Mycoplasma Diversity in Arctic Permafrost

© 2016, Springer Science+Business Media New York.Viable bacterial cells and its genetic material can be stably maintained in Arctic permafrost for a long geological time. Because of the seasonal melting of permafrost strata, it cannot be excluded an access to the surface of ancient highly invasive species with increased pathogenicity. Mycoplasmas are very successful pathogens in humans, mammals, birds, insects, and plants, with high genome plasticity and ability to avoid immune response of host organism. The metagenomic approach allowed us to predict mycoplasma diversity in the Arctic permafrost. The number of mycoplasma DNA fragments in soil deposits of comparable age (∼30,000 years) and origin (the late Pleistocene Ice Complexes) is not so abundant compared with other microorganisms, but it is enough for a chance in the presence of living mycoplasmal cells in permafrost. DNA fragments of human, animal, insect, and plant pathogens were identified. The “ubiquitous” mycoplasma Acholeplasma laidlawii is the undisputed leader in the number of identified sequences in all three metagenomes. It may indicate a higher adaptive capacity and more powerful metabolic potential of A. laidlawii among Mollicutes

Source, transport and fate of soil organic matter inferred from microbial biomarker lipids on the East Siberian Arctic Shelf

The Siberian Arctic contains a globally significant pool of organic carbon (OC) vulnerable to enhanced warming and subsequent release by both fluvial and coastal erosion processes. However, the rate of release, its behaviour in the Arctic Ocean and vulnerability to remineralisation is poorly understood. Here we combine new measurements of microbial biohopanoids including adenosylhopane, a lipid associated with soil microbial communities, with published glycerol dialkyl glycerol tetraether (GDGTs) and bulk δ13C 5 measurements to improve knowledge of the fate of OC transported to the East Siberian Arctic Shelf (ESAS). The microbial hopanoid-based soil OC proxy R'soil ranges from 0.0 to 0.8 across the ESAS, with highest values near shore and decreases offshore. Across the shelf R'soil displays a negative linear correlation with bulk δ13C measurements (r2 = −0.73, p = < 0.001). When compared to the GDGT based OC proxy, the Branched and Isoprenoid tetraether (BIT) index, a decoupled (non-linear) behaviour on the shelf was observed, particularly in the Buor-Khaya Bay where the R'soil shows limited 10 variation, whereas the BIT index shows a rapid decline moving away from the Lena River outflow channels. This reflects a balance between delivery and removal of OC from different sources. The good correlation between the hopanoid and bulk terrestrial signal suggests a broad range of hopanoid sources, both fluvial and via coastal erosion whilst GDGTs appear to be primarily sourced via fluvial transport. Analysis of ice complex deposits (ICDs) revealed an average R'soil of 0.5 for the Lena delta, equivalent to that of the Buor-Khaya Bay sediments, whilst ICDs from further East showed higher values (0.6–0.85). Al15 though R'soil correlates more closely with bulk OC than the BIT, our understanding of the endmembers of this system is clearly still incomplete with east-west variations potentially reflecting differences in environmental conditions (e.g. temperature, pH) but other physiological controls on microbial BHP production under psychrophilic conditions are as yet unknown

Изучение бактериальных сообществ многолетнемерзлых пород оазисов Антарктиды методами культивирования

Aerobic and anaerobic bacteria from the permafrost of King George Island, Schirmacher, Larsemann, Banger oases and Hobbs Coast have been cultured. Based on the qualitative and quantitative composition of the cultivated community of samples, a comparative analysis of the biodiversity of marine, lake and fluvioglacial deposits of different geocryological conditions and age was made.Проведено культивирование аэробных и анаэробных бактерий из многолетнемерзлых пород острова Кинг Джордж, оазисов Ширмахера, Холмы Ларсеманн, Бангера и Берега Хоббса. На основе качественного и количественного состава культивируемого сообщества образцов проведена сравнительная характеристика разнообразия морских, озерных и флювиогляциальных отложений различных геокриологических условий и возраста

