Ecological stoichiometry

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The tiny crustacean creature Daphnia is a key inhabitant of freshwater systems. It is also a favourite tool for laboratory studies. It has asexual reproduction (i.e. mothers produce real clones), and is an excllent “aquatic fruitfly” for genetic studies. We also use these for effects studies of UV-radiation, toxisity studies and not the least as model organisms in prey-predator systems. Much of this research is based on the concept of ecological stoichiometry, covering topics such as the determination of growth rate via a reciprocal regulation of protein synthesis (N-limitation) and ribosome synthesis (P-limitation) to carbon transfer efficiency accross trophic levels and up to stoichiometric regulation of carbon cycling at the ecosystem level. Daphnia was the point of departure for the coming studies that evolved into Ecological Stoichiometry, that covers as differnt aspects as regulation of growth rate via rDNA to ecosystem regulation of carbon sequestration.

Our laboratory set-up with two-step chemostats is a major tool for studying these processes and principles, but more on this subject, emprical works and models, may be found in papers listed in the CV, eg. this paper based on the chemostat facilities. Our international collaboration includes several european, US and Japanese partners, and an international workshop held in Oslo (2000) may shed light on some of these aspects (Trends in Evolution and Ecology vol. 15: p. 393-394) or the Arizona group on biological stoichiometry lifesciences.asu.edu/irceb/stoichiometry and sterner.cbs.umn.edu).

Hosted by the Center of Advanced Study (www.cas.uio.no) I was head of an international group working on various principles in Ecological Stoichiometry in 2003-2004. This year yielded a long list of ideas and papers, and this process continues. At the end of the year, the scientific happening "Woodstoich 2004" took place at the Alpine research station at Finse, culmination in a series of papers in Oikos (and a party plus a glacier tour). This fairly unusual process is described here.

More to come ....