Environmental factors influencing diatom communities in Antarctic cryoconite holes

• Published in: Environmental Research Letters
• Main Authors: L F Stanish, E A Bagshaw, D M McKnight, A G Fountain, M Tranter
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2013
• Subjects: diatoms; cryoconite holes; dry valley glaciers; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Antarctic; McMurdo Dry Valleys; Taylor Valley; Antarc*; Antarctica
• Online Access: https://doi.org/10.1088/1748-9326/8/4/045006; https://doaj.org/article/73b796a9e7634a40a80a82e093ee5c81

Cryoconite holes are ice-bound habitats that can act as refuges for aquatic and terrestrial microorganisms on glacier surfaces. In the McMurdo Dry Valleys of Antarctica, these holes are often capped by an ice lid that prevents the exchange of material and gases with the surrounding atmosphere and aquatic environment. Diatoms have been documented in cryoconite holes, and recent findings suggest that these habitats may harbour a distinctive diatom flora compared to the surrounding aquatic environments. In this study, we examined diatom community composition in cryoconite holes and environmental correlates across three glaciers in Taylor Valley, Antarctica. The diatom communities were dominated by two genera, Muelleria and Diadesmis , both of which had high viability and could have been seeded from the surrounding ephemeral streams. The location of the cryoconite hole within the valley was a key determinant of community composition. A diatom species richness gradient was observed that corresponded to distance inland from the coast and co-varied with species richness in streams within the same lake basin. Cryoconite holes that were adjacent to streams with higher diversity displayed greater species richness. However, physical factors, such as the ability to withstand freeze–thaw conditions and to colonize coarse sediments, acted as additional selective filters and influenced diatom diversity, viability and community composition.