长江中下游滩地的独特性与血吸虫病防治

湿地是地球上重要的生存环境和生态系统,有“自然 之肾”的美誉。长江中下游流域是我国湿地分布集中的区 域,我国著名的五大淡水湖均分布于此。长江中下游滩地比 较独特的特征可以概括为:冬陆夏水,枯水一线、丰水一片; 面积广大、生物多样性丰富;条件优越、经济发达;人口密 集、灾害频繁等。长江中下游湿地的重要性不但吸引了广大 学者、专家对其进行研究,而且也引起了国家和国家领导人 的重视。彭镇华、江泽慧等本着以人为本的湿地保护原则, 创造性地提出了抑螺防病林作为一个新林种的新概念,建立 了一套较为完整的理论和实践体系。这一理论不但极大地丰 富了我国滩地林业生态工程理论,而且实践证明其经济、生 态、社会等复合效益十分可观,是灭螺防病和长江中下游流 域湿地开发相结合的行之有效的生态措施。长江中下游湿地 的建设要遵循国家正确方针的指导,本着以人为本,坚持生 态建设的道路,加强长江中下游湿地建设的立法工作,着重 就长江中下游湿地关系到国计民生和地区可持续发展的功能 进行深入研究。在党和国家的关怀、支持下,在广大学者、 专家的努力下,长江中下游湿地必然会发挥出其重要的作 用,为国家的可持续发展做出其应有的贡献。     

台风季节朱家尖岛砂、砾质岬湾海滩的不同沉积地貌动态变化

岬湾砂、砾质海岸是海岛、海岸带重要的旅游资源, 具有较高的社会经济和生态价值, 长期以来备受关注。本文以浙江朱家尖岛东岸的5个代表性岬湾海滩为例, 基于2019年台风季节早期、中期及晚期测量获得的海滩地形和沉积物数据, 结合海滩近岸的水动力数据, 分析了砂质海滩和砾石海滩这两种不同类型岬湾海滩的沉积地貌动态变化。结果表明, 朱家尖岛东岸5个海滩在台风季节出现了不同的体积变化, 大沙里、东沙、千沙、乌石塘和小乌石塘海滩的单宽体积变化分别为11.93m³·m^-1、-54.41m³·m^-1、-19.75m³·m^-1、2.19m³·m^-1和-1.96m³·m^-1。砾石滩较砂质海滩更为稳定, 无人类活动干扰的砂质海滩在台风季节侵蚀更少、变化更小。台风季节大沙里、东沙、千沙、乌石塘和小乌石塘海滩表层沉积物的平均粒径分别为2.47Փ、2.24Փ、2.64Փ、-5.96Փ和-6.03Փ, 粒径粗化和离岸输运是5个海滩表层沉积物在台风季节的主要表现, 砂质海滩的沉积物粒度特征变化比砾石海滩要大。沉积物粒径、台风强度及台风期间的主要波向与海滩走向之间的关系、海岸工程这3种因素都可能对海滩在台风季节的沉积地貌动态变化产生影响。本文研究结果可为台风季节的海滩管理提供参考。     

沙坝海岸沿岸流速度剖面特征研究

通过对两个坡度沙坝地形沿岸流实验测量和基于能量方程的沿岸流数值模拟,研究了沙坝海岸平均沿岸流速度剖面的双峰剖面特征,重点分析了第二个峰值的特征和两峰值的比值。综合考虑入射波高、入射波类型和坡度对波生沿岸流垂直岸线速度剖面的影响。结果表明,平均沿岸流速度剖面出现双峰剖面特征:第一峰值发生在沙坝向岸侧面的中部,第二个峰值发生在靠近岸线处;同一坡度情况两个峰值的位置和比值,不受入射波类型、入射波高的影响。数值模型中包括了侧混、底摩擦和水滚等因素,其数值模拟结果和实验值拟合较好,并讨论了有无侧混和水滚对速度剖面的影响。     

Vegetation dynamics on eroding to accreting beach‐foredune systems,Florida panhandle

Vegetation surveys were conducted on a variety of coastal foredunes in a largely natural region along the Gulf County region of the Florida panhandle. Species presence, absence and percentage cover were surveyed on 12 foredune profiles during different seasons. The vegetation data were analyzed using the Shannon–Wiener Diversity Index and Sørensen Index. Uniola sp. and Andropgon sp. were the dominant species on foredunes. Uniola sp. was found predominantly on the gulfward facing or stoss slopes, and Andropgon sp. was found to be dominant on the inland or lee slopes of foredunes. While they are present on all foredunes, their presence and percentage cover are dominant on rapidly prograding coasts. Prograding/accretional beaches had higher Sørensen Index values (i.e. higher similarities) than did the foredune‐vegetation profiles on eroding beaches. Diversity as indicated by the Shannon–Wiener analysis (H’) is greatest on the highest, and generally eroding dunes. Foredune diversity increased with foredune height, and the tallest foredunes were found on shorelines with relatively low erosion rates, where dunes were slowly translating landwards, cannibalizing older dunes, and moving into areas colonized by late successional species, such as Quercus sp. These observations of foredune species richness, diversity, profile similarities, and the use of ecological indices can provide excellent proxy evidence of shoreline dynamics, and in particular the degree of beach erosion and accretion, in the absence of historical erosion/accretion data. Copyright © 2013 John Wiley & Sons, Ltd.     

First record of an odontaspidid shark in New Zealand waters

Photographs and a preserved head are identified as Odontaspis herbsti Whitley, 1950, an Australian sand shark growing to about 3 m long and similar to the Mediterranean O. ferox Risso, but differing in having a uniform grey body without black markings on the back or sides. No living odontaspidids have previously been reported from New Zealand. Six specimens were trawled in 119–165 m off Table Cape, Hawke Bay, in October‐November 1972. Californian and. East Atlantic (Madeira) specimens are treated as conspecific with O. herbsti. It is suggested that O. herbsti is normally an inhabitant of the continental slope, and that the present records are of a few individuals that have strayed on to the shelf.     

海滩也缺乏砂-砾过渡粒级的沉积物

沉积物的粒度是最重要的沉积物参数之一,在河床中,表层沉积物缺乏砂–砾过渡粒级（即1～10 mm）的沉积物,被称为Grain size gap,得到广泛关注。海滩沉积物是否也是如此,是一个基本而又未知的问题。本文分析了中外228处海滩共456个表层沉积物平均粒径数据,发现海滩大概率或是平均粒径几十毫米的砾石滩,或是平均粒径几百微米的砂滩,也缺乏砂–砾过渡粒级沉积物,其粒度范围是−3.5～−1 ϕ（2～11 mm）,这一结果和河床的情况基本相同。造成砂–砾过渡粒级缺乏的原因应从物源、颗粒磨损和分选以及广义的物质收支分析中去寻找。