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721.
Wayland M Alisauskas RT Kellett D Traylor J Swoboda C Neugebauer E Mehl K 《Environmental pollution (Barking, Essex : 1987)》2007,150(3):329-337
Sea duck populations have declined in North America. Contaminants, especially metals, have been listed as possible contributing factors. Sea ducks are long-lived. Thus, individuals chronically exposed to elevated metal levels may be at greatest risk. Information about long-term exposure (> or =1year) of individuals to metals is absent. To address this information gap, we examined year-to-year correlations among individual White-Winged Scoters and King Eiders in levels of blood cadmium, lead, mercury and selenium. Positive correlations (r> or =0.43), were found in six, five, five and two of seven correlations for cadmium, selenium, lead and mercury. Thus, certain individuals of these species may be exposed over two or more years to higher levels of cadmium, selenium and lead (but apparently not mercury) than other individuals. Single blood samples are appropriate metrics of exposure for studies that examine long-term effects of certain metals on these birds. 相似文献
722.
张愈 《防灾减灾工程学报》2001,21(4):33-38
吴佳翼等研究华北地震同日本地震的相关性 ,提出日本地震活动的 3个区 :日本海沟地震活动区(A区 )、日本海西部的深源地震区 (B区 )和日本浅源地震区 (C区 )如果相继发生地震活动 ,则中国华北地区 (D区 )将发生 6级以上响应地震。作者用 1 979年以来江苏及其黄海的 3个 6级震例 ,说明D区应扩大到江苏及其附近地区 ,并对历史地震进行检验。如果把D区改为大华北东部范围 ,在地球自转减速段 ,响应震将发生在华北东部 35°N~ 39°N地区 ;在地球自转加速段 ,响应震将发生在 φN≤ 35°或 φN>39°的地区。江苏及南黄海 6级响应地震发生的时间 ,可以用东北深震区与黄海地震带的相关性来估计 相似文献
723.
Su Mei Liu Xiao Na Li Jing Zhang Hao Wei Jing Ling Ren Gui Ling Zhang 《Water, Air, & Soil Pollution: Focus》2007,7(6):625-643
Three cruises were carried out in Jiaozhou Bay (JZB) in the neap tide in October 2002 (fall) and in both neap and spring tides
in May 2003 (spring) to understand the relative importance of external nutrient inputs versus physical transport and internal
biogeochemical processes. Nutrients (, , , , silicic acid, total dissolved nitrogen (TDN) and phosphorus (TDP), dissolved organic nitrogen (DON) and phosphorus (DOP))
were measured. The concentrations of nutrients were higher in the northern part than in the southern part. High concentrations
of and DON in JZB demonstrated the anthropogenic input. Ambient nutrient ratios indicated that the potential limiting nutrients
for phytoplankton growth were silicon, and then phosphorus. Nutrients showed an obvious tidal effect with low values at flood
tide and high values at ebb tide. Nutrient elements were transported into JZB in the north and output in the south (i.e.,
into the Yellow Sea), which varied with season, tidal cycle and investigation sites. Water exchange between JZB and the Yellow
Sea exports , and DON out of JZB, while it inputs , silicic acid and DOP into JZB. Nutrient budgets demonstrate that riverine input and wastewater discharge are major sources
of nutrients, while residual flow is of minor importance in JZB ecosystem. JZB is a sink for the nutrient elements we studied
except for DON. Stoichiometric calculations demonstrate that JZB is a net autotrophic system. 相似文献
724.
PAH Metabolites in Bile Fluids of Dab (Limanda limanda) and Flounder (Platichthys flesus): Spatial Distribution and Seasonal Changes (7 pp) 总被引:1,自引:0,他引:1
Kammann U 《Environmental science and pollution research international》2007,14(2):102-108
Background, Aim and Scope
Polycyclic aromatic hydrocarbons (PAH) are important environmental contaminants which may lead to increased levels of neoplastic
aberrations or tumours in fish liver. Therefore, monitoring of PAH and their effects are part of several international environmental
programmes. The aim of the present field study was to investigate the concentrations of the PAH metabolites in fish bile,
to elucidate spatial, seasonal and species differences as well as to discuss different strategies of normalisation with regard
to environmental monitoring.
