Hydrobiology of the Marennes-Oléron bay. Seasonal indices and analysis of trends from 1978 to 1995

A hydrobiological monitoring network has been in place since 1977 in the Bay of Marennes Oleron (France). Data collected for physical variables (seawater temperature, salinity, oxygen concentration), nutrients (ammonium, nitrates, phosphates and silicates) and chlorophyll a and pheophytin, from 5 representative stations in the bay, were examined by time-series analysis (Census II method) to study seasonal variability and trends. The seasonal changes were similar over the entire Marennes Oleron Bay for all variables and were chiefly influenced by fluxes in the Charente river. The seasonal range reached 180 units for nitrates and 70 and 100 units respectively for phosphates and silicates. These values were similarly mostly correlated with the Charente River fluxes. With regard to long-term trends, seawater temperature has shown a significantly increasing trend close to 2 °C over 18 years. At the same time, a 1 °C gradient was demonstrated from the northern to the southern part of the Bay. The salinity trend varied between 30 and 34‰for all stations. The trend for oxygen concentration, ranged from 90 to 100% but during a specific two year period (1980–1982) saturation decreased to 76% in the northern part of the Bay. The trend analysis for nitrates showed a significant relationship with the water output level of the Charente. Phosphate inputs have been irregular during the two last decades which has affected primary productivity along the coastline (e.g., spring 1979–1983; 1990; 1993–1995). Since 1988, a significant increasing trend for ammonium was observed at the mouth of the Seudre river (4 μmoles l−1 ) while other stations were well below this, ranging from 1 to 3 μmoles l−1 . This should be considered as an indicator of seawater deterioration within the southern part of the Marennes Oleron Bay. This revised version was published online in July 2006 with corrections to the Cover Date.     

浙江近海后鳃类软体动物的分布及其区系

报道了浙江近海的后鳃类97种,分别隶属于7目30科44属。其中我国沿岸广温广布种14种,主要分布于东海和南海的亚热带种50种,南海的热带种18种,渤、黄海延伸到东海北部的暖温带种15种。     

Comparison of Four Mendelian Loci of the California Sea Hare (Aplysia californica) from Populations of the Coast of California and the Sea of Cortez

Aplysia californica is a species widely used in neurobiology, and specimens are collected from a wide range of places along its distribution range. A. californica is endemic to the coast of California and the Gulf of California. On the west coast, this is an unusual distribution range relative to other benthic species from that region. Four polymorphic nuclear Mendelian markers were identified (three single-copy nuclear DNA loci and one microsatellite) for an initial survey of genetic variation of wild populations. F _ST values not significantly different from 0 (overall F _ST= 0.0148) suggest there was no geographic genetic population subdivision in 177 individuals examined. Received December 3, 1999; accepted March 3, 2000.     

盐沼湿地大规模恢复的概念生态模型——以盐城为例

大规模湿地生态恢复是一项耗资巨大、复杂的系统工程,需要以整个区域湿地结构和功能恢复作为基本目标,将时间和空间上分散的研究成果进行系统梳理,形成对区域湿地生态变化及其驱动因素的规律性认识。本研究以盐城盐沼湿地为案例,以1987年作为未干扰或干扰较少的状态,从结构-过程-功能耦合作用角度,确定区域湿地恢复的关键生态特征,包括:健康与动态潮间带湿地系统、碱蓬生态系统生产力与弹性、复杂景观镶嵌与相互作用、潮间带底栖动物丰富与鸟类觅食基地,以及濒危与关键水鸟种群保护。在此基础上,将围垦与土地利用、水管理、全球变化与海平面上升作为驱动区域湿地生态变化的三大外部因素;海岸侵蚀与沉积、区域水格局变化、地形地貌变化、湿地空间变化与连通性丧失,以及互花米草入侵等是影响湿地生态系统变化的内在压力因子;基于这些压力因子与湿地生态系统变化之间复杂作用关系分析,形成了外部驱动力-内在压力源-生态影响-生态特征之间联合作用下的区域湿地恢复概念生态模型。此模型以复杂因果关系研究为基础,直观展示了湿地恢复需要去除或减缓各种压力因子的一般路径,有利于指导大规模盐沼湿地恢复规划与实践。     

Description of Antichthomysis notidana n.g. n.sp. from southern Tasmania. (Crustacea: Mysidacea: Leptomysini)

Antichthomysis notidana n.g. n. sp. belonging to the Tribe Leptomysini is described from the coastal waters of south-eastern Tasmania. The genus is at present monospecific.     

