web
ICES Journal of Marine Science. 77: 1639-1647.
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