Gravitational Sedimentation Behavior of Sensitive Marine Ariake Clays

It has been well documented that natural marine Ariake clays are sensitive clays. In this study, extensive data of marine Ariake clays are obtained to investigate the gravitational compression behavior for sensitive clays. Analysis results indicate that the compression behavior of remolded Ariake clays is not different from that of other remolded/reconstituted soils. But natural Ariake clays do not follow the gravitational compression pattern reported by Skempton (1970) for natural sedimentary soils. At a given value of effective overburden pressure, the void ratios of natural Ariake clays are almost independent of liquid limits. Most natural Ariake clays lie above the sedimentation compression line proposed by Burland (1990). When the liquid limit is larger than 90% and the ratio of natural water content over liquid limit ranges 0.8-1.1, the natural Ariake clays lie around the sedimentation compression line. In addition, the natural Ariake clay with higher value of the ratio of natural water content over liquid limit lies above the natural Ariake clay with lower value of the ratio of natural water content over liquid limit. Salt removal is the most probable cause for such a phenomenon.     

天然海水河蟹工厂化育苗研究——大水体生产性育苗试验

本文报导了利用对虾育苗设施，进行天然海水河蟹工厂化育苗生产性试验。试验结果令人满意，６９６只亲蟹产出蟹苗１７６４万只。文中讨论了亲蟹的暂养与促产、幼体孵化、幼体培育等主要技术环节。     

Effects of long-term sample preservation on flow cytometric analysis of natural populations of pico-and nanophytoplankton

The effects of long-term preservation on flow cytometric parameters of natural oceanic populations of pico-and nanophytoplankton have been examined. Populations collected at oligotrophic subtropical and subarctic locations in the North Pacific were fixed with glutaraldehyde and frozen in liquid nitrogen, according to Vaulot et al. (1989). During six months’ storage, chlorophyll red fluorescence declined in all the groups examined, while forward light scatter was enhanced in Synechococcus and Prochlorococcus, and weakened in nanoeucaryotes. Cell loss was not significant except for Synechococcus. Caution is required when analyzing flow cytometric data of samples stored for more than a month.     

Strength Sensitivity of Marine Ariake Clays

Natural Ariake clays are characterized by high sensitivity. In this study, the mechanism and the factors controlling undrained shear strengths of both undisturbed and remolded Ariake clays are discussed. A series of unconfined compressive tests were performed on undisturbed samples of natural Ariake clays. The remolded undrained shear strength is predicted using a quantitative expression derived from extensive data of remolded undrained shear strength for a number of soils compiled from resources in the literature. The sensitivity of natural Ariake clays derived from the ratio of half of unconfined compressive strength for undisturbed samples to remolded undrained shear strength is found to be affected by both natural water content and normalized water content that is defined as the ratio of natural water content to liquid limit. The smaller the natural water content, the higher the sensitivity is at the same normalized water content. At the same natural water content, the larger the normalized water content, the higher the sensitivity is.     

基于信息熵的溢油对天然渔业可持续承载力损害的评估

作者基于信息熵理论,以溢油事故对海洋天然渔业损害为切入点探讨海洋生态系统可持续承载力损害评估方法。论文从生态系统状态、功能、污染、修复等4个方面构建了熵流和熵产生指标体系,以"塔斯曼海"轮溢油事故为例进行计算和评估,结果表明:溢油使海洋生态系统的价值产出能力下降94.7%、总的承载力下降194.9%,溢油治理的效果小于溢油对生态承载力的损害。本评价是现有溢油生态损害评价的补充,可为长期生态损害评估、生态修复和环境管理决策提供科学依据。     

A Quantitative Study of the Stony Coral Fishery in Cebu, Philippines

Abstract. The Philippines is generally accepted to be the center of the international trade of stony corals for ornamental use. Despite existing legal bans on the collection and export of stony corals in the Philippines, the coral trade continues to date, particularly in Cebu. This paper reports on the specific market demand for stony corals in Cebu and the effects of commercial collection based on the results of a quantitative study of two shallow coral reef areas subjected to large differences in collection effort. Comparison of the measured coral community parameters suggests selective population changes and reduced abundance of exploited coral populations as a result of commercial collection. Estimates of the natural mortality, fishing mortality and yield are presented for the two sampled populations of Pocillopora verrucosa , utilizing the method of GRIGG (1976). Based on the study results and a review of reported coral growth rates and coral colony size at reproductive maturity, the potential for resource management of stony corals on a sustainable yield basis is - discussed.     

