A Community of Snow Algae on a Himalayan Glacier: Change of Algal Biomass and Community Structure with Altitude

1997 ◽  
Vol 29 (1) ◽  
pp. 126 ◽  
Author(s):  
Yoshitaka Yoshimura ◽  
Shiro Kohshima ◽  
Shuji Ohtani
Keyword(s):  
Community Structure ◽  
Algal Biomass ◽  
Glacier Change ◽  
Snow Algae ◽  
Himalayan Glacier

scholarly journals Himalayan ice-core dating with snow algae

2000 ◽  
Vol 46 (153) ◽  
pp. 335-340 ◽  
Author(s):  
Yoshitaka Yoshimura ◽  
Shiro Kohshima ◽  
Nozomu Takeuchi ◽  
Katsumoto Seko ◽  
Koji Fujita
Keyword(s):  
Vertical Profile ◽  
Algal Biomass ◽  
Ice Core ◽  
Algal Growth ◽  
Ice Cores ◽  
Late Summer ◽  
Layer Formation ◽  
Snow Algae ◽  
Potential Use ◽  
Ice Core Dating

AbstractSnow algae in shallow ice cores (7 m long) from Yala Glacier in the Langtang region of Nepal were examined for potential use in ice-core dating. Ice-core samples taken at 5350 m a.s.l. in 1994 contained more than seven species of snow algae. In a vertical profile of the algal biomass, 11 distinct algal layers were observed. Seasonal observation in 1996 at the coring site indicated most algal growth occurred from late spring to late summer. Pit observation in 1991, 1992 and 1994 indicated that algal layer formation takes place annually. δ18O, chemical ions (Na+, Cl−, SO42− and NO3−) and microparticles failed to show any clear seasonal variation, particularly at depths exceeding 2 m, possibly due to heavy meltwater percolation. Snow algae in ice cores would thus appear to be accurate boundary markers of annual layers and should prove useful for ice-core dating in Himalayan-type glaciers.

scholarly journals Copper affects composition and functions of microbial communities in marine biofilms at environmentally relevant concentrations

2018 ◽  
Author(s):  
Natàlia Corcoll ◽  
Jianghua Yang ◽  
Thomas Backhaus ◽  
Xiaowei Zhang ◽  
Martin Karl Eriksson ◽  
...  
Keyword(s):  
Community Structure ◽  
Primary Production ◽  
Microbial Communities ◽  
Algal Biomass ◽  
Amplicon Sequencing ◽  
Quality Standard ◽  
Aquatic Communities ◽  
Static Test ◽  
Community Function ◽  
Eukaryotic Organisms

Cu pollution in coastal areas is a worldwide threat for aquatic communities. This study assesses the effects of Cu exposure on microbial diversity, community structure and functions of microbial communities in marine periphyton biofilms at environmental relevant concentrations. Periphyton was exposed for 18 days to five Cu concentrations, between 0.01 and 10 μM, in a semi-static test. Diversity and community structure of prokaryotic and eukaryotic organisms were assessed by 16S and 18S amplicon sequencing, respectively. Community function was studied as impacts on algal biomass and primary production. Additionally, we studied Pollution-Induced Community Tolerance (PICT) using photosynthesis as the endpoint. Sequencing results detected an average of 9504 and 1242 OTUs for 16S and 18S, respectively, reflecting the huge biodiversity of marine periphytic biofilms. Eukaryotes represent the most Cu-sensitive kingdom, where effects were seen already at concentrations as low as 10 nM. The structure of the prokaryotic part of the community was impacted at slightly higher concentrations (60 nM), which is still in the range of the Cu concentrations observed in the area (80 nM).The current environmental quality standard for Cu of 70 nM therefore does not seem to be sufficiently protective for periphyton. Cu exposure resulted in a more Cu-tolerant community, which was accompanied by a reduced total algal biomass, increased relative abundance of diatoms and a reduction of primary production. Cu exposure changed the network of associations between taxa in the communities. A total of 23 taxa, including species within Proteobacteria, Bacteroidetes, Stramenopiles and Hacrobia, were identified as being particularly sensitive to Cu. DNA metabarcoding is presented as a sensitive tool for community-level ecotoxicological studies that allows to observe impacts simultaneously on a multitude of pro- and eukaryotic species, and therefore to identify particularly sensitive, non-cultivable species and taxa.

scholarly journals Snow algae in a Himalayan ice core: new environmental markers for ice-core analyses and their correlation with summer mass balance

2006 ◽  
Vol 43 ◽  
pp. 148-153 ◽  
Author(s):  
Yoshitaka Yoshimura ◽  
Shiro Kohshima ◽  
Nozomu Takeuchi ◽  
Katsumoto Seko ◽  
Koji Fujita
Keyword(s):  
Mass Balance ◽  
Snow Cover ◽  
Air Temperature ◽  
Algal Biomass ◽  
Ice Core ◽  
Algal Growth ◽  
Environmental Indices ◽  
Snow Algae ◽  
Annual Layer ◽  
Cover Thickness

