移植大叶藻提高池养对虾产量的研究

本实验首次用移植的方法在虾池内栽培大叶藻。结果表明,大叶藻可以净化虾池水质,改善虾池底质条件,丰富了饵料生物,促进了对虾的生长,提高了产量,每亩虾池的产量提高26.6％,纯利润提高190.5％。文章讨论了提高产量的原因。     

中国近海的蔓足类 Ⅳ.花笼科

花笼亚目(Verrucomorpha)是蔓足类中较独特的一个类群,它的左右两侧売板不对称，一侧背板及楯板与壁板愈合而不能活动。它们一般栖息于深度超过100米的较深水域,固着于岩石、泥块、贝壳、海胆棘、海绵骨针或其他物体上,分布范围较广。这类动物一般不易采到,在我国过去尚未见报道。本文是我国海区花笼类第一篇研究报告。搞清它们的种类对分析底栖生物群落组成和分布具有一定的意义。 本文根据的材料是1975-1981年东海大陆架调查和1959-1960年全国海洋综合调查采集的底栖动物标本。由于深海调査采集不够,标本数量不多,共发现6种,分隶于花笼科 Family Verrucidae 花笼属 Genus Verruca 的4个亚属,皆为我国首次记录。该6种栖息的水深从110米到2150米,其中驼背花笼 Verruca( Altiverruca) gibbosa为世界各大洋的广布种；雕板花笼 Verruca(Metaverruca) sculpta为分布于三大洋的环热带种；其余4种为印度一西太平洋暖水种。     

紧密角管藻雄配子的超微结构

紧密角管藻精子发生是由精母细胞减数分裂产生双鞭毛体，然后双鞭毛体分裂形成单裂毛的精子。精子鞭毛器的结构包括鞭毛轴丝和集体，鞭毛轴丝含有9对二联体组成的周位微管，但无中央微管，属于“9＋0”微管构型，基体靠近细胞核，由9对二联体周位微管和中央结构组成“车轮”状结构，在过渡区存在基板，精原细胞、双鞭毛体和精子的细胞器组成及结构与营养细胞相似，在生殖细胞中未发现高尔基体，却存在电子致密体。     

Study on fluctuations of plume front and turbidity maximum in the Hangzhou Bay by remote sensing data

On the basis of the time series of AVHRR data from NOAA satellites and the geographical information system PURSIS, fluctuations of the plume front and the turbidity maximum in the Hangzhou Bay, reflected by the distributions of temperature and suspended sediment concentration respectively, are studied in view of long-term behaviors or seasonal and tidal cycles. The data suggest that the effect of front plays an important role in the development of the turbidity maximum close to the Changjiang Estuary > while the effect of tide dominates over the development of another very turbid water situated in the shoal areas in the southern Hangzhou Bay.     

A Bayesian Network Approach for Offshore Risk Analysis Through Linguistic Variables

This paper presents a new approach for offshore risk analysis that is capable of dealing with linguistic probabilities in Bayesian networks(BNs).In this paper,linguistic probabilities are used to describe occurrence likelihood of hazardous events that may cause possible accidents in offshore operations.In order to use fuzzy information,an f-weighted valuation function is proposed to transform linguistic judgements into crisp probability distributions which can be easily put into a BN to model causal relationships among risk factors.The use of linguistic variables makes it easier for human experts to express their knowledge,and the transformation of linguistic judgements into crisp probabilities can significantly save the cost of computation,modifying and maintaining a BN model.The flexibility of the method allows for multiple forms of information to be used to quantify model relationships,including formally assessed expert opinion when quantitative data are lacking,or when only qualitative or vague statements can be made.The model is a modular representation of uncertain knowledge caused due to randomness,vagueness and ignorance.This makes the risk analysis of offshore engineering systems more functional and easier in many assessment contexts.Specifically,the proposed f-weighted valuation function takes into account not only the dominating values,but also the α-level values that are ignored by conventional valuation methods.A case study of the collision risk between a Floating Production,Storage and Off-loading(FPSO) unit and the authorised vessels due to human elements during operation is used to illustrate the application of the proposed model.     

