Polar cyanobacteria, toxins and climate change

In harsh polar environments as found in Antarctica and the Arctic, cyanobacteria are the most important primary producers, i.e. drivers of N- and C-fixation and as key taxa in food webs. They occupy freshwater habitats as well as marine shores and cryocognite holes on glaciers, and are able to adapt to almost every environmental condition. Cyanobacterial mats (cyanomats) are complex communities which act as refugia for various other polar organisms such as other bacteria, archaea, viruses and diverse eukaryotes. Despite the enormous geographical distance, previous research of our group comparing the cyanobacterial mat species diversity from the Arctic to those of the Antarctic Peninsula demonstrated high species overlap (Kleinteich et al., 2017). As serendipitous simultaneous development of these cyanomat species appears highly unlikely, it is assumed that cyanobacteria are transported from the Arctic to the Antarctic Peninsula via birds or aerosols. With this project, we aim to investigate the possible exchange of cyanobacteria, cyanobacteria parasitic fungi and viruses and the impact of climate change on the potential establishment of more temperate tolerant species in Antarctica. Our findings (Kleinteich et al., 2012) indeed showed a change in species diversity and and cyanotoxin production upon exposure of Antarctic cyanomats to increased temperatures. With various field sampling campaigns (anticipated are Svalbard, Norway in summer 2022; Antarctic Peninsula in Winter 2022/23 and 2023/24) and collaborations with Anne Jungblut (Natural History Museum London, UK), Ian Hawes (University of Waikato, NZ), Antonio Quesada (University of Valencia, Spain), Peter Convey (British Antarctic Survey), Lucy Hawkes (University of Exeter, UK) and Susie Wood (Cawthron Institute, NZ) we work towards understanding the historical presence of cyanomat parasites (fungi and viruses), species diversity of cyanomat parasites and the impact of a warming climate on parasite infections with concomitant changes in species diversity and toxin production.

Contact: eva.riehle@uni-konstanz.de, daniel.dietrich@uni-konstanz.de