University of Innsbruck

Photophysiological investigations of the temperature stress responses of Zygnema spp (Zygnematophyceae) from subpolar and polar habitats (Iceland, Svalbard)

Climate change in the form of elevated temperatures is predicted to affect areas in high latitudes especially. The Arctic even bears the unfortunate title of the fastest-warming area worldwide. An increase of only a few degrees can severely affect the flora in polar and subpolar regions. The already harsh environmental conditions of these habitats, result in a flora containing only a low amount of vascular plants. Zygnematophycea, a class of freshwater green algae, which are well adapted to these conditions are one of the main primary producers in polar hydro-terrestrial habitats. Studying their adaptation strategies and response to increased temperatures is vital in predicting the future of these ecosystems.

In the present study, we exposed two field sampled strains of Zygnema, originating from a subpolar (Iceland) and a polar (Svalbard) island, to experimentally elevated temperatures of up to 25°C. To quantify their responses, we measured a variety of different photo-physiological parameters and their phenolic content. Our results show, that both Zygnema strains were not able to adapt to the elevated temperatures, as for example, their photosynthetic performance decreased with increased temperatures. This suggests a low-temperature adaptation and a high sensitivity of the photosynthetic apparatus to higher temperatures for (sub-) polar Zygnematophhycae.

Overall, our study illustrates the negative effect of temperature increase on Zygnematophyceae and highlights the possible severity of global warming. As global change proceeds at an alarming rate, such studies are highly relevant for predicting the future development of plant communities in these ecosystems.


Zygnema strains were sampled from Iceland and Svalbard (with picture from the sampling site in Iceland). The algal strains were not able to adapt to elevated temperatures and showed a decrease in photosynthetic activity, suggesting a low-temperature adaptation.

Permann, C., Pierangelini, M., Remias, D., Lewis, L.A., Holzinger, A. (2022). Photophysiological investigations of the temperature stress responses of Zygnema spp (Zygnematophyceae) from subpolar and polar habitats (Iceland, Svalbard). PHYCOLOGIA, 61(3): 299–311. DOI:

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