Effect of Climatic Changes on the Formation of Siberian Spruce Generations in Subglotsy Tree Stands of the Southern Urals

The correlation between climatic changes and the numbers of trees in the generations of Siberian spruce (Picea obovata Ledeb.) in subgoltsy tree stands of the Southern Urals was analyzed over the past 200 years. The results showed that the most abundant generations appeared in 1809–1816, 1821–1827, 1839–1845, 1850–1867, 1875–1887, 1891–1896, 1900–1904, 1911–1918, 1923–1932, 1944–1952, 1958–1966, and 1975–1995. Their formation proved to be related to the improvement of thermal conditions of the warm season during the five to seven years before and after the emergence of trees and conditions of the cold season in the year of their emergence, as well as to the periods of increased snow depth in late April in the years 27–32 of tree growth.     

Monitoring of Vegetation Development in Technogenically Disturbed Areas of the Usinskoe Oil Field

Vegetation development and changes in the characteristics of the substrate in technogenically disturbed sites in the Usinskoe oil field were monitored for ten years (1992–2002). It has been demonstrated that 86 species of vascular plants and 12 species of bryophytes constitute the vegetation formed on fill-up soils during the first stages of recovery succession. A succession of dominant species was observed in the tenth year of monitoring. Differences in plant composition on the ground surface of different technological zones of plots located in different landscapes are described.__________Translated from Ekologiya, No. 4, 2005, pp. 269–274.Original Russian Text Copyright © 2005 by Zheleznova, Kuznetsova, Evdokimova, Turubanova.     

Studying Trophic Relationships of the Bee Seladonia subaurata (Rossi) (Hymenoptera,Halictidae) by Analyzing Pollen from Nest Cells

Abstract–Pollen of 42 plant species from 17 families has been found in the food stores of Seladonia subaurata nests, with 61–86% of the pollen being accounted for by the Compositae. The foragers are characterized by strict flower preferences: more than 90% of the pollen in each cell belongs to two or three, sometimes four, plant species. At the eusocial stage of the existence of a colony, two or three foragers usually provision each cell. In especially large colonies, foragers are divided into groups and provision several cells during the day.     

Comparative Assessment of the Effects of Livestock Grazing and Periodic Cutting on Steppe Plants of Tuva

A comparative study of the effects of heavy grazing load and periodic low cutting of above-ground phytomass on three plant species—Carex pediformis, Iris humilis, and Artemisia frigida—was performed in central Tuva in 1985–1989. Similar changes in the size of anatomical structures and ecophysiological characteristics of steppe plants were observed under the impact of both factors. They included signs of accelerated aging combined with adaptive reactions aimed at the most rapid development of shoots after the cessation of stress.     

Three-dimensional modelling of the tide-induced dispersion of radionuclides in the sea

A three–dimensional marine dispersion model for radionuclieds has been developed. The model solves the three–dimensional hydrodynamic equations and, simultaneously, the three–dimensional advective–diffusive dispersion equations. Thus the tide–induced dispersion of radionuclides is obtained. The equations are solved using a finite difference explicit scheme using a time step of a few seconds with appropriate boundary conditions. As an example the model has been applied to study the dispersion of ¹³⁷Cs in the Irish Sea which is released from the nuclear fuel reprocessing plant at Sellafield. Tidal amplitudes and current profiles obtained with the model have been compared with observations in the Irish Sea: both sets of data are in good agreement. Observed and computed ¹³⁷Cs distributions in waters have also been compared. The model gives a good representation of the dispersion of this radionuclide in the Irish Sea.     

Impact of European legislation on marketed pesticides — A view from the standpoint of health impact assessment studies

