地表水体中藻类的生长对pH值及溶解氧含量的影响

论述了水质富营养化后藻类生长对pH值及DO的影响,并对pH的变化给出了定量公式,对水中藻类的生长给出了pH限值。     

An examination of the effect of landscape pattern, land surface temperature, and socioeconomic conditions on WNV dissemination in Chicago

This paper developed an approach by the synthesis of remote sensing, landscape metrics, and statistical methods to examine the effects of landscape pattern, land surface temperature, and socioeconomic conditions on the spread of West Nile virus (WNV) caused by mosquitoes and animal hosts in Chicago, USA. Land use/land cover and land surface temperature images were derived from Terra’s Advanced Spaceborne Thermal Emission and Reflection Radiometer imagery. An analytical procedure using landscape metrics was developed, applying configuration analysis of landscape patterns in the study area. The positive reports of mosquitoes and animal hosts for WNV in fall, 2001–2006, were collected from the Cook County Public Health Department. Forty-nine municipalities were found to have WNV-positive records in mosquitoes and animal hosts in fall 2004. Socioeconomic data were obtained from the 2000 US Census. Statistical analysis was applied to WNV data in fall 2004 to identify the relationship between potential predictors and WNV spread. As a result, landscape factors, such as landscape aggregation index and the urban areas and areas of grass and water, showed strong correlations with the WNV-positive records. Socioeconomic conditions, such as the population over 65 years old, also showed a strong correlation with WNV-positive records. Thermal conditions of water showed a less but still considerable correlation to WNV-positive records. This research offers an opportunity to explore the effects of landscape pattern, land surface temperature, and socioeconomic conditions on the spread of WNV caused by mosquitoes and animal hosts. Results can contribute to public health and environmental management in the study area.     

Acidification in Arabian Gulf--insights from pH and temperature measurements

The detrimental effects of increasing atmospheric levels of carbon dioxide (CO(2)) and other greenhouse gases since the industrial revolution has led to a concerted international effort to control their release and abate the environmental and human health impacts. CO(2) is removed from the atmosphere by photosynthesis of plants in the terrestrial environment and by aquatic sequestration. In the Middle East and other arid countries, terrestrial removal is minimal. The most likely removal pathway for CO(2) in arid regions around the world is by aquatic sequestration. In the Middle East the major sink is the Arabian Gulf which leads to acidification of the marine environment. Biweekly pH concentration measurements in surface waters of the northern Arabian Gulf over a four year period in this study suggest that the Arabian Gulf waters are becoming increasingly acidic with time. Supporting evidence for increased CO(2) sequestration comes from increased marine primary productivity over the past decade. Biological effects, such as coral bleaching, observed during this period suggest that urgent action is required to reverse the trend and protect marine life. The data highlight the fact that this semi-enclosed sea is undergoing a rapid degradation which may affect the oceanic chemistry and biogeochemical cycle much earlier than predicted for most oceanic waters.     

Assessing the influence of altitude and temperature on biological monitoring of freshwater quality: A preliminary investigation

The effect of altitude and water temperature on biomonitoring of freshwater quality was examined along an unpolluted area (36 km in length) of the upper Río Tajo (central Spain). The macrobenthic and fish communities were studied, and the Biological Monitoring Water Quality (BMWQ) method was applied. As expected, values of altitude and temperature respectively decreased and increased with increasing distance from the river source; these two physical parameters exhibited a negative and significant (P<0.05) correlation coefficient between them. However, despite evident changes in the functional structure of both aquatic communities along the study area, BMWQ scores were similar at all sampling sites. Pearson correlation coefficients between physical and biological parameters were not significant (P>0.05). The BMWQ index only exhibited significant (positive) correlation coefficients with macrobenthic and fish biomasses, indicating that freshwater quality could affect the biological production of fluvial ecosystems. It is concluded that biomonitoring of freshwater quality may be independent of the influence of altitude and water temperature at local spatial scales. Nonetheless, further investigations would be needed to clearly differentiate between the effects of anthropogenic and natural causes on biological monitoring at larger spatial scales.     

