Johannes Björk

Johannes Bjork

PhD student

Marine Biologist

My research interest lies in the fields of ecology and evolution with special emphasis on the marine environment. I have a keen interest in ecological interactions and dynamics at various scales (e.g. population/community & spartial/temporal), including behavioural aspects (e.g. social interactions, cooperation & resource competition).

I am a PhD student at the Department of Marine Biology and Oceanography at the Institute of Marine Sciences, Barcelona, Spain. I study prokaryote-eukaryote multispecies networks by using sponge and coral hosts and their dense and diverse extra- and intracellular microbial community (Bacteria & Archaea) as a model system. The main goal is to create a comprehensive view of prokaryote-eukaryote symbiotic networks in order to elucidate how coevolution and reciprocal specialization operates in complex ecosystems. In order to do that, I am (i) assesing the geographical differences in the structure of prokaryote-eukaryote multispecies networks belonging to two very distinct habitat types in comparison to prokaryotic free-living communities in the surrounding seawater and sediment biofilm, (ii) determining the role of past evolutionary history versus current ecological conditions in shaping these prokaryote-eukaryote networks, (iii) assesing whether Archaea assemblages are less host-specific than Bacteria and if the former are more similar to their corresponding free-living assemblages in the surrounding seawater and sediment biofilm, and (iv) searching for differences and commonalities between symbiotic prokaryote-eukaryote multispecies networks and other know mutualistic webs in order to build a coevolutionary theory of symbiotic networks. I am funded through a FPI scholarship (Professional Researcher Formation Scholarships), issued by the CSIC.

I received my Bachelor (Hons) and my Master degree in Natural Sciences, Major in Biology, from the University of Gothenburg, Sweden. In my bachelor, I studied fish cognition and behaviour with emphasis on the foraging activity and seach image formation in brown trout (Salmo trutta) and the effects of prey crypsis and motivation, while I in my MSc-thesis, studied sexual selection and parental care. More specifically, I focused on proximate mechanisms behind size-assortative nest choice by males of the sand goby (Pomatoschistus minutus) in absence of intrasexual competition. The latter has been published in the journal of Animal Behaviour.