Levels and Distribution of Petroleum Hydrocarbons in the Coastal Waters and Sediments of the United Arab Emirates in the Arabian Gulf and the Gulf of Oman

The levels and distributions of petroleum hydrocarbons incoastal waters and sediments of the United Arab Emirates (U. A. E.) along theArabian Gulf and the Gulf of Oman were investigated. Oil concentrations in the waters ofthe U. A. E. were below the 15 μg L^-1 and ranged from 1.6 to 13 μg L^-1.Petroleum hydrocarbons showed different pattern of distribution in the Arabian Gulf and the Gulf of Oman withmore or less similar values. Horizontal distribution of petroleum hydrocarbons atthe Arabian Gulf showed significant differences between most sites. At the Gulf ofOman, similar oil concentrations were measured at different sites. Meanwhile,vertical distributions of petroleum hydrocarbons indicated higher concentrations atsurface layers of the Arabian Gulf compared to bottom layers. Whereas, more or less similarconcentrations were measured at the Gulf of Oman. The concentration of petroleum hydrocarbons in marinesediments varied from 2.5 to 8.2 μg g^-1 (dry sediment weight), with higher concentrations at theArabian Gulf compared to the Gulf of Oman. The pattern of distribution for petroleumhydrocarbons in marine sediments resembled to some extent the distribution of organiccarbon in marine sediments. The study revealed that the concentrations ofpetroleum hydrocarbons in waters and sediments of the investigated area are not highcompared to other areas of the world.     

渭干河上游流域近60年的入库水沙变化特征及趋势分析

研究干旱半干旱地区多沙河流的水沙特性及趋势，对流域内水沙调控、水沙预测具有重要意义。基于宏观(微观)的角度来详细研究干旱半干旱地区多沙河流的水沙特性及趋势，以期为流域内水沙调控、水沙预测提供理论帮助。应用累积距平法、ITA法和ITA-CB法计算克孜尔水库入库流量、入库输沙率，并分别从年内、年际、年代际3个尺度系统地分析流量、输沙率的变化特征与趋势。结果表明：(1)年内水沙分布特征高度相似，二者的最高值均分布在7月，其最低值分别分布在3月和1月，年际尺度上波动性强且差异明显；(2)年度入库流量呈现上升趋势且有增加倾向，夏季表现为上升趋势且存在减弱倾向，其中高值区升高趋势减弱，需要注意干旱的极端气候；(3)年度输沙率呈上升趋势，季度尺度下的趋势特征均表现为下降趋势，其中夏秋两季下降趋势有减弱倾向，冬季出现增强倾向。与传统分析方法相比，ITA与ITA-CB方法能够有效识别出序列内部间存在的微观趋势，有助于详细分析区域水沙的变化特征。     

Diversity and dominance of crop plantations in the agroecosystems of the Kujawy and Pomorze region in Poland

Abstract

The Kujawy and Pomorze Province with 127 rural and municipal-and-rural communes in 19 districts is a typical agricultural region, with the highest plant farming intensity in Poland. The diversity and dominance of crop plantations in the agroecosystems in communes were calculated based on percentage share of 21 kinds of crops in the cropland structure. The algorithms applied in ecological research of biodiversity were used: the Shannon–Weaver diversity index (H’) and Simpson's dominance index (λ). The diversity (H’) of crops in arable land in the Kujawy and Pomorze Province ranges from 1.68 to 2.54. The diversity of crop plantations in the region was bigger in the communes in which there are: better soil, a higher share of arable land in the agricultural acreage and cropland in the arable land as well as with a higher share of barley, corn for grain and sugar beet in the cropland structure. The highest dominance index (λ) for crops in the whole province is 0.291. The index of dominance of agricultural crops in this region increases with an increase in the share of: woodland in the total area, meadows and pasture in the agricultural acreage and rye in the cropland structure.     