Measurements of atmospheric dimethyl sulfide and carbon disulfide in the western Atlantic boundary layer

Shipboard measurements of atmospheric dimethyl sulfide were made during two transects along the east coast of the United States and at several stations in the Gulf of Maine. Limited measurements of carbon disulfide and hydrogen sulfide are also reported. The mean DMS mixing ratio was 29 pptv (=25, n=84, median 19 pptv) during the Atlantic transects, and 101 pptv (=67, n=77, median 79 pptv) in the Gulf of Maine. Distinct diurnal variations were found in the DMS data from the transects. The meteorology of the study area appears to control day-to-day differences in the magnitude of these diurnal variations, although rapid daytime oxidation is suggested in some cases. Diurnal variations were also evident in near-shore stations in the Gulf of Maine due to nocturnal boundary-layer inversion. Diurnal variation was not evident at other sites in the Gulf due to large scale changes in the atmospheric circulation pattern, which effectively masked any effects due to oxidation processes. Model simulations confirm that the DMS levels and diurnal variation found during the transects are not consistent with atmospheric oxidation processes alone. Atmospheric CS₂ and H₂S mixing ratios were less than 3 pptv during the transects, except for a single period of higher CS₂ mixing ratios (reaching 11 pptv) during advection of continental air. Calculations of the flux of oceanic sulfur to the eastern United States show that the contribution of natural sulfur to the North American sulfur budget is small compared to anthropogenic sources.     

中仑昆山北坡黄土特征及其环境

根据野外调查和实验分析资料,阐述和分析中昆仑山北坡黄土的形成时代、物质成分和结构及沉积条件,认为黄土属晚第四纪风积物质,现代黄土堆积持续进行,物质主要来源于塔克拉玛沙漠。在干旱气候背景上,7000—5000a.B.P.为明显相对湿润时期。     

基于城市生态空间土地整治的生物群落构建

随着城市生态文明建设步伐加快,城市建设对生态用地的需求日益增加。然而中国城市生态空间土地整治工程建设中存在过度注重美学和视觉效应、盲目引进外来种、植物配置不合理、大面积运用草坪等现象,在城市生态文明建设的同时也引发了很多问题。通过分析生态文明背景下中国城市生态空间规划与建设存在的问题,结合城市土地整治生态空间特点,总结提出了“人+植物”群落城市土地整治生态修复基础理论,并以陕西省渭南市渭东新城综合整治项目为例,重点阐述了城市土地整治过程中生态空间群落构建的方法要点和具体思路。结果表明:在城市土地整治修复和生态空间建设中,重点利用本土植物群落特性,构建复层植物群落;丰富区域生物多样性,打造平衡的生态链;充分考虑人与自然的耦合关系,并以“人+植物”群落为单位与城市设施、人类活动、环境承载力综合考虑设计城市生态景观,最终可以构建优美、可持续的城市生态空间。     

Conjoint analysis of small‐boat recreational fishers in New Zealand

Conjoint analysis is a useful technique to assist recreational managers formulate policy, and develop strategies to efficiently and effectively distribute resources. Accurate estimates of the value of natural resources remain challenging, despite the development of a number of decision analysis techniques. This recreation geography study uses conjoint analysis to examine the relative importance of attributes associated with small‐boat recreational fishing experiences and demonstrates the value of conjoint analysis as a non‐market valuation tool. We found that the choices associated with companionship are the most important factors of recreational fishing and more tangible attributes such as the quality of launch facilities and catch probability are the least important factors.