Study on Eco-environmental Stress Based on the Method of Entropy-GM(1,1) ——A Case Study in Tongyu County of Jilin Province

This paper takes the Tongyu County as an example, based on the evaluation indicator system of eco-environmental stress, using the method of the entropy- GM（1,1 ）, the eco-environmental stress is evaluated and forecasted, Results show that the shortage of water resources, the desertification, the salinization, the grassland degeneration and the population increase are major stress factors of eco-environment worsening in the Tongyu County; eco-environmental stress coefficient from 1994 to 2013 in the region was increasing year by year, and the stress degree jumped from level-Ⅲ to level-Ⅳ. The forecast results show that if the measures don＇t be taken to protect eco-environment, the stress coefficient still grows, and the stress degree aggravates. In view of the above situation, we take the measures to lighten eco-environment stress, and promote the coordi- nated development of resources, environment and social economy, which is linking rivers and lakes, water resources optimization, preventing and controlling the desertification and the salinization, improving the degenerated grassland.

Seasonal Variations of Picoeukaryote Community Structure in Zhoushan Fishing Ground,East China Sea

Picoeukaryotes(<2-3μm)are major oceanic primary producers and play a crucial role for the functioning of marine ecosystems.However,the community structure of such communities remains poorly understood,especially in the East China Sea(ECS).We investigated the seasonal variations of abundance and diversity of picoeukaryotes,and recorded environmental variables,along a transect in Zhoushan Fishing Ground.High-throughput sequencing was used for sequencing the V4-V5 variable region within the 18S rRNA gene to analyze genetic diversity and relative abundance of picoeukaryotes.A total of 40 phyla,68 classes,99 orders,126 families,and 140 genera were observed.The estimated richness and diversity indices were both higher in each season.The composition and dominant picoeukaryotes changed significantly at the class level with the seasons alternating.Basidiomycota,Ciliophora,Ascomycota and Cryptomonadales were observed throughout the year.The Linear Discriminant Analysis(LDA)revealed the predominant discriminant taxa of four seasonal groups.Redundancy analysis(RDA)showed that NO2^−and salinity played very important roles to picoeukaryotes for all the spring samples and DS5 sample in winter,PO4^3−and pH affected mostly picoeukaryotes for winter samples and autumn samples.

Bacterial Community Structure of Sediment in Upstream Ecological Wetland of Guanting Reservoir under the Action of Different Plants in Winter

In order to study the effect of reed and cattail on the bacterial community structure of surface sediments of wetland in winter,highthroughput sequencing technology was used to analyze the bacterial composition. The results showed that 134 228 high-quality gene sequences were obtained by high-throughput sequencing in sediments of natural wetland in winter,and there were 13 866 OTUs,in which the number of OUT in sediments of reed wetland and cattail wetland was 6 677 and 7 189 respectively. The richness and diversity of bacterial communities in sediments of cattail wetland in winter were higher than those in sediments of reed wetland. Relative abundance of Proteobacteria in sediments of reed wetland and cattail wetland was 0. 54 and 0. 52,respectively. The dominant classes of bacteria were Betaproteobacteria,Deltaproteobacteria,Gammaproteobacteria and Epsilonproteobacteria,which belonged to gram-negative bacteria,indicating that the rhizosphere of wetland was easier to enrich gram-negative bacteria. Under the genus level,the dominant bacteria in the sediments were not obvious.

Present Situation of West Wetland in Jilin Province and Countermeasures for Restoration

The western region of Jilin Province is rich in wetland resources,and its biodiversity is rich. However in recent years,due to the reduction of natural precipitation,human activities and other causes,wetland shrivels and degenerates,biodiversity reduces,and ecosystem security is threatened. In this paper,the rivers and lakes connecting project in western Jilin Province is proposed to restore the damaged wetlands and protect important wetlands.