Potential responses of terrestrial biodiversity in Southern Africa to anthropogenic climate change

Key studies supported by species-level data collection have provided early indications of the potential implications of unmitigated change for the ecosystems and biodiversity of southern Africa. These suggest a significant threat to biodiversity, both from changing bioclimatic suitability and changing atmospheric CO₂ level that seems to affect the competitive balance between woody and herbaceous plants in the dominant savanna biome of this region. Modeling efforts suggest significant implications of unmitigated climate change for this region, but assumptions underpinning methods such as bioclimatic modeling must be recognized, some of which might lead to over estimates of the rate and extent of the potential impacts. General trends and level of coincidence between various types of studies do support a high degree of concern for a substantial portion of southern African biodiversity under unmitigated climate-change scenarios. The most significant changes in ecosystem structure (both increases and decreases in woody plant cover), and associated faunal diversity changes, are projected in the dominant savanna vegetation type in this region, while the most significant biodiversity loss is projected for the winter rainfall region. Follow-up work to detect early signs of climate change identify regions of high- and low-potential impacts, and experimental work to test some important hypotheses relating to the future evolution of climate-change impacts across the region are very few and urgently required.     

Distribution of carbon 14 in the terrestrial environment close to French nuclear power plants

For 10 years, (14)C measurements have been performed around French nuclear power plant sites, both in zones influenced and zones not influenced by gaseous releases. Examining the results from these measurements in the terrestrial environment shows that the discharges have a very slight impact on the radiocarbon level (with a relative increase in the specific activity of the order of 3 Bqkg(-1)C in the influenced areas). In correlation, there is a near-negligible increase in dose, on average less than 0.1 microSvyr(-1), with reference to a dose from background radiation, which is of the order of 10 microSvyr(-1). The deltaC13 values are very similar between the influenced zone and the non-influenced zone, with a mean of -27 per thousand. The mean DeltaC14 varies from 101 per thousand in the non-influenced zone to 123 per thousand in the influenced zone. Moreover, a general reduction in (14)C concentration was found, with a time constant of the order of 95 years. The current level of (14)C specific activity in terrestrial environment is estimated to be 242+/-6 Bqkg(-1)C.     

The connection between urbanization and carbon emissions: a panel evidence from West Africa

Environment, Development and Sustainability - This study examined the nexus between urbanization and carbon emissions in West Africa. Second-generation econometric techniques that are robust to...     

环渤海地区海洋经济发展进程中的生态环境响应及其影响因素

基于海洋经济发展进程的生态环境演化模型,建立了环渤海地区海洋经济与生态环境发展水平评价指标体系,通过构建响应度模型定量分析2004至2014年环渤海地区海洋经济发展的海洋生态环境响应变化及影响因素,得出以下结论:(1)通过构建海洋经济与生态环境发展水平评价指标体系及综合评价模型进行测算发现,环渤海地区海洋经济发展综合评价值由2004年的0.135提升至2014年的0.850,表明环渤海地区海洋经济发展水平不断提高,并呈现出良好的发展势头;海洋生态环境发展综合评价值先由2004年的0.647降至2012年的0.335,后又缓慢回升至2014年的0.374,表明环渤海地区海洋生态环境水平虽在2012至2014年间略有好转,但总体仍呈波动下降趋势。(2)通过构建海洋生态环境响应度模型进行测算发现,环渤海地区海洋经济发展的生态环境响应指数由2004年的-0.073下降至2012年的-0.576,而后又增大至2014年的-0.297,表明环渤海地区海洋经济发展对生态环境演变产生了"胁迫"影响,总体呈现出由"弱胁迫"向"强胁迫"变化的态势,但胁迫程度在2012至2014年间有所缓和。(3)通过多元回归分析发现,与海洋生态环境响应指数的偏回归系数较高的3个自变量分别为海洋科技课题成果应用数量、海域利用效率、单位面积工业废水排放达标量,且海域利用效率的回归系数最高为0.749。表明海域利用效率是影响环渤海地区海洋生态环境响应演变的主要因素,此外,海洋科技发展水平的提高以及海洋污染治理力度加强等因素也对胁迫程度的减小具有一定的推动作用。     

