Vegetation-permafrost relationships in the zone of sporadic permafrost distribution in the Kamchatka Peninsula

Studies on vegetation and permafrost table depth in the zone of sporadic permafrost distribution in the Uksichan River valley (the central Kamchatka Peninsula) have provided evidence that these components of biogeocenosis are interrelated and develop coordinately. In open larch forests with green forest mosses dominating in the ground vegetation layer, the permafrost table lies approximately 60 cm below the soil surface. When the ground vegetation layer is dominated by sphagnums, the permafrost table rises to 40–20 cm. In areas with a dwarf shrub-lichen ground layer, the soil thaw depth increases. A hypothesis is proposed that cyclic successional replacement of plant communities may take place in open larch forests on permafrost soils, including four consecutive stages with dominance of green mosses, sphagnums, lichens, and dwarf shrubs. In areas disturbed by fires, pioneer moss or herbaceous communities develop in the ground layer.     

Traces of DU in samples of environmental bio-monitors (non-flowering plants, fungi) and soil from target sites of the Western Balkan region

This paper reports results of gamma and alpha spectrometric measurements for mosses, lichens, fungi and soil samples from areas in the Balkans targeted by depleted uranium (DU). Samples were collected in 2002 and 2003 in the vicinity of several villages, principally Han Pijesak (Bosnia and Herzegovina, hit by DU in 1995) and Bratoselce (South Serbia, hit by DU in 1999) and in lesser numbers from Gornja Stubla, Kosovo (which is identified as a high natural radon/thoron area) and Presevo close to the Kosovo border. In the course of gamma spectrometric measurements some results suggested samples with unusual high uranium contents which might be considered to be a signature for the presence of DU, although many samples had very high detection limits. Alpha spectrometric measurements directly proved the presence of DU for five samples, all from directly targeted places. These were samples of mosses, lichens and soil. For some samples homogeneity tests were applied which showed a rather even distribution of DU in these samples. No trace of DU was found in any sample from a dwelling.     

Effect of Extractive Compounds from Lichens and Mosses on the Development of Basidiospores and Mycelium of Tinder Fungus

It has been shown that extracts from the thalli of lichens and mosses have an adverse effect on the viability and germination of spores and suppress the asexual reproduction of the haploid mycelium. The dikaryotic mycelium and its conidial spores are more resistant to the action of extractive compounds from lichens and mosses.     

137Cs and 40K in the terrestrial vegetation of the Yenisey Estuary: landscape, soil and plant relationships

Plant species, forming important components of Arctic food chains and of interest from a monitoring perspective, were studied at 36 plots representing flood plain and terrace landscapes of the Yenisey River and Estuary from its upper delta to the gulf. (137)Cs contamination densities at the plots varied from 0.35kBq/m(2) (central delta, sandy riverside plot) to 88kBq/m(2) (the upper delta plot) indicating both global and regional sources of anthropogenic pollution. Cs-137 levels in plants were within the range expected from global fallout inputs and varied from 31 to 140Bq/kg d.w. increasing in dominant groups in the order: grasses相似文献   

Influence of Clear Fellings on the Bryophyte Component of the Broad-leaved Forests of the Bashkir Cis-Ural Region

The change in the composition of the bryophyte component of succession communities that occur in the process of natural regeneration at the site of clear felling of the indigenous elm—maple–linden forests of the Bashkir Cis-Ural Region has been studied. The vulnerability of species to the consequences of felling is affected by their substrate confinement, ecological amplitude in relation to the factors of temperature, humidity, variability of soil moisture, and type of life strategy. In the secondary aspen forests, the absence or low constancy of nemoral epiphytic and ground mosses was noted.     

