We stay at the poles for the day 7 of our Microbial Advent Calendar with a recent study (paper here) on the bacterial communities associated with the stomach contents of two different species of Penguins.
The study took place on the British Antartic Survey station located on Signy Island (google map link here), where two species of penguins, the Adélie (Pygoscelis adeliae) and Chinstrap (Pygoscelis antarctica), are nesting. The stomach content of 6 individual adults of each species was sampled by flushing with seawater every 5 days. DNA was extracted and a variable region (V4) of the 16S rRNA was sequenced with Miseq technology.
The results showed that there are quite some individual and species variations in both genus and ratio composition of the different bacterial group (or OTU). Besides the small sample size (6 penguin per species), this variation could be due to individual host influence on the bacterial composition of the bacterial communities. A previous study suggested (here) that the penguin microbiome is mainly influenced by the penguin phylogeny rather than the geography indicating that the microbiome would be transmitted to the offspring by the parent by the feeding process. Also, we cannot exclude that the host’s genetic background could also influence the bacterial composition.
Nevertheless, a part of the community is shared, around 39% of the different genera are found in both species. This could be linked to the penguin’s diet. They feed exclusively on krill and would therefore harbour similar bacteria capable of digesting compounds specific to krill (e.g chitin). This study also suggests that many of the bacterial genera found in the Pygoscelis species are also found in other species of penguin present in the Antarctic, for example they share 63% of the same genus as the King penguin in Possession Island, indicating a potential for a core “penguin” stomach microbiota