Limits...
Microbial diversity on Icelandic glaciers and ice caps.

Lutz S, Anesio AM, Edwards A, Benning LG - Front Microbiol (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Cohen Laboratories, School of Earth and Environment, University of Leeds Leeds, UK.

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.

No MeSH data available.


Related in: MedlinePlus

Map showing the 2012 (red dots), 2013 (blue dots), and 2014 (green dot) sampling sites (further details see Table 1). Image Source Google Earth (June 2013).
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Figure 1: Map showing the 2012 (red dots), 2013 (blue dots), and 2014 (green dot) sampling sites (further details see Table 1). Image Source Google Earth (June 2013).

Mentions: A total of 33 snow and 1 ice samples (labeled with “ICE” for Iceland, followed by the collection year and sample number: ICE-12_1–7, ICE-13_1–24 and ICE-14_1–3; Table 1) was collected from seven glaciers and one ice cap in Iceland (see Figure 1 and Table 1 for details). Snow fields in the terminus areas of the western glacier Snaefellsjökull, the northern glacier Drangajökull, the central glacier Hofsjökull, as well as a large permanent snow field near Laugafell in the Central Highlands were sampled at the end of July in 2012. In early June 2013 we sampled the terminus areas of the southern glaciers Vatnajökull, Eyafjallajökull, Mýrdalsjökull, and Solheimajökull and the western glaciers Snaefellsjökull and Langjökull. Finally, we sampled three snow fields that covered fresh lava fields from the 2010 eruption of Eyafjallajökull at the end of August in 2014 in order to also assess how and if fresh microbial colonization had occurred. It is worth noting that in 2012 and 2014 melting had been very advanced leading to thin snow covers on the termini of all glaciers and smaller permanent snow fields. However, microbial colonization was well-developed at all sites. In contrast, the samples in 2013 were collected in early June, when melting had just been initiated and thick snow packs were still present at all sites and microbial colonization was less prominent or widely distributed. Nevertheless, at each site, regardless of years and stage of the melting season, we collected where possible two adjacent samples: one clean snow sample (no macroscopically visible particles) and one red snow sample (with visible particles). The exceptions were Solheimajökull, sampled in 2013, where snow patches were only present at the edges of deep crevasses and thus only bare, gray ice was sampled and Eyafjallajökull sampled from 2014, where only red snow and no “clean” snow could be found at the late stage in the melt season. It is important to note that all samples that are labeled “red snow” or “gray ice” in Table 1 always contained high loads of volcanic ash or dust debris, while the samples termed “clean snow” did not contain ash, dust or any macroscopically visible biomass and filtering of the clean snow did not result in enough biomass for genomic or other analyses of the particulates.


Microbial diversity on Icelandic glaciers and ice caps.

Lutz S, Anesio AM, Edwards A, Benning LG - Front Microbiol (2015)

Map showing the 2012 (red dots), 2013 (blue dots), and 2014 (green dot) sampling sites (further details see Table 1). Image Source Google Earth (June 2013).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403510&req=5

Figure 1: Map showing the 2012 (red dots), 2013 (blue dots), and 2014 (green dot) sampling sites (further details see Table 1). Image Source Google Earth (June 2013).
Mentions: A total of 33 snow and 1 ice samples (labeled with “ICE” for Iceland, followed by the collection year and sample number: ICE-12_1–7, ICE-13_1–24 and ICE-14_1–3; Table 1) was collected from seven glaciers and one ice cap in Iceland (see Figure 1 and Table 1 for details). Snow fields in the terminus areas of the western glacier Snaefellsjökull, the northern glacier Drangajökull, the central glacier Hofsjökull, as well as a large permanent snow field near Laugafell in the Central Highlands were sampled at the end of July in 2012. In early June 2013 we sampled the terminus areas of the southern glaciers Vatnajökull, Eyafjallajökull, Mýrdalsjökull, and Solheimajökull and the western glaciers Snaefellsjökull and Langjökull. Finally, we sampled three snow fields that covered fresh lava fields from the 2010 eruption of Eyafjallajökull at the end of August in 2014 in order to also assess how and if fresh microbial colonization had occurred. It is worth noting that in 2012 and 2014 melting had been very advanced leading to thin snow covers on the termini of all glaciers and smaller permanent snow fields. However, microbial colonization was well-developed at all sites. In contrast, the samples in 2013 were collected in early June, when melting had just been initiated and thick snow packs were still present at all sites and microbial colonization was less prominent or widely distributed. Nevertheless, at each site, regardless of years and stage of the melting season, we collected where possible two adjacent samples: one clean snow sample (no macroscopically visible particles) and one red snow sample (with visible particles). The exceptions were Solheimajökull, sampled in 2013, where snow patches were only present at the edges of deep crevasses and thus only bare, gray ice was sampled and Eyafjallajökull sampled from 2014, where only red snow and no “clean” snow could be found at the late stage in the melt season. It is important to note that all samples that are labeled “red snow” or “gray ice” in Table 1 always contained high loads of volcanic ash or dust debris, while the samples termed “clean snow” did not contain ash, dust or any macroscopically visible biomass and filtering of the clean snow did not result in enough biomass for genomic or other analyses of the particulates.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Cohen Laboratories, School of Earth and Environment, University of Leeds Leeds, UK.

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.

No MeSH data available.


Related in: MedlinePlus