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951.
Hanna Eriksson H?gg Steve W. Lyon Teresia W?llstedt Carl-Magnus M?rth Bj?rn Claremar Christoph Humborg 《Ambio》2014,43(3):337-351
Dynamic model simulations of the future climate and projections of future lifestyles within the Baltic Sea Drainage Basin (BSDB) were considered in this study to estimate potential trends in future nutrient loads to the Baltic Sea. Total nitrogen and total phosphorus loads were estimated using a simple proxy based only on human population (to account for nutrient sources) and stream discharges (to account for nutrient transport). This population-discharge proxy provided a good estimate for nutrient loads across the seven sub-basins of the BSDB considered. All climate scenarios considered here produced increased nutrient loads to the Baltic Sea over the next 100 years. There was variation between the climate scenarios such that sub-basin and regional differences were seen in future nutrient runoff depending on the climate model and scenario considered. Regardless, the results of this study indicate that changes in lifestyle brought about through shifts in consumption and population potentially overshadow the climate effects on future nutrient runoff for the entire BSDB. Regionally, however, lifestyle changes appear relatively more important in the southern regions of the BSDB while climatic changes appear more important in the northern regions with regards to future increases in nutrient loads. From a whole-ecosystem management perspective of the BSDB, this implies that implementation of improved and targeted management practices can still bring about improved conditions in the Baltic Sea in the face of a warmer and wetter future climate. 相似文献
952.
Coastal development has severely affected habitats and biodiversity during the last century, but quantitative estimates of the impacts are usually lacking. We utilize predictive habitat modeling and mapping of human pressures to estimate the cumulative long-term effects of coastal development in relation to fish habitats. Based on aerial photographs since the 1960s, shoreline development rates were estimated in the Stockholm archipelago in the Baltic Sea. By combining shoreline development rates with spatial predictions of fish reproduction habitats, we estimated annual habitat degradation rates for three of the most common coastal fish species, northern pike (Esox lucius), Eurasian perch (Perca fluviatilis) and roach (Rutilus rutilus). The results showed that shoreline constructions were concentrated to the reproduction habitats of these species. The estimated degradation rates, where a degraded habitat was defined as having ≥3 constructions per 100 m shoreline, were on average 0.5 % of available habitats per year and about 1 % in areas close to larger population centers. Approximately 40 % of available habitats were already degraded in 2005. These results provide an example of how many small construction projects over time may have a vast impact on coastal fish populations.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-014-0522-y) contains supplementary material, which is available to authorized users. 相似文献953.
Bingzi?ZhaoEmail author Yan?Jiang Yan?Jin Jiabao?Zhang 《Environmental science and pollution research international》2014,21(15):9242-9250
The potential influence of autochthonous microorganisms on virus fate in soil is usually determined through extreme conditions of sterilization vs. nonsterilization; however, the relative importance of microbial cells and their exudates remains unclear. In this study, bacterial cells (cell) were harvested, and their exuded extracellular polymeric substances (EPS) were extracted from three strains of bacteria, namely, Gram-negative bacteria Pseudomonas putida and Pseudomonas aeruginosa as well as Gram-positive bacterium Bacillus subtilis. This study aimed to evaluate virus removal in solutions in the presence of cell, EPS, and their combination (cell/EPS), as well as to investigate how their presence affects virus removal efficiencies by four red soils based on batch experiments. Results showed that virus removal percentage in solutions ranged from 11 to 23 in the presence of cells only and from 12 to 15 in the presence of EPS only. The removal percentage in the combined cell/EPS treatment can be estimated by summing the results achieved by the cell and EPS treatments, separately. Meanwhile, cell presence had a negligible effect on virus removal by red soils. EPS and combined cell/EPS significantly reduced virus removal by 20 to 69 % and 16 to 50 %, respectively, which indicated that EPS served a dominant function in reducing virus removal. This study clearly demonstrated that the prediction of virus removal by red soils must consider the effect of bacteria, especially those producing large quantities of EPS, which can be responsible for the underestimation of viral load in certain studies. 相似文献
954.
The water-soluble fraction (WSF) of petroleum contains a mixture of polycyclic aromatic hydrocarbons, volatile hydrocarbons, phenols, and heterocyclic compounds, considered deleterious to aquatic biota. Marine “pejerrey” Odontesthes argentinensis (Teleostei: Atherinopsidae) has a great commercial importance in local fisheries and a high potential for aquaculture. The aim of this study was to evaluate the histopathological effects in “pejerrey” larvae exposed to different concentrations of petroleum WSF. The chronic toxicity test was conducted with newly hatched larvae exposed for 21 days to sublethal concentrations of WSF (2.5, 5, 10, and 20 % of WSF), plus one control. Survival and growth were significantly lower in the highest concentration. Several histopathological changes were found in the gills (e.g., hyperplasia, aneurisms, edema, and necrosis), kidney (e.g., nuclear alterations, decrease in the hematopoietic cells), and liver (e.g., hypertrophy, karyorrhexis, and karyopyknosis). An index of branchial lesion was proposed to standardize gill lesions to different pollutants. 相似文献
955.
Duarte CM Agustí S Wassmann P Arrieta JM Alcaraz M Coello A Marbà N Hendriks IE Holding J García-Zarandona I Kritzberg E Vaqué D 《Ambio》2012,41(1):44-55
The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem. 相似文献
956.
