China
Africa
Explore chapters and articles related to this topic
Microorganisms from Permafrost and their Possible Applications
Published in Ajar Nath Yadav, Ali Asghar Rastegari, Neelam Yadav, Microbiomes of Extreme Environments, 2021
A. Brouchkov, V. Melnikov, G.I. Griva, E. Kashuba, V. Kashuba, M. Kabilov, O. Fursova, V. Bezrukov, Kh. Muradian, V. Potapov, G. Pogorelko, N. Fursova, S. Ignatov, V. Repin, L. Kalenova, A. Subbotin, Y.B. Trofimova, E.V. Brenner, S. Filippova, V. Rogov, V. Galchenko, A. Mulyukin
Permafrost is defined as a lithosphere material (soil and sediment) that is permanently exposed to temperatures ≤ 0°C and remains frozen for at least two consecutive years, usually hundreds and thousands of years. It covers about 26% of terrestrial soil ecosystems in the Northern Hemisphere and can extend down to more than 1500 m into the subsurface (Steven et al. 2006). Permafrost is regarded as the natural depository of extant microorganisms that have survived for up to millions of years (Friedmann et al. 1994; Vorobjova 1997; Gilichinsky et al. 2007; Steven et al. 2008). Members of the major phyla (Proteobacteria and/or Actinobacteria) were found using culture-dependent and independent approaches in Alaskan, Canadian and Siberian permafrost of different ages and genesis (Shi et al. 1997; Vishnivetskya et al. 2000; 2006; Katayama et al. 2007; 2009; Steven et al. 2008; Yergau et al. 2010; Rivkina et al. 2015). Microorganisms have been recently found in ice-sediment communities in the surface layers of perennial and permanent lake ice (Psenner and Sattler 1998), in a high Arctic glacier (Skidmore et al. 2000), Greenland glacier (Sheridan et al. 2003) and sub glacial lake and rivers (Yadav et al. 2015a; Yadav et al. 2015b). Parkes (2000) reviewed convincing cases of bacteria in diverse environments which have remained viable over inordinate lengths of time.
Permafrost
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Soils and Terrestrial Systems, 2020
Spatially extensive permafrost can be found in Russia and Canada as far south as 45°N, and even farther south on the elevated Tibetan Plateau and Himalayan Mountains.[2] Approximately 25 million km2 of permafrost exist in the northern hemisphere. In the higher latitudes, permafrost is continuous under the land surfaces. At intermediate latitudes permafrost is discontinuous or sporadic. Legget[3] reported that 20% of the land surface of the world is underlain by permafrost. More than 50% of Russia and Canada are underlain by permafrost. Alaska has continuous permafrost in the northern 1/3 of the state and discontinuous permafrost in the rest of the state, excluding the coastal areas from the Aleutian Islands to southeastern Alaska (Figure 1). In the southern hemisphere, permafrost distribution is confined to Antarctica and high alpine or mountainous regions. Isolated permafrost is common at higher elevations, and evidence of past permafrost is common in areas that no longer have permafrost. The thickness of permafrost can vary from a thin lens of less than 1 m to greater than 1000 m (Figure 1). Permafrost can also be found in coastal areas at the bottom of seas.
The Continental Sedimentary Environment
Published in Aurèle Parriaux, Geology, 2018
Temperature variations at depth in boreal and polar areas follow the same pattern. However, these zones are unusual in that their temperatures are below 0°C. Thus, these regions may have no glaciers at the surface but ice is present. Instead of forming perennial accumulations at the surface, the ice occupies a part of the subsurface: it is the permafrost, a stratum where groundwater is permanently frozen. The permafrost can be several hundred meters thick, as in the very cold regions of Siberia, for example. In more temperate zones, it thins and becomes discontinuous. Permafrost sometimes occurs close to the surface of the soil, as ice bombs, called pingo (Eskimo term meaning “pregnant woman”), surrounded by a cap of loose sediments. Pingos can reach a considerable size, up to several hundred meters in diameter and tens of meters high (Fig. 8.68).
Limnology and diatom ecology of shallow lakes in a rapidly thawing discontinuous permafrost peatland
Published in Inland Waters, 2023
Kristen A. Coleman, Grace N. Hoskin, Laura Chasmer, Joshua R. Thienpont, William L. Quinton, Jennifer B. Korosi
Permafrost peatlands cover ∼19% of the circumpolar permafrost region (Tarnocai et al. 2009) and contain globally significant stores of terrestrial carbon (Harris et al. 2022). Climate change and an accelerated rate of permafrost thaw have raised concerns about their future role in the global carbon cycle under a warming climate (Hugelius et al. 2020). Shallow lakes are abundant features across many permafrost peatland landscapes of the circumpolar North. They play a critical role in the cycling of water and chemical constituents across the landscape and act as both sentinels and agents of environmental change. Consequently, attempts to decipher the future role of permafrost peatlands in the global carbon balance must include an understanding of how shallow lake ecosystem structure and function are likely to be altered with climate change (Cole et al. 2007).
Research agenda for the Russian Far East and utilization of multi-platform comprehensive environmental observations
Published in International Journal of Digital Earth, 2021
Tuukka Petäjä, Kirill S. Ganzei, Hanna K. Lappalainen, Ksenia Tabakova, Risto Makkonen, Jouni Räisänen, Sergey Chalov, Markku Kulmala, Sergej Zilitinkevich, Petr Ya Baklanov, Renat B. Shakirov, Natalia V. Mishina, Evgeny G. Egidarev, Igor I. Kondrat’ev
The Pan Eurasian Experiment (PEEX) Science Plan (Lappalainen, Kulmala, and Zilitinkevich 2015) introduced the large- scale research questions relevant to Northern Eurasian region. The quantified environmental information and data from Russian Far East play a critical role in this context and the research questions are: What are the net effects of various feedback mechanisms in (i) land cover changes (ii) photosynthetic activity, (iii) GHG exchange and BVOC emissions (iv) aerosol and cloud formation and radiative forcing? How do these vary with climate change on regional and global scale?How fast will permafrost thaw proceed, and how will it affect ecosystem processes and ecosystem-atmosphere feedbacks, including hydrology and greenhouse gas fluxes?How will the extent and thickness of the Arctic sea ice and terrestrial snow cover change and what are the interconnections of the sea ice-free periods of the Arctic Ocean?
Load transfer of pile foundations in frozen and unfrozen soft clay
Published in International Journal of Geotechnical Engineering, 2020
Abdulghader A. Aldaeef, Mohammad T. Rayhani
Frozen ground may fail to maintain its frozen condition in confrontation of global warming. In warm permafrost, a small temperature increase may be sufficient to cause extensive thawing. In cold permafrost, temperature increase by couple of degrees may result in significant increase in active layer depth (annual thaw depth), which can promote significant thaw settlement and increase the potential frost heave upon freezing. The thaw settlement in ice-rich soils could be more disruptive and cause inclusive damage to the structures (Esch and Osterkamp 1990). Temperature record in high-latitude regions of earth has shown 0.6°C increase per decade over the last 30 years, which represent twice the global average (IPCC 2013). This normally would result in thawing the frozen ground and reduce the frozen depth (Brown and Romanovsky 2008). Lawrence and Slater (2005) used weather data to model permafrost area in the Northern Hemisphere under global warming impact predicting present-day permafrost as well as permafrost condition over the 21st century. The model showed that a reduction in near surface permafrost area from 12 to 10.5 million of Km2 has occurred between 1900 and 2000. Dramatic permafrost degradation was predicted by 2100 yielding 1 million km2 of near surface permafrost area.