The first cultivation of the glacier ice alga Ancylonema alaskanum (Zygnematophyceae, Streptophyta): differences in morphology and photophysiology of field vs laboratory strain cells

Melting glacier surfaces are unique ecosystems for specialized microbes, frequently harbouring blooms of microalgae with pigments contributing to the darkening of ice surfaces, reducing albedo and enhancing melt rates. The main cause of this phenomenon is algae of the genus Ancylonema. Prior investigation depended on field-collected material because these algae resisted cultivation. To enhance research on how these algae dominate melting ice, we established a strain of Ancylonema alaskanum from an alpine glacier and exposed to temperatures around the freezing point at irradiations of similar to 10% of full sunlight. The morphology of the culture changed, with the cells becoming longer and turning green by losing their brownish pigmentation, indicating that these dark phenols are crucial for survival in the cryosphere. Photophysiological comparisons of strain and glacial material showed adaptation of the photosynthetic apparatus to prevailing conditions. This laboratorial strain opens possibilities for a wide range of comparative 'omics' research.

Automated summary

Melting glacier surfaces are unique ecosystems for specialized microbes, frequently hosting blooms of microalgae that contribute to the darkening of ice surfaces and accelerating melting rates. The main cause of this phenomenon is a type of algae called Ancylonema. Previous research relied on field-collected samples because these algae were difficult to cultivate. To enhance the understanding of their dominance in melting ice, a strain of Ancylonema alaskanum was established in a laboratory setting, mimicking freezing temperatures and low levels of sunlight. The strain exhibited changes in morphology and pigmentation, indicating the importance of dark phenols for survival in the cryosphere. Comparative studies between the strain and glacial material revealed adaptations of the photosynthetic apparatus to the prevailing conditions. This laboratory strain opens up possibilities for comprehensive omics research.