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Jens C Nejstgaard

Blurred image of the arch used as background for stylistic purposes.
LakeLab Scientific Coordinator
Leibniz-Institute of Freshwater Ecology
  • B.A. Gothenburg University, Sweden, Geology, Biology & Oceanography 1987
  • M.S. University of Bergen, Norway, Marine Biology 1991
  • Ph.D. University of Bergen, Norway, Marine Biology, Plankton 1997
Research Interests:

My main research interest is pelagic food web interactions and aquatic ecosystem functioning. I have worked with organisms from virus to fish, but the focus has been on feeding and reproduction of zooplankton. I am particularly interested in quantifying the complex interactions in natural plankton food webs, in relation to both individual interactions as well as to large-scale drivers such as climate and human environmental perturbations. Among the specific mechanisms I am working with are: prey-predator behavior, nutritional quality, feeding deterrents, toxins and other potential metabolites regulating the interactions. I have until now focused on the role of common but enigmatic bloom algae such as the haptophyte genera (Phaeocystis, Emiliania and Prymnesium) and diatoms, both as harmful algal blooms (HAB) and as food supporting higher production.

 On the small/individual scale interactions I have developed methods to enhance classical bottle incubation approaches to determine zooplankton grazing while correcting for inherent trophic cascades in incubations using natural plankton (see Nejstgaard et al 2001 and 1997 below).

To further, avoid inherent problem with manipulative incubation approaches to estimate feeding in zooplankton I have been developing molecular based approaches together with Dr. Marc Frischer at SkIO and several other colleagues (see e.g. Barofsky et al 2010, Simonelli et al 2009, Troedsson et al 2009, Nejstgaard et al 2008, Troedsson et al 2007, Nejstgaard et al 2003). This has lately also been successfully used to show feeding in hard and soft corals (Leal et al in press a and b).

On larger scales, I am convinced the that much of the important complex interactions in natural food webs may be lost in systems caged in the laboratory. Therefore a majority of my work has been conducted in the field or in different mesocosms (multiple cubic meter large water enclosures) from Arctic (foremost Thingstad et al 2008) to the Mediterranean, especially at the field station, Espegrend, of University of Bergen, Norway. The last of several national and international projects I was developed and conducted there was the EU FP7 project MESOAQUA-the first European network of mesocosm facilities to advance the studies of future aquatic ecosystems from the Arctic to the Mediterranean ( I was the Coordinator until Dec 2010, when I moved to my current position at SkIO.

Before I left Norway, I was awarded the 2011-2014 Norwegian Research Counsel project: “PHAEONIGMA-A novel cross-disciplinary approach to solve an old enigma: the food-web transfer of the mass-blooming phytoplankter Phaeocystis.”, which I now collaborate on as a Co-PI at SkIO.

Since my start at SkIO in Jan 2011 I am leading the US, NSF project: “Are Feeding and Growth Rates of Planktonic Ciliates Overestimated from Experiments in the Absence of Copepod Predators?”

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