Proliferative Activity of Corneal Epithelium and Specific Features of Morphogenesis in Postmetamorphic Rana arvalisNilss. in Urbanized Areas

The mitotic activity and sizes of corneal epithelial cells in postmetamorphic Rana arvaliswere studied in the populations exposed to different degrees of anthropogenic impact in the city of Yekaterinburg. The studies were conducted at the initial stages of frogs' terrestrial life in three consecutive years. Mitotic activity exhibited a slight positive correlation with the liver index, which indirectly reflects the general metabolic rate in young frogs. The combined estimation of proliferative activity, epithelial cell size, and relative liver weight had the highest information value. There was a relationship between the mitotic index and liver index in young frogs from habitats with the highest level of anthropogenic transformation. This indicates that morphogenesis is well-balanced and is likely to decrease the probability of morphological abnormalities in frogs developing in the unstable environment. This physiological property allows the populations to exist and reproduce in urbanized areas.     

Diversity of corals and benthic algae across the shallow-water reefs of Andaman Islands: managing the valuable ecosystems

The Andaman Islands characterize one of the relatively unexplored coral reef zones of the Indian subcontinent. A few benthic biodiversity studies have been carried out to date, but several coral and algal species still remain to be evaluated in terms of their abundance, vigour and conservation priority. In absence of a comprehensive, reliable dataset, inter-relationships between anthropogenic impacts and climate alterations with the coral reefs cannot be assessed authentically. This paper addresses the coupled themes of biodiversity and reef management in the Andaman Islands by examining the percentage cover of corals and benthic algae from shallow-water ecosystems across the coasts of Havelock, Neil, Ross, Jolly Buoy Islands and Chidiyatapu beach proximal to Port Blair. Four major reef types were observed: coral-dominated, algae-dominated, neutral setting and algae overgrowing dead reefs. Jolly Buoy Island had the highest percentage cover of scleractinian corals and crustose coralline algae. Turf algae were most abundant at the Ross Island, while other macroalgae showed highest abundance at Chidiyatapu. Overall species diversity values for corals and algae were highest at the Jolly Buoy and Chidiyatapu, respectively. Given that corals and algae are critical reef components, management paradigms must consider the abundance and frequency of both these biogenic entities in the seascape. The needs, expectations and objectives of the people dependent on coral reef ecosystems also need to be considered. Long-term monitoring is imperative in understanding the natural typology of reefs and managing the possible algal encroachments. Refined management efforts that include greater thrust on development of marine protected areas and reserves; establishment of connectivity between various coral ecosystems of the region; control of invasive algae; and increasing awareness among the local people as well as tourists will ensure continued support of ecosystem to maintain healthy reefs. Collectively, the results are used to promote some strategies to conserve the Andaman coral reefs and cope with the detrimental anthropogenic and climate changes in these coastal habitats.     

Distribution of Zooplankton along the Longitudinal Profile of Two Disturbed Small Rivers of the Upper Volga Basin

The abundance and trophic structure of zooplankton along the longitudinal profile of two typical rivers in the Yaroslavl sector of the Volga region are determined by anthropogenic and zoogenic factors. The distribution of zooplankton under the influence of these factors is described by the concept of patch dynamics. The abundance of zooplankton reaches the highest values in the ameliorated upper reaches of rivers and in beaver ponds.     

14C content in vegetation in the vicinities of Brazilian nuclear power reactors

(14)C specific activities were measured in grass samples collected around Brazilian nuclear power reactors. The specific activity values varied between 227 and 299 Bq/kg C. Except for two samples which showed (14)C specific activities 22% above background values, half of the samples showed background specific activities, and the other half had a (14)C excess of 1-18%. The highest specific activities were found close to the nuclear power plants and along the main wind directions (NE and NNE). The activity values were found to decrease with increasing distance from the reactors. The unexpectedly high (14)C excess values found in two samples were related to the local topography, which favors (14)C accumulation and limits the dispersion of the plume. The results indicate a clear (14)C anthropogenic signal within 5 km around the nuclear power plants which is most prominent along northeastwards, the prevailing wind direction.     