Labile pools of Pb in vegetable-growing soils investigated by an isotope dilution method and its influence on soil pH

Pollution of Pb in the surface of agricultural soils is of increasing concern due to its serious impact on the plant growth and the human health through the food chain. However, the mobility, activity and bioavailability of Pb rely mainly on its various chemical species in soils. In the present study, E and L values, the labile pools of isotopically exchangeable Pb, were estimated using the method of isotope dilution in three vegetable-growing soils. The experiments involved adding a stable enriched isotope ((206)Pb > 96%) to a soil suspension and to soils in which plants are subsequently grown, the labile pools of Pb were then estimated by measuring the isotopic composition of Pb in soil solutions and in the plant tissues, respectively. In addition, the correlation of E values and soil pH was investigated at the ranges of pH 4.5-7.0. The amount of labile Pb in soils was also estimated using different single chemical extractants and a modified BCR approach. The results showed that after spiking the enriched isotopes of (206)Pb (>96%) for 24 hours an equilibration of isotopic exchanges in soil suspensions was achieved, and the isotope ratios of (208)Pb/(206)Pb measured at that time was used for calculating the E(24 h) values. The labile pools of Pb by %E(24 h) values, ranging from 53.2% to 61.7% with an average 57%, were found to be significantly higher (p < 0.05) than the values estimated with L values, single chemical extractants and the Σ(BCR) values obtained with the BCR approach, respectively. A strong negative correlation (R(2) = 0.984) between E(24 h) values and soil pH was found in the tested soil sample. The results indicate that the %E(24 h) value can more rapidly and easily predict the labile pools of Pb in soils compared with L values, but it might be readily overestimated because of the artificial soil acidity derived from the spiked isotopic tracer and the excess of spiked enriched isotopes. The results also suggest that the amounts of Pb extracted with EDTA and the Σ(BCR) values extracted with the modified BCR approach are helpful to detect the labile pools of Pb in soils. In addition, the negative correlation between soil pH and the labile pools of Pb in soils may be useful for further remediation to reduce the bioavailability of Pb in contaminated soils.     

湖泊中水下植物光合作用对溶解氧和pH值的影响

文章研究了湖泊中水下植物光合作用对湖水ＤＯ和ｐＨ的影响,提出了预测ＤＯ和ｐＨ变化的计算方法     

The devil is in the details (or the surface): impact of surface structure and surface energetics on understanding the behavior of nanomaterials in the environment

Metal and metal oxide nanomaterials are found in many consumer products for use in a wide range of applications including catalysis, sensors and contaminant remediation. Because of the extensive use of metal-based nanomaterials, there are concerns that these materials have the potential to get into the environment sometime during production, distribution, use and/or disposal. In particular, there exists the potential that they will make their way into water systems, e.g. drinking water systems, ground water systems, estuaries and lakes. In this review, some of the uncertainties in understanding nanoparticle behavior, which is often due to a lack of fundamental knowledge of the surface structure and surface energetics for very small particles, are discussed. Although classical models may provide guidance for understanding dissolution and aggregation of nanoparticles in water, it is the detailed surface structure and surface chemistry that are needed to accurately describe the surface free energy, a large component of the total free energy, in order to fully understand these processes. Without this information, it is difficult to develop a conceptual framework for understanding the fate, transport and potential toxicity of nanomaterials. Needed research areas to fill this void are discussed.     

Seasonal variations in the relationship between landscape pattern and land surface temperature in Indianapolis, USA

This paper intended to examine the seasonal variations in the relationship between landscape pattern and land surface temperature based on a case study of Indianapolis, United States. The integration of remote sensing, GIS, and landscape ecology methods was used in this study. Four Terra's ASTER images were used to derive the landscape patterns and land surface temperatures (LST) in four seasons in the study area. The spatial and ecological characteristics of landscape patterns and LSTs were examined by the use of landscape metrics. The impact of each land use and land cover type on LST was analyzed based on the measurements of landscape metrics. The results show that the landscape and LST patterns in the winter were unique. The rest of three seasons apparently had more agreeable landscape and LST patterns. The spatial configuration of each LST zone conformed to that of each land use and land cover type with more than 50% of overlap in area for all seasons. This paper may provide useful information for urban planers and environmental managers for assessing and monitoring urban thermal environments as result of urbanization.     

