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- Stratigraphy of peat deposits and mire development in the south and middle
taiga zones of Westerns Siberia in Holocene
Authors: E. D. Lapshina, E. A. Zarov
Pages: 70 - 101
Abstract: This article provides a historical review of the peatlands study in the Middle and South taiga, as well as Subtaiga zone of Western Siberia, and summarizes the data on the structure of peat deposits in mires of the region, accumulated by the senior author over many years of field research (1980-2004). The features of the main types of stratigraphic structure, as well as a description of the development history of peat mires, are given based on a detailed study of macrofossil composition of peat cores and peat sections. Peat cores were selected within the landscape-ecological profiles, covering all relief elements from the raised bogs of the watershed plains to the mires of river valleys and gullies of ancient water runoff in different climatic zones and subzones (Subtaiga, Southern taiga and Middle taiga). The oldest peat deposits are associated with the deep thalwegs and ancient hydrological system. Peat formation started simultaneously within the taiga zone and the present subarctic zone of Western Siberia and reached the high distribution level in Boreal period. The peatlands development process tightly followed the climate humidity – in the wet periods, the watershed mires actively developed and floodplain mires’ development was constrained by the alluvial deposition process; in the dry periods, the floodplain mires developed actively and the watershed mires grow was stagnated.
PubDate: 2023-10-01
DOI: 10.18822/edgcc568688
Issue No: Vol. 14, No. 2 (2023)
- Photosynthetic gas exchange in seedlings of Hopea odorata ROXB. (South
Vietnam)
Authors: Nikolay Zhirenko, Manh Vu, Van Thinh Nguyen, Juliya Kurbatova
Pages: 102 - 115
Abstract: The paper presents the results of studies related to the study of photosynthetic gas exchange at the leaf level in situ of three-year-old seedlings of Hopea odorata Roxb. during the dry season (South Vietnam). The results obtained will contribute to a better theoretical understanding of the growth and development of plants of this species. The obtained quantitative values of the daily fluxes of photosynthetic gas exchange, as well as the physiological reactions of the plant to environmental conditions, will allow a more qualitative approach to the assessment of carbon fluxes in the corresponding ecosystems. OBJECTS AND METHODS OF RESEARCH The research was conducted from January to April 2020 on the territory of the Cat Tien National Park (South Vietnam) (11.41530° s.w., 107.42460° v.d.) during the dry season. Three-year-old H. odorata seedlings planted in mid-January 2020 were selected as the object of the study. 25 seedlings were selected for observation. The average height of seedlings is 110.0± 0.5 cm (SD = 14.4 cm), and their average diameter at a height of ~10 cm is 8.3± 0.1 mm (SD = 0.6 mm). According to the illumination conditions of the site and the location of the seedlings, the site was divided into three experimental sites (SA1, SA2, SA3), Fig. 1. The SA1 site (seedlings № 1-16) was located in a relatively open space. The total value of photosynthetically active radiation (FAR) per seedling of this site was 25.7±1.2 mol·m-2. The SA2 site (seedlings № 17-20) was located under the crowns of adult trees. The total value of FAR is 10.8±0.5 mol·m-2. The SA3 site (seedlings № 21-25) was adjacent to an untouched part of the forest. The total value of FAR is 9.2±0.4 mol·m-2. During planting, as well as on 12.02 and 19.03, the seedlings were watered. On 17.02 there was heavy rain at the site. To clarify the question of the effect of the moisture content in the soil on the condition of the studied plants, seedlings № 4-9 were watered from 26.03 to 5.04. The processes of photosynthesis were considered from the standpoint of CO2 gas exchange. Photosynthesis was measured in situ using the Portable Photosynthesis System LI-6800 (Li-Cor, USA). The formed intact leaves in the upper part of the crowns were used for the study. The moisture content in the soil was determined in a 12 cm surface layer using the HydroSense II soil moisture meter (Campbell Scientific, Inc. USA). Soil moisture below 10% corresponded to withering humidity. To study the growth of seedlings in thickness, the stem diameters were measured at a height of 10 cm. The Michaelis–Munten equation was used as a basis for the