Johann Breitenstein

Johann Breitenstein
An oceanographer "lost" in the forest sciences...


I work on small seas -called lakes- and how the methylmercury in is impacted by the light, the water characteristics and their seasonalities.


Methylmercury is a neurotoxin dangerous for both environment and human healthes. One of the principal biogeochemical process which allows its degradation involves light. So I conduct experiments in the lab but also in situ on/in the lake to estimate how the photodegradation operates.

But, this story has another protagonist : the dissolved organic matter, responsible for the brown color of the lakes. It's main characteristic is to play a double-game. It can helps the photodegradation process as much as bloqued it. This will depend of its nature, or in others words of its (chemical) composition and its concentration.

So for that, I aim to study differents lakes based on their organic matter characteristics : from dark brown to transparent. Seasonality would be also a strong factor because the yearly cycle will change both methylmercury and dissolved organic matter concentrations and nature.


I am working with Ulf Skyllberg - supervisor of this postdoc in SLU, Erik Björn from Umeå university, Anders Lindfors from Helsinki university and Andrea Garcia Bravo from the Institute of Marine Sciences of Barcelona.


I started as an organic chemist. Lab, mixtures, (not so often) explosions.

I branched off towards oceanography by specializing me in marine chemistry. I have studied the dissolved organic matter composition since and its role in the carbon transfer along the land-to-sea continuum during my Ph.d.

Then, I have landed in the Skogen, Ekologi och Kötsel Institutionen of SLU for my first postdoc. I still deal with the dissolved organic matter to understand how it impacts the photodegradation of the methylmercury in the swedish lakes and quantify it.


Postdoktor vid Institutionen för skogens ekologi och skötsel; Institutionen för skogens ekologi och skötsel, gemensamt
Telefon: +33677597162
Skogens ekologi och skötsel
901 83 Umeå
Besöksadress: Skogsmarksgränd 17, Umeå