九龙江口红树林上附着动物的生态

福建九龙江口红树林附着动物７种，白脊藤壶Ｂａｌａｎｕｓ ａｌｂｉｃｏｓｔａｔｕｓ和白条地藤壶Ｅｕｒａｐｈｉａ ｗｉｔｈｅｒｓｉ在数量上占绝对优势，是危害红树的主要附着动物。附着动物在河口红树林区的数量分布随着盐度的降低而减少，其栖息密度和生物量的高峰期在夏，秋两季。生长茂密的红树林（郁蔽度大于０．５），附着动物主要分布于水流畅通的向海边缘和潮沟边缘的红树上。水流畅通程度是影响附着动物在红树林区向纵     

Spatial Variation in the Structure of Kelp Forest Communities Along a Wave Exposure Gradient

Abstract. Four sites were sampled in kelp (Macrocysiis pyrifera) forests occupying rocky bottom habitats along a wave exposure gradient in central California. Consistent betwecn-site differences were found in the three major structural elements - the surface canopy, the undcrstory assemblage, and the ground cover/turf assemblage - of kelp forