基于ASP.NET MVC的海域海岸带整治修复项目信息管理系统的设计和实现          下载免费PDF全文

于新宇  李家  郝杰  闫吉顺 《海洋开发与管理》2018,35(2):71-73+93

文章在国家大力开展海域海岸带整治修复的背景下,利用Visual Studio 2013开发平台和SQL Server 2014数据库软件,采用ASP.NET MVC架构设计海域海岸带整治修复项目信息管理系统,实现整治修复项目信息的快速录入,并可进行查询、展示和互动等操作。相比传统信息管理系统,本系统大大提高了可维护性、可扩展性、灵活性和封装性,可促进我国海域海岸带整治修复项目信息管理实现现代化。  相似文献   

Sustainable shellfish aquaculture in Saldanha Bay,South Africa     

A Santa Marta  JG Ferreira  GC Pitcher  J Lencart e Silva 《African Journal of Marine Science》2020,42(2):151-166

The carrying capacity for bivalve shellfish culture in Saldanha Bay, South Africa, was analysed through the application of the well-tested EcoWin ecological model, in order to simulate key ecosystem variables. The model was set up using: (i) oceanographic and water-quality data collected from Saldanha Bay, and (ii) culture-practice information provided by local shellfish farmers. EcoWin successfully reproduced key ecological processes, simulating an annual mean phytoplankton biomass of 7.5 µg Chl a l^–1 and an annual harvested shellfish biomass of about 3 000 tonnes (t) y^–1, in good agreement with reported yield. The maximum annual carrying capacity of Small Bay was estimated as 20 000 t live weight (LW) of oysters Crassostrea gigas, or alternatively 5 100 t LW of mussels Mytilus galloprovincialis, and for Big Bay as 100 000 t LW of oysters. Two production scenarios were investigated for Small Bay: a production of 4 000 t LW y^–1 of mussels, and the most profitable scenario for oysters of 19 700 t LW y^–1. The main conclusions of this work are: (i) in 2015–2016, both Small Bay and Big Bay were below their maximum production capacity; (ii) the current production of shellfish potentially removes 85% of the human nitrogen inputs; (iii) a maximum-production scenario in both Big Bay and Small Bay would result in phytoplankton depletion in the farmed area; (iv) increasing the production intensity in Big Bay would probably impact the existing cultures in Small Bay; and (v) the production in Small Bay could be increased, resulting in higher income for farmers.  相似文献   

Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: 3. Secondary Inhabitants     

James E.  Hook Stjepko  Golubic 《Marine Ecology》1992,13(2):119-131

Abstract. Vacated microborings in periostracum of live mussels of the Florida Escarpment redox community (depth of 3266 m) become a habitat for a prolific secondary microbiota consisting of a variety of prokaryotic and a few eukaryotic organisms. Periostracum surface is also colonized by diverse microorganisms, dominated by presumed chemolithotrophic bacteria with stacks of intracellular lamellae. Unlike sheltered microflora within borings, the surface community is heavily grazed upon by numerous archaeogastropods and ciliates.  相似文献   

贻贝(Mytilus edulis)的核型与减数分裂     

王金星  赵小凡  周岭华  相建海 《海洋科学》1996,20(2):44-47

利用体内注射ＰＨＡ和秋水仙素的方法，以锶和生殖腺为材料，对贻贝ＭｙｔｉｌｕｓｅｄｕｌｉｓＬｉｎｎａｅｕｓ的核型和减数分裂进行了观察分析，结果为，二倍体数２ｎ＝２８，核型为１０ｍ＋１２ｓｍ＋６ｓｔ，ＮＦ＝５０。没有发现异形性染色体，贻贝的减数分裂与其他动物类似，也没有发现异形染色体的特殊行为。  相似文献   

A rationale for beach selection by the public on the coast of Wales, UK     

D T Tudor  A T Williams 《Area》2006,38(2):153-164

Questionnaires were completed by 2306 beach users at 19 Welsh beaches with respect to beach selection parameters. The modal group of respondents was female aged 30–39. Beach choice was primarily determined by clean litter-free sand and seawater, followed by safety. Refreshment facilities and beach awards were deemed minor considerations by the public when choosing a beach to visit. Approximately 58 per cent of respondents were aware of beach award and rating schemes. Of coastal visitors interviewed for this paper, 67 per cent rated a beach as 'important' or 'very important' to their holiday, with just 2 per cent replying that they were unimportant.  相似文献   

History and necessity: the evolution of soil conservation technology in a Jamaican farming system     

Rebecca J. Kent 《The Geographical journal》2002,168(1):48-56

The soil conservation campaigns that have been a prominent feature of Jamaican agricultural policy since the 1950s are frequently presented as having failed to ameliorate the problem of soil erosion in hillside agriculture. A case study of a small farming community in the Blue Mountains explores the development of the soil conservation practices currently employed by farmers. The use of trash barriers in carrot farming is described and the origins of this technology and its subsequent adaptation are considered. The study concludes that extension interventions and government policy have influenced the development of current soil conservation practices; practices which have their roots in indigenous techniques. Other factors such as the adaptation of trash barriers to suit local conditions and their importance in soil fertility management also play a role in their widespread use in the study area. The study demonstrates that to understand the process of technical change in farming communities, it is necessary to consider a range of factors, external and internal, technical and social, that have over time influenced farmers' decision making.  相似文献   

Stabilization of swelling clays by Mg(OH)₂. Changes in clay properties after addition of Mg-hydroxide     