Comparative Analysis of the Number and Structure of the Complexes of Microscopic Fungi in Tundra and Taiga Soils in the North of the Kola Peninsula

The number, biomass, length of fungal mycelium, and species diversity of microscopic fungi have been studied in soils of the tundra and taiga zones in the northern part of the Kola Peninsula: Al-Fe-humus podzols (Albic Podzols), podburs (Entic Podzols), dry peaty soils (Folic Histosols), low-moor peat soils (Sapric Histosols), and soils of frost bare spots (Cryosols). The number of cultivated microscopic fungi in tundra soils varied from 8 to 328 thousand CFU/g, their biomass averaged 1.81 ± 0.19 mg/g, and the length of fungal mycelium averaged 245 ± 25 m/g. The number of micromycetes in taiga soils varied from 80 to 350 thousand CFU/g, the number of fungal propagules in some years reached 600 thousand CFU/g; the fungal biomass varied from 0.23 to 6.2 mg/g, and the length of fungal mycelium varied from 32 to 3900 m/g. Overall, 36 species of fungi belonging to 16 genera, 13 families, and 8 orders were isolated from tundra soils. The species diversity of microscopic fungi in taiga soils was significantly higher: 87 species belonging to 31 genera, 21 families, and 11 orders. Fungi from the Penicillium genus predominated in both natural zones and constituted 38–50% of the total number of isolated species. The soils of tundra and taiga zones were characterized by their own complexes of micromycetes; the similarity of their species composition was about 40%. In soils of the tundra zone, Mortierella longicollis, Penicillium melinii, P. raistrickii, and P. simplicissimum predominated; dominant fungal species in soils of the taiga zone were represented by M. longicollis, P. decumbens, P. implicatum, and Umbelopsis isabellina.     

Seasonal changes in the communities of microorganisms and algae in the litters of tree plantations in the steppe zone

Specific structural and dynamic parameters of communities from various ecological and trophic groups of microorganisms and algae in the litter of artificial tree stands were studied using the example of the Staro-Berdyansky Forest in the steppe zone of Ukraine. The composition of the communities was shown to vary by seasons and depend on the forest-forming woody species. In spring, in all the litters, the maximal number of actinomycetes and aminotrophs was recorded; in the leaf litter, the number of phosphate-mobilizing organisms was also the largest. In summer, the development of cellulolytic organisms, ammonifiers, and nitrogen-fixers was intensified; in autumn, the number of micromycetes and oligotrophic organisms decreased. The composition of dominants, the species richness of algae and their abundance also varied by seasons. Representatives of the Chlorophyta division predominated. The highest species richness of algae was characteristic of the spring litter samples, and their number, for the spring and autumn ones. The positive correlation was established between the numbers of micromycetes and oligotrophs, micromycetes and algae. The negative correlation was found between the numbers of micromycetes and actinomycetes, cellulose-decompose bacteria and algae in the litters.     

Nutrient disturbances in forest trees and the nature of the forest decline in Quebec and Germany

The serious decline of forest trees in Quebec and adjacent areas of the U.S. parallel those observed in Germany. In certain locations, in both cases, K deficiency is now occurring on glacial tills and outwash soils and is associated with a low concentration of exchangeable K⁺ and a high molar ratio of exchangeable Ca⁺ ions to K⁺ ions in the soil. This deficiency results from the so-called Ca-K antagonism in which an increased concentration of Ca²⁺ ions blocks the entry of a reduced concentration of K. Mg deficiency is occurring on granitic soils and results from a low concentration of exchangeable Mg²⁺ and a high molar ratio of A1³⁺ ions to Mg²⁺ ions. The role of the parent rock, weathering reactions and atmospheric inputs are discussed in relation to the changes that have resulted from the cumulative effect of acid deposition. The changes in storage, transfer and losses of cationic nutrients in soil and trees can explain the development of these imbalances, which are still increasing, and are resulting in these forest declines.     

Transformation of the Bryansk Paleosol in Microdepressions in the Center of the East European Forest-Steppe during the Maximum of Valdai Glaciation and in the Holocene

Eurasian Soil Science - Recent and Late Pleistocene soils of the central forest-steppe in the East European Plain have been studied. The main objective of the work is to reveal changes in the...     

Mobility and breakdown of asulam in the soil and the possible impact on the environment

Asulam reaching the soil either directly as spray drift or as rain washings from bracken fronds would, due to its rapid mobility in soil, be expected to leach down the soil profile into the drainage water and thereby contaminate streams and water catchments. The mobility of asulam in soil is influenced by pH, where undissociated asulam will leach less rapidly than the associated form (asulam pK_a 4·82). This is particularly relevant in the case of bracken as it can grow satisfactorily over a wide range of pH values (3·6 – 7·6). Adsorption coefficients expressed as Kd values [(μg asulam/g soil)/(μg asulam/ml solution)] were 2·54, 1·94 and 0·96 at pH readings of 4·0, 4·3 and 4·9 respectively. Another factor involved, the breakdown of asulam, was shown to be temperature dependent, 30·95, 7·65 and 2·50% remaining after 28 days at 5, 18 and 25°C respectively, thus underlining the influence of geographical regions and climatic conditions on asulam behaviour.     