AbstractSnow algae in a shallow ice core (6.98 m long) from Yala glacier in the Langtang region of Nepal were examined for potential use as environmental markers in ice-core analysis. The ice core, taken at 5350m a.s.l. in 1994, was estimated to contain 11 annual layers from 1984 to 1994 from the profile of algal biomass. Algal biomass in each annual layer was noted to be correlated with air temperature, and the following two environmental indices which were calculated from air temperature and precipitation at Kyangjing (3920m a.s.l.), the village nearest to Yala glacier: estimated mean snow-cover thickness (MST) and estimated summer mass balance (SMB). Both parameters reflect snow-cover thickness on algal layers, which would be a major determinant of the light available for algal growth on the glacier. Snow algal biomass in the ice core appears to be a good environmental marker for indicating air temperature and accumulation during summer, which is important for understanding the mass balance of summer-accumulation-type glaciers in this region.

scholarly journals Copper affects composition and functions of microbial communities in marine biofilms at environmentally relevant concentrations

2018 ◽  
Author(s):  
Natàlia Corcoll ◽  
Jianghua Yang ◽  
Thomas Backhaus ◽  
Xiaowei Zhang ◽  
Martin Karl Eriksson ◽  
...  
Keyword(s):  
Community Structure ◽  
Primary Production ◽  
Microbial Communities ◽  
Algal Biomass ◽  
Amplicon Sequencing ◽  
Quality Standard ◽  
Aquatic Communities ◽  
Static Test ◽  
Community Function ◽  
Eukaryotic Organisms

Cu pollution in coastal areas is a worldwide threat for aquatic communities. This study assesses the effects of Cu exposure on microbial diversity, community structure and functions of microbial communities in marine periphyton biofilms at environmental relevant concentrations. Periphyton was exposed for 18 days to five Cu concentrations, between 0.01 and 10 μM, in a semi-static test. Diversity and community structure of prokaryotic and eukaryotic organisms were assessed by 16S and 18S amplicon sequencing, respectively. Community function was studied as impacts on algal biomass and primary production. Additionally, we studied Pollution-Induced Community Tolerance (PICT) using photosynthesis as the endpoint. Sequencing results detected an average of 9504 and 1242 OTUs for 16S and 18S, respectively, reflecting the huge biodiversity of marine periphytic biofilms. Eukaryotes represent the most Cu-sensitive kingdom, where effects were seen already at concentrations as low as 10 nM. The structure of the prokaryotic part of the community was impacted at slightly higher concentrations (60 nM), which is still in the range of the Cu concentrations observed in the area (80 nM).The current environmental quality standard for Cu of 70 nM therefore does not seem to be sufficiently protective for periphyton. Cu exposure resulted in a more Cu-tolerant community, which was accompanied by a reduced total algal biomass, increased relative abundance of diatoms and a reduction of primary production. Cu exposure changed the network of associations between taxa in the communities. A total of 23 taxa, including species within Proteobacteria, Bacteroidetes, Stramenopiles and Hacrobia, were identified as being particularly sensitive to Cu. DNA metabarcoding is presented as a sensitive tool for community-level ecotoxicological studies that allows to observe impacts simultaneously on a multitude of pro- and eukaryotic species, and therefore to identify particularly sensitive, non-cultivable species and taxa.

scholarly journals Biological ice-core analysis of Sofiyskiy glacier in the Russian Altai

2006 ◽  
Vol 43 ◽  
pp. 70-78 ◽  
Author(s):  
J. Uetake ◽  
S. Kohshima ◽  
F. Nakazawa ◽  
K. Suzuki ◽  
M. Kohno ◽  
...  
Keyword(s):  
Algal Biomass ◽  
Major Ions ◽  
Ice Core ◽  
Ice Cores ◽  
Seasonal Cycles ◽  
Altai Mountains ◽  
Snow Algae ◽  
The Mean ◽  
Potential Use ◽  
Snow Samples

AbstractWe examined microorganisms and pollen in a pit (4.5m deep) and a shallow ice core (25.01m long) from Sofiyskiy glacier in the Altai mountains of Russia for potential use in dating ice cores from a mid-latitude glacier. The ice-core and pit samples contained various green algae, cyanobacteria, bacteria, fungi and pollen. In the vertical profiles of the pit, algal biomass peaks corresponded to high δ18O layers and Pinaceae pollen peaks, suggesting that these algae grew during the melt season. In contrast, the layer with the lowest δ18O contained almost no algal cells. Major peaks of the cyanobacteria, bacteria and a fungus roughly corresponded to those of the algae. However, seasonal changes in these microorganisms became indistinct deeper in the core, as did the seasonal variation in δ18O and major ions, most likely due to heavy meltwater percolation and/or post-depositional decomposition. In contrast, clear seasonal cycles were evident in the algal biomass and pollen in snow samples. Assuming that the peaks of the snow algae and Pinaceae pollen marked summer layers and that the layers with almost no snow algae represented the winter layers, we estimated that the ice core contained 16 annual layers (1985–2001). The mean annual mass balance for the period was estimated to be 1.01mw.e. The value agreed well with those estimated from stake measurements, indicating that snow algae and pollen could provide reliable boundary markers of annual layers in the ice cores of this region.

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