scholarly journals Carbon dynamics in boreal peat-lands of the Yenisey region, Western Siberia

2015 ◽  
Vol 12 (14) ◽  
pp. 11279-11311 ◽  
Author(s):  
E. D. Schulze ◽  
E. Lapshina ◽  
I. Filippov ◽  
I. Kuhlmann ◽  
D. Mollicone

Abstract. Here we investigate the vegetation history and peat accumulation at the eastern boarder of the West Siberian plain, near the river Yenisey, south of permafrost. In this region peat started to accumulate 15 000 yr ago as gyttia of shallow lakes in ancient river valleys. This peat is older than previously reported mainly due to separating particulate organic carbon (POC) from dissolved organic carbon (DOC), which was 1900 to 6500 yr younger than POC. The probability to finding peat layers older than 12 000 yr is about 2 %. Peat accumulated as fen-peat at a constant rate of 0.2 mm yr−1 and 0.01 kg C m2 yr−1. The accumulation was higher in ancient river valley environments. Since 2000 yr these bogs changed into Sphagnum mires which accumulate up to about 0.1 kg C m2 yr−1 until present. The long-lasting fen stage, which makes the Yenisey bogs distinct from the West Siberian bogs is discussed as a consequence of the local hydrology. The high accumulation rate of peat in un-frozen mires is taken as an indication that thawing of permafrost peat may change northern peatlands also into long-lasting carbon sinks.

2015 ◽  
Vol 12 (23) ◽  
pp. 7057-7070 ◽  
Author(s):  
E. D. Schulze ◽  
E. Lapshina ◽  
I. Filippov ◽  
I. Kuhlmann ◽  
D. Mollicone

Abstract. Here we investigate the vegetation history and peat accumulation at the eastern boarder of the West Siberian Plain, near the Yenisey River, south of permafrost. In this region, peat started to accumulate 15 000 years ago as gyttja of shallow lakes in ancient river valleys. This peat is older than previously reported, mainly due to separating particulate organic carbon (POC) from dissolved organic carbon (DOC), which was 1900–6500 years younger than POC. The probability of finding peat layers older than 12 000 years is about 2 %. Peat accumulated as fen peat at a constant rate of 0.2 mm yr−1 and 0.01 kg C m−2 yr−1. The accumulation was higher in ancient river valley environments. Over the last 2000 years these bogs changed into Sphagnum mires which have accumulated up to about 0.1 kg C m−2 yr−1 until present. The long-lasting fen stage, which makes the Yenisey bogs distinct from the western Siberian bogs, is discussed as a consequence of the local hydrology. The high accumulation rate of peat in unfrozen mires is taken as an indication that thawing of permafrost peat may also change northern peatlands into long-lasting carbon sinks.


2011 ◽  
Vol 75 (3) ◽  
pp. 531-540 ◽  
Author(s):  
Shanshan Cai ◽  
Zicheng Yu

AbstractStudying boreal-type peatlands near the edge of their southern limit can provide insight into responses of boreal and sub-arctic peatlands to warmer climates. In this study, we investigated peatland history using multi-proxy records of sediment composition, plant macrofossil, pollen, and diatom analysis from a 14C-dated sediment core at Tannersville Bog in northeastern Pennsylvania, USA. Our results indicate that peat accumulation began with lake infilling of a glacial lake at ~ 9 ka as a rich fen dominated by brown mosses. It changed to a poor fen dominated by Cyperaceae (sedges) and Sphagnum (peat mosses) at ~ 1.4 ka and to a Sphagnum-dominated poor fen at ~ 200 cal yr BP (~ AD 1750). Apparent carbon accumulation rates increased from 13.4 to 101.2 g C m− 2 yr− 1 during the last 8000 yr, with a time-averaged mean of 27.3 g C m− 2 yr− 1. This relatively high accumulation rate, compared to many northern peatlands, was likely caused by high primary production associated with a warmer and wetter temperate climate. This study implies that some northern peatlands can continue to serve as carbon sinks under a warmer and wetter climate, providing a negative feedback to climate warming.