The very significant impact of European legislation (Directive 91/414/EEC) on the authorization of plant protection products is reviewed herein, which has resulted in withdrawal of 704 active substances (AS) out of 889 assessed so far. The list of currently approved 276 AS includes 194 AS “existing” in the market before 1993 and 82 “new” AS introduced during the last 15 years. Results of toxicity characterization of the approved AS are also summarized, utilizing several well-known databases. Although significant data gaps exist for a rather large part of the approved AS, it is found that 84 AS are positive for at least one health effect (after chronic and/or acute exposure) including carcinogenicity, reproductive and neuro-developmental disorders, as well as endocrine disruption. The toxicity characterization results of this study are compared to those of recent assessments by other organizations (KemI, the Swedish Chemicals Agency, and the Pesticide Safety Directorate of the UK), where interpretation and use is made of AS “cut-off” criteria foreseen in new EU legislation. These studies report a comparatively smaller AS number with positive toxicity characterization. The possibility of some additional AS withdrawal in the near future, combined with the rather small rate of new AS introduction (approx. 5 per year) suggest that the list of approved AS over the next 10–15 years may not change very drastically. Consideration of the above trends is necessary and instructive in evaluating results of existing health impact assessment (HIA) studies, as well as in planning new ones. Due to the very drastic change in the number and type of marketed AS, that took place within the past 8–9 years, it is suggested that new HIA studies (based on epidemiological data after year 2000) should focus on a rather short time frame and, therefore, on appropriate cohort groups, e.g. young children. For the same reason, results of epidemiological studies of the past (involving banned AS) should be carefully interpreted and used with caution.     

The influence of ventilation on indoor/outdoor air contaminants in an office building

The air quality in a newly built preschool was investigated in a longitudinal study. Typical air contaminants emanating from building materials were determined, their variation over time (0–18 months) was measured, and the influence of the ventilation system (81%–91% recirculation of return air) on contaminant concentrations was studied. Volatile organic compounds were sampled by adsorption on porous polymer, analysed by a GC/FID system, and identified by MS. A spatial build-up in concentration (ppb or μg/m³ levels) is evident for all the organic compounds, as well as for CO₂, from the outdoor air, through the ventilation system, and through the rooms to the exhaust air. The longitudinal comparison over time shows that all the organic compounds decline in concentration mainly within the first 6 months of occupancy: 1-butanol 4–14 times, toluene and pentanal + hexanal 2–4 times, while formaldehyde remained at a constant low level of 90 ppb (110 μg/m³). It is difficult to believe that the problems of poor air quality in 100 preschools in Stockholm are caused by the organic compounds alone unless interactions occur. A preschool building needs to be gassed off during the first 6 months after its construction with no recirculation of return air allowed (outdoor air rate approx 4–5 ach). During at least 1–2 additional years, it is desired that the recirculation rate of return air is restricted, perhaps to 50%.     

Paleoecology and dynamics of forest ecosystems in Central Evenkia during the past 2400 years

New data on the composition of surface assemblages of plant macroremains from soil and swamp samples have been obtained in the study of geomorphologically different localities in the middle reaches of the Nizhnyaya Tunguska River. The results of paleocarpological analysis of forest soil sections supported by relevant palynological and geochronological data are presented. Natural changes of the forest cover over the past 2400 years and quantitative characteristics of the paleoclimate during each stage are described.Translated from Ekologiya, No. 1, 2005, pp. 3–10.Original Russian Text Copyright © 2005 by Koshkarova, Koshkarov.     

The Volta Lake and Declining Rainfall and Streamflows in the Volta River Basin

This paper looks at the rainfall and streamflow patterns over two distinct time periods, i.e., 1950–1970 and 1971–1991 within the two most prominent catchments in the Volta river system – White Volta and the Oti basins. The first period (1950–1970) represents relatively vegetated catchments and low population whilst the latter (1971–1990) represents intense land use practices resulting from increased population that have severely degraded the environment. These two catchments are among the most significant contributors to the Volta lake. The Volta lake, which was formed between 1962 and 1966 in Ghana and created primarily for hydroelectric power generation, will probably be one of the greatest man-made lakes for a long time. It produces 912MW of electricity at its maximum operating capacity. Recently, there have been declines in the lake levels resulting most probably from inadequate rainfall and/or runoff from the river catchments that feed the lake. Comparisons of runoffs for the two time periods show reductions in mean streamflows of 32.5% at Saboba on the Oti and 23.1% at Nawuni on the White Volta.     

Morphological-anatomical features of underground organs in some higher plant species in relation to their adaptation to ecological conditions

In seven higher plant species of different taxa, structural features of underground organs have been considered, and the levels of intraspecific variation in some characters of these organs have been determined. Different pathways of the structural adaptation of these species to the environment are demonstrated on the morphological and anatomical levels.Translated from Ekologiya, No. 2, 2005, pp. 97–105.Original Russian Text Copyright © 2005 by Tarshis.     

