scholarly journals Изменение сукцессионных систем палеофитоценозов на границе межледниковья и ледниковья позднего эоплейстоцена в пыльцевой записи оз. Эльгыгытгын (Центральная Чукотка)

2021 ◽  
pp. 63-70
Author(s):  
E. Yu. Nedorubova ◽  
Keyword(s):  
Vegetation Cover ◽  
Sharp Increase ◽  
Abrupt Change ◽  
The Arctic ◽  
Meteorite Impact ◽  
Arctic Circle ◽  
Forest Tundra ◽  
Birch Trees ◽  
Lake El’Gygytgyn ◽  
Succession Processes

Lake El'gygytgyn is located beyond the Arctic Circle in Chukotka at 67°30' N, 172°05' E and formed following a meteorite impact that occurred 3.6 million years ago (core interval 45.79-43.65 m). In its sediments, 5 palinologic zones are distinguished; they reflect changes in paleosuccessional systems and are consistent with MIS 33, 32, and 31 (1.114-1.062 mya). During warmings, thickets of birch trees and alder were widely spread. Cliseries, caused by macroclimate changes in cold substages, are characterized by a significant reduction in tree and shrub vegetation as well as by expansion of the arctic and subarctic tundras. Grass tundras dominated and were replaced by forest tundra communities in the valleys of the Anadyr Plateau surrounding the lake. The most abrupt change of phytocenosis succession systems is observed at the border of 32 and 31 isotopic stages. The succession processes are primarily expressed in a sharp increase of birch-shrub communities in the vegetation cover and in the appearance of late succession edificators (Carpinus, Corylus, Myrica, Quercus) forming forest climax associations.

scholarly journals Amplified bioproductivity during Transition IV (332 000–342 000 yr ago): evidence from the geochemical record of Lake El'gygytgyn

2013 ◽  
Vol 9 (2) ◽  
pp. 679-686 ◽  
Author(s):  
L. Cunningham ◽  
H. Vogel ◽  
V. Wennrich ◽  
O. Juschus ◽  
N. Nowaczyk ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Biogenic Silica ◽  
Ice Cores ◽  
Climatic Conditions ◽  
The Arctic ◽  
Significant Shift ◽  
Geochemical Parameters ◽  
Lake El’Gygytgyn ◽  
Arctic Russia

Abstract. To date, terrestrial archives of long-term climatic change within the Arctic have widely been restricted to ice cores from Greenland and, more recently, sediments from Lake El'gygytgyn in northeast Arctic Russia. Sediments from this lake contain a paleoclimate record of glacial-interglacial cycles during the last three million years. Low-resolution studies at this lake have suggested that changes observed during Transition IV (the transition from marine isotope stage (MIS) 10 to MIS 9) are of greater amplitude than any observed since. In this study, geochemical parameters are used to infer past climatic conditions thus providing the first high-resolution analyses of Transition IV from a terrestrial Arctic setting. These results demonstrate that a significant shift in climate was subsequently followed by a rapid increase in biogenic silica (BSi) production. Following this sharp increase, bioproductivity remained high, but variable, for over a thousand years. This study reveals differences in the timing and magnitude of change within the ratio of silica to titanium (Si/Ti) and BSi records that would not be apparent in lower resolution studies. This has significant implications for the increasingly common use of Si/Ti data as an alternative to traditional BSi measurements.

scholarly journals Post-fire vegetation succession in the Siberian subarctic tundra over 45 years

2019 ◽  
Author(s):  
Ramona J. Heim ◽  
Anna Bucharova ◽  
Leya Brodt ◽  
Johannes Kamp ◽  
Daniel Rieker ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Vegetation Cover ◽  
The Arctic ◽  
Vegetation Recovery ◽  
Long Term Effects ◽  
Forest Tundra ◽  
Permafrost Thaw ◽  
Legacy Effect ◽  
Thaw Depth

