Roundup: Cyanobacteria, Glacier Calving and Glacier Fluctuations

Arctic biocrust cyanobacterial communities

Microcystins Souce: Flickr

“In the polar regions cyanobacteria are an important element of plant communities and represent the dominant group of primary producers. They commonly form thick highly diverse biological soil crusts that provide microhabitats for other organisms. Cyanobacteria are also producers of toxic secondary metabolites. The north-west coast of Spitsbergen, are able to synthesize toxins, especially microcystins and anatoxin-a. To the best of our knowledge, this is the first report on the presence of ANTX-a in the entire polar region. The occurrence of cyanotoxins can exert a long-term impact on organisms co-existing in biocrust communities and can have far-reaching consequences for the entire polar ecosystem.”

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Dynamics of Glacier Calving

Glacier Calving Source: Flickr

“During summer 2013 we installed a network of nineteen GPS nodes at the ungrounded margin of Helheim Glacier in south-east Greenland together with three cameras to study iceberg calving mechanisms… The glacier calved by a process of buoyancy-force-induced crevassing in which the ice downglacier of flexion zones rotates upwards because it is out of buoyant equilibrium. Calving then occurs back to the flexion zone… “

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Reconstruction of glacier fluctuations

Reconstruction of glacier fluctuations Source: Flickr

“It is presented the results of study of bottom sediments of the proglacial lakes enriched with meltwater of Peretolchin Glacier, Chersky Glacier and glaciers of the Kodar Ridge. Bottom sediments were investigated with time resolution in year-season, using X-ray fluorescence. We have defined three periods in significant increase of glacier flow/melting during the last 210 years. The first period (ca. 1800–1890), supply of suspended material by meltwater into Lake Ekhoy and Lake Preobrazhenskoe, was not intense until 1850 and 1875, respectively. However, the rate of meltwater supply into Lake Izumrudnoe was high during the Little Ice Age, and it is likely attributed to local moisture from Lake Baikal. The regional glacier water balances were most likely positive during the second period (ca. 1890–1940). The third period (ca. 1940–till present) was characterised by moderate melting rate of glaciers located on the Kodar and Baikalsky Ridges, in contrast to Peretolchin Glacier that demonstrated the highest rate of melting and changes in outlines during this period.”

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