Heavy metals in four fish species from the French coast of the Eastern English Channel and Southern Bight of the North Sea

Shallow coastal waters act as nurseries for various fish species and have been recognized as essential fish habitat. We studied heavy metal concentrations in four fish species (plaice, dab, flounder and cod) as an indicator of large-scale habitat quality. The study took place along the French coasts between the Eastern English Channel and the Southern Bight of the North Sea. All species show different concentrations of measured metals (e.g., Cd, Cu, Mn and Pb) in liver but not in muscle. The highest concentrations are found for the flounder and the lowest for cod which is consistent with their habitat and diet. Although our results do not highlight levels of appreciable pollution within the study area, inter-site differences are mainly observed in the muscle tissues and are generally in agreement with the known environmental data (e.g., anthropogenic pressure). However, in the Bay of Seine, one of the most contaminated estuaries in Europe, metal concentrations are in the same range or even lower than those found in fish collected from areas distant from any anthropogenic pressures. At one site, the comparisons of the Cd, Cu and Pb concentrations between healthy and diseased dabs have been carried out on the muscle and liver tissues. The results of this preliminary study show a relationship between metal concentrations and the pathological status of the fish. The use of fish health as indicator of habitat quality is discussed.     

Special features of fish species composition and community structure in small rivers of the Udmurt Republic

The composition and species richness of ichthyofauna have been studied in 36 stretches of small rivers in the Udmurt Republic to estimate the dependence of species richness on the distance from the river source and the level and type of anthropogenic load. Some specific features of modification of the fish community structure under the influence of agriculture, urbanization, and industry (oil production) have been revealed. Basic trends in the change of dominant complexes of fish species with an increase in the distance from the river source are described for small rivers flowing in different natural and anthropogenic landscapes of the Udmurt Republic.     

Fish Communities of Small Ponds in the Udmurt Republic: Structural Features and Trends in Anthropogenic Successions

The ichthyofauna of 20 small ponds in the Udmurt Republic was studied to estimate the dependence of fish species abundance on pond size and anthropogenic load, as well as trends in the succession of dominant species complexes in ponds exposed to the prevailing impact of agricultural activity. Changes in the ecological structure of fish communities in small ponds upon an increase in the anthropogenic load were analyzed. Some specific features of the species composition of ichthyofauna in technogenic pond biocenoses were revealed.     

Biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in harbour seals and harbour porpoises from the Southern North Sea

Harbour seals and harbour porpoises are top predator species from the North Sea, have long life spans and hence, are known to accumulate high levels of anthropogenic contaminants. To gain knowledge about the behaviour of naturally-produced compounds in these marine mammals, the biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) was assessed. The biomagnification of MeO-PBDEs (2′-MeO-BDE 68 and 6-MeO-BDE 47) was lower in harbour seals (all biomagnification factors (BMFs) < 1) compared to the same age–gender groups of the harbour porpoises (all BMFs > 1). This may indicate a better metabolic breakdown of MeO-PBDEs in harbour seals, as was previously suggested for polybrominated diphenyl ethers (PBDEs). In both predators, 6-MeO-BDE 47 had the highest concentrations (range: 45–483 ng/g lw and 2–38 ng/g lw for harbour porpoises and seals, respectively) compared to 2′-MeO-BDE 68 (range: 2–28 ng/g lw and 1–6 ng/g lw for harbour porpoises and seals, respectively). In general, the highest concentrations were found in juveniles, suggesting an increased biotransformation capacity with age or the influence of dilution by growth for both species. Here we show that naturally-produced brominated organic compounds can biomagnify and accumulate in North Sea top predators, although to a lesser extent than anthropogenic lipophilic contaminants, such as polychlorinated biphenyls (PCBs) or PBDEs.     

Relict Crustaceans under Conditions of Long-Term Pollution of Subarctic Lake Imandra: Results of Observations in 1930–1998

Changes in the role of relict crustaceans in the zoobenthic communities of large subarctic Lake Imandra are analyzed over the long period of economic development in its drainage area. To date, Mysis relicta as a species highly sensitive to anthropogenic pollution has apparently disappeared from the lake fauna. The currently recorded maximum values of Pontoporeia affinis abundance and biomass are more than 20 times as great as those between 1968 and 1986. As in other lakes with mass development of P. affinis, the populations of this crustacean inhibit chironomid larvae in the communities of Lake Imandra.     

