11 research outputs found
Rock Glacier Outflows May Adversely Affect Lakes: Lessons from the Past and Present of Two Neighboring Water Bodies in a Crystalline-Rock Watershed
Despite
the fact that rock glaciers are one of the most common
geomorphological expressions of mountain permafrost, the impacts of
their solute fluxes on lakes still remain largely obscure. We examined
water and sediment chemistry, and biota of two neighboring water bodies
with and without a rock glacier in their catchments in the European
Alps. Paleolimnological techniques were applied to track long-term
temporal trends in the ecotoxicological state of the water bodies
and to establish their baseline conditions. We show that the active
rock glacier in the mineralized catchment of Lake Rasass (RAS) represents
a potent source of acid rock drainage that results in enormous concentrations
of metals in water, sediment, and biota of RAS. The incidence of morphological
abnormalities in the RAS population of <i>Pseudodiamesa nivosa</i>, a chironomid midge, is as high as that recorded in chironomid populations
inhabiting sites heavily contaminated by trace metals of anthropogenic
origin. The incidence of morphological deformities in <i>P. nivosa</i> of ā¼70% persisted in RAS during the last 2.5 millennia and
was ā¼40% in the early Holocene. The formation of RAS at the
toe of the rock glacier most probably began at the onset of acidic
drainage in the freshly deglaciated area. The present adverse conditions
are not unprecedented in the lakeās history and cannot be associated
exclusively with enhanced thawing of the rock glacier in recent years
RDA biplot visualizing the effects of physical environmental variables (dashed arrows for quantitative and filled triangles for categories) on the chemistry (solid arrows) of cryoconite holes on Aldegondabreen
<p><strong>FigureĀ 3.</strong>Ā RDA biplot visualizing the effects of physical environmental variables (dashed arrows for quantitative and filled triangles for categories) on the chemistry (solid arrows) of cryoconite holes on Aldegondabreen. Only significant factors (<em>p</em>Ā <Ā 0.01) are shown.</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Phylogenetic analysis of the nitrososphaeraceae sequences identified in the 454 pyrosequencing dataset from cryoconite sample A1 (in bold)
<p><strong>FigureĀ 6.</strong>Ā Phylogenetic analysis of the nitrososphaeraceae sequences identified in the 454 pyrosequencing dataset from cryoconite sample A1 (in bold). The maximum likelihood tree was constructed based on 406-base-pair-long 16S rRNA sequences and rooted with <em>Methanocaldococcus jannaschii</em>.</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
(A)Ā Aldegondabreen in GrĆønfjorden, the study site in Svalbard
<p><strong>FigureĀ 1.</strong>Ā (A)Ā Aldegondabreen in GrĆønfjorden, the study site in Svalbard. (B)Ā Location of the sampling sites on the surface of Aldegondabreen. Transects (A)ā(B) are numbered from the lowest point upstream. In transect (B) only the point B2 was analysed. (C)Ā Northern margin of Aldegondabreen with sampling points A3 and A4 as seen from point A2 with marked areas of bird nesting activity and occurrence of large cryoconite granules. White circles indicate the area in the slopes of Productustoppen (527Ā m) with nesting seabirds. (D)Ā Large cryoconite aggregate in detail with visible cyanobacterial mat on its surface. (E)Ā View on the glacier surface at transect (A). The scale was derived from an 3Ā m long avalanche probe with cm scale. The probe is visible in the lower right part of the shot. The cryoconite aggregates cover the surface without producing deep melt ponds due to prevailing effect of conductive heat flux. (F)Ā Large cryoconite sediment aggregates at point A2.</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Sequencing depth and diversity and dominance indices for the selected samples of cryoconite from Aldegondabreen
<p><b>TableĀ 5.</b>Ā
Sequencing depth and diversity and dominance indices for the selected samples of cryoconite from Aldegondabreen.
</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Abundances of the 16S rRNA gene and bacterial and archaeal <em>amoA</em> genes (gene copies g<sup>ā1</sup>) in cryoconite on Aldegondabreen (meanĀ Ā±Ā sd; <em>n</em>Ā =Ā 3)
<p><b>TableĀ 4.</b>Ā
Abundances of the 16S rRNA gene and bacterial and archaeal <em>amoA</em> genes (gene copies g<sup>ā1</sup>) in cryoconite on Aldegondabreen (meanĀ Ā±Ā sd; <em>n</em>Ā =Ā 3). b.d. below detection limit.
</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Diversity of prokaryotic phyla in the samples selected for pyrosequencing, expressed as a proportion of the total sequences
<p><strong>FigureĀ 5.</strong>Ā Diversity of prokaryotic phyla in the samples selected for pyrosequencing, expressed as a proportion of the total sequences. Eubacterial phyla accounting for less than 0.5% of the sequences were pooled into 'others'.</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Primer sets used for qPCR of 16S rRNA and <em>amoA</em> genes from the cryoconite samples
<p><b>TableĀ 1.</b>Ā
Primer sets used for qPCR of 16S rRNA and <em>amoA</em> genes from the cryoconite samples.
</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Histogram of aggregate diameters at transect A, site A2
<p><strong>FigureĀ 2.</strong>Ā Histogram of aggregate diameters at transect A, site A2.</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p
Nutrient concentrations in cryoconite sediment, supraglacial meltwater, and surface ice on Aldegondabreen
<p><b>TableĀ 3.</b>Ā
Nutrient concentrations in cryoconite sediment, supraglacial meltwater, and surface ice on Aldegondabreen. TC (total carbon), TN (total nitrogen), TP (total phosphorus) in mgĀ g<sup>ā1</sup> (meanĀ Ā±Ā sd, <em>n</em>Ā =Ā 3); DOC (dissolved organic carbon) in mgĀ l<sup>ā1</sup>, TDN (total dissolved nitrogen), NO<sub>3</sub><sup>ā</sup>, NH<sub>4</sub><sup>+</sup> in Ī¼gĀ l<sup>ā1</sup>. b.d. below detection limit; n.d. not determined.
</p> <p><strong>Abstract</strong></p> <p>The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and <em>amoA</em> genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.</p