Reconstruction of the paleotemperature and precipitation in the Pleistocene according to the isotope composition of humus and carbonates in loess on the Russian Plain

The isotope composition of carbon and oxygen in humus and carbonates has been studied in the Pleistocene loess and soil of the Russian Plain in order to reconstruct the paleoclimatic parameters during the time of their formation. It is established that most of the buried soils were formed upon the mean annual temperature exceeding the modern temperature by 1–2°C. The climate aridity (the portion of C4 plants in the ecosystem) varied from 0 to 25%. It is shown that the isotope composition of carbon and oxygen in the humus and carbonates may be a reliable indicator of the paleoclimate (i.e., the paleotemperature, paleoprecipitation, and aridity dynamics). An isotope procedure of culling soil samples unsuitable for paleoclimatic reconstruction is proposed.     

论全域土地综合整治的水土保持理念和生态文明价值

近年来,全域土地综合整治与生态修复工程协同并进的发展模式在江浙地区的环境治理实践中取得了显著成效。以衢州市全域土地综合整治实例为基础,阐述了全域土地综合整治实施过程中的水土保持理念,深入剖析了土地整治的生态文明价值,积极探索了推进农村环境高水平保护的新举措,旨在为类似地区提供可复制、可推广的环境治理经验,全面推进水土保持生态文明建设。     

Total carbon and nitrogen in the soils of the world

The soil is important in sequestering atmospheric CO₂ and in emitting trace gases (e.g. CO₂, CH₄ and N₂O) that are radiatively active and enhance the ‘greenhouse’ effect. Land use changes and predicted global warming, through their effects on net primary productivity, the plant community and soil conditions, may have important effects on the size of the organic matter pool in the soil and directly affect the atmospheric concentration of these trace gases. A discrepancy of approximately 350 × 10¹⁵ g (or Pg) of C in two recent estimates of soil carbon reserves worldwide is evaluated using the geo-referenced database developed for the World Inventory of Soil Emission Potentials (WISE) project. This database holds 4353 soil profiles distributed globally which are considered to represent the soil units shown on a ¹/₂° latitude by ¹/₂° longitude version of the corrected and digitized 1:5 M FAO–UNESCO Soil Map of the World. Total soil carbon pools for the entire land area of the world, excluding carbon held in the litter layer and charcoal, amounts to 2157–2293 Pg of C in the upper 100 cm. Soil organic carbon is estimated to be 684–724 Pg of C in the upper 30 cm, 1462–1548 Pg of C in the upper 100 cm, and 2376–2456 Pg of C in the upper 200 cm. Although deforestation, changes in land use and predicted climate change can alter the amount of organic carbon held in the superficial soil layers rapidly, this is less so for the soil carbonate carbon. An estimated 695–748 Pg of carbonate-C is held in the upper 100 cm of the world's soils. Mean C: N ratios of soil organic matter range from 9.9 for arid Yermosols to 25.8 for Histosols. Global amounts of soil nitrogen are estimated to be 133–140 Pg of N for the upper 100 cm. Possible changes in soil organic carbon and nitrogen dynamics caused by increased concentrations of atmospheric CO₂ and the predicted associated rise in temperature are discussed.     

探讨动画课件在教学中的利与弊

随着IT事业的不断发展,运用动画技术制作的多媒体课件已逐渐应用于教学中。计算机辅助教学（CAI）是教育技术的重要组成部分,它的产生和发展对促进教育、教育技术的变革与发展有着巨大的推动作用。     

知识传播和创新是图书馆的重要职能

知识传播是图书馆的重要职能,创新是社会发展的需要。知识创新促进了知识传播,可适应和谐社会的发展。     

Assessment of the living and total biomass of microbial communities in the background chestnut soil and in the paleosols under burial mounds

