Abstract
Algae are important primary colonizers of snow and glacial ice, but hitherto little is known about their ecology on Iceland's glaciers and ice caps. Due do the close proximity of active volcanoes delivering large amounts of ash and dust, they are special ecosystems. This study provides the first investigation of the presence and diversity of microbial communities on all major Icelandic glaciers and ice caps over a 3 year period. Using high-throughput sequencing of the small subunit ribosomal RNA genes (16S and 18S), we assessed the snow community structure and complemented these analyses with a comprehensive suite of physical-, geo-, and biochemical characterizations of the aqueous and solid components contained in snow and ice samples. Our data reveal that a limited number of snow algal taxa (Chloromonas polyptera, Raphidonema sempervirens and two uncultured Chlamydomonadaceae) support a rich community comprising of other micro-eukaryotes, bacteria and archaea. Proteobacteria and Bacteroidetes were the dominant bacterial phyla. Archaea were also detected in sites where snow algae dominated and they mainly belong to the Nitrososphaerales, which are known as important ammonia oxidizers. Multivariate analyses indicated no relationships between nutrient data and microbial community structure. However, the aqueous geochemical simulations suggest that the microbial communities were not nutrient limited because of the equilibrium of snow with the nutrient-rich and fast dissolving volcanic ash. Increasing algal secondary carotenoid contents in the last stages of the melt seasons have previously been associated with a decrease in surface albedo, which in turn could potentially have an impact on the melt rates of Icelandic glaciers.
Highlights
Glaciers and ice sheets cover about 10% of the Earth’s surface and are the largest freshwater reservoir
This is of special interest in Iceland where glaciers have been shown to be retreating very fast (Staines et al, 2014) and where albedo is affected by the presence of volcanic dust and ash on snow and ice surfaces
With this study we aimed to identify the presence of snow and ice algae on Icelandic glacial surfaces
Summary
Glaciers and ice sheets cover about 10% of the Earth’s surface and are the largest freshwater reservoir. We have recently shown that they are important primary colonizers and net primary producers supporting other snow and ice microbial communities as carbon and nutrient sources (Lutz et al, 2014) As part of their life cycle and as a mechanism of protection from high irradiation, snow algal species produce red pigments (carotenoids). Through this protective reaction, algal blooms color snow and ice surfaces and cause a darkening of glacial surfaces which in turn leads to a decrease in surface albedo (Thomas and Duval, 1995; Yallop et al, 2012; Takeuchi, 2013; Benning et al, 2014; Lutz et al, 2014). This is of special interest in Iceland where glaciers have been shown to be retreating very fast (Staines et al, 2014) and where albedo is affected by the presence of volcanic dust and ash on snow and ice surfaces
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