G. S. Xeidakis 《Engineering Geology》1996,44(1-4):107-120

Stabilization of the swelling clay structure is attempted by intercalation of Mg(OH)₂ and the development of a brucite interlayer between the clay layers. The properties of the product obtained by applying the technique, formulated as described in a previous work, are considered here. The materials used were Wyoming bentonite (USA), Fuller's Earth (UK), kaolinite, illite, lignite, and silica gels. The Mg(OH)₂-clay products were examined by the methylene blue dye test, X-ray diffraction analysis (XRD), differential thermal analysis (DTA), and derivative thermogravimetry analysis (DTGA). From the results obtained it is concluded that: the Mg-hydroxide is adsorbed by swelling clays both on their external and internal surface, whereas it is adsorbed on the external surface by non-swelling clays. The internally adsorbed phase of Mg-hydroxide forms an ill-defined interlayer of brucite, retarding swelling, whereas the external phase covers the particles modifying drastically their surface properties, like the adsorption of the MB dye. The material produced after precipitation of Mg-hydroxide on swelling clays (smectites) did not re-expand on wetting or after glycolation. The adsorption of MB dye was also reduced by some 80–90%, due to coating effect, preventing the measurements of the external surface area of the clay by polar molecules. The principal forces involved in the process are believed to be physical adsorption on the external surface, along with chemisorption and some chemical bonding, mostly in the internal surface. Cementation due to crystallization and, in the long term, some pozzolanic reactions take also place. Internal adsorption of the Mg-hydroxide is postulated to be in the form of positively charged mono- and/or small polymers and it is, chiefly, diffusion controlled. Since Mg-hydroxide is internally adsorbed by swelling clays, whereas Ca-hydroxide(lime) is not, and the (Mg, Ca)-clay aggregates are more stable than the Ca-clay or the Mg-one, the combination of the two hydroxides could give better results in soil stabilization than each hydroxide alone.  相似文献   

辽宁省海洋生态修复现状、存在的问题及对策建议          下载免费PDF全文

王鹏  张连杰  闫吉顺  于永海  张盼 《海洋开发与管理》2019,36(7):49-52

随着沿海经济带的开发建设,海洋生态环境承受着巨大压力,湿地、河口、海湾、海岛等重要生态系统面临前所未有的威胁。对海洋生态的保护修复已经迫在眉睫、刻不容缓。文章基于辽宁省海洋资源环境的特征,结合海域开发利用及海洋生态修复现状,探索辽宁省海洋生态修复工作面临的主要问题,并提出生态修复重点及对策建议,截至2017年,累计整治修复岸线长度约140km,整治修复海域面积超过50km~2。辽宁省海洋生态修复工作面临的主要问题有:近岸局部海域水体污染、生态受损;湿地、滩涂面积有缩减趋势;河口生态系统脆弱,生物多样性指数降低;海湾生态功能退化;海岛生态环境失衡。辽宁省应重点开展海湾环境综合治理以及滨海湿地、岸滩、岛礁等整治修复工作。  相似文献   

Hydrologic responses to land cover change: the case of Jedeb mesoscale catchment,Abay/Upper Blue Nile basin,Ethiopia          下载免费PDF全文

S. Tekleab  Y. Mohamed  S. Uhlenbrook  J. Wenninger 《水文研究》2014,28(20):5149-5161

The objective of this study was to quantify the impacts of land use/land cover (LULC) change on the hydrology of the Jedeb, an agricultural dominated mesoscale catchment, in the Abay/Upper Blue Nile basin, Ethiopia. Two methods have been used. First, the trends of certain daily flow variability parameters were evaluated to detect statistical significance of the change of the hydrologic response. Second, a conceptual monthly hydrological model was used to detect changes in the model parameters over different periods to infer LULC change. The results from the statistical analysis of the daily flows between 1973 and 2010 reveal a significant change in the response of the catchment. Peak flow is enhanced, i.e. response appears to be flashier. There is a significant increase in the rise and fall rates of the flow hydrograph, as well as the number of low‐flow pulses below a threshold level. The discharge pulses show a declining duration with time. The model result depicts a change in model parameters over different periods, which could be attributed to an LULC change. The model parameters representing soil moisture conditions indicated a gradual decreasing trend, implying limited storage capacity likely attributed to increasing agricultural farming practices in the catchment. This resulted in more surface runoff and less infiltration into the soil layers. The results of the monthly flow duration curve analysis indicated large changes of the flow regime. The high flow has increased by 45% between the 1990s and 2000s, whereas the reduction in low flows was larger: a 15% decrease between 1970s and 1980s, 39% between 1980s and 1990s and up to 71% between 1990s and 2000s. These results, could guide informed catchment management practices to reduce surface runoff and augment soil moisture level in the Jedeb catchment. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Impact of deforestation on pearl mussel habitats in the Russian section of the Baltic Sea basin     

《Limnologica》2015

Changes in the vegetation cover associated with intensive forest extermination may have a strong effect on the riverine environment, including the chances of survival for bivalve mollusc populations in small streams and rivers. In order to check this hypothesis, drainage area properties of the rivers with extinct and existing pearl mussel populations in the Russian section of the Baltic Sea basin were compared. Preservation of forest vegetation along the river banks of the studied rivers was correlated with the presence of pearl mussel populations. Traditional agriculture turned out to be, in some cases, more harmful for river ecosystems than urbanization and industrialization.  相似文献