Potentially pathogenic yeast isolated from the throat and cloaca of an Arctic colonial seabird: the little auk (Alle alle)

Yeasts are a distinctive group of microfungi, but compared to other microorganisms, their ecological function and biodiversity are poorly known. This is especially so where polar ecosystems are concerned. With climate changes and increasing pollution levels in the Arctic, it can be anticipated that there will be an increase in the prevalence and diversity of fungi colonizing live organisms. With these changes, it is crucial to investigate and monitor species diversity and prevalence of fungi in this fragile environment. In this study, yeasts were examined from throat and cloaca of a small colonial seabird, the little auk (Alle alle), a keystone species in the Arctic ecosystem. Samples were collected from 94 adults and 17 nestlings in breeding colony in Magdalenefjorden (NW Spitsbergen) in 2009. In total, twelve species of yeast from eight genera were found in 12 % of the samples, with the Dipodascus genus being the most prevalent. All yeast species were found in the adults, but only one species, Cryptococcus macerans, was found in a single nestling. In individuals where fungus was isolated, it was only isolated from either the throat or the cloaca, except for two cases, where fungus was found in both throat and cloaca. The presence of yeast was not related to sex but age of the birds, with adults being more prone to colonization by yeasts than the nestlings. The relatively low prevalence and diversity of yeast in little auks suggest that these birds are random carriers of fungi, with minor health impacts.