Johan Weijers

The 2009 Outstanding Young Scientist Award is awarded to Johan Weijers for his distinguished multidisciplinary work on biomarkers.

Johan was trained as a physical geographer and did a PhD in molecular organic geochemistry. During his thesis work at the NIOZ Royal Netherlands Institute for Sea Reseach, he turned out to be a very productive and innovative young researcher. The subject of his PhD thesis was a specific class of lipids, the branched tetraether lipids which we encountered in coastal marine sediments. Johan was able to find out that these are derived from soils and transported by rivers to the ocean and that they can be used as tracers for soil organic matter input in the ocean. Furthermore, he showed by advanced chemistry techniques that the lipids are produced by bacteria and not by archaea.

Probably the most innovative part of his PhD work was that he figured out that there are subtle variations in the distribution of these lipids and that they can be related to temperature and pH of the soil. Using this observation he was able to make a reconstruction of the past continental climate of tropical Africa (in terms of air temperature and rainfall) for the last 25 kyr. This work was published in Science last year and was followed by an application of this new method to reconstruct the temperature change during the Palaeocene Eocene thermal maximum in the Arctic region published in EPSL. This novel method is now receiving a lot of attention from other research groups since it allows to develop a quantitative picture of continental climate change.

His PhD thesis impressively combines various disciplines: analytical chemistry, microbial ecology, organic geochemistry and palaeoclimatology. His dissertation got the the distinction “cum laude”. His excellence is clear from the impressive number of very good papers (including two papers in Science) for somebody in his age group. Johan has also shown to be able to explain his research to his pears and the general public.

In 2007 he obtained a prestigious Rubicon fellowship from the Dutch funding agency NWO to gain experience at a foreign research group. He joined the famous Organic Geochemistry Unit of Bristol University to work with Dr. R. Pancost. This summer he got another prestigious fellowship from NWO; a VENI grant. He will test if the method he developed during his thesis work can also be applied using lake sediments.