Microbial extracellular enzyme activities in Humex Lake Skjervatjern

Two microbial extracellular enzyme activities (MEEA) were studied in HUMEX Lake Skjervatjern: acid phosphatase (APHA) and leucine aminopeptidase (LeuAMPA). Both enzyme activities varied in the vertical and horizontal scale in both lake sites. APHA varied in the acidfied Basin A between 945–1706 nmol L⁻¹ h⁻¹ and LeuAMPA between 3.7–25 nmol L⁻¹ h⁻¹. Both MEEA reached maxima in 0.5 m depth. In the control site (Basin B), APHA was lower by a factor of two, and varied between 156–669 nmol L⁻¹ h⁻¹. LeuAMPA reached similar values as in Basin A and varied between 7.8–34.8 nmol L⁻¹ h⁻¹. Maxima of APHA were found in the upper layer (0–2 m), while LeuAMPA had only one distinct maxima at 2–2.5 m depth. The number of bacteria (AFDC) varied between 4.4–8.8 10⁶ cells mL⁻¹ and was not significantly different in either side, but both had maxima in the thermocline. Highest specific LeuAMPA activities were found in the thermocline (3.2–4.5 fmol L⁻¹ h⁻¹ cell⁻¹) in both sides and varied between 0.4–4.5 fmol L⁻¹ h⁻¹ cell⁻¹ in both water columns. The main contributor (60–70%) to LeuAMPA was found in the microplankton fraction, retained on Nuclepore filters with pore sizes between 2.0-0.2 μm. APHA was retained less even on a filter with pore size smaller than 0.2 μm. About 50–70% of APHA passed through 0.2 μm-0.1 μm Nuclepore filters and could be found in the dissolved organic matter (DOM) fraction. APHA and bacteria counts (AFDC) showed a distinct gradient from the littoral zone to the pelagial in the surface water samples (0.2 m depth). APHA and LeuAMPA are regarded as important regulators for nutrient availability to microplankton. However, all data from vertical as important regulators for nutrient availability to microplankton. However, all data from vertical and horizontal samples showed that Lake Skjervatjern is a strongly gradient-dominated aquatic ecosystem. Watershed-littoral effects are more pronounced in the shallow, acidified Basin A than in the control side, Basin B.     

Characteristics of Cajander Larch (<Emphasis Type="Italic">Larix cajanderi</Emphasis> Mayr) on Dredging Waste Dumps in the Amur Region

Former dredging sites were studied in the taiga zone of the Amur region (in Khabarovsk Krai). The involvement of Larix cajanderi in plant succession on dredging waste dumps was revealed. Some morphological-anatomical parameters of L. cajanderi needles were compared in trees growing on the dumps and in adjacent open larch stands on waterlogged peaty soils.__________Translated from Ekologiya, No. 4, 2005, pp. 259–263.Original Russian Text Copyright © 2005 by Osipov, Burundukova.     

Accumulation of metals by vegetation in a small drainage area exposed to aerotechnogenic pollution

Trends in the accumulation of metals by different plant species have been analyzed in a forest phytocenosis of the southern taiga zone of the Middle Urals, which is polluted by emissions from a copper-smelting plant. The rate of metal accumulation in the course of annual and net phytomass production and metal outflow with surface waters beyond the biogeocenosis boundaries have been estimated.Translated from Ekologiya, No. 1, 2005, pp. 26–31.Original Russian Text Copyright © 2005 by Fedorova, Odintseva.     

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.     

Plutonium isotopes in surface air of Prague in 1986–2006

Monitoring of ^239,240Pu in surface air of Prague started in 1986 in connection with the Chernobyl accident. Measurable activities of 10–28 μBq m⁻³ were found from 29 April 1986 to 5 May 1986. In the most of the monitoring periods of 1987–1996, activities of ^239,240Pu in air were not measurable. Positive values for ^239,240Pu and ²³⁸Pu in air could be obtained after installation of an aerosol sampler with higher flow-rate in 1997. Activity concentrations of ^239,240Pu and ²³⁸Pu in Prague air in the most of quarters of 1997–2006 were in the range 0.53–5.06 and <0.16–1.10 nBq m⁻³, respectively. Seasonal fluctuations can be found in content of ^239,240Pu in air. Activity ratios of ²³⁸Pu/^239,240Pu in air are higher than those in top soil, so it can be supposed that ²³⁸Pu is coming to air of Prague also from other sources than resuspension of fallout from atmospheric nuclear tests.     