Composition of plant communities in natural and technogenically disturbed ecotopes on watersheds of the Yamal Peninsula: Floristic diversity

Specific features in the overgrowing of technogenically disturbed areas with completely destroyed soil and plant cover (a sand pit, a causeway, and an off-road vehicle trail) have been studied in the environs of the Bovanenkovo Oil-Gas Condensate Field. It is shown that the vegetation of natural ecotopes and ecotopes disturbed approximately 20 years ago is characterized by a relatively high similarity in the composition of vascular plants. The total species composition of plant communities (including mosses and lichens) and their structure show a considerable loss of floristic and phytocenotic diversity.     

Productivity of mosses and organic matter accumulation in the litter of sphagnum larch forest in the permafrost zone

Productivity of the moss cover and necromass accumulation in the litter of a sphagnum larch forest have been estimated on the basis of tree age. It has been shown that the total carbon stock in the litter of a 100-year-old stand, including organic matter not destroyed by fire, exceeds the corresponding value for the tree stand itself by more than an order of magnitude. The accumulation of organic matter on the soil surface inhibits the growth of larch. In particular, this factor impairs hydrothermal conditions in the soil and causes a rise of the permafrost table; as a consequence, lower layers of the root system die off.     

Analysis of Factors Determining Accumulation of 137Cs by Woody Plants

The accumulation of ¹³⁷Cs by coniferous (Pinus sylvestris) and deciduous (Betula pendula) trees was studied in the area contaminated with radioactive products after the Chernobyl accident. The availability of ¹³⁷Cs to woody plants is determined by its vertical distribution in the soil profile, the proportion of its exchangeable form, and the distribution of tree roots in the soil. The index of biological availability of ¹³⁷C in the soil is proposed, and its linear dependence on the coefficients of ¹³⁷Cs transfer to wood is demonstrated.     

Aquatic mosses as a monitoring tool for 137Cs contamination in streams and rivers-a field study from central southern Norway

Mosses are frequently used as biomonitors for trace element pollution in the aquatic environment. The purpose of this study was to assess their usefulness as a tool in monitoring and in regional surveys of radioactive contamination. Specimens of the aquatic mosses, Fontinalis antipyretica and F. dalecarlica, were transplanted from non-contaminated areas to streams and rivers in the Norwegian Jotunheimen Mountains and neighbouring lowland areas that had received radioactive fallout after the Chernobyl accident. Equilibrium concentrations of 137Cs in the exposed mosses were reached after a few weeks. Two series from 20 streams in 1994 and 1996 show linear correlations between activities in water and moss samples and biomagnification ratios of 10(4) - 10(5). We conclude that mosses are better suited for monitoring purposes than water samples, because they provide values integrated over weeks while the radioactivity in surface waters can be subject to rapid variations according to hydrological events. The activity concentrations in aquatic mosses can be easily measured with good precision even when aqueous concentrations are below the limit of detection. Use of aquatic mosses also reduces the logistic problems of transporting large volumes of water, especially in areas inaccessible by road.     

Possible use of terrestrial mosses in detection of atmospheric deposition of 7Be over large areas

The activities of naturally occurring radionuclides (7)Be, (214)Bi and (210)Pb were measured in samples of terrestrial mosses collected in Serbia (42 degrees 26'19'N-45 degrees 23'12'N). The objective of this work was to establish if detectable amounts of (7)Be and (210)Pb can be found in mosses and investigate their possible variabilities over some area. These are the first steps in introducing mosses as a medium in possible monitoring of spatial distribution of (7)Be atmospheric deposition. The mean value of 360 Bq/kg of (7)Be activity was found in collected moss samples and some nonuniformity in spatial distribution (a 2.8-fold range in measured values) was observed.     

Heavy metal contents of epiphytic acrocarpous mosses within inhabited sites in Southwest Nigeria

The levels of the metals Pb, Zn, Cu, Cd, Ni, Mn, and Fe accumulated in acrocarpous mosses within inhabited parts of villages and towns in the southwest region of Nigeria were determined, and then used for a classification of the area into relative pollution zones. Ibadan City was found to be the most polluted in the study area. Other zones of “low” and “medium” polluted villages and towns were identified. The zonations based on metal levels in these mosses were to some extent similar to that already obtained in a separate study of the same area with epiphytic forest mosses. The enrichment factors show that the gradients between zones of different pollution levels were higher in mosses within the inhabited sites.     

