Roundup: Midges, Rotifers, and Iron-Eating Bacteria

Posted by on May 16, 2016

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Each week, we highlight three stories from the forefront of glacier news.

 

Diversity of Midge Flies Near Italian Glaciers

From Insect Conservation and Diversity:

A winter-emerging midge. Courtesy of Flickr user thepiper351.

A winter-emerging midge. Courtesy of Flickr user thepiper351.

“A collection of approximately 100 000 chironomids (Diptera; Chironomidae) inhabiting glacial areas of the Southern Alps that were collected over a period of approximately four decades from 1977 to 2014 were analysed to evaluate the impact of environmental traits on the distribution of chironomid species. Although the list of species has not substantially changed over time, some rare species captured in the 1970s have not been collected in recent years, while other species have only been collected recently.”

Read more here.

Rotifers Colonize Maritime Glacier Ice

From Molecular Phylogenetics and Evolution:

Bdelloid rotifer, the species studied. Courtesy of Flickr user Ian Sutton.

Bdelloid rotifer. Courtesy of Flickr user Ian Sutton.

“Very few animal taxa are known to reside permanently in glacier ice/snow. Here we report the widespread colonization of Icelandic glaciers and ice fields by species of bdelloid Rotifera. Specimens were collected within the accumulation zones of Langjökull and Vatnajökull ice caps, among the largest European ice masses. Rotifers reached densities up to ∼100 individuals per liter-equivalent of glacier ice/snow, and were freeze-tolerant. ”

Read more here.

 

Bacteria Turn Iron into Food Under Glaciers

“Geochemical data indicate that protons released during pyrite (FeS2) oxidation are important drivers of mineral weathering in oxic and anoxic zones of many aquatic environments including those beneath glaciers.

Bacteria, courtesy of Flickr user AJ Cann.

Bacteria, courtesy of Flickr user AJ Cann.

Subglacial meltwaters sampled from Robertson Glacier (RG), Canada over a seasonal melt cycle reveal concentrations of S2O32- that are typically below detection despite the presence of available pyrite and several orders of magnitude higher concentrations of the FeS2 oxidation product sulfate (SO42-). Here we report the physiological and genomic characterization of the chemolithoautotrophic facultative anaerobe Thiobacillus sp. RG5 isolated from the subglacial environment at RG. The RG5 genome encodes pathways for the complete oxidation of S2O32-, CO2 fixation, and aerobic and anaerobic respiration with nitrite or nitrate.”

Read more here.

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