mathematical description of the dependence of photosynthesis on FAR. We used this equation in a modified form [Kaibeyainen, 2009]: A = Am·Q/(Q + KM) + Ad. (1) To evaluate the efficiency of photosynthesis, we used the angular coefficient of the tangent (a) to the curve of the function (1) at the point corresponding to KM. From a physical point of view, this coefficient reflects the rate of change in photosynthesis when the headlights change by one unit. RESULTS Figures 3, 4, 5 show graphs showing the daily dynamics of photosynthesis and FAR of seedlings growing on SA1, SA2, SA3. Figure 6 shows graphs showing the daily dynamics of photosynthesis and FAR of watered and non-watered seedlings. The soil moisture under the watered seedlings was ~25.1%, under the non-watered ones - ~8.0%. Photosynthesis of watered seedlings was well associated with FAR, r = 0.84 (for non-watered seedlings, r = -0.34). Fig. 7 shows the values of photosynthesis depending on the FAR, the curves approximating these values obtained according to (1), and tangents to these curves at points corresponding to KM. The indicators characterizing the photosynthetic features of the leaves of seedlings obtained according to (1) are summarized in Table.1. Figure 8 (a) shows the dynamics of the growth of the studied plants by the diameter of the trunk, and Figure 8 (b) shows its derivative, showing the rate of growth per day. DISCUSSION In the morning, the daily dynamics, Fig. 3-5, were characterized by a high degree of association of photosynthesis with FAR, as well as a rapid increase in the values of photosynthesis to maximum values. At the same time, saplings growing on SA1 had a high degree of association of photosynthesis with FAR and in the evening hours, with the decline of FAR. In the midday hours, except for SA2 seedlings, the values under consideration were not associated, and the midday depression of photosynthesis was clearly traced on the daily curves. At the same time, on SA3 seedlings, midday depression was trace...
PubDate: 2023-10-01
DOI: 10.18822/edgcc429889
Issue No: Vol. 14, No. 2 (2023)
- Moscow region’s swamp forests mapping for inventory of CH4 and CO2
fluxes from soil.
Authors: D. V. Ilyasov, S. Y. Mochenov, A. I. Rokova, M. V. Glagolev, I. V. Kupriianova, G. G. Suvorov, A F Sabrekov, I. E. Terentieva
Pages: 116 - 132
Abstract: Introduction. Methane and carbon dioxide are the most important greenhouse gases, the increase in the concentration of which in the atmosphere is the main cause of climate change [Taylor and Penner, 1994; Drösler et al., 2014; Hoegh-Guldberg et al., 2019]. In addition to relatively constant sources of methane and carbon dioxide into the atmosphere (such as oligotrophic bogs of the boreal zone), there are sporadic sources (SS): intermittently flooded floodplains, boreal swamp forests, some intermittently swamp forests, etc. Despite the variability of SS as sources of methane, CH4 fluxes in floodplains and in swamp forests can reach 0.1–12.5 [Whalen et al., 1991; Van Huissteden et al., 2005; Terentieva et al., 2019] and 0.7 – 17.1 mgC m-2 h-1 [Moore and Knowles, 1990; Ambus and Christensen, 1995; Aronson et al., 2012; Koskinen et al., 2016; Glagolev et al., 2018], respectively. These values are comparable, and exceed those observed in bogs under certain conditions (a combination of soil moisture and temperature, and other factors) [Gulledge and Schimel, 2000; Vasconcelos et al., 2004; Ullah and Moore, 2011; Shoemaker et al., 2014; Christiansen et al., 2017; Torga et al., 2017; Glagolev et al., 2018; Mochenov et al., 2018]. Unfortunately, in Russia, studies of CH4 and CO2 fluxes from sporadic sources are extremely limited (one-time measurements were performed without reference to spatial, seasonal, and interannual variability of conditions) and were carried out mainly in Western Siberia [Sabrekov et al., 2013; Mochenov et al., 2018; Glagolev et al., 2018; Terentieva et al., 2019] and the European part of Russia [Kuznetsov and Bobkova, 2014; Ivanov et al., 2018; Glukhova et al., 2021; Glukhova et al., 2022]. In general, medium-scale (at the Federal subject level) studies of bogs and forests in Russia have not been carried out in all regions, although they are of particular interest due to the possibility of maintaining a balance between the detailing of estimates and the magnitude of spatiotemporal coverage [Zatsarinnaya and Volkova, 2011; Grishutkin et al., 2013; Baisheva et al., 2015; Ilyasov et al., 2019; Suslova, 2019]. Besides, estimates