Is there a density compensation effect in plant communities of anthropogenic habitats?

The occurrence of density compensation effect (DCE) has been estimated in areas occupied by synanthropic communities in the Western Caucasus. The density of dominant plant species has been estimated from their coverage, and that of subordinate species, from their frequency in 0.5-m² squares within 15 (16)-m² plots, using natural and seminatural communities as a reference standard. The factual material has been analyzed by the method of numerical experiments. The results show that the transformation of natural habitats into anthropogenic ones has led to a decrease in the species diversity of plant communities, but without causing a widespread occurrence of DCE. It is hypothesized that relatively high average values of species frequency in low-diversity synanthropic communities are more likely accounted for by random rather than compensatory processes.     

Pb, Zn, and Cu levels in tree barks as indicator of atmospheric pollution

Barks of seven species of trees were sampled at 32 locations having different pollution levels in Abeokuta, Nigeria. The concentrations of Pb, Zn, and Cu were determined by atomic absorption spectrometry. The Pb and Zn contents, 1.9-159.8 and 16.5-659.1 micrograms g-1, dry weight respectively, correlate with traffic volume, indicating pollution from anthropogenic sources. The results obtained for Cu, 4.2-20.7 micrograms g-1, dry weight, though lower, were still significant but did not show any correlation with traffic density. The study also confirms the suitability of Azadirachta indica (Dogoyaro--a very popular local tree) as a suitable bio-indicator of aerial fallout of heavy metals.     

Spatial distribution of 3H, 90Sr, 137Cs and (239,240)Pu in surface waters of the Pacific and Indian Oceans--GLOMARD database

The data stored in the IAEA's Global Marine Radioactivity Database (GLOMARD) developed in the framework of the IAEA's project "Worldwide Marine Radioactivity Studies (WOMARS)" have been evaluated for Pacific and Indian Ocean surface waters. Four anthropogenic radionuclides-- 3H, 90Sr, 137Cs and (239,240)Pu --have been chosen as the most representative of anthropogenic radioactivity in the marine environment, comprising beta, gamma and alpha-emitters which are the most frequently analysed in the marine environment and which have (with the exception of tritium) the highest potential contribution to radiation doses to humans via seafood consumption. For the purposes of this study, the Pacific and Indian Oceans were divided into latitudinal boxes for which average radionuclide concentrations were estimated for the year 2000. The highest concentrations have been observed in the Japan Sea/East Sea and the North-West Pacific Ocean, the lowest in the Southern Ocean.     

Ecological Characteristics of Small Rodents Living in Collective Gardens

The small-rodent populations of five collective gardens have been studied. The example of one of the populations has been used to monitor the annual cycle of population size. The species composition and animal number depends on the biotope, climatic conditions, and the anthropogenic load. The ratios between species in the gardens and neighboring biotopes differ from each other, with different species being dominant. It is assumed that small mammals use garden plots as refugia.     

