Distribution of heavy metals in sediments of the Pearl River Estuary,Southern China:Implications for sources and historical changes

The distribution of heavy metals （Pb, Zn, Cd and As） in sediments of the Pearl River Estuary was investigated. The spatial distribution of heavy metals displayed a decreasing pattern from the turbidity maxima to both upstream and downstream of the estuary, which suggested that suspended sediments played an important role in the trace metal distribution in the Pearl River Estuary. In addition, metal concentrations were higher in the west part of the estuary which received most of the pollutants from the Pearl River. In the sediment cores, fluxes of heavy metals were consistent with a predominant anthropogenic input in the period 1970-1990. From the mid-1990s to the 2000s, there was a significant decline in heavy metal pollution. The observed decline has shown the result of pollution control in the Pearl River Delta. However, it is noteworthy that the metal concentrations in the most recent sediment still remained considerably high. Taken together, the enrichment of heavy metals in sediments was largely controlled by anthropogenic pollution.

Numerical Experiment Research of a Marine Fog Event in the Pearl River Estuary Region

A marine fog event that occurred near the Pearl River Estuary region on 26March 2002 was investigated with the fifth-generation Pennsylvania State University/National Centerfor Atmospheric Research Mesoscale Model (MM5). The results of numerical experiment are veryconsistent with the surface observations, especially in the processes of marine fog formation andevolution. Besides, a series of sensitivity numerical experiments were performed by varying thedistribution of landuse type and the turbulence exchange process. It is shown that the marine fogforms along the coastal line. Tests have indicated that when the distribution of landuse type ismodified, the regions where the marine fog can intrude into are obviously different. The turbulenceprocess in the model is important for fog formation and evolution. If the influence of turbulenceprocess is ignored in numerical simulation experiment, the simulated maximum of the cloud liquidwater content and the height of fog top will be decreased greatly.

A REVIEW OF HEAVY METAL POLLUTION IN THE PEARL RIVER ESTUARY

Since 70'' s, the economy and society in the Pearl River Delta region havebeen undergoing a great development. Pollution control and environment protection have received muchpublic attention. As heavy metals are an important toxic pollutant source in this area and are notbiodegradable in general, a lot of scientists in China, especially in Southern China, devote theirfocus on studying the pollution caused by heavy metals in the Pearl River Estuary (PRE). This paperpresents a comprehensive review on the heavy metal pollution research and its related research inthis area. It is suggested that the study of heavy metal pollution in PRE should be coupled withwater movement, sediment motion and tidal characteristics in this region. Studying core sediments invarious locations is recommended to reveal the history of heavy metal pollution in PRE and improvethe understanding of the fate and transport of metals.

Spatial assessment of water quality using chemometrics in the Pearl River Estuary, China

A cruise was commissioned in the summer of 2009 to evaluate water quality in the Pearl River Estuary （PRE）. Chemometrics such as Principal Component Analysis （PCA）, Cluster analysis （CA） and Self-Organiz- ing Map （SOM） were employed to identify anthropogenic and natural influences on estuary water quality. The scores of stations in the surface layer in the first principal component （PC1） were related to NH4-N, PO4-P, NO2-N, NO3-N, TP, and Chlorophyll a while salinity, turbidity, and SiO3-Si in the second principal component （PC2）. Similarly, the scores of stations in the bottom layers in PC1 were related to PO4-P, NO2-N, NO3-N, and TP, while salinity, Chlorophyll a, NH4-N, and SiO3-Si in PC2. Results of the PCA identified the spatial distribution of the surface and bottom water quality, namely the Guangzhou urban reach, Middle reach, and Lower reach of the estuary. Both cluster analysis and PCA produced the similar results. Self-organizing map delineated the Guangzhou urban reach of the Pearl River that was mainly influenced by human activities. The middle and lower reaches of the PRE were mainly influenced by the waters in the South China Sea. The information extracted by PCA, CA, and SOM would be very useful to regional agencies in developing a strategy to carry out scientific plans for resource use based on marine system functions.

A Comparative Study of Fish Community in Four Main Estuaries of China Southeastern Coastal Areas and Their Adjacent Waters

Based on literature and survery data of fish composition collected by bottom trawl investigation from 2006 to 2007 infour main estuaries of China southeastern coastal areas and their adjacent waters,changes of the taxonomic diversity across spatialand temporal scales of fish community were analyzed by taxonomic diversity indices.The results are as follows:a total number of1397 fish species(including some freshwater species),belonging to 2 classes,42 orders,186 families and 593 genera,were collected inthe studied sea areas.The species richness increased with lower latitudes,particularly so with Perciformes.There were 339 fish spe-cies in the Yangtze River Estuary and adjacent waters,belonging to 2 classes,31 orders,101 families and 231 genera.There were 535fish species in the Minjiang River Estuary and adjacent waters,belonging to 2 classes,33 orders,133 families and 323 genera.A totalnumber of 803 fish species were collected in the Jiulongjiang River Estuary and adjacent waters,which belonged to 2 classes,35 orders,155 families and 419 genera.And 1021 fish species which belonged to 2 classes,32 orders,153 families,and 466 genera were collectedin the Pearl River Estuary and adjacent waters.The numbers of orders and families of fish species from the northern to the southern wa-ters first increased and then decreased.The average variation in taxonomic distinctness(Λ+)gradually decreased with lower latitudes inthe four estuaries and adjacent waters.There were no significant differences in the average taxonomic distinctness(△+)among the fourestuaries and adjacent waters,and fish fauna were closely related with each other,and all of them belonged to the same zoogeographicalfauna(Indian-Malaysia fauna).Fish composition in the Minjiang River Estuary and adjacent waters was more similar to that in the Jiu-longjiang River Estuary and adjacent waters among the four estuaries.Compared with the historical data,the average taxonomic dis-tinctness of fish community showed a great decrease in the Minjiang River Estuary and the Jiulongjiang River Estuary and their adjacentwaters.

清前中期粤海关对珠江口湾区贸易的监管---以首航中国的法国商船安菲特利特号为线索的考察

大航海时代,对于欧洲国家来说,就是探索的时代,它伴随着基督教的传播、海外贸易的扩张以及海上的掠夺。在此期间,葡萄牙最先崛起,带着武装商船沿着非洲海岸进入印度洋,强行参与亚洲贸易。之后十几年,西班牙急起直追。葡萄牙主要向东行,发现西非沿岸,开设殖民点或者商埠,发现了西非以外有一个叫“CapeVerde”(佛得角)的群岛。西班牙主要向西行,发现了新大陆,来到加勒比海、西班牙岛(伊斯帕尼奥拉岛)、古巴等地。其间二者冲突不断。