Speciation of selected heavy metals geochemistry in surface sediments from Tirumalairajan river estuary, east coast of India

Surface sediment samples from the Tirumalairajan river estuary were studied for grain size pattern, organic matter, and heavy metals (Fe, Mn, Zn, and Pb) using the sequential and bulk metal extraction methods to evaluate metal behavior. Ten surface sediment samples were collected during the monsoon and summer seasons of the year 2009. The observed orders of concentrations of heavy metals in the sediments were as follows: Fe?>?Mn?>?Zn?>?Pb. The results obtained from sequential extraction showed that, among the metals studied, a larger portion of the metals were associated with the residual phase, although they are available in other fractions. The low concentration of metals available in bioavailable phases indicated that the sediments of Tirumalairajan river estuary were relatively unpolluted. Correlation analysis was also carried out to understand the associations of metals in different phases with sand, silt, clay, and organic matter. To understand the risk of heavy metals to sediment-dwelling organisms, the data were compared with risk assessment code and sediment quality values using the screening quick reference table. The main source of metals to the estuary is from the irrigation field and its associated activities in the study area.     

The influence of pH on trace element uptake by an alga (Scenedesmus pannonicus subsp. Berlin) and Fungus (Aureobasidium Pullulans)

Experiments were carried oud in order to obtain information on the uptake characteristics of metals in the algal and fungus components of lichens. The uptake of ¹¹⁵Cd, ⁶⁵Zn, ⁶⁴Cu, ¹⁴⁰La, ¹⁸⁷W, ⁷⁵Se, and ⁷⁶As in the alga Scenedesmus pannonicus, subsp. Berlin and the fungus Aureobasidium pullulans was determined during 11 days of incubation at pH 5 and pH 7. The results indicate different acid-sensitivity of the alga and the fungus. The metal uptake in the alga was generally faster at pH 7, in the fungus uptake rates were higher at pH 5. In both the alga and the fungus for different pH-values hardly any differences in ultimate metal levels could be observed for Cd²⁺, Zn²⁺, La³⁺, and SeO _inf3 ^sup2- . In algae, the ultimate levels of the accumulated anionic forms of W and As appeared to be independent of pH; in the fungi the ultimate W and As levels were higher at pH 5. No differences could be observed in the Zn²⁺ accumulation capacities of both organisms. The As accumulation capacity of the alga was estimated to be about 10 times the As uptake capacity of the fungus. The results indicate the component-specific uptake and accumulatiom behaviour in intact lichens.     

Determining the impact of urban components on land surface temperature of Istanbul by using remote sensing indices

For the past 60 years, Istanbul has been experiencing an accelerated urban expansion. This urban expansion is leading to the replacement of natural surfaces by various artificial materials. This situation has a critical impact on the environment due to the alteration of heat energy balance. In this study, the effect upon the urban heat island (UHI) of Istanbul was analyzed using 2009 dated Landsat 5 Thematic Mapper (TM) data. An Index Based Built-up Index (IBI) was used to derive artificial surfaces in the study area. To produce the IBI index, Soil-Adjusted Vegetation Index, Normalized Difference Built-up Index, and Modified Normalized Difference Water Index were calculated. Land surface temperature (LST) distribution was derived from Landsat 5 TM images using a mono-window algorithm. In addition, 24 transects were selected, and different regression models were applied to explore the correlation between LST and IBI index. The results show that artificial surfaces have a positive exponential relationship with LST rather than a simple linear one. An ecological evaluation index of the region was calculated to explore the impact of both the vegetated land and the artificial surfaces on the UHI. Therefore, the quantitative relationship of urban components (artificial surfaces, vegetation, and water) and LST was examined using multivariate statistical analysis, and the correlation coefficient was obtained as 0.829. This suggested that the areas with a high rate of urbanization will accelerate the rise of LST and UHI in Istanbul.     

The influence of metallurgy on the formation of welding aerosols

Recent research has indicated that insoluble ultrafine aerosols (ie., particles whose physical diameters are less than 100 nm) may cause adverse health effects due to their small size, and that toxicological response may be more appropriately represented by particle number or particle surface area. Unfortunately, current exposure criteria and the associated air-sampling techniques are primarily mass-based. Welding processes are high-temperature operations that generate substantial number concentrations of ultrafine aerosols. Welding aerosols are formed primarily through the nucleation of metal vapors followed by competing growth mechanisms such as coagulation and condensation. Experimental results and mathematical tools are presented to illustrate how welding metallurgy influences the chemical aspects and dynamic processes that initiate and evolve the resultant aerosol. This research suggests that a fundamental understanding of metallurgy and aerosol physics can be exploited to suppress the formation of undesirable chemical species as well as the amount of aerosol generated during a welding process.     