Assessment of marine pollution in Izmir Bay: nutrient, heavy metal and total hydrocarbon concentrations

Izmir Bay (western Turkey) is one of the great natural bays of the Mediterranean. Izmir is an important industrial and commercial centre and a cultural focal point. The main industries in the region include food processing, oil, soap and paint production, chemical industries, paper and pulp factories, textile industries and metal processing. The mean concentrations showed ranges of 0.01-0.19 and 0.01-10 microM for phosphate, 0.10-1.8 and 0.12-27 microM for nitrate+nitrite, and 0.30-5.8 and 0.43-39 microM for silicate in the outer and middle-inner bays, respectively. The TNO(x)/PO(4) ratio is significantly lower than the Redfield's ratio and nitrogen is the limiting element in the middle-inner bays. Diatoms and dinoflagellates were observed all year around in the bay and are normally nitrogen limited. Metal concentrations ranged between Hg: 0.05-1.3, Cd: 0.005-0.82, Pb: 14-113 and Cr: 29-316 microg g(-1) in the sediments. The results showed significant enrichments during sampling periods from Inner Bay. Outer and middle bays show low levels of heavy metal enrichments except estuary of Gediz River. The concentrations of Hg, Cd and Pb in the outer bay were generally similar to the background levels from the Mediterranean. The levels gradually decreased over the sampling period. Total hydrocarbons concentrations range from 427 to 7800 ng g(-1) of sediments. The highest total hydrocarbon levels were found in the inner bay due to the anthropogenic activities, mainly combustion processes of traffic and industrial activities. The concentrations of heavy metals found in fish varied for Hg: 4.5-520, Cd: 0.10-10 and Pb: 0.10-491 microg kg(-1) in Izmir Bay. There was no significant seasonal variation in metal concentrations. An increase in Hg concentration with increasing length was noted for Mullus barbatus. A person can consume more than 2, 133 and 20 meals per week of fish in human diet would represent the tolerable weekly intake of mercury, cadmium and lead, respectively, in Izmir Bay. Heavy metal levels were lower than the results in fish tissues reported from polluted areas of the Mediterranean Sea.     

Sources and sinks of carbon dioxide in terrestrial ecosystems: Is the land's carbon budget balanced under the influence of man?

This contribution deals with the controversy between certain scientists on the role of terrestrial vegetation and soils in the global carbon cycle. The hypothesis of a significant net release from the vegetation, is rejected by geochemists because of the limited capacity of the ocean to take up this excess carbon dioxide. As for the man-influenced tropics, a comparison of the figures for the potential and the current phytomass, as well as plausible demographic arguments, support the assertion put forward by ecologists that the carbon budget of this zone cannot be balanced. The tropics lose about 1.7-3.9 × 10¹⁵ g/yr of carbon to the atmosphere; however, for several reasons, 0.5-2.8 × 10¹⁵ g/yr may be returned to land ecosystem, mostly in other climatic zones. Thus, a balance is achieved on combining low estimates for the losses with high estimates for the gains. From an ecological perspective, this solution is not a very probable one; nevertheless, it cannot conclusively be eliminated.     

Long-term dynamics of terrestrial carbon stocks in Austria: a comprehensive assessment of the time period from 1830 to 2000