The contents of phospholipids and carbon of the total microbial biomass were determined in the modern chestnut soil and in the paleosols buried under mounds of the Bronze and Early Iron Ages (5000–1800 years ago) in the dry steppe of the Lower Volga River basin. Judging from data on the ratio between the contents of phospholipids and organic carbon in the microbial cells, the carbon content of the living microbial biomass was calculated and compared with the total microbial biomass and total organic carbon in the studied soils. In the background chestnut soil, the content of phospholipids in the A1, B1, and B2 horizons amounted to 452, 205, and 189 nmol/g, respectively; in the paleosols, it was 28–130% of the present-day level. The maximum content was measured in the paleosols buried 5000 and 2000 years ago, in the periods with an increased humidity of the climate. In the background chestnut soil, the total microbial biomass was estimated at 5680 (the A1 horizon), 3380 (B1), and 4250 (B2) μg C/g; in the paleosols, it was by 2.5–7.0 times lower. In the upper horizons of the background soil, the portion of the living microbial biomass in the total biomass was much less than that in the paleosols under the burial mounds; it varied within 8.5–15.3% and 15–81%, respectively. The portion of living microbial biomass in the total organic carbon content of the background chestnut soil was about 4–8%. In the paleosols buried in the Early Iron Age (2000 and 1800 years ago), this value did not exceed 3–8%; in the paleosols of the Bronze Age (5000–4000 years ago), it reached 40% of the total organic carbon.     

Changes in soil acidity and the size and activity of the microbial biomass in response to the addition of sugar mill wastes

The effects of additions of three wastes from sugar mills on the properties of two acid soils were investigated. The wastes used were boiler ash and filter cake from a conventional mill and fly ash from a new mill, where filter cake is burnt. Additions of each of the wastes raised soil pH, reduced concentrations of exchangeable Al and total and monomeric Al in soil solution and increased maize yields in a pot experiment. Microbial biomass C and the percentage of organic C present as microbial biomass were decreased by additions of wastes but the effect was less marked at the higher rate of addition. Although basal respiration was decreased or unaffected by the lower rate of addition of wastes it was increased by the higher rate. The metabolic quotient increased in the order: control4⁺ and NO₃^- accumulated during incubation and arginine ammonification rate were all less at the higher rate of addition of each of the wastes. This was attributed to microbial immobilization of mineral N and arginine due to the wide C/N ratio of light fraction organic matter present in the study soil. It was concluded that all three waste materials were effective liming materials but their effect on soil microbial activity was complex.     

河套灌区农田防护林网内土壤季节性冻融过程及水盐运移

为了解内蒙古河套灌区农田防护林内冻融期土壤水盐状况及运移规律,在2020年10月至2021年4月实测土壤水分、盐分、温度及相关气象数据,并进行相关分析.结果 表明:土体表层温度波动较大,随土层深度加深土体温度变化逐渐平缓.冻结期气温下降速率低于消融期气温回升速率,加之土壤温度变化的滞后性,冻结期比消融期长10天左右.季...     

Fertilization of declining conifer stands in the vosges and in the French Ardennes

Twenty fertilization experiments were set up in 1985 and 1986 in the Vosges mountains, using mostly calcareous or Mg fertilizers, in order to verify whether fertilization can attenuate defoliation and yellowing recently recorded in Silver fir and Norway spruce. In the Ardennes, a fertilization experiment set up in Norway spruce stands prior to the appearance of yellowing was assessed. In these areas, the total acid deposition is about 2 kg eq H⁺ ha^–1 yr^–1. Nitrogen deposition is much more important in the Ardennes (52 kg N ha^–1 yr^–1 in form of wet and dry deposition) than in the Vosges (16 kg N ha^–1 yr^–1). The results in the eight adult stands showed no uniform reaction to the treatments. Spontaneous improvement, further deterioration independently of the treatment, as well as a positive reaction to fertilization were observed. Additional N or P fertilization sometimes had a beneficial effect on Ca or Mg treatments. The selection of the stands with the best response turns out to be difficult, as the nutrient contents of needles alone seem not to be a satisfactory criterion for selection. Young plantations reacted positivley to the treatments. Soluble Mg fertilizer leads to an immediate response. Low solubility Ca-Mg fertilizers (Ca-Mg lime) did not produce reactions until three years after the application. In the Ardennes, in a 40 yr old spruce stand suffering from severe Mg deficiency, a Ca and Ca-phosphate fertilization applied 5 yr before yellowing appeared had positive effects on crown density, discoloration and wood production. Conversely, a single N fertilization in this experiment, as well as in a young plantation in the Vosges, had a marked negative effect on Mg nutrition, even at low levels.     