High biolability of ancient permafrost carbon upon thaw

Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and fate of this ancient OC in coastal and fluvial environments still remains rudimentary. Here, we show that ancient dissolved OC (DOC, &gt;21,000 (14)Cyears), the oldest DOC ever reported, is mobilized in stream waters draining Yedoma outcrops. Furthermore, this DOC is highly biolabile: 34 +/- 0.8% was lost during a 14 day incubation under dark, oxygenated conditions at ambient river temperatures. Mixtures of Yedoma stream DOC with mainstem river and ocean waters, mimicking in situ mixing processes, also showed high DOC losses (14 days; 17 +/- 0.8% to 33 +/- 1.0%). This suggests that this exceptionally old DOC is among the most biolabile DOC in any previously reported contemporary river or stream in the Arctic.</p

МЕТАН В ПОДЗЕМНЫХ ЛЬДАХ И МЁРЗЛЫХ ОТЛОЖЕНИЯХ НА ПОБЕРЕЖЬЕ И ШЕЛЬФЕ КАРСКОГО МОРЯ

Summary Degradation of permafrost on the continental shelf and shores of the Arctic seas may be a main cause of the methane emission to the atmosphere from marine sediments. To quantify this effect it is necessary to have reliable data on the methane content in the underground ice and frozen Quaternary deposits. Samples of frozen (permafrost) sediments and ground ice, taken in three reference coastal sections made in the Mid- and Late Pleistocene coastal exposures and on the Kara sea shelf, were collected and studied. The samples were analyzed to determine composition, salinity, organic carbon content, and other characteristics of the underground ices. About 270 samples allowed determination of the gas composition and the methane concentration. The gas is present in the pores of the rocks and air bubbles in the ice. Gas was present in pores of sediments and in bubbles within the ice. It has been established that the composition of non-hydrocarbon gases in the underground ice does not correspond to the composition of the atmosphere in the time of formation of them. The methane content in the underground ice and frozen sediments is characterized by very high variability. The highest concentrations of methane are inherent in layers of the massive ground ice and reach up to 23000 ppm; the maximum concentration of methane in the massive vein ices does not exceed 900 ppm. High concentrations of methane in layers of the massive ice confirm their non-glacier formation. The highest, up to 6400 ppm, methane concentrations in permafrost sediments are characteristic for the Late Pleistocene marine clays, while in the Mid Pleistocene marine clays it does not exceed 1700 ppm. The isotopic composition of methane in frozen sediments and ground ice in both, the Cara Sea coast and shelf, is indicative of similar bacterial genesis of the gas. The total organic carbon content plays the limiting role in the methane production and its accumulation in the frozen sediments and ground ice.В трёх береговых разрезах и в одной точке на шельфе Карского моря исследованы состав и свойства подземных льдов и мёрзлых отложений, включая газовый состав и концентрацию метана. Наиболее высокие концентрации метана (до 23 352 ppm) установлены в пластовых льдах, а в жильных льдах она достигает лишь 1112 ppm. Большие концентрации метана в воздушных пузырьках пластовых льдов и их изотопный состав указывают на не ледниковый генезис этих льдов

Биогеохимия мерзлых толщ арктического побережья полуострова Гыдан

Biogeochemistry of permanently frozen deposits on the arctic shore of Gydan peninsula Core drilling was performed in four regions of arctic shore on Gydan peninsula. Complex laboratory analysis of cores allowed to characterize biochemistry of Gydan permafrost. These results are compared with data from other permafrost provinces and are applied for paleoreconstructions.В четырех районах арктического побережья полуострова Гыдан проведено колонковое бурение и отобраны керны мерзлых отложений. Комплекс лабораторных анализов впервые позволил дать биогеохимическую характеристику мерзлых толщ на Гыдане, сравнить полученные результаты с другими районами криолитозоны и применить их для палеореконструкций

Cryogenesis as a factor of methane distribution in layers of permafrost

The gas seeps in Kolyma lowland are associated with methane inclusions in permafrost. These inclusions are formed by methane squeezed by epigenetic freezing of methane saturated deposits. This is proved by the biological genesis of the methane, by the isotopic data and the lower radiocarbon age of the methane from the gas seep in comparison with the radiocarbon age of the host deposits. The experimental data and observations of methane distribution in permafrost indicate that the methane distribution in the stra tum of frozen deposits is a result of methane migration during cryolithogenesis. The regularities of methane distribution in the deposits and formation of methane inclusions may change the idea of the character and volumes of emission of greenhouse gases into the atmosphere upon degradation of permafros