The Holocene ◽  
2020 ◽  
Vol 30 (5) ◽  
pp. 618-631
Author(s):  
Leeli Amon ◽  
Ansis Blaus ◽  
Tiiu Alliksaar ◽  
Atko Heinsalu ◽  
Elena Lapshina ◽  
...  

The hemispheric-scale climatic fluctuations during the Holocene have probably influenced the large Siberian rivers. However, detailed studies of the West Siberian Plain postglacial environmental change are scarce and the records of millennial-scale palaeohydrology are nearly absent. This paper presents the Holocene palaeoecological reconstruction based on the sedimentary record of Lake Svetlenkoye, located near the confluence of major Siberian rivers Ob and Irtysh. Postglacial history of flooding, dynamics of regional and local vegetation, sedimentation regime, geochemical changes and lake water pH were reconstructed based on multi-proxy studies. We used palaeobotanical (plant macrofossils, pollen, diatoms), geochemical (organic matter, total organic carbon and nitrogen content, carbon/nitrogen ratio) and chronological (14C dates, spheroidal fly-ash particle counts) methods. The studied sediment section started to accumulate ~11,400 cal. yr BP. The initial shallow water body was flooded by Ob River waters ~8100–8000 cal. yr BP as confirmed by a remarkable increase in the sedimentation rate and the accumulation rate of the aquatic vegetation proxies. The period of flooding coincides with the high humidity periods reconstructed from regional palaeobotanical records. About 6800–6700 cal. yr BP, the study site became isolated from the Ob River floodplain and remained a small lake until present. The diatom-based lake water pH estimates suggest fluctuations in the pH values during the Holocene, the recent decrease since 1960s being the most notable. The vegetation record revealed constant postglacial presence of tree taxa – Betula, Pinus and Picea – although in different pollen ratios and accumulation rates through time. The paludification of the surroundings occurred since ca. 8500 cal. yr BP.


2017 ◽  
pp. 116-118
Author(s):  
E. A. Volkova

The monograph presents an overview of the forest-steppe vegetation of the West Siberian Plain and the Altai-Sayan mountain region. The questions of bioclimatic zonation of the Altai-Sayan mountain region are discussed. The biodiversity of foreststeppe is characterized, the floristic classification is performed, the scheme of eco-phytocoenotic classification is given, the basic types of plant communities are described in comparative terms. The diversity of forest-steppe landscapes is revealed, the structure of their vegetation is analyzed. The phytogeographical division of forest-steppe is worked out.


2017 ◽  
pp. 114-116
Author(s):  
B. M. Mirkin ◽  
L. G. Naumova

The monograph presents an overview of the forest-steppe vegetation of the West Siberian Plain and the Altai-Sayan mountain region. The questions of bioclimatic zonation of the Altai-Sayan mountain region are discussed. The biodiversity of foreststeppe is characterized, the floristic classification is performed, the scheme of eco-phytocoenotic classification is given, the basic types of plant communities are described in comparative terms. The diversity of forest-steppe landscapes is revealed, the structure of their vegetation is analyzed. The phytogeographical division of forest-steppe is worked out.


2004 ◽  
Vol 38 ◽  
pp. 309-313 ◽  
Author(s):  
Jun Li ◽  
H. Jay Zwally

AbstractVapor-transfer theory is incorporated into a previous firn-densification model to investigate the effect of vapor-transfer processes on densification in firn within 10 m of the surface. The densification rate in the model is governed by the change of overburden pressure (determined by the accumulation rate), the firn temperature, and the temperature gradient. The time of exposure to temperature gradients at shallow depths is a critical factor determining the importance of vapor-transfer processes. In high-accumulation and high-temperature conditions such as for the Greenland ice sheet, the temperature gradient and vapor transfer are less important due to the shorter exposure times. The high summer temperatures dominate the rate of densification and annual variations in density. In low-accumulation and low-temperature conditions, such as for inland Antarctica, the vapor transfer driven by the temperature gradient has a stronger effect on the densification rate, and temperature-driven processes are less important. These factors determine both the rate of density increase with depth and the amplitudes of annual variations in density with depth.


2011 ◽  
Vol 436 (1) ◽  
pp. 113-116 ◽  
Author(s):  
D. N. Troshkin ◽  
M. V. Kabanov ◽  
V. E. Pavlov ◽  
A. N. Romanov

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