The moss Sanionia uncinata could possibly serve as an indicator species for climate change in the north of the Antarctic Peninsula. A team of scientists found numerous sporophytes of the moss, which are normally very rare in the Antarctic and only occur during sexual reproduction.
A Brazilian research team led by Professor Filipe de Carvalho Victoria, coordinator of the Antarctic Vegetation Research Center at the Federal University of Pampa, made a very rare discovery on King George Island in the past two Antarctic summers, 2021/2022 and 2022/2023.
In their article, which is currently in press and will appear in Polar Science, the team reports on a large number of sporophytes of the moss species Sanionia uncinata, which they found at eight different locations on the island. Sporophytes of mosses are tiny stalked spore capsules that form only during sexual reproduction and grow out of the individual moss plants.
In the Antarctic, S. uncinata reproduces mainly vegetatively by budding and has only very rarely been observed reproducing sexually, as Professor Victoria explained to PolarJournal. “It expands a lot in Antarctica, forming huge green carpets, probably through clonal growth. But as stated in our recent work, in the last 2 years a massive occurrence of sporophytes has been observed, which indicates that, at least in recent years, it is dedicating more efforts to sexual reproduction,” he writes in an email to PolarJournal.
Professor Victoria further explains that the increased occurrence of sporophytes “could have repercussions on the understanding of how climate change is affecting the physiology of polar plants and hence the future can be speculated about the greening of Antarctica, for example, but with changes in the behavior and biology of these species.”
Although the team does not yet have any evidence for this, the researchers suspect that the rapid regional warming near the Antarctic Peninsula is responsible for the increased formation of sporophytes. S. uncinata prefers water-saturated areas and is often found near riverbanks and meltwater streams. Changes in the microclimate, such as higher air temperatures, can influence the freeze-thaw cycles and lead to more ice-free areas and thus new habitat for mosses. Proximity to defrost drain lines in mountainous regions and to coasts appears to favor sporophyte formation, and even small-scale climate changes could lead to more frequent sexual reproduction, according to the authors.
If there is a connection between the changing climatic conditions and the occurrence of sporophytes, S. uncinata could act as an indicator species for climate change in the region.
Mosses in general – inconspicuous individual plants and even as bright green carpets, probably only marginally noticed by most non-botanists – play an important ecological role in the water and nutrient cycle, especially in polar regions where liquid water is scarce. The moss species investigated in the study is able to absorb and release water and nutrients over its entire surface, from which other organisms benefit.
According to Professor Victoria, S. uncinata is a species of moss that occurs naturally in both the extreme south and the extreme north of the planet. In the northern hemisphere, it can be found in Europe, North America and Greenland.
Julia Hager, PolarJournal
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