This study investigated the removal of Reactive Black 5 (RB5) textile dye from aqueous solutions using cotton (Gossypium hirsutum) seed shell (CSS) as low cost adsorbents. The data were described according to the Freundlich and Langmuir isotherm models. Of these, the Langmuir model provided the best fit for the experimental data. The highest measured adsorption density was 12.19 mg/g at pH 2. An equilibrium adsorption rate of RB5 by CSS (q(e) = 11.879 mg/g) was observed at 30 minutes. In order to evaluate the adsorption kinetic mechanisms, pseudo first and second order rate kinetic models and an intraparticle diffusion model were applied, with the pseudo second order model providing an excellent fit for the data. 相似文献
957.
958.
García FP García MA Drożdżak J Ruiz-Samblás C 《Environmental science and pollution research international》2012,19(8):3317-3326
Purpose
Exploratory data analysis (EDA) is applied in this research to study the behavior of radioactive aerosols present in the surface atmosphere of Granada, using 7Be as radiotracer. The reason for this study is to reduce the large number of parameters involved in understanding their behavior, given the complexity of the atmosphere.Methods
Aerosol particles were collected weekly in Granada (Spain) over a 5-year period. Low-background gamma spectrometry was used to determine concentrations of 7Be-aerosol activity. The variables studied were: 7Be concentration, cosmic ray intensity, temperature, temperature interval, rainfall, relative humidity, and Saharan intrusions. Least significant difference test (LSD), hierarchical cluster analysis (HCA), and principal component analysis (PCA) with varimax rotation have been applied to study the datasets.Results and discussion
The results of our study reveal that aerosol behavior is represented by two principal components which explain 86.23?% of total variance. Components PC1 and PC2 respectively explain 74.61 and 11.62?% of total variance. PC1 explains the cyclical and seasonal pattern of the samples, while PC2 is related to the production of 7Be. In addition, PCA and HCA show good distribution of the samples by families with two groups, summer and winter, at the extremes and spring?Cautumn in the middle. This result corroborates that there are no differences between spring and autumn in the climate of Granada.Conclusions
EDA has been found to be quite useful in studying the behavior of radioactive aerosols in the surface atmosphere of a city with the climate and geographical characteristics of Granada. 相似文献959.
Başak S Cokgör EU Insel G Orhon D 《Environmental science and pollution research international》2012,19(8):3412-3420
Background
This study investigated the acute effect of benzo[a]anthracene, a significant compound among polycyclic aromatic hydrocarbons, on the biodegradation of a synthetic organic substrate??a peptone/meat extract mixture??under aerobic conditions.Methods
A laboratory-scale sequencing batch reactor was sustained at steady state at a sludge age of 10?days with substrate feeding. Inhibition tests involved running a series of batch reactors initially seeded with the biomass obtained from the parent reactor. After the biomass seeding, the reactors were started with the peptone mixture and a range of initial benzo[a]anthracene concentrations between 0.5 and 88?mg/L. Experimental profiles of oxygen uptake rates and polyhydroxyalkanoates were evaluated by calibration of a selected model.Results
Lower doses of benzo[a]anthracene had no effect on process kinetics. The noticeable acute impact was only observed with the addition of 88?mg/L of benzo[a]anthracene, but it was limited with the storage mechanism: the amount of organic substrate diverted to polyhydroxyalkanoates was significantly reduced with a corresponding decrease in the maximum storage rate, k STO, from 2.7 down to 0.6?day?1. Similarly, the maximum growth rate from internally stored polyhydroxyalkanoates was lowered from 2.3 to 1.0?day?1.Conclusion
Among the mechanisms for direct substrate utilization, only the hydrolysis rate was slightly reduced, but otherwise, the overall COD removal efficiency was not affected. 相似文献960.
J Molnar J Agbaba B Dalmacija S Rončević M Prica A Tubić 《Environmental science and pollution research international》2012,19(8):3079-3086
This study investigated the effects of pH (6-10) and ozone dose [0.4-3.0?mg O(3)/mg dissolved organic carbon (DOC)] on the content and structure of haloacetic acid (HAA) precursors in groundwater rich in natural organic matter (NOM; DOC 9.85?±?0.18?mg/L) during drinking water treatment. The raw water was ozonated in a 2 L glass column. NOM fractionation was carried out using XAD resins. HAA formation potential (HAAFP) was determined according to standard EPA Method 552. NOM characterization revealed it is mostly hydrophobic (65?% fulvic and 14?% humic acids). Hydrophobic NOM significantly influences HAA formation, as confirmed by the high HAAFP (309?±?15?μg/L). Ozonation at pH?6-10 led to changes in NOM structure, i.e. complete humic acid oxidation, and increased the hydrophilic NOM fraction content (65-90?% achieved using 3.0?mg O(3)/mg DOC). The highest degree of NOM oxidation and HAA precursor removal was achieved at pH?10 (up to 68?% HAAFP). Ozonation pH influenced the distribution of HAA precursor content, as increasing the pH from 6 to 10 increased the reactivity of the hydrophilic fraction, with the HAAFP increasing from 19.1?±?6.0?μg/mg DOC in raw water to 152?±?8?μg/mg DOC in ozonated water. The degree of HAA precursor removal depends on the dominant oxidation mechanism, which is related to the applied ozone dose and the pH of the oxidation process. Ozonation at pH?10 favours the mechanism of radical NOM oxidation and was the most effective for HAAFP reduction, with the efficacy of the process improving with increasing ozone dose. 相似文献