Integrated assessment of sea water quality based on BP artificial neural network

In order to carry out an integrated assessment of sea water quality objectively, this paper based on the concept and principle of artificial neural network, generated appropriate training samples for BP artificial neural network model through the method of producing samples to the concentration of various pollution index of sea water quality from the viewpoint of threshold, established the BP artificial neural network model of sea water quality assessment using multi-layer neural network with error back-propagation algorithm. This model was used to assess water environment and obtain sea water quality categories of offshore area in Bohai Bay through calculating. The calculations shown that pollution index in river＇s wet season was higher than that in dry season from 2004 to 2007, and the pollution was particularly serious in 2005 and 2006, but a little better in 2007. The assessed results of cases shown that the model was reasonable in design and higher in generalization, meanwhile, it was common, objective and practical to sea water quality assessment.

Coastal Sea Water Quality of Nha Trang Bay, Khanh Hoa, Viet Nam

Nha Trang Bay is famous not only because of its beauty, but also of the biodiversity values, especially coral reefs. Thus, the sea water quality monitoring systems are necessary for effective and available managements to protect the ecosystems and for sustainable development. There have been several monitoring systems here but they have been done separately and unconnectedly. This research was done to take an overview and access the status and changes of water quality from 2007-2014. The data obtained rainy seasons over the years showed a quite good environment here. The environment changes were also monitored and there were some changes between seasons and over years, decreasing, increasing, or unobvious trends. However, the difference was not so much; and there was not the sign of environmental degradation in the bay from 2007 to 2014. Besides, the stoichiometric nutrients limitations were initially assessed. Since Si ratios here were always higher compared to N and P, there was not increased potential for non-diatom algal blooms. Together with the recorded nutrients concentration data, it can be said that there was no evidence of eutrophication in the bay. Although there was partial contamination of some parameters at few moments, the sea water quality of Nha Trang bay was still in a good condition （according to Vietnamese and ASEAN criteria）.

Analysis of water quality pollution sources in Dafeng near-shore sea based on principal component analysis

According to 12 kinds of water quality elements(salt,COD,DO,PO_(4)^(3)--P,inorganic nitrogen,Oil,Cu,Pb,Zn,Cd,Hg,As)in 20 sampling stations in Dafeng sea area.The single factor index method was used to evaluate the water pollution level,the clustering method was used to identify the pollution area,and the source of pollution was analyzed by principal component analysis.The results show:the water quality environment in Dafeng Sea is generally good,and inorganic nitrogen and phosphate are the main over-standard factors.;The spatial cluster analysis shows that the distribution of water quality pollution in Dafeng sea area is low in the south and high in the north,and a gradual increase from the shore to the sea;Principal component analysis results display,sources of pollution include the input of terrestrial pollution(nutrient salts,Cd,As),the marine aquaculture pollution(nutrient salts,Cu),port pollution(Oil,Zn,Pb,Hg).

Nematode community structure in relation to metals in the southern of Caspian Sea

Spatial distribution and structure of nematode assemblages in coastal sediments of the southern part of the Caspian Sea were studied in relation to environmental factors. By considering metals, organic matter, Shannon diversity index（H）, maturity index（MI） and trophic diversity（ITD）, ecological quality status of sediment was also determined. Fifteen nematode species belonging to eleven genera were identified at the sampling sites. Average density of nematode inhabiting in sediment of the studied area was 139.78±98.91（ind. per 15.20 cm^2）. According to redundancy analysis（RDA）, there was high correlation between metals and some species. Based on biological indicators, the studied area had different environmental quality. Generally, chemical and biological indices showed different results while biological indices displayed similar results in more sites.

Santiago,A Warrior of Life——A hero in The old man and the sea

The old man and the sea is Hemingway’s masterpiece,and it is also a classical works in the history of literature.The image of the hero,Santiago,is brilliant and moving.This article starts with the description of Santiago,showing his excellent qualities.Meanwhile,with Hemingway’s working style and working principles,this article further discovers the symbolism of Santiago as well as the reasons for the success of the creation of the image.