This article presents a comprehensive data set on Austria’s terrestrial carbon stocks from the beginnings of industrialization in the year 1830 to the present. It is based on extensive historical and recent land use and forestry data derived from primary sources (cadastral surveys) for the early nineteenth century, official statistics available for later parts of the nineteenth century as well as the twentieth century, and forest inventory data covering the second half of the twentieth century. Total carbon stocks—i.e. aboveground and belowground standing crop and soil organic carbon—are calculated for the entire period and compared to those of potential vegetation. Results suggest that carbon stocks were roughly constant from 1830 to 1880 and have grown considerably from 1880 to 2000, implying that Austria’s vegetation has acted as a carbon sink since the late nineteenth century. Carbon stocks increased by 20% from approximately 1.0 GtC in 1830 and 1880 to approximately 1.2 GtC in the year 2000, a value still much lower than the amount of carbon terrestrial ecosystems are expected to contain in the absence of land use: According to calculations presented in this article, potential vegetation would contain some 2.0 GtC or 162% of the present terrestrial carbon stock, suggesting that the recent carbon sink results from a recovery of biota from intensive use in the past. These findings are in line with the forest transition hypothesis which claims that forest areas are growing in industrialized countries. Growth in forest area and rising carbon stocks per unit area of forests both contribute to the carbon sink. We discuss the hypothesis that the carbon sink is mainly caused by the shift from area-dependent energy sources (biomass) in agrarian societies to the largely area-independent energy system of industrial societies based above all on fossil fuels.     

The influence of urbanization on vegetation carbon pools under a tele-coupling framework in China

Environment, Development and Sustainability - Carbon emissions will exacerbate the process of global warming, and urbanization can cause carbon loss from terrestrial ecosystems by occupying...     

Role of allochthonous carbon in the energy of terrestrial invertebrate communities at different distances from the Black Sea and a freshwater lake (Isotopic Evidence)

Isotopic analysis has become an important tool in the study of lateral links between ecosystems. The isotopic composition of carbon in terrestrial and aquatic primary producers can differ significantly, which provides an opportunity to identify the “marine” or “freshwater” carbon in the tissues of terrestrial animals. We measured the isotopic composition of C and N in tissues of soil invertebrates and estimated the proportion of “aquatic” carbon in the energy budget of terrestrial food webs at different distances from the Black Sea and a freshwater lake. Terrestrial predators are actively subsidized with carbon from the Black Sea to distance of up to about 50 m. The carbon subsidy from the freshwater lake is significant in the zone extending no farther than the forest border (ca. 15 m). Thus, the effect of allochthonous organic matter on terrestrial communities in both cases manifests itself only in a relatively narrow coastal strip.     

Acid-base characteristics of organic carbon in the HUMEX lake Skjervatjern

The Humic Lake Acidification Experiment (HUMEX) was launched in 1988 to study the role of humic substances in the acidification of surface waters and the impacts of acidic deposition on the chemical and biological properties of humic substances. This subproject was designed to determine the contribution of organic acids to the acidity of Lake Skjervatjern (the HUMEX Lake) and the impacts of the acidification on the characteristics of organic carbon. In order to get an empirical measure for organic acidity, dissolved organic carbon (DOC) was fractionated, isolated, and base-titrated from each half of Lake Skjervatjern. Hydrophobic acids were the dominant organic carbon fraction; the total organic acid content was generally greater than 80% of the DOC. The reliability of the fractionation procedure was tested with synthetic acids and the Nordic Fulvic acid. The DOC fractions did not show high variation over the 1.5-y acidification period. Hydrophilic acids had consistently greater exchange acidities compared to hydrophobic acids, averaging 12.9 μeq/mg DOC vs. 10.9 μeq/mg DOC, respectively. The dissociation of organic acids during acid-base titrations clearly increased with increasing pH. The high organic anion contribution to the ion balances indicates that humic matter is an important acidity source in Lake Skjervatjern. There are slight signs that the contribution of organic acids to overall lake acidity has decreased since acidification was initiated.     

137Cs and 210Po dose assessment from marine food in Cienfuegos Bay (Cuba)

One part of Radiological Monitoring Programme in central Cuba (1991-1995) was dedicated to study the background levels of natural and anthropogenic radioactivity in Cienfuegos Bay in the vicinity of the first Cuban nuclear power station under construction. 210Po and 137Cs concentrations in fish, molluscs and crustaceans collected in Cienfuegos Bay were determined and the committed effective doses (CED) were calculated for two population groups inhabiting this region. The highest values of 210Po concentrations were found in crustaceans, but significant accumulation was also observed in fish and molluscs. The mean 137Cs concentrations in organisms are several times lower with respect to 210Po, a situation that characterises the regions affected by the global fallout only. Values of CED from the consumption of crustaceans and molluscs are very low both from 210Po and 137Cs. The mean individual dose from 210Po in the seafood consumed varies from 39 microSv for general populations to 2802 microSv for the "critical group" consuming 320 kg of fish per year. The dose from 137Cs is negligible.     