颗粒物质和微量金属在东海北部的沉积通量

于1990年运用沉积物捕捉器采样,实测了东海北部(32.00°N,126.00°E)海域颗粒物质和微量金属(Cu,Pb,Zn,Cr,Fe,Mn和Al)的海洋垂直通量。结果表明,颗粒物质的沉积通量随深度和季节而变化,明显地受上升流的影响。沉积的颗粒物质以0.45—63μm的小颗粒为主;Cu和Zn主要以有机物形式作垂直转移,Pb,Cr,Fe和Mn主要以弱键结合形式作垂直转移,Al则以硅酸盐的形式作垂直转移。沉积物中,颗粒Cu,Fe,Mn和Al以0.45—63μm的颗粒为主;颗粒Pb和Cr以大于63μm的颗粒为主;0.45—63μm和大于63μm的颗粒Zn在沉积物中占相近的比例。     

论现实主义原则在海洋地质学中的应用——以中国海岸带及近海大陆架为例

近年来,在海洋地质学和沉积学中广泛应用模式概念,试图建立模式以说明或解释某些海洋地质学现象.建立模式的理论根据是经典地质学的一条著名原则,即“现在是过去的钥匙”,这就是一致论或现实主义原则.最近十多年来,研究古代沉积岩的论文绝大多数都有现代或全新世类比(analogue)一节,即主要根据与现代现象的类比,来解释古代沉积岩的发生和成因.这种类比促进了近年海洋地质学和沉积学的巨大发展.但简单的类比往往存在若干缺点和问题,甚至导致错误的结论.     

Separating climate change and human contributions to variations in streamflow and its components using eight time‐trend methods

Separating impacts of human activities and climate change on hydrology is essential for watershed and ecosystem management. Many previous studies have focused on the impacts on total streamflow, however, with little attentions paid to its components (i.e., baseflow and surface run‐off). This study distinguished the contributions of climate change and human activities to the variations in streamflow, baseflow, and surface run‐off in the upstream area of the Heihe River Basin, a typical inland river basin in northwest China, by using eight different forms of time‐trend methods. The isolated contributions to streamflow variation were also compared with those obtained by two Budyko‐based approaches. Our results showed that the time‐trend methods consistently estimated positive contributions of climate variability and human activities to the increases in streamflow and its components but with obviously varying magnitudes. With regard to streamflow, the time‐trend method double‐mass‐curve–Wei, with a physical basis, produced a reasonable smaller contribution of human activities than climate changes, inconsistent with the Budyko‐based approaches. However, all the other time‐trend methods led to contrary results. The contributions to baseflow variation diverged more significantly than those to streamflow and surface run‐off, ranging from 24% to 92% for human activities and from 8% to 76% for climate variability. In terms of surface run‐off, most of the time‐trend approaches produced smaller contributions of human activities (ranging from 21% to 49%) than climate change. The uncertainties associated with the various time‐trend approaches and the baseflow separation algorithm were revealed and discussed, along with some recommendations for future work.     

Effects of suspended sediment characteristics and bed sediment transport on streambed clogging

Fine sediment deposition in streambeds can reduce pore water fluxes and the overall rate of hyporheic exchange, producing deleterious effects on benthic and hyporheic ecological communities. To increase understanding of the factors that control the reduction of hyporheic exchange by fine sediment deposition, we conducted experiments in a laboratory flume to observe changes in the rates of solute exchange and kaolinite clay deposition as substantial amounts of kaolinite accumulated in the streambed. Two long‐term experiments were conducted, with durations of 14 days and 29 days. Use of a laboratory flume system allowed steady stream flow conditions to be maintained throughout both experiments, and alternating injections of known quantities of kaolinite and a sodium chloride tracer were used to assess the effect of clay accumulation on hyporheic exchange directly. In the first experiment, there was no bed sediment transport and kaolinite deposition formed a highly clogged near‐surface layer that greatly reduced hyporheic exchange. Application of a fundamental model for advective hyporheic exchange indicated that the effective permeability and porosity of the streambed decreased substantially during the course of the experiment. In the second experiment, the kaolinite was prepared with different surface properties to be more mobile, and the experiment was conducted with a small degree of bed sediment transport. As a result, no distinct clogged layer developed, and the rate of hyporheic exchange was found to remain approximately constant throughout the experiment (29 days). These results indicate that increasing fine sediment loads, e.g. those that occur from changes in land use, can have substantially different impacts on hyporheic exchange and associated ecological processes depending on the stream flow conditions, the rate and frequency of bed sediment transport, and the extent of interaction of the introduced fines with bed sediments. Copyright © 2004 John Wiley & Sons, Ltd.