Fertilization of declining conifer stands in the Vosges and in the French Ardennes

Twenty fertilization experiments were set up in 1985 and 1986 in the Vosges mountains, using mostly calcareous or Mg fertilizers, in order to verify whether fertilization can attenuate defoliation and yellowing recently recorded in Silver fir and Norway spruce. In the Ardennes, a fertilization experiment set up in Norway spruce stands prior to the appearance of yellowing was assessed. In these areas, the total acid deposition is about 2 kg eq H⁺ ha⁻¹ yr⁻¹. Nitrogen deposition is much more important in the Ardennes (52 kg N ha⁻¹ yr⁻¹ in form of wet and dry deposition) than in the Vosges (16 kg N ha⁻¹ yr⁻¹). The results in the eight adult stands showed no uniform reaction to the treatments. Spontaneous improvement, further deterioration independently of the treatment, as well as a positive reaction to fertilization were observed. Additional N or P fertilization sometimes had a beneficial effect on Ca or Mg treatments. The selection of the stands with the best response turns out to be difficult, as the nutrient contents of needles alone seem not to be a satisfactory criterion for selection. Young plantations reacted positivley to the treatments. Soluble Mg fertilizer leads to an immediate response. Low solubility Ca-Mg fertilizers (Ca-Mg lime) did not produce reactions until three years after the application. In the Ardennes, in a 40 yr old spruce stand suffering from severe Mg deficiency, a Ca and Ca-phosphate fertilization applied 5 yr before yellowing appeared had positive effects on crown density, discoloration and wood production. Conversely, a single N fertilization in this experiment, as well as in a young plantation in the Vosges, had a marked negative effect on Mg nutrition, even at low levels.     

Local variation in climate and land use during the time of the major kingdoms of the Tigray Plateau in Ethiopia and Eritrea

The Tigray Plateau of Ethiopia and Eritrea is vulnerable to environmental change, yet environmental influences on the rise and fall of the civilizations that once existed there are almost unexplored. We sampled sections of gully walls for palaeoenvironmental proxies from two sites: 1) Adi Kolen on the southern outskirts of the Plateau's most developed former empire, the Aksumite, and 2) Adigrat near polities dating to at least ca. 3000 cal yr BP. A multi-proxy approach for examining local variation in palaeoenvironments was evaluated that included stable isotopic and elemental analyses (δ¹³C_SOM, δ¹⁵N, %TOC, and %TN) of soil, and charcoal identification. An increase in δ¹⁵N values from older soils in Adi Kolen (4400 cal yr BP) and Adigrat (2900 cal yr BP) until 1200 cal yr BP is not explained by changes in δ¹⁵N that occur with time in an unchanging environment. It may instead indicate an overall decrease in rainfall from the earlier times until 1200 cal yr BP. In one Adigrat section, the decreases in organic δ¹³C and increases in C/N molar ratios from older to younger soil could have resulted from changes that occur over time, per se. In the remaining sections, however, δ¹³C_SOM trends more likely reflect changes in the biomass of C₄ relative to C₃ plants (% C₄ biomass). Changes in% C₄ biomass may reflect climate and/or land use. Deciphering which may be aided by analyses of the other proxies. Identified charcoal suggests that both sites supported some juniper forest types until very recently but that forests may have been a more important and dynamic component of Adigrat's vegetation history than Adi Kolen's. If environment affected the trajectories of the kingdoms of the Tigray Plateau, these results suggest that the exact nature of the changes in climate differed among kingdoms. The kingdoms prior to 1200 cal yr BP may have been exposed to increasing aridity punctuated with relatively wetter intervals. Thereafter, general changes in climate are not apparent. Land clearing dynamics are likely to have had a more consistent effect on the trajectories of kingdoms than climate changes.     

安塞纸坊沟小流域投入产出规划预测研究

本文运用投入产出分析原理及方法以安塞试验区为例,诊断黄土高原沟壑区小流域的历史与现状,建立投入产出平衡表,通过计算机的运算来预测小流域经济的中期发展前景,从而把小流域治理规划的可行性建立在科学分析的基础上。这是一个有意义的尝试。