The influence of geometry and draught shields on the performance of passive samplers

Passive samplers provide an excellent opportunity to perform indicative measurements or establish a dense network of measuring sites. A drawback compared with conventional active measuring methods is the larger spread of results. This variation can, to a large extent, be attributed to the influence of temperature, sampler geometry and wind on sampling results. A proper design of sampler geometry and optimum choice of draught shield can reduce the influence of wind velocity on a badge type sampler to less than 10%. Wire mesh screens prove to be inadequate in damping turbulence. Filters give good results. Attention should be paid to the size and isolation value of the walls of the sampler to prevent thermal updrafts occurring within the sampler. Tube type samplers are less influenced by wind, provided that turbulence is prevented from influencing diffusion within the sampler.     

Accuracy assessment of land surface temperature retrievals from Landsat 7 ETM + in the Dry Valleys of Antarctica using iButton temperature loggers and weather station data

The McMurdo Dry Valleys of Antarctica are the largest snow/ice-free regions on this vast continent, comprising 1 % of the land mass. Due to harsh environmental conditions, the valleys are bereft of any vegetation. Land surface temperature is a key determinate of microclimate and a driver for sensible and latent heat fluxes of the surface. The Dry Valleys have been the focus of ecological studies as they arguably provide the simplest trophic structure suitable for modelling. In this paper, we employ a validation method for land surface temperatures obtained from Landsat 7 ETM + imagery and compared with in situ land surface temperature data collected from four transects totalling 45 iButtons. A single meteorological station was used to obtain a better understanding of daily and seasonal cycles in land surface temperatures. Results show a good agreement between the iButton and the Landsat 7 ETM + product for clear sky cases. We conclude that Landsat 7 ETM + derived land surface temperatures can be used at broad spatial scales for ecological and meteorological research.     

Meteorological influence on predicting surface SO2 concentration from satellite remote sensing in Shanghai,China

In this study, we explored the potential applications of the Ozone Monitoring Instrument (OMI) satellite sensor in air pollution research. The OMI planetary boundary layer sulfur dioxide (SO₂_PBL) column density and daily average surface SO₂ concentration of Shanghai from 2004 to 2012 were analyzed. After several consecutive years of increase, the surface SO₂ concentration finally declined in 2007. It was higher in winter than in other seasons. The coefficient between daily average surface SO₂ concentration and SO₂_PBL was only 0.316. But SO₂_PBL was found to be a highly significant predictor of the surface SO₂ concentration using the simple regression model. Five meteorological factors were considered in this study, among them, temperature, dew point, relative humidity, and wind speed were negatively correlated with surface SO₂ concentration, while pressure was positively correlated. Furthermore, it was found that dew point was a more effective predictor than temperature. When these meteorological factors were used in multiple regression, the determination coefficient reached 0.379. The relationship of the surface SO₂ concentration and meteorological factors was seasonally dependent. In summer and autumn, the regression model performed better than in spring and winter. The surface SO₂ concentration predicting method proposed in this study can be easily adapted for other regions, especially most useful for those having no operational air pollution forecasting services or having sparse ground monitoring networks.     

Development of MODIS data-based algorithm for retrieving sea surface temperature in coastal waters

A new algorithm was developed for retrieving sea surface temperature (SST) in coastal waters using satellite remote sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua platform. The new SST algorithm was trained using the Artificial Neural Network (ANN) method and tested using 8 years of remote sensing data from MODIS Aqua sensor and in situ sensing data from the US coastal waters in Louisiana, Texas, Florida, California, and New Jersey. The ANN algorithm could be utilized to map SST in both deep offshore and particularly shallow nearshore waters at the high spatial resolution of 1 km, greatly expanding the coverage of remote sensing-based SST data from offshore waters to nearshore waters. Applications of the ANN algorithm require only the remotely sensed reflectance values from the two MODIS Aqua thermal bands 31 and 32 as input data. Application results indicated that the ANN algorithm was able to explaining 82–90% variations in observed SST in US coastal waters. While the algorithm is generally applicable to the retrieval of SST, it works best for nearshore waters where important coastal resources are located and existing algorithms are either not applicable or do not work well, making the new ANN-based SST algorithm unique and particularly useful to coastal resource management.     

环境温度对噪声测量仪器性能的影响

针对环境温度给噪声测量仪器性能造成的影响,在常温、高温与低温的测量环境中,对多台仪器的相关性进行了对比测试与研究。为了保证监测数据的准确性,提出了不同环境温度的测量措施。