A model testing study for the transfer of radioactivity to fruit

This paper compares predictions of the foodchain model SPADE with experimental data for the transfer of (134)Cs and (85)Sr to strawberry plants following acute foliar and soil contamination. The transfer pathways considered in this exercise included direct deposition to fruit, leaf-to-fruit, soil-to-leaf and soil-to-fruit transfers. Following foliar contamination, the difference between predicted and measured radionuclide activity values varied between a factor of 0.5-10 for fruit and 4.5-7 for leaf. Following soil contamination, the difference between predicted and measured values varied between a factor of 3-74 for fruit and 32-44 for leaf. In all cases the difference between measured and predicted values was smaller for (85)Sr than (134)Cs. Measured and predicted activities were higher for leaf than fruit. Both measured and predicted (134)Cs concentrations in fruit and leaf are higher when deposition occurs at ripening than at anthesis. These results confirm the need for more data on fruit, even for Cs and Sr, to support models in predicting the transfer of radionuclides to fruit crops. Ongoing research projects funded by the UK Food Standards Agency aim to provide some data on radionuclide transfer to herbaceous, shrub and tree fruits, which will help improve radiological assessment models in order to provide better protection for consumers.     

长江源区基于坡面尺度的土壤水热过程模拟研究

长江源多年冻土区土壤水热传输过程机理与模拟,是广泛关系到高原生态环境保护恢复和区域水文过程的关键科学问题。因此,以GEOtop模型为研究平台,以长江源不同植被盖度下（裸地、30%、65%和92%）高寒草甸的观测数据为基础,检验模型对土壤水热迁移过程的描述与模拟精度。总体而言,GEOtop模型需要率定的参数较少,从而减少模型模拟的不确定性,提高了模拟精度。对不同植被盖度下土壤温度、水分和实际蒸散发模拟的NSE 系数基本达到08,表明模型能准确模拟高寒生态系统土壤的水热传输过程,可以作为长江源区土壤水热过程的有效模拟工具     

Radiocesium accumulation in mosses from highlands of Serbia and Montenegro: chemical and physiological aspects

The aim of this work was (i) to determine the activity levels of 137Cs in mosses from highland ecosystems of Serbia and Montenegro, (ii) to find out if radiocesium is associated with essential biomacromolecules, and (iii) to investigate 137Cs distribution among intracellular compartments. It was found that biomolecules of mosses do not bind significant amounts of radiocesium (2.3-3.3% of the absorbed 137Cs), a behavior that was independent of the moss species. Cellular fractionation of mosses showed that membranes are the primary 137Cs-binding sites at the cellular level. They contained 26.1-43.1% of the initial radiocesium activity. It seems that 137Cs-binding molecules in different mosses are of similar chemical nature, and their distribution between various cellular compartments is not species specific.     

Current Contents of 90Sr and 137Cs in the Moss–Lichen Cover of Piedmont and Mountain Landscapes of the Northern Urals

The contents of long-lived artificial radionuclides, ⁹⁰Sr and ¹³⁷Cs, were determined in lichens and mosses of different taxa and in the samples of moss–lichen cover taken from the mountain and lowland plant communities of the Northern Urals. The effects of Chernobyl fallout and the dynamics of radionuclide contents in lichens and mosses were analyzed. The concentration of ¹³⁷Cs in the moss–lichen cover was higher in the mountain ecosystems than in the lowland plant communities.     