made throughout the country require clarification at the regional level [Vompersky et al., 2005]. The aim of our work was the simplest inventory of swamp forests of the Moscow region as sources of CH4 and CO2 using GIS mapping and field measurements. Objects and methods. The basis for the map of swamp forests of the Moscow region (hereinafter, by this term we mean the total territory of Moscow and the Moscow region) was a mosaic of 6 Landsat-8 satellite images. The mapping was carried out using the Supervised Classification algorithm in the Multispec program (Purdue Research Foundation, USA). For each decryption class, at least 7 training polygons were set and the classification module was launched using the maximum likelihood estimation. After the classification, the decryption classes were combined into typological ones: “forest” (automorphic forests), “water surfaces” (rivers, lakes, other water bodies), “swamp forest” (excessively moist forests with a water table level (WTL), predominantly located on the soil surface or close to it) and “wet forest” (excessively moist forests with predominant WTL below the soil surface). We considered the classes of swamp forests and wet forests, regardless of the presence or absence of peat layer in them: the key criterion was WTL. To assess the accuracy of the classification, an error matrix was compiled. For that purpose, on the resulting map, the first operator identified 75 points evenly distributed in space within each typological class; the coordinates of these points without specifying the belonging to the class were randomly sorted and passed to the second operator. Further, the points were assigned to one of the mapped classes based on “blind” visual expert interpretation using ultra-high resolution satellite images. The overall classification accuracy was determined as the ratio of the sum of points, whose mapped and real classes coincide, to the total number of points (Table 1). Measurements of carbon dioxide and methane fluxes were carried out from 2019 to 2022 in the Dorokhovo mixed black alder moist grass forest, located 66 km west of the border of Moscow, using the static chamber method [Hutchinson and Mosier, 1981; Terent'eva et al., 2017]. Opaque chambers were used in the measurements, so the term “CO2 flux” used in the paper implies the sum of the respiration of the soil-grass-moss cover. The calculation of the annual flux of methane and carbon dioxide from the swamp forests of the Moscow region was performed seasonally using the simplest inventory method [Glagolev, 2010]: ФОРМУЛА НЕ РИСУНОК where Aij – is the area (m2) occupied by the i-th source type in the j-th region; fi – is the surface flux density (mgC m-2 h-1), characteristic of the i-th source type; Tj – is the duration of the emission period (hour), characteristic of the j-th region. The duration of the methane emission period within individual seasons was taken on the basis of hydrothermal coefficients and the radiation index as follows: summer – 122 days (from June to September inclusive), autumn – 76 days (from October to mid-December), winter – 90 days (from mid-December to mid-March), spring – 77 days (from mid-March to the end of May). The surface flux density was calculated as the medi...
PubDate: 2023-10-01
DOI: 10.18822/edgcc568952
Issue No: Vol. 14, No. 2 (2023)
- (THE FIFTH ALL-RUSSIAN SCIENTIFIC AND PRACTICAL CONFERENCE “SAFE NORTH
– CLEAN ARCTIC”)
Authors: G. M. Kukurichkin
Pages: 132 - 139
Abstract: Пятая Всероссийская научно-практическая конференция (с международным участием) «Безопасный Север – чистая Арктика» состоялась 13-14 апреля 2023 г. на базе Сургутского государственного университета. Этот традиционный форум объединил 280 участников из различных регионов России, а также коллег из Казахстана. Тематика выступлений (всего более 80 докладов) охватывала широкий круг вопросов: изучение и сохранение биоразнообразия, создание биоресурсных коллекций, экологический мониторинг, экология человека, рациональное природопользование, формирование комфортной и безопасной среды для жизнедеятельности человека в условиях северных регионов. К 85-летию со дня рождения основателя кафедры экологии Сургутского госуниверситета был организован круглый стол «Научное наследие профессора Ю.В. Титова (1938-2001)». Участники круглого стола обсудили роль Ю.В. Титова как организатора науки и образования в Югре.
PubDate: 2023-11-08
DOI: 10.18822/edgcc623119
Issue No: Vol. 14, No. 2 (2023)
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