Annual Cycles of Two Cyanobacterial Mat Communities in Hydro-Terrestrial Habitats of the High Arctic

• Published in: Microbial Ecology
• Main Authors: Tashyreva, D., Elster, J. (Josef)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Phormidium; Life cycle; Polar Regions; Antarctic; Arctic; Svalbard; Antarc*
• Online Access: https://doi.org/10.1007/s00248-016-0732-x; http://hdl.handle.net/11104/0265096

Cyanobacteria form extensive macroscopic mats in shallow freshwater environments in the High Arctic and Antarctic. In these habitats, the communities are exposed to seasonal freezing and desiccation as well as to freeze-thawing and drying-rewetting cycles. Here, we characterized the annual cycles of two Phormidium communities in very shallow seepages located in central Svalbard. We observed the structure of the communities and the morphology, ultrastructure, metabolic activity, and viability of filaments and single cells. The communities overwintered as frozen mats, which were formed by long filaments enclosed in thick multilayered polysaccharide sheaths. No morphologically and/or ultrastructurally distinct spore-like cells were produced for surviving the winter, and the winter survival of the communities was not provided by a few resistant cells, which did not undergo visible morphological and ultrastructural transformations.