Exploring the causal relationship between carbon emissions and land urbanization quality in China using a panel data analysis

Land use and carbon emissions have long been a heated topic in China as well as developing countries. This paper contributes to the study of the related area as to investigate the causal relationship between the land urbanization quality and carbon emissions using panel data from 30 provinces in China over the period of 2004–2013. The empirical results show that: There exists bidirectional causality between land urbanization quality and carbon emissions across the country; land urbanization quality has negative effects on carbon emissions in all areas, with its effects largest in the Central region, followed by the Eastern, and the Western ranked at last; causal relationship exists in all regions, in addition to Eastern China; Central region has the highest potential of energy conservation. These findings provide new insights and valuable information for optimizing land use and urban development in China. In particular, to actively adjust the industrial structure, innovation in science and technology, and separate policy focus can contribute to energy conservation and urban land use.     

Simulating the effects of urbanization,afforestation and cropland abandonment on a regional carbon balance: a case study for Central Germany

The newly developed model system HILLS is used to simulate recent (1990–2000) and future (up to 2020) changes in land use and carbon sequestration over Central Germany. HILLS is unique as that it integrates the spatially explicit land-use-change model LUC-Hesse with the dynamic ecosystem model Century under a GIS platform. With this new tool, the concurrent effects of urbanization, afforestation and cropland abandonment on regional carbon sequestration are analyzed for an exemplary “Business as Usual” scenario. During the simulation period, afforestation was estimated to sequester 880 Gg C and cropland abandonment 783 Gg C. Urbanization was estimated to release 336 Gg C formerly stored in soil organic matter and thereby offsets about 20% of the C sequestered by cropland abandonment and afforestation. The case study shows that urbanization can partly counteract the benefits of carbon sequestration resulting from other land-use changes and should be investigated in other carbon balances.     

Application of the Weibull extrapolation to 137Cs geochronology in Tokyo Bay and Ise Bay, Japan

Considerable doubt surrounds the nature of processes by which 137Cs is deposited in marine sediments, leading to a situation where 137Cs geochronology cannot be always applied suitably. Based on extrapolation with Weibull distribution, the maximum concentration of 137Cs derived from asymptotic values for cumulative specific inventory was used to re-establish 137Cs geochronology, instead of original 137Cs profiles. Corresponding dating results for cores in Tokyo Bay and Ise Bay, Japan, by means of this new method, are in much closer agreement with those calculated from 210Pb method than the previous method.     

Efficiency of the activated carbon filtration in the natural organic matter removal

The removal and transformation of natural organic matter were monitored in the different stages of the drinking water treatment train. Several methods to measure the quantity and quality of organic matter were used. The full-scale treatment sequence consisted of coagulation, flocculation, clarification by flotation, disinfection with chlorine dioxide, activated carbon filtration and post-chlorination. High-performance size-exclusion chromatography separation was used to determine the changes in the humic substances content during the purification process; in addition, a UV absorbance at wavelength 254 nm and total organic carbon amount were measured. A special aim was to study the performance and the capacity of the activated carbon filtration in the natural organic matter removal. Four of the activated carbon filters were monitored over the period of 1 year. Depending on the regeneration of the activated carbon filters, filtration was effective to a degree but did not significantly remove the smallest molar mass organic matter fraction. Activated carbon filtration was most effective in the removal of intermediate molar mass compounds (range 1,000-4,000 g/mol). Regeneration of the carbon improved the removal capacity considerably, but efficiency was returned to a normal level after few months.     

