英国的自然保护

就英国自然保护区的八种主要类型：国家公园、国家风景区、自然遗产区、自然风景名胜区、遗产海岸、环境敏感区、特殊科学意义区、国家自然保护区;以及自然保护区的保护管理机构分别进行了概略介绍,以便有助于对英国自然保护区的了解。     

南沙群岛电子地图及其多媒体模式研究

近十年来随着高新技术发展应运而生的电子地图,具有信息丰富、直观易读、更新方便、使用灵活等优点。本文对南沙群岛中多国领土之争的大片航行危险区与他国非法侵占地、且自然条件复杂与调研程度不断深入的地区,进行了制作电子地图的科学依据和实际意义的论述。同时指出电子地图多媒体在该海域应用的前景与作用。     

暗纹东方鲀温室养殖技术及其经济效益分析

利用养鳗温室养殖暗纹东方,经过一年半的养殖,共养殖商品河鱼5272．5公斤,每平方米生产河鱼2．3公斤,成活率达72．8％,盈利64．88万元,取得了较好的经济效益。同时,总结了一套较为有效的温室养殖技术。     

Remote sensing composite information's trend surface analysis of Nansha Islands coral islets and reefs'top

INTRODUCTIONIntheseaareaofNanshaIslands,therearemanyshoalpatchandrapids.Themajorareaisclassifiedas"dangerouszone".Thereforeitisverydifficulttomakeanormalinvestigationonit.Consideringtheremotesensinginformationfeaturesreflectedbythecontrolfunctionoflocalgeographicstructureandthegrowthofcoralisletsandreefs,wefindthatthemostimportantfeatureofthegeographicsystemofNanshaIslandsisthatitsdistributionisregional.Thetrendsurfaceanalysissystembasedontheremotesensingcompositeinformationistoemulatet…     

Study on topographic compensation model of the Okinawa Trough I. Calculation of theoretical isostatic response function

INTRODUCTIONTo study the compensation model of sea topography and isostatic states by using toPOgraphicand gravity data, is an imPOrtant mean for further researching deep structures as elastic structure,stress state of lithosphere, and so on. Since Airy and Pratt proPOsed local isostatic model in the1850' s, greater development on the theoretical study has been attained. Veining Meinesz (1941 )introduced regional compensation mechanism by considering it as floating crust in elastic fie…     

Distribution characteristics of size-fractionated chlorophyll a and primary productivity in Beibu Gulf

The distribution of the abundance of phytoplankton, chlorophyll a (Chl.a) concentration and primary productivity in the Beibu Gulf were observed from May 23 to June 4, 1994.The results show that there were marked featares of spatial zonation in the survey area due to the differences between the geographic environment and the hydrological conditions.Chlorophyll a and primary productivity were higher in the inshore than in the middle area and higher in the north than in the south of the Beibu Gulf.The average concentration of Chl.a, primary productivity and the abundance of phytoplankton were 0.94±0.45 μg/dm³, 351±172 mg/(m²·d) (C) and 0.97×10⁴-10.050×10⁴ ind./m³ in the area, respectively.There were 176 species belonging to 4 phyla and 56 genera based on microscope identification.The results of the size-fractionation show that the contribution of nanoplankton and picoplankton was 77% to total Chl.a and 91% to total primary productivity, which proved their importance to phytoplankton communities in the Beibu Gulf.     

The importance of extratropical and tropical cyclones on the short-term evolution of barrier islands along the northern Gulf of Mexico, USA

Data are presented indicating the complexity and highly variable response of beaches to cold front passages along the northern Gulf of Mexico, in addition to the impacts of tropical cyclones and winter storms. Within the past decade, an increase in the frequency of tropical storms and hurricanes impacting the northern Gulf has dramatically altered the long-term equilibrium of a large portion of this coast. A time series of net sediment flux for subaerial and nearshore environments has been established for a section of this coast in Florida, and to a lesser extent, Mississippi. The data incorporate the morphological signature of six tropical storms/hurricanes and more than 200 frontal passages.

Data indicate that (1) barrier islands can conserve mass during catastrophic hurricanes (e.g., Hurricane Opal, a strong category 4 hurricane near landfall); (2) less severe hurricanes and tropical storms can promote rapid dune aggradation and can contribute sediment to the entire barrier system; (3) cold fronts play a critical role in the poststorm adjustment of the barrier by deflating the subaerial portion of the overwash terrace and eroding its marginal lobe along the bayside beach through locally generated, high frequency, steep waves; and (4) barrier systems along the northern Gulf do not necessarily enter an immediate poststorm recovery phase, although nested in sediment-rich nearshore environments. While high wave energy conditions associated with cold fronts play an integral role in the evolution and maintenance of barriers along the northern Gulf, these events are more effective in reworking sediment after the occurrence of extreme events such as hurricanes. This relationship is even more apparent during the clustering of tropical cyclones.

It is anticipated that these findings will have important implications for the longer term evolution of barrier systems in midlatitude, microtidal settings where the clustering of storms is apparent, and winter storms are significant in intensity and frequency along the coast.     

On the radiation and diffraction of linear water waves by an infinitely long rectangular structure submerged in oblique seas

The radiation and diffraction of linear water waves by an infinitely long rectangular structure submerged in oblique seas of finite depth is investigated. The analytical expressions for the radiated and diffracted potentials are derived as infinite series by use of the method of separation of variables. The unknown coefficients in the series are determined by the eigenfunction expansion matching method. The expressions for wave forces, hydrodynamic coefficients and reflection and transmission coefficients are given and verified by the boundary element method. Using the present analytical solution, the hydrodynamic influences of the angle of incidence, the submergence, the width and the thickness of the structure on the wave forces, hydrodynamic coefficients, and reflection and transmission coefficients are discussed in detail.     

沉积物孔隙毛细管压力与甲烷水合物饱和度关系研究

To better understand the relationship between the pore capillary pressure and hydrate saturation in sediments, a new method was proposed. First, the phase equilibria of methane hydrate in fine-grained silica sands were measured. As to the equilibrium data, the pore capillary pressure and saturation of methane hydrate were calculated. The results showed that the phase equilibria of methane hydrates in fine-grained silica sands changed due to the depressed activity of pore water caused by the surface group and negatively charged characteristic of silica particles as well as the capillary pressure in small pores together. The capillary pressure increased with the increase of methane hydrate saturation due to the decrease of the available pore space. However, the capillary-saturation relationship could not yet be described quantitatively because of the stochastic habit of hydrate growth.     

中华绒螯蟹人工半咸水工厂化育苗试验研究报告

在盐度为14—19‰的人工海水中,温度20—25℃条件下,189只平均体重100g的抱卵亲蟹产蚤状幼体4025万只。布苗密度为50—100万只/m~3为宜。必须经常换水,保持水质良好。人工饵料以单胞藻和丰年虫无节幼体为主,可适当加喂蛋黄。