Prospects of using mosses (<Emphasis Type="Italic">Fontinalis antipyretica</Emphasis> Hedw. and <Emphasis Type="Italic">Pylaisia polyantha</Emphasis> (Hedw.) Bruch et al.) as indicators of environmental contamination with heavy metals

The contents of Al, Ti, Fe, Cr, Cu, Zn, As, Se, Cd, Pb, and rare earth elements (REEs) were determined in mosses (the hydrophyte Fontinalis antipyretica and the epiphyte Pylaisia polyantha) by the inductively coupled plasma-mass spectrometry (ICP-MS) method. These plants were used for estimating the spatial distribution of heavy metals (HMs) in the basins of small and medium rivers of Vologda and Kostroma oblasts (Russia). It was shown that water mosses are good indicators of REEs and epiphytic mosses, of the pollutant metals Cu, Zn, Se, and Pb. The epiphytic and hydrophytic mosses did not differ in the macroelement (Al, Ti, and Fe) content.     

Radioactivity measurements in moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis) samples collected from Marmara region of Turkey

The present study was conducted to compare the ¹³⁷Cs, ⁴⁰K, ²³²Th, and ²³⁸U activity concentrations in epigeic moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis). The activity levels in 37 moss and 38 lichen samples collected from the Marmara region of Turkey were measured using a gamma spectrometer equipped with a high purity germanium (HPGe) detector. The activity concentrations of ¹³⁷Cs, ⁴⁰K, ²³²Th, and ²³⁸U in the moss samples were found to be in the range of 0.36-8.13, 17.1-181.1, 1.51-6.17, and 0.87-6.70 Bq kg⁻¹ respectively, while these values were below detection limit (BDL)-4.32, 16.6-240.0, 1.32-6.47, and BDL-3.57 Bq kg⁻¹ respectively in lichen. The average moss/lichen activity ratios of ¹³⁷Cs, ⁴⁰K, ²³²Th, and ²³⁸U were found to be 1.32 ± 0.57, 2.79 ± 1.67, 2.11 ± 0.82, and 2.19 ± 1.02, respectively. Very low ¹³⁷Cs concentrations were observed in moss and lichen samples compared to soil samples collected from the same locations in a previous study. Seasonal variations of the measured radionuclide activities were also examined in the three sampling stations.     

Biomonitoring persistent organic pollutants in the atmosphere with mosses: Performance and application

Persistent organic pollutants (POPs) have aroused environmentalists and public concerns due to their toxicity, bioaccumulation and persistency in the environment. However, monitoring atmospheric POPs using conventional instrumental methods is difficult and expensive, and POP levels in air samples represent an instantaneous value at a sampling time. Biomonitoring methods can overcome this limitation, because biomonitors can accumulate POPs, serve as long-term integrators of POPs and provide reliable information to assess the impact of pollutants on the biota and various ecosystems. Recently, mosses are increasingly employed to monitor atmospheric POPs. Mosses have been applied to indicate POP pollution levels in the remote continent of Antarctica, trace distribution of POPs in the vicinity of pollution sources, describe the spatial patterns at the regional scale, and monitor the changes in the pollution intensity along time. In the future, many aspects need to be improved and strengthened: (i) the relationship between the concentrations of POPs in mosses and in the atmosphere (different size particulates and vapor phases); and (ii) the application of biomonitoring with mosses in human health studies.     

Quantification of transfer of U, Ra, Th, K and Cs in mosses of a semi-natural ecosystem

There is a lack of appropriate data on transfer of some radionuclides on many terrestrial biota groups. To expand the available data concentration ratios of ²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs in mosses are presented in this paper. The relationship between concentration ratios of radionuclides and physicochemical characteristics of the underlying soil was also investigated. The data on concentration ratios obtained here will provide a useful addition to the currently used database of transfer parameters, particularly for natural radionuclides.     

Long-term dynamics of technogenic radionuclide concentrations in moss-lichen cover

Ample factual data has been used to analyze the long-term dynamics of ⁹⁰Sr and ¹³⁷Cs concentrations in moss-lichen cover. The stocks of radionuclides in lichens, mosses, and the moss-lichen cover of northern regions of the Urals and Siberia has been estimated for the first time. The data on recent ranges of ⁹⁰Sr and ¹³⁷Cs concentrations in lichens and mosses can serve as a basis for determining the background levels of radionuclide contamination for long-term monitoring and prognostic radioecological studies.