Arsenic mobilization from iron oxyhydroxides is regulated by organic matter carbon to nitrogen (C:N) ratio

Arsenic (As) is mobilized from delta and floodplain aquifer sediments throughout S.E. Asia via reductive dissolution of As bound to iron (Fe) oxyhydroxides. The reductive driving force is organic carbon, but its source and constitution is uncertain. Here batch incubation experiments were conducted to investigate the role of organic matter (OM) carbon:nitrogen (C:N) ratio on the mobilization of arsenic, Fe and N from As dosed, Fe oxyhydroxide coated sands. As mobilization into pore waters from the sand was strongly regulated by the C:N ratio of the OM, and also the concentration of OM present. The lower the C:N, the more As released. Fe and ammonium release were similarly dependent on the quality and quantity of OM, but Fe mobilization was more rapid and ammonium release slower than As suggesting that the mobilization of these 3 moieties although interdependent, were not directly linked. It was concluded that low C:N ratios for OM responsible for reducing aquifers were As in groundwater is observed were likely.     

Cobalt and secondary poisoning in the terrestrial food chain: data review and research gaps to support risk assessment

Cobalt is a naturally occurring element found in rocks, soil, water, plants, and animals and has diverse industrial importance. It is cycled in surface environments through many natural processes (e.g. volcanic eruptions, weathering) and can be introduced through numerous anthropogenic activities (e.g. burning of coal or oil, or the production of cobalt alloys). The environmental behaviour of cobalt in terrestrial environment is relatively poorly studied and in particular where Co is used in industrial processes, the baseline information to support wider and long-term environmental impacts is widely dispersed. To support the adoption of new EU regulations on the risk assessment of chemicals, we review here the various aspects of the environmental chemistry, fate and transport of Co across environmental interfaces and discuss the toxicology and potential for bio magnification and food chain accumulation. The soil-to-plant transfer of Co appears to be viable route to expose lower trophic levels to biologically significant concentrations and Co is potentially accumulated in biomass and top soil. Evidence for further accumulation through soil-invertebrate transfer and to higher trophic levels is suggested by some studies but this is obscured by the relatively high variability of published transfer data. This variation is not due to one particular aspect of the transfer of Co in terrestrial environments. Influences are from the variability of geological sources within soil systems; the sensitivity of Co mobility to environmental factors (e.g. pH) and the variety of life strategies for metal elimination/use within biological species. Toxic effects of Co have been suggested for some soil-plant animal studies however, uncertainty in the extrapolation from laboratory to field is a major limitation.     

The composting potential of different organic solid wastes: experience from the island of Crete

For the past 20 years, the National Foundation for Agricultural Research in Crete and the School of Agricultural Technology of the Technological and Educational Institute of Crete have been involved in a number of research and development activities, related to the production and evaluation of compost derived from a variety of local solid, mainly agricultural organic wastes. Materials such as olive press cake, olive tree leaves (OTL) and branches, vine branches (VB), pressed grape skins (PGS), pig manure (PM), sewage sludge and the organic fraction of municipal solid waste (OFMSW) have been evaluated for their behaviour during composting, their compatibility in mixtures and the quality of the end product. The quality evaluation included both a detailed physiochemical (pH, electrical conductivity (EC), nutrients concentration, heavy metal concentration, etc.) and biological analyses (pathogenic microorganisms). It also included an agronomic evaluation, in which composts were used either as a soil amendment or as a component for substrates in open air or covered (greenhouse) cultivation mainly of local vegetables (tomatoes, cucumbers, etc.). All materials were composted successfully, especially when mixed. The end products contained large amounts of organic matter, usually combined with an increased EC value. Pressed grape skins should be considered as the ideal raw material, producing a high quality compost, with the lowest EC value (1.57 mS cm(-1)) and the largest organic matter concentration (84.50%), compared to all other materials. When any of the produced compost was used in a ratio of 30% by volume (v/v), it increased plant growth, whereas in larger volumes, it presented phytotoxic behaviour, inhibiting both root and shoot development.