Main scientific interests and areas

Stoichiometric principles from genes to ecosystems. I.e. how elements like carbon, nitrogen and phosphorus and elemental ratios regulates RNA-content, RNA:DNA-ratios and growth rates in organisms, trophic transfer efficiency in food webs and biogeochemical cycling of these key elements. Starting off from the favourite lab pet Daphnia, these studies now include various taxa (C. elegans, Drosophila, collebola, rotifers)
Genome size evolution in organisms and the link between genome size, growth and metabolism accross phyla.
Carbon flux and sequestration in individuals and ecosystems, linked with stoichiometry and climate change.
UV-radiation, ozone depletion and effects on alpine and Arctic ecosystems.
The role of polyploidy (multiple chromosome copies) for life cycle strategies, genetic diversity and speciation.
Patterns and causes of species diversity within lakes, focussing phyto- and zooplankton.
Ecology and evolutionary biology in general, environmental issues and the philosophical implications of biology in general and evolutionary aspects in particular.

For master students, PhDs and post.docs: There are possibilities for interesting topics of research and ongoing projects, both at various field sites (including the high Arctic), lab experiments and more theoretical studies and lab experiments. My work is mostly performed at Biological Institute at University of Oslo, where I am affiliated as core member at Center for Ecological and Evolutionary Synthesis (http://www.cees.no/). A general presentation of my research group and activities is given at: http://www.bio.uio.no/akv/ansatte/biografi/hessen_Dag.html.

For those with their interest devoted to science, an updated (more or less) list of books, publications and some more general scientific writings and merits are given in my CV.