AbstractWildfires are relatively rare in subarctic tundra ecosystems, but they can strongly change ecosystem properties. Short-term fire effects on subarctic tundra vegetation are well documented, but long-term vegetation recovery has been studied less. The frequency of tundra fires will increase with climate warming. Understanding the long-term effects of fire is necessary to predict future ecosystem changes.We used a space-for-time approach to assess vegetation recovery after fire over more than four decades. We studied soil and vegetation patterns on three large fire scars (>44, 28 and 12 years old) in dry, lichen-dominated forest tundra in Western Siberia. On 60 plots, we determined soil temperature and permafrost thaw depth, sampled vegetation and measured plant functional traits. We assessed trends in NDVI to support the field-based results on vegetation recovery.Soil temperature, permafrost thaw depth and total vegetation cover had recovered to pre-fire levels after >44 years, as well as total vegetation cover. In contrast, after >44 years, functional groups had not recovered to the pre-fire state. Burnt areas had lower lichen and higher bryophyte and shrub cover. The dominating shrub species, Betula nana, exhibited a higher vitality (higher specific leaf area and plant height) on burnt compared with control plots, suggesting a fire legacy effect in shrub growth. Our results confirm patterns of shrub encroachment after fire that were detected before in other parts of the Arctic and Subarctic. In the so far poorly studied Western Siberian forest tundra we demonstrate for the first time, long-term fire-legacies on the functional composition of relatively dry shrub- and lichen-dominated vegetation.

scholarly journals Lake El'gygytgyn water and sediment balance components overview and its implications for the sedimentary record

2012 ◽  
Vol 8 (4) ◽  
pp. 3977-4001 ◽  
Author(s):  
G. Fedorov ◽  
M. Nolan ◽  
J. Brigham-Grette ◽  
D. Bolshiyanov ◽  
G. Schwamborn ◽  
...  
Keyword(s):  
Sediment Flux ◽  
The Arctic ◽  
Meteorite Impact ◽  
Clastic Material ◽  
Water And Sediment ◽  
Quantitative Estimates ◽  
Modern Process ◽  
Lake El’Gygytgyn ◽  
Process Studies ◽  
Paleoclimate Records

Abstract. Modern process studies of the hydrologic balance and sediment flux into and out of Lake El'gygytgyn, central Chukotka, provide important quantitative estimates for better understanding the lacustrine paleoclimate record from this basin. Formed ca. 3.6 Ma as a result of a meteorite impact, the basin contains one of the longest paleoclimate records in the Arctic. Fluvial activity into the basin today is concentrated over the short snowmelt period. Recent lake-level changes have a slow regressive character due to active underground runoff, even during winter. The residence time of the lake-water is estimated to be about 100 yr. The main source of clastic material are incoming steams. The amount of sediment discharge through the outflow river is insignificant and completely compensated even by little aeolian input.

Energy outlook for the Arctic: 2020 and beyond

Polar Record ◽  
2015 ◽  
Vol 52 (2) ◽  
pp. 170-175 ◽  
Author(s):  
Graça Ermida
Keyword(s):  
Oil And Gas ◽  
Oil Prices ◽  
The Arctic ◽  
Hydrocarbon Production ◽  
Arctic Circle ◽  
The Us ◽  
Energy Issues

ABSTRACTAt least four littoral countries have Arctic strategies that address energy issues. However, US, Canada, Russia and Norway strategies up to 2020 and beyond, reveal different interests in exploring Arctic resources. While Arctic oil and gas are of strategic importance to Russia and to Norway, Canada and the US seem content with continuing their current extraction predominantly south of the Arctic Circle. Despite the different approaches, the outcomes seem strangely similar. Indeed, despite the hype concerning the Arctic in the last decade, and for very diverse reasons, it is unlikely that any of these four countries will increase hydrocarbon production in the Arctic during the period under analysis. This was true even before the recent drop in oil prices. For all its potential, it is unclear what lies ahead for the region.

