Eutrophication Evaluation of Water Body at Huailai Section of the Yongding River

In order to understand the water pollution characteristics in Huailai section of the Yongding River,the monitoring from November of 2016 to October of 2017 was conducted. 6 sampling points were selected for monitoring 6 indicators,and the temporal-spatial variation characteristics of nitrogen and phosphorus in the river were explored. Moreover,the ratio of nitrogen to phosphorus and an exponential universal formula of power function in logarithmic form were used to analyze temporal-spatial variation rules of nitrogen and phosphorus in water,assess the degree of eutrophication,and analyze eutrophication risk. The results showed that water pollution in Huailai section of the Yongding River was more serious. TN was13. 25 times of concentration limit of class III water in the dividing of surface water environment function area in the " 13 thFive-year" Development Planning" of National Environmental Protection Standard. ON and NO-3-N were the main forms of TN,while mean value of TP was 0. 64 mg/L,and each index had the characteristics of agricultural non-point source pollution. The temporal-spatial distribution characteristics of nitrogen and phosphorus in the water body was obvious. At the time scale,the concentrations of nitrogen and phosphorus in the water body showed seasonal variation; at the space scale,the distribution of nitrogen and phosphorus in the water body was similar. The annual average ratio of nitrogen and phosphorus in Huailai section of the Yongding River was 32. 78,and the phytoplankton was in the overall state of phosphorus limitation. During the flat water period,phosphorus was the limiting nutrient element,and the ratio of nitrogen and phosphorus in the dry period and the abundant water period was suitable for the growth and reproduction of algae. The temporal-spatial variation of water body in Huailai section of the Yongding River was mostly in the " eutrophication" stage. The maximum EI value was 228. 11 in dry season,and the lowest was 213. 06 in flood season,while it was218. 30 in flat water period. The fluvial dynamics process in Huailai section of the Yongding River was good,and the flow pattern of the river was continuous. The flow velocity of the main stream was 0. 43-1. 45 m/s,which was much larger than that of the algal bloom. The risk of cyanobacteria blooms in the main stream was low.

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.

精准扶贫政策与农村相对贫困——基于贫困村与建档立卡的分析

在绝对贫困即将消除的背景下,建档立卡与贫困村两项政策在农村脱贫过程中发挥了重要作用。这两项政策在帮助贫困户提高收入的同时,还存在优化收入分配、降低相对贫困的外溢作用。2018年12月中部地区实地调研数据的实证研究结果表明:第一,在标准1(家庭人均收入中位数的50%)下,有近9.6%的个体处于相对贫困状态,如果考虑家庭结构,相对贫困发生率有所减缓,相对贫困深度与贫困强度的结果表明,目前的相对贫困程度与前几年国家绝对贫困标准下的贫困程度类似;第二,贫困村与建档立卡政策存在改善收入分配、降低相对贫困的外溢作用。建档立卡政策这一外溢作用要高于贫困村政策,与此同时,建档立卡与贫困村政策的外溢作用可以叠加;第三,在贫困村与建档立卡政策下,农户生产、生活等各类条件的提高可以降低农村相对贫困。

MARINE ENVIRONMENT AND THE INTERNATIONAL TRIBUNAL FOR THE LAW OF THE SEA:TWENTY YEARS'PRACTICES AND PROSPECTS

The marine environment is severely threatened by human activities. The United Nations Convention on the Law of the Sea of 1982 established the International Tribunal for the Law of the Sea （1TLOS） to adjudicate disputes arising out of the interpretation and application of the Convention. Marine environment is an essential part of the Convention. This paper aims at discussing the role of the 1TLOS in protecting the world＇s oceans through analyzing environmental aspects of the 1TLOS＂ jurisprudence. The second chapter discusses environmental concerns in the mandate of the ITLOS. Chapter three explores environmental concerns in the adjudication of lTLOS through reviewing the 25 cases submitted to the ITLOS in the past 20 years. Chapter four discusses the contributions and challenges of the 1TLOS in marine environmental protection through assessing its environmental jurisprudence from practical and theoretical perspectives. It then comes to a conclusion that the ITLOS has adopted a proactive stance towards the protection of marine environment, and that a big progress has been made in protecting marine environment by the ITLOS.

Feedbacks between vegetation restoration and local precipitation over the Loess Plateau in China

The implementation of large-scale vegetation restoration over the Chinese Loess Plateau has achieved clear improvements in vegetation fraction,as evidenced by large areas of slopes and plains being restored to grassland or forest.However,such large-scale vegetation restoration has altered land-atmosphere exchanges of water and energy,as the land surface characteristics have changed.These variations could affect regional climate,especially local precipitation.Quantitatively evaluating this feedback is an important scientific question in hydrometeorology.This study constructs a coupled land-atmosphere model incorporating vegetation dynamics,and analyzes the spatio-temporal changes of different land use types and land surface parameters over the Loess Plateau.By considering the impacts of vegetation restoration on the water-energy cycle and on land-atmosphere interactions,we quantified the feedback effect of vegetation restoration on local precipitation across the Loess Plateau,and discussed the important underlying processes.To achieve a quantitative evaluation,we designed two simulation experiments,comprising a real scenario with vegetation restoration and a hypothetical scenario without vegetation restoration.These enabled a comparison and analysis of the net impact of vegetation restoration on local precipitation.The results show that vegetation restoration had a positive effect on local precipitation over the Loess Plateau.Observations show that precipitation on the Loess Plateau increased significantly,at a rate of 7.84 mm yr^(-2),from 2000 to 2015.The simulations show that the contribution of large-scale vegetation restoration to the precipitation increase was about 37.4%,while external atmospheric circulation changes beyond the Loess Plateau contributed the other 62.6%.The average annual precipitation under the vegetation restoration scenario over the Loess Plateau was 12.4%higher than that under the scenario without vegetation restoration.The above research results have important theoretical and practical significance for the ecological protection and optimal development of the Loess Plateau,as well as the sustainable management of vegetation restoration.

Did the modern Yellow River form at the Mid-Pleistocene transition?

The incision of the Sanmen Gorge marks the birth of the modern Yellow River,but its timing varies from the late Miocene-early Pliocene to the late Pleistocene(~0.15 Ma),and the suggested forcing mechanisms vary from the uplift of the Tibetan Plateau to global climate change.Here,we report sedimentologic,geochronologic,and provenance data from a drill core near the Sanmen Gorge,the last gorge along the main course of the Yellow River.Our results indicate that typical river channel deposits,with detritus from the Ordos Block in the upstream regions,started to accumulate in the Sanmen Gorge at~1.25 Ma.When integrated with river terrace evidence from the upstream and downstream regions,the results provide robust evidence that the final integration of the modern Yellow River occurred at~1.25 Ma,consistent with the beginning of the Mid-Pleistocene transition(MPT).We propose that the accelerated lowering of eustatic sea level during the MPT may play as important a role as tectonism in driving the birth and evolution of the modern Yellow River.