Materials and Methods:
PAH metabolites were determined in the bile fluid of dab (Limanda limanda) and flounder (Platichthys flesus) caught in the
North Sea and Baltic Sea between 1997 and 2004. After enzymatic deconjugation, two metabolites were determined by means of
HPLC. The limit of detection and the limit of quantification were calculated. The accuracy of the method was tested with a
standard reference material. Results were referred to bile volume as well as to biliverdin.
Results:
The main metabolite, 1-hydroxypyrene, was determined in concentrations from <0.7 to 838 ng/ml in bile of dab (Limanda limanda)
and flounder (Platichthys flesus) caught between 1997 and 2004. The values for 1-hydroxyphenanthrene in fish bile were considerably
lower (<0.4 – 87 ng/ml). Significant differences in the 1-hydroxypyrene levels were found between summer and winter surveys
as well as between the sampling sites in the data set from 2004 (383 dabs and 62 flounders): Highest levels of PAH contamination
were found in dab from the German Bight and in flounder from the Baltic Sea.
Discussion:
Spatial differences in 1-hydroxypyrene concentrations between North Sea and Baltic Sea were discussed, as well as differences
in relation to season, sex and species. Three parameters of normalisation (biliary protein, biliverdin and bile pigments)
were discussed. Biliverdin was identified as a suitable parameter for the normalisation of PAH metabolites in field samples.
Conclusions:
Spatial differences in 1-hydroxypyrene concentrations of dab demonstrate the usefulness of PAH metabolites in fish bile as
a monitoring parameter in marine regions. Significant differences in 1-hydroxypyrene concentrations were found between summer
and winter sampling campaigns. This may be linked to an annual cycle of 1-hydroxyprene in dab. It is also possible that bile
synthesis/release in dab differs between the seasons. There is no indication for a time trend from 1997 to 2004.
Recommendations and Perspectives:
It is recommended to relate PAH metabolites in fish bile to biliverdin concentrations. Although the concentrations are low
in offshore regions and bile volumes are small, the method presented here allows one to measure PAH metabolites on an individual
level which is a crucial prerequisite for meaningful monitoring studies. 相似文献
725.
Water quantity and quality dynamics of the THC — Tuyamuyun Hydroengineering Complex — And implications for reservoir operation 总被引:2,自引:0,他引:2
Froebrich J Bauer M Ikramova M Olsson O 《Environmental science and pollution research international》2007,14(6):435-442
Background In the Aral Sea basin, safe water resources are scarce and steadily becoming scarcer. Particularly high quality water is going
to become a rare good.
The object of the study was the Tuyamuyun Hydroengineering Complex (THC), a complex of artificial water reservoirs located
in the lower Amu Darya River, which provides water for irrigation, industry, and drinking for the lower Amu Darya region.
The focus was on operation of one of its four reservoirs, the Kaparas, which is mainly used for drinking water supply. The
objective includes the investigation of impacts of conventional operation schemes on the reservoir water quality for improving
drinking water quality (salinity). Basic operation rules for Kaparas, which can be considered as representative for conventional
dam operation under dry year conditions, had to be identified and improved operation schemes derived.
Methods Existing data archives were analysed, and further data were acquired from field surveys, data processing and modelling studies.
Historical data were identified, which are appropriate to determine representative schemes for the conventional operation.
For the simulation of time-dependent and depth-dependent changes of reservoir salinisation, the reservoir water quality model
Lac was used and linked with the THC model.
Results and Discussion Modelling results for the simulation of temperature dynamics and density stratification showed a sufficient congruence with
the measured temperature profiles. The conformity of measured and calculated salt concentration is basically ensured. The
reservoir, which fill with higher saline water at the end of the summer, aggravates the entrainment of high saline water in
the entire water column.
Conclusions The current conventional operation regime mainly leads to filling the Kaparas reservoir with high saline water during the
winter months. Even in the event of starting with comparable low salinity levels, the simulation demonstrates the rapid deterioration
of the reservoir water quality. Under dry year conditions, the WHO standards for drinking water will be exceeded by 30% after
two years, so that the impact of dry years in the context of water stress becomes visible.
