Large jellyfish blooms have occurred in the East China Sea (ECS) during the last decade, a period also characterized by increasing fishing pressure, eutrophication, and changing climatic conditions. As large jellyfish bloomsmay have detrimental effects on fishery resources and ecosystem functioning it is desirable to understand the factors leading to jellyfish blooms. Therefore an Ecopath model covering the whole territorial waters of the ECS has been developed to address a number of questions about the impact and control mechanism of large jellyfish blooms on trophic structure and energy flows in the ECS. Model data collection for the ECS is based on records from 1997 to 2000. Forty-five functional groups are defined in the model including 32 fish (19 single species and 10multispecies), 2 benthic and 1 for each of the following: mammals, sea birds, sea turtles, primary producers, large jellyfish, cephalopods, shrimp, crabs, zooplankton, heterotrophic bacteria and detritus. The average trophic level of fishery catch in the ECS ecosystem for the period 1997-2000 was 2.71 while the mean value for all groups was 2.87. Analysis of the trophic interactions as identified a possible positive pelagic feedback loop allowing large jellyfish blooms to develop as a result ofmutual competition and predation between large jellyfish and Stromateoidae. This could be initiated by exploitation of Stromatidae. The pelagic pathway of the ecosystem will be disrupted at the initial stage of a large jellyfish bloom.

人类活动对地球系统的影响，已由“局部”进入到“全球”。河口是一个复杂的自然综合体，在地球系统中能体现全球的变化，也能敏感地响应流域的自然变化和人类的作用。由于资源开发和人工控制增强，第三驱动力在长江河口过程中已经和将要发挥越来越重要的作用。因此,如何体现人与自然的和谐，河口怎样才能健康地发展，将是河口研究的重要理论和实践问题。文中以长江河口为例，探讨它的自然演变与自然适应、发展中的人工控制、自然资源的开发以及涉及河口当前的悬念问题，并就人与自然的和谐提出建议。

The response of subaqueous dunes to the variation of riverine sediment supply in an estuary is rarely reported. Five sets of field measurements of bed sediments and topography were made in the Changjiang estuary, China during dry and flood seasons for the past 9 years. Results show that dunes were mainly three-dimensional (3D) during flood seasons and two-dimensional (2D) dunes during dry seasons. Dunes were also much larger in flood seasons. Dunes mainly occurred within the main channels of the estuary although they extended 11.7 km seaward of their normal extent in the South Channel during dry seasons from 2002 to 2006. This extension of the dune field is likely due to a sharp decline of sediment discharge caused by large reservoirs such as Three Gorges.

用ICP-AES测定了2001年4月来自崇明东滩高、中、低潮滩柱状沉积物中重金属含量，并以上海土壤环境为背景值，用均方根法对长江口滨岸湿地表层沉积物重金属进行了污染综合指数计算，并对崇明东滩重金属分布和污染状况作出评价和分析.结果表明，重金属分布从低潮滩向高潮滩呈增加趋势，铁、锰、铜、锌、铬、铅、钴和镍浓度变化范围分别为212%～416%，400～1050，10～50，50～160，30～95，10～70，8～18，14～43mg/kg；高潮滩重金属在根系沉积物中（3～10cm）明显富集;在高潮滩30～70cm和中潮滩10～40cm波动较大；粒径控制柱状沉积物中重金属的分布；崇明东滩细颗粒粒径与有机碳呈显著正相关，有机质是粒径控制重金属分布的潜在因子；以上海土壤环境背景值为评价标准，崇明东滩湿地属轻度污染1

在2l世纪世界环境与发展相互协调的历史背景下，有着自然优势的崇明岛开发成为上海现代化发展第三次飞跃的战略性目标之一。从长江口和崇明岛发育自然和人工控制后自然适应演变规律的历史和现状、探讨实现崇明岛开发的自然秉赋与制约因素，近两千年来长江河口自然演变规律的分析结果表明：弯道侧向环流及其对泥沙的输运对河口沙坝和汉道发育演变以及流域内众多大型工程对河口环流结构的影响研究.将是对长江口综合治理的理论前提，更是崇明岛实现人与自然协调开发的基础。而且，风能、湿地生态功能和岛内沟河网的自然生态功能、湿地生态功能和岛内沟河网的自然生态功能等可再生资源的充分利用可以实现崇明岛的零污染开发和治理。