The influence of air temperature on the perception of body odor

Ambient temperature may influence both the emission and the perception of human odor. This paper studies how human odor is perceived at different temperatures. The intensity of human odor in an auditorium was judged by an odor panel in an adjacent space. The ventilation rate of the occupied auditorium was 5–17 L/sec person. A continuous sample of odorous air was exhausted from the auditorium through a glass tube to an odor test station. One-half of the air flow was heated 1–7 K, and the other half was unheated. The odor panel was asked to compare the odor intensity of the two air flows. The air flow judged to have the strongest odor was stepwise dilluted with clean air (air temperature difference maintained). The dilution required to provide the same odor intensity in the two air flows was estimated. At air temperatures 23–32 °C no significant influence of temperature on perceived intensity of body odor was found. The ventillation requirement in auditoria and similar spaces is likely to be independent of the temperature level, provided that the occupants are kept thermally neutral or cooler, so that little or no perspiration occurs.     

Confronting a Surfeit of People: Reducing Global Human Numbers to Sustainable Levels An Essay on Population Two Centuries after Malthus

It has become increasingly evident over the past several decades that there is a growing tension between two seemingly irreconcilable trends: (1) moderate to conservative demographic projections that world population size could easily reach 9 billion (or more) by the mid-to-late twenty-first century; and (2) prudent and increasingly reliable scientific estimates suggesting that the Earth's long-term sustainable carrying capacity (at an 'adequate to comfortable' standard of living) may not be much greater than 2–3 billion. I therefore argue that it is now time – indeed, past time – to develop and implement a set of well-conceived, clearly articulated, broadly equitable and internationally coordinated sociopolitical initiatives that go beyond merely slowing the growth – or even the stabilization – of global human numbers. After summarizing a number of 'inescapable realities' that the human species must soon confront, and notwithstanding the considerable difficulties involved in establishing rational and defensible global population optimums, I conclude with several suggestions relevant to the next logical step: how best to bring about a very significant reduction in global population size over the next two to three centuries. To the extent that there is still time to choose whether this dramatic decrease will be under conscious control or essentially chaotic, these proposals are cautiously optimistic.     

Management of an Agroecosystem

Agroecosystems (AESs) are autotrophic ecosystems managed by man. The goal of the management is to obtain the maximum possible amount of high-quality agricultural products while preserving agricultural resources, primarily the soils and biodiversity. The main components of the management of AES structures and functions, including primary and secondary biological production, the ratio between the energy flows in the plant–man and plant–livestock–man food chains, the efficiency of energy transfer in the plant–livestock link, and conservation of agricultural resources, are considered.     

The Potential of Soil Carbon Sequestration Through Improved Management Practices in Norway

The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO₂ in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH₄) and nitrous oxide (N₂O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr^–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr^–1 for adopting conservation tillage, 0.011–0.035 MMTC yr^–1 for crop residue management, 0.026 MMTC yr^–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr^–1 for manure application, and 0.036 MMTC yr^–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr^–1 with an average value of 0.806 MMTC yr^–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to: bhaskarn ath@aol.com within 3 months of publication of this issue.     

Some characteristics of plutonium distribution in the atmospheric air and plants in the zone surrounding the Mayak Production Association

The results of long-term studies on plutonium distribution in the atmospheric air and plants in the area surrounding the Mayak Production Association in the years 1976–1995 are summarized. Data are presented on the changes in plutonium concentration in the air overtime at some points located in the survey zone and the impact zone of the industrial enterprise as compared to those in the control region. In addition, data on the changes in air plutonium concentration depending on the season and direction of wind are presented; the ratios between plutonium concentrations in the air and the fallout are analyzed.Translated from Ekologiya, No. 1, 2005, pp. 20–25.Original Russian Text Copyright © 2005 by Chudin, Shcherbakova, Maslovskii, Kocheva, Iovlev, Denisenko, Demin, Mamin, Chebotina.