Recommendations and Outlook Processed data and results are now available to identify enhanced reservoir operation strategies for salinity reduction by
changing the period of reservoir filling and release, as well as to initiate a detailed analysis of how water deficits in
dry years may be reduced by improved operation regimes. Using adapted and enhanced operation rules for THC reservoirs, the
local population within the lower Aral Sea basin might be supplied with more potable water of higher quality in future. 相似文献
726.
A 3-D hybrid flow/transport model is developed to predict the dispersal of oil pollution in coastal waters. The transport module of the model takes predetermined current and turbulent diffusivities and uses Lagrangian tracking to predict the motion of individual particles (droplets), the sum of which constitutes a hypothetical oil spill. Currents and turbulent diffusivities used in the model are generated by a numerical ocean circulation model (POM) implemented for the Caspian Sea. The basic processes affecting the fate of the oil spill are taken into account and parameterised in the transport model. The process of evaporation is modeled with the pseudo-component approach. The model is implemented for a simulated continuous release in the coastal waters of the south part of the Caspian Sea. Numerical experiments simulate 5- and 10-day blowout scenarios resulting from sources situated in areas were intensive and extensive development of oil deposits is expected soon. Oil slick movement and risk of coastline contamination by beaching of offshore oil spills are illustrated for different wind conditions. 相似文献
727.
728.
Roberta Minutoli Giacomo Zagami Cinzia Brugnano Letterio Guglielmo Marco Pansera Antonia Granata 《Chemistry and Ecology》2017,33(4):352-373
Zooplankton represents a key contributor to the ocean biological pump through its consumption of sinking and suspended carbon. A specific and highly sensitive method to evaluate zooplankton carbon requirement from the sinking flux is through the estimation of the activity of the electron transport system. The present study was carried out from samplings in 2006, and it was focused on the spatial 200–0?m zooplankton carbon demand across 24 sampling stations, along the Mediterranean Sea, from the island of Crete to the Strait of Gibraltar. Its potential day/night variability was evaluated. The zooplankton composition, abundance and biomass were investigated. The carbon demand per unit zooplankton biomass indicates geographical and diel differences among the sampling stations. A higher mean carbon demand was seen for the western Mediterranean with respect to the eastern Mediterranean, which can be justified through the observed ratio of gelatinous:crustacean taxa and the water temperatures recorded. Higher carbon demand was measured in samples collected during the dark hours. The relation to the presence and abundance of actively migrating euphausiids and copepods was discussed. A comparison with data from another of our study carried out in the same study area but in another seasonal period was done. 相似文献
729.
Climate change and sea level rise urge low-lying countries to draft adaption policies. In this context, we assessed whether,
to what extent and when the Netherlands’ current flood risk management policy may require a revision. By applying scenarios
on climate change and socio-economic development and performing flood simulations, we established the past and future changes
in flood probabilities, exposure and consequences until about 2050. We also questioned whether the present policy may be extended
much longer, applying the concept of ‘policy tipping points’. Climate change was found to cause a significant increase of
flood risk, but less than economic development does. We also established that the current flood risk management policy in
the Netherlands can be continued for centuries when the sea level rise rate does not exceed 1.5 m per century. However, we
also conclude that the present policy may not be the most attractive strategy, as it has some obvious flaws. 相似文献
730.
Since 2001/2002, the correlation between North Atlantic Oscillation index and biological variables in the North Sea and Baltic Sea fails, which might be addressed to a global climate regime shift. To understand inter-annual and inter-decadal variability in environmental variables, a new multivariate index for the Baltic Sea is developed and presented here. The multivariate Baltic Sea Environmental (BSE) index is defined as the 1st principal component score of four z-transformed time series: the Arctic Oscillation index, the salinity between 120 and 200 m in the Gotland Sea, the integrated river runoff of all rivers draining into the Baltic Sea, and the relative vorticity of geostrophic wind over the Baltic Sea area. A statistical downscaling technique has been applied to project different climate indices to the sea surface temperature in the Gotland, to the Landsort gauge, and the sea ice extent. The new BSE index shows a better performance than all other climate indices and is equivalent to the Chen index for physical properties. An application of the new index to zooplankton time series from the central Baltic Sea (Latvian EEZ) shows an excellent skill in potential predictability of environmental time series. 相似文献