A test of Brown's principle in the intertidal limpet Collisella scabra (Gould, 1846)

Aim Brown's principle predicts that a species will peak in density near its range centre, and decline gradually towards the margins of its geographical distribution. The decline is assumed to reflect a decrease in individual performance near range margins. I test this abundance–performance hypothesis by comparing patterns in density and size across the northern half of the geographical distribution of the marine patellogastropod Collisella scabra (Gould, 1846). Location Collisella scabra is a high intertidal patellogastropod species distributed along the Pacific coast of North America from Cape Mendocino (CA, USA) to southern Baja California (Mexico). I surveyed 11 research sites spanning c. 36–44° N. Methods In each of the 11 research sites I surveyed four distinct microhabitats, and compared spatial patterns in density and in the size of solitary limpets. Results Both density and size were highly variable across the species range. Density peaked near the northern range margin, and showed greater variance at small spatial scales (< 10 km) than at large scales (> 100 km). In contrast, large size occurred uniformly across the survey area, and size was strongly associated with microhabitat. Main conclusion Collisella scabra does not show spatial patterns of density or performance that are consistent with Brown's principle. The underlying assumptions of Brown's principle may conflict with specific characteristics of C. scabra's life history and/or patterns of environmental variation across its range. Because such conflicts may be common in a large number of marine and terrestrial species, the generality of Brown's principle is questioned.     

Distribution and morphology of the sea lamprey from the Balkan coast of the Adriatic Sea

In contrast to the Apennine Peninsula coast, the relatively rare occurrence of sea lampreys Petromyzon marinus in the Balkan Peninsula (eastern coast of the Adriatic Sea) is probably due to the closeness of the steep mountains causing unsuitable hydrological conditions of streams and impeded access to the coast. Most specimens are probably represented by invaders carried from the Mediterranean and other regions of the Adriatic Sea. Morphology was similar to that recorded for the sea lampreys from other geographical regions.     

中国沿海洛氏角毛藻复合群的多样性组成及地理分布

洛氏角毛藻复合群(Chaetoceros lorenzianus complex)指具有与洛氏角毛藻相似形态学特征的物种集合, 它们广泛分布于全球近岸水域。近年国际上关于该复合群的分类学研究取得新进展, 而我国相关研究仍较为滞后。为了弄清我国沿海洛氏角毛藻复合群的物种多样性, 明确物种信息, 厘清种间界限, 为相关研究提供准确的物种鉴定依据, 本研究陆续在中国沿海建立了该复合群的332个单克隆培养株系, 利用光学显微镜、扫描电镜和透射电镜进行了较为详尽的形态学研究, 基于核糖体大亚基编码基因D1-D3区序列, 构建了分子系统学关系。结果表明其形态聚类与分子系统学结论相一致, 显示我国洛氏角毛藻复合群具有较高的物种多样性, 共鉴定到5个物种, 分别是并基角毛藻(C. decipiens)、优美角毛藻(C. elegans)、平孢角毛藻(C. laevisporus)、曼纳角毛藻(C. mannaii)和稀树角毛藻(C. pauciramosus)。研究表明传统认知的光镜下特征, 如群体特征、角毛走势等易变化, 其分类学价值需谨慎应用。角毛的超微结构, 如角毛孔纹的形状、大小、密度等是有效的种间区别特征, 休眠孢子亦是重要的物种识别依据。并基角毛藻和平孢角毛藻在我国沿岸的分布范围最为广泛, 而稀树角毛藻的分布较为有限。     

Histology of gonads and cephalic brood pouch of the marine gastropod Planaxis sulcatus of Karachi Coast (Pakistan)

This histological study of 141 specimens of adult Planaxis sulcatus from Karachi showed thepresence of only female gametes in gonadal follicles,supporting the conclusion of earlier workers that thespecies may be parthenogenetic. The gonadal folliclesof several snails were occupied by an unidentifiedtrematode parasite.     

Potential Impact of an Exotic Mammal on Rocky Intertidal Communities of Northwestern Spain

Being the interface of sea and land, the coast can be invaded by introduced species coming from either of these two worlds. Recent reviews of coastal invasions emphasize the human-mediated transport of non-indigenous marine plants and invertebrates, forgetting the potential role of invaders of terrestrial origin. By studying the diet of the introduced American mink (Mustela vison) on a rocky shore of southwestern Europe, we draw attention to the potential impact on intertidal communities of exotic species coming from inland. We analysed 199 mink faeces collected in August 1997 and August 1999 in Baiona, a coastal and urban area of northern Spain recently invaded by minks. The diet of the species was based almost exclusively on crabs (45.4% of individual prey) and fish (53.3%). Most crabs were marbled crabs (Pachygrapsus marmoratus) and most fish were adult blennies (Coryphoblennius galerita and Lipophrys pholis). Given its energy requirements (about 1250 kJ/day), a single mink will consume during the month of August approximately 945 blennies and 496 crabs. Although we lack accurate data on mink abundance, a cautious estimation (4 mink/km before dispersal), supported by field observations, suggests that predation in August may reach 3780 blennies and 1984 crabs per km of shoreline. This predation pressure could affect the numbers of blennies and (less probably) crabs, indirectly benefiting the populations of their prey, that is, sessile invertebrates and snails. More field research is needed, but our results suggest that an exotic non-marine top predator such as the American mink could affect intertidal communities in Eurasia.