Pseudoditrichum mirabile gen. et sp. nov. (Musci: Pseudoditrichaceae fam. nov.), a unique moss from Great Bear Lake, Northwest Territories

1974 ◽  
Vol 52 (4) ◽  
pp. 701-705 ◽  
Author(s):  
William Campbell Steere ◽  
Zennoske Iwatsuki
Keyword(s):  
Northwest Territories ◽  
New Genus ◽  
The Arctic ◽  
Phylogenetic Position ◽  
New Genus And Species ◽  
Arctic Circle ◽  
New Family ◽  
Bear Lake ◽  
Evolutionary Level

The name Pseudoditrichum mirabile Steere et Iwatsuki is proposed for a minute moss with leafy stem 1-3 mm high and seta 6 mm long; it was collected on calcareous silt near the Sloan River, Great Bear Lake, Northwest Territories, only a few miles south of the Arctic Circle. The gametophytic characters agree well with those of the Ditrichaceae, a relatively primitive family, but the peristome is clearly double, with the inner and outer teeth opposite, which thereby indicates a much more advanced phylogenetic position, perhaps at the evolutionary level of the Funariaceae. As the combination of gametophytic and sporophytic characteristics exhibited by this moss does not occur in any existing family of mosses, it is therefore deemed necessary to create the new family Pseudoditrichaceae for the new genus and species described here.

Northward ho! Obama, Diefenbaker and the North American Arctic

Polar Record ◽  
2015 ◽  
Vol 52 (2) ◽  
pp. 252-255
Author(s):  
Klaus J. Dodds
Keyword(s):  
Native American ◽  
Aleutian Islands ◽  
The Arctic ◽  
Arctic Circle ◽  
The North ◽  
American President ◽  
North American Arctic ◽  
To Come ◽  
Franklin Delano Roosevelt ◽  
Lying Down

President Barrack Obama became, in September 2015, the first US president to travel north of the Arctic Circle. Having started his Alaskan itinerary in Anchorage, attending and speaking at a conference involving Secretary of State John Kerry and invited guests, the president travelled north to the small town of Kotzebue, a community of some 3000 people with the majority of inhabitants identifying as native American. Delivered to an audience in the local high school numbering around 1000, the 41st US president placed his visit within a longer presidential tradition of northern visitation: I did have my team look into what other Presidents have done when they visited Alaska. I’m not the first President to come to Alaska.Warren Harding spent more than two weeks here – which I would love to do. But I can't leave Congress alone that long. (Laughter.) Something might happen. When FDR visited – Franklin Delano Roosevelt – his opponents started a rumor that he left his dog, Fala, on the Aleutian Islands – and spent 20 million taxpayer dollars to send a destroyer to pick him up. Now, I’m astonished that anybody would make something up about a President. (Laughter.) But FDR did not take it lying down. He said, “I don't resent attacks, and my family doesn't resent attacks – but Fala does resent attacks. He's not been the same dog since.” (Laughter.) President Carter did some fishing when he visited. And I wouldn't mind coming back to Alaska to do some fly-fishing someday. You cannot see Alaska in three days. It's too big. It's too vast. It's too diverse. (Applause.) So I’m going to have to come back. I may not be President anymore, but hopefully I’d still get a pretty good reception. (Applause.) And just in case, I’ll bring Michelle, who I know will get a good reception. (Applause.) . . .. But there's one thing no American President has done before – and that's travel above the Arctic Circle. (Applause.) So I couldn't be prouder to be the first, and to spend some time with all of you (Obama 2015a).

The Martian chronicles: remotely guided diagnosis and treatment in the arctic circle

2010 ◽  
Vol 24 (9) ◽  
pp. 2170-2177 ◽  
Author(s):  
Christian Otto ◽  
Jean-Marc Comtois ◽  
Ashot Sargsyan ◽  
Alexandria Dulchavsky ◽  
Ilan Rubinfeld ◽  
...  
Keyword(s):  
Diagnosis And Treatment ◽  
The Arctic ◽  
Arctic Circle
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