Metal enrichment in beach sediments from Chennai Metropolis, SE coast of India

A survey on the Partially Extracted Trace Metals (PETMs) concentration (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) in beach sediments is reported for the first time from 57 different locations in Chennai Metropolitan City of Southeast coast of India. The concentration of PETMs suggests that they are mainly concentrated with organic matter in the crowded part of the industrial regions in the beaches from the northern part rather than the tourist beaches in the southern part of the city. The comparison on enrichment of trace metals indicates higher values of Pb, Ni in the beaches than lowest effect level (LEL) and effects range low (ERL) than the tourist beaches.     

Embryonic exposure to environmentally relevant concentrations of PCB126 affect prey capture ability of Fundulus heteroclitus larvae

Early life stages from a marine fish species, Fundulus heteroclitus, were exposed to sublethal doses of 3,3',4,4',5 pentachlorobiphenyl (PCB126) to evaluate its effects on ecologically relevant responses: growth and behavior. A few hours after fertilisation, eggs were treated topically with PCB126 (2.5-50 pg egg?1). Four days post-hatching (dph), morphological changes (body length and malformations), spontaneous locomotor activity (active swimming speed, rate of travel, % inactivity), prey capture ability (Artemia franciscana nauplii) and whole body EROD activity were evaluated in larvae. Untreated larvae collected at 0.5, 1, 2, 3, 4 dph were also examined. PCB126 did not increase the mortality or malformation rates. Body length and spontaneous locomotor activity were altered only in larvae treated with the highest dose. Treatment with PCB126 caused a dose-responsive reduction in prey capture ability (rate of decline in the number of Artemia) and induction of EROD activity. The lowest observed effective dose for both of these responses was 5.0 pg PCB126 egg?1 or 5.0 TCDD-toxic equivalents pg g?1 egg, using a TCDD-toxic equivalent factor of 0.005 and an egg mass of 5 mg. Prey capture efficiency (number of Artemia captured per feeding strike) was reduced at ≥ 10.0 pg egg?1. In untreated developing larvae, prey capture ability and efficiency increased as post-hatching development progressed and EROD activity remained low. The pattern of behavioral responses observed in PCB126-exposed Fundulus larvae differed from that observed in less-developed larvae indicating that other mechanisms than retarded development were involved. Behavioral dysfunction was a more sensitive response to PCB126 than morphological alterations and it occurred at environmentally relevant concentrations.     

Sediment-related distribution patterns of nematodes and macrofauna: two sides of the benthic coin?

We investigated the sediment-related distribution of both nematodes and macrofauna on the Belgian part of the North Sea (Southern Bight of the North Sea) in order to evaluate whether both faunal groups reflect similar patterns in community composition and diversity. Fine-grained sediments (median grain size <200μm) were inhabited by nematode communities characterised by a low diversity and dominated by non-selective deposit-feeding nematodes. Nematode communities from coarser sediments were significantly different in terms of community composition and diversity. Moreover, all nematode feeding types were present in coarser sediments. These differences were explained by the contrasting biogeochemical processes prevailing in both sediment types, rather than granulometry and food availability per se. Macrofaunal distribution patterns were different from those of the nematode communities and seem to be related to water column processes (SPM loading, food availability, hydrodynamic stress) that promote the establishment of diverse communities in the coarser sediments but not in the finest sediments. This suggests that data on nematodes and macrofauna reveal different, complementary aspects of the factors structuring the benthic ecosystem that can be of importance in assessing the ecological status of the seafloor.     

Ground-Based In Situ Measurements of Near-Surface Aerosol Mass Concentration over Anantapur: Heterogeneity in Source Impacts

Surface measurements of aerosol physical properties were made at Anantapur(14.62°N,77.65 °E,331 m a.s.l),a semiarid rural site in India,during August 2008-July 2009.Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity(RH<75%) using a Quartz Crystal Microbalance(QCM) in the 25-0.05 μm aerodynamic diameter range.The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 μg m-3,with a mean value of 34.02±9.05μgm-3 for the entire study period.A clear diurnal pattern appeared in coarse,accumulation and nucleation-mode particle concentrations,with two local maxima occurring in early morning and late evening hours.The concentration of coarse-mode particles was high during the summer season,with a maximum concentration of 11.81±0.98μgm-3 in the month of April,whereas accumulationmode concentration was observed to be high in the winter period contributed >68% to the total aerosol mass concentration.Accumulation aerosol mass fraction,A f(=Ma/Mt) was highest during winter(mean value of Af～0.80) and lowest(Af～0.64) during the monsoon season.The regression analysis shows that both R eff and R m are dependent on coarse-mode aerosols.The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm(AOD500) and PM 2.5 mass concentration([PM2.5]) shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period.     

比较资源分布的目标法

对空间形式的分析已经引起许多地理学者的关注。大地理区上样本变量间关系的分析成功的借用了相关分析法。谢尼尔(1977)用因子分析研究过树木分布和气候地理变化间的空间关系。费歇(1968)亦通过因子分析直观地绘出了气候因子变化等直线图。克利夫(1981)采用联合计数和I统计量揭示了理论分布图和实际观测图之间的对应关系。     

用光电扫描仪测定面积的精度估计

用自动化设备测定图上面积时，需记录扫描线与地物图斑周界线的交点[1]或逐一记录地形要素的二元光栅[4]．众所周知，各种不同的作业——地籍、设计与勘测、建筑、市政管理、环境保护措施等——要求测定图上面积的相对误差由1／25到1／2000．