Lead contamination and isotope signatures in the urban environment of Hong Kong

The source and the extent of Pb pollution in the urban environment of Hong Kong were investigated at five different urban settings selected on the basis of their annual average daily traffic (AADT) varying from less than 100 to 61,700. In addition, a small distant island without any traffic was selected to establish the possible baseline values. The surface environmental samples studied consisted of street and tunnel dusts, gully sediments, and a limited number of roadside topsoils. The analytical results clearly indicated variable degrees of Pb contamination in these urban settings. However, the level of contamination varied significantly among different types of samples collected at the same location. Pb concentrations of roadside topsoils (79+/-22 micrograms/g) and gully sediments (278+/-88 micrograms/g) were lower than those of the corresponding road dusts (327+/-54 micrograms/g). The Pb isotope compositions in different urban settings varied considerably. The bedrock in the small island had the lowest Pb concentration (12 micrograms/g) but with the highest 206Pb/207Pb ratio (1.2206), whereas the tunnel ceiling dusts with the highest level of Pb (1410 micrograms/g) had the lowest 206Pb/207Pb ratio (1.1062). Despite the significant differences in vehicle types and traffic volumes, and the presence of several different petroleum retailers in Hong Kong, the Pb isotope ratios of road dusts (206Pb/207Pb: 1.1553+/-0.0043, 208Pb/207Pb: 2.4408+/-0.0084) varied within a relatively narrow range among all the five urban sampling sites. On the other hand, the Pb isotopic compositions of gully sediments (206Pb/207Pb: 1.1515+/-0.0145, 208Pb/207Pb: 2.4322+/-0.0198) varied noticeably within the same setting, but were reasonably comparable across the different study sites. In general, the 206Pb/207Pb ratios of road dusts can be used to estimate the direct contribution from automobile emissions, whereas those of gully sediments might reflect the effects of the mixing of different anthropogenic sources. The Pb isotope signatures in the urban environment of Hong Kong clearly suggested that anthropogenic Pb in the environment originated from Pb ore with a low 206Pb/207Pb ratio (such as the Australian Pb ore and similar sources in Southeast Asia) were significantly different from those of the anthropogenic Pb present in the neighboring Pearl River Delta (PRD) region.     

Impact of demographic dynamics on CO_2 emissions in Sichuan,China

Global climate change is one of the major environmental issues faced by humans.Existing evidence indicates that the anthropogenic push for a rise in the atmospheric concentration of greenhouse gases(GHGs)(particularly CO_2)has been a primary cause for global warming.Aside from economic and teclinological factors,demographic dynamics(including human consumption in a broad demographic sense)has been a major driver for CO_2 emissions.In this paper,we performed both nonlinear regression analysis(based on the STIRPAT model)and gray correlation degree analysis(based on gray system theory)on the impact of demographic dynamics on CO_2 emissions.Our results reveal that CO_2 emissions are positively correlated with population size and GDP per capita and negatively correlated with energy intensity.We also show that gray correlation degree with CO_2 emissions for five variables(i.e.,household consumption,urbanization rate,household size,population aging rate,population size)varies substantially:household consumptionurbanization ratehousehold sizepopulation aging ratepopulation size,with household consumption being the highest,and population size the lowest.To mitigate the impact of demographic dynamics on CO_2 emissions,it is of vital significance to nurture people's awareness of sustainable consumption and to adhere to current population control policies.     

Relationship between the Biodiversity of phyto- and zoobenthos in the continuum of the model mountain river Komarovka (Primorye,Russia)

The structure of benthic communities was studied in the continuum of the model mountain river Komarovka, which flows in the conifer-broadleaf forest subzone in the southwest of the Silkhote-Alin Mountain Range (Primorye, Russia). The lowest species diversity of phyto- and zoobenthos was recorded in the upper reaches of the river, in a heterotrophic area; the highest species diversity, in the central part of autotrophic area. At the same time, the Shannon index for algal communities had the highest values in the heterotrophic area, while that for bottom invertebrate communities, within the autotrophic area. Thus, the increase in invertebrate species diversity in the river continuum was accompanied by complication of the structure of zoobenthos, while the increase in the taxonomic diversity of phytobenthos took place against the background of increasing dominance of a few algal species.     

40K/137Cs discrimination ratios to the aboveground organs of tropical plants

In the present work, the accumulation of caesium and potassium in aboveground plant parts was studied in order to improve the understanding on the behaviour of monovalent cations in several compartments of tropical plants. We present the results for activity concentrations of (137)Cs and (40)K, measured by gamma spectrometry, from five tropical plant species: guava (Psidium guajava), mango (Mangifera indica), papaya (Carica papaya), banana (Musa paradisíaca), and manioc (Manihot esculenta). Caesium and potassium have shown a high level of mobility within the plants, exhibiting the highest values of concentration in the growing parts (fruits, leaves, twigs, and barks) of the woody fruit and large herbaceous shrub (such as manioc) species. In contrast, the banana and papaya plants exhibited the lowest levels of (137)Cs and (40)K in their growing parts. However, a significant correlation between activity concentrations of (137)Cs and (40)K was observed in these tropical plants. The (40)K/(137)Cs discrimination ratios were approximately equal to unity in different compartments of each individual plant, suggesting the possibility of using caesium to predict the behaviour of potassium in several tropical species.     

