Johann Breitenstein

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.