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Permafrost temperature profile. Permafrost occupies the middle zone, with the active layer above it, while geothermal activity keeps the lowest layer above freezing. The vertical 0 °C or 32 °F line denotes the average annual temperature that is crucial for the upper and lower limit of the permafrost zone, while the red lines represent seasonal temperature changes and seasonal temperature ...
The permafrost carbon cycle or Arctic carbon cycle is a sub-cycle of the larger global carbon cycle. Permafrost is defined as subsurface material that remains below 0 o C (32 o F) for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within ...
Drunken trees are not a completely new phenomenon—dendrochronological evidence can date thermokarst tilting back to at least the 19th century. [13] The southern extent of the subarctic permafrost reached a peak during the Little Ice Age of the 16th and 17th centuries, [24] and has been in decline since then.
The land began to sink due to the thawing permafrost in the 1960s after the surrounding forest was cleared. [3] Flooding also contributed to the enlargement of the crater. Paleontologists have found Ice Age fossils buried in the mud around the rim of the crater. [ 3 ]
Cryoturbation is the dominant force operating in the active layer, and tends to make it generally uniform in composition throughout. However, variation in the composition of soils due to differences in parent rock are very marked in permafrost regions due to the low rate of weathering in the very cold climate.
A talik is a layer of year-round unfrozen ground that lies in permafrost areas. In regions of continuous permafrost, taliks often occur underneath shallow thermokarst lakes and rivers, where the deep water does not freeze in winter and thus the soil underneath does not freeze either. Sometimes closed, open, and through taliks are distinguished.
Antibiotics to which permafrost bacteria have displayed at least some resistance include chloramphenicol, streptomycin, kanamycin, gentamicin, tetracycline, spectinomycin and neomycin. [18] Some scientists consider horizontal gene transfer of novel antibiotic resistance sequences from otherwise harmless ancient bacteria into modern pathogens to ...
Methane emissions by the permafrost carbon feedback—amplification of surface warming due to enhanced radiative forcing by carbon release from permafrost—could contribute an estimated 205 Gt of carbon emissions, leading up to 0.5 °C (0.9 °F) of additional warming by the end of the 21st century. [17]