Meise, 25/01/2021

The terrestrial life in Antarctica is dominated by very small organisms, also known as "micro-organisms". For a long time, it was thought that this micro-life had only few species, occurring in almost all ice-free regions of the "White Continent" and, moreover, differing little from species observed in the Arctic. Recent research, conducted by an international team led by Meise Botanic Garden (Prof. Dr Bart Van de Vijver) and Ghent University (Prof. Dr Elie Verleyen and Prof. Dr Wim Vyverman), showed that the microflora in Antarctica is not only very species-rich , but also that most of these species have a very limited distribution.

Figure 1. Lake on Livingston Island, South Shetland Islands

The research focused on diatoms in Antarctic lakes. Diatoms, also called siliceous algae, are single-celled, microscopic algae that are characterized by their external shell that is made up entirely of silicon dioxide (SiO2), say glass. Worldwide they are one of the most diverse algal groups. Diatoms are important players in the global carbon cycle and are also responsible for almost 25% of global oxygen production. Their outer shells have very ornate drawings that are unique to each species and make it possible to distinguish species from each other.

The species composition in more than 430 lakes from all over the Antarctic was examined using light and electron microscopy techniques. Most of the 370 species observed were found nowhere else in the world and are thus unique to Antarctica. But even within the Antarctic region almost every species turned out to have a very limited distribution area. Most of the species (about 270) were found in the lakes on the sub-Antarctic islands that circle the Antarctic Continent like a belt. On the White Continent itself, the scientists found "only" 152 species. In addition, few species occurred in multiple places. This suggests that the successful distribution of these diatomaceous algae to, but also within, Antarctica is very limited.

 
Figure 2. Michelcostea linearis, a unique species from Kerguelen Archipelago, one of the sub-Antarctic islands







 

The results of this study once again emphasize the importance of protecting this still pristine continent. There is an urgent need for measures to ensure that the special character of these algal flora is not disturbed in the future.

The results of this study were recently published in the scientific journal Ecography (https://doi.org/10.1111/ecog.05374).

More information: Bart Van de Vijver (bart.vandevijver@plantentuinmeise.be, +32 473 777 234)