During the first week of our trip, we made an exciting discovery! In one of the ponds in Maiviken Cove, we found cyanobacterial mats.
Maiviken is a a beautiful cove on Thather Peninsula,only a 1 hour walk away from KEP. The cyanobacterial mat were in a small pond close to the scree slopes on the eastern side of the valley. The cyanobacterial-based mats were a lot more gelatinous than, for example, mats from the McMurdo Ice Shelf, but nevertheless clearly definiable as lift-off mats of up to 1 cm thickness.
Back in the lab, I had a look under the microscope and the mats were comprised of various morphotypes of Oscillatoriales includig Phormidium and Leptolyngbya, the unicellular order Chroococcales as well as Nodularia, which is a genus in the nitrogen-fixing order Nostocales.
A few weeks later, I also found cyanobacterial mats with a similar taxa composition in apond in Hapon Bay, which is also on Thather Peninsula. This finding is interesting as there is very little know about mat-forming cyanobacteria from South Georgia. Therefore, we collected material for more detailed microscopic and DNA analyses of the cyanobacterial diversity in these mats.
On Barff Peninsula, I found a meltwater stream where the cyanobacterial genus Nostoc was growing on some of the rocks. The Nostoc nodules were ca 1 cm in diameter. It was difficult to get a good image beause of the reflection of the sun in the fast flowing water.