荔波板寨小流域水化学和溶解无机碳的稳定同位素特征

通过采集贵州荔波自然保护区内的板寨地上河小流域的地表和地下水样品,测试了阴阳离子含量及其HCO_3~-中的δ~(13)C同位素值,分析不同季节该流域水体的水化学特征,并结合δ~(13)C同位素值探讨水体溶质的来源和水化学过程。结果表明:小流域水体的主要阴离子为HCO_3~-和SO_4~(2-),二者分别占了水体总阴离子当量的86.2%和10.4%,主要阳离子Ca~(2+)和Mg~(2+)则分别占总阳离子当量的76.9%和20.5%。河水较多的Mg~(2+)表明其可能受白云岩风化的影响。小流域水体DIC的δ~(13)C值在-16.87‰至-10.80‰之间,夏季相对于冬季偏负,并且HCO_3~-含量与其δ~(13)C值之间存在负相关关系,这可能是不同季节温度和降水强度共同作用的结果。水体的SO_4~(2-)含量与DIC的δ~(13)C同位素值之间存在明显正相关性,这说明H_2SO_4可能参与了小流域内碳酸盐岩的风化过程。     

Cypress tree (Cupressus semervirens L.) bark as an indicator for heavy metal pollution in the atmosphere of Amman City,Jordan

Bio-monitoring of air quality in Amman City was investigated by analyzing 36 cypress tree (Cupressus semervirens L.) bark samples from three sites of different anthropogenic activities at the end of summer season 2001. Cypress barks were found to be a good bio-indicator for air pollution in arid regions. Variation in Pb, Zn, Mn, Cr, Ni, Cd, and Cu contents between sites was observed due to different types of activities. Traffic emissions were found to be the main source of heavy metal pollution in the atmosphere of Amman. Lead content was found to be the highest in highly traffic density areas. The industrial part of the city was characterized by high Zn, Mn, Cr, Ni, and Co contents. No significance variations were found in pH values of the bark between the sites. This was attributed to buffering effect of carbonate in the atmosphere originated from soil of the area.     

Causes and ecological effects of resuspended contaminated sediments (RCS) in marine environments

Sediments act as a net sink for anthropogenic contaminants in marine ecosystems and contaminated sediments may have a range of toxicological effects on benthic fauna and associated species. When resuspended, however, particulate-bound contaminants may be remobilised into the water column and become bioavailable to an additional assemblage of species. Such resuspension occurs through a range of natural and anthropogenic processes each of which may be thought of as pulsed disturbances resulting in pulsed exposures to contaminants. Thus, it is important to understand not only the toxicological responses of organisms to resuspended contaminated sediments (RCS), but also the frequency, magnitude and duration of sediment disturbance events. Such information is rarely collected together with toxicological data. Rather, the majority of published studies (> 50% of the articles captured in this review) have taken the form of fixed-duration laboratory-based exposures with individual species. While this research has clearly demonstrated that resuspension of contaminated sediments can liberate sediment-bound contaminants leading to toxicity and bioaccumulation under controlled conditions, the potential for ecological effects in the field is often unclear. Monitoring studies suggest that recurrent natural disturbances such as tides and waves may cause the majority of contaminant release in many environments. However, various processes also act to limit the spatial and temporal scales across which contaminants are remobilised to the most toxic dissolved state. Various natural and anthropogenic disturbances of contaminated sediments have been linked to both community-level and sub-lethal responses in exposed populations of invertebrates and fish in the field. Together these findings suggest that resuspension of contaminated sediments is a frequently recurring ecological threat in contaminated marine habitats. Further consideration of how marine communities respond to temporally variable exposures to RCS is required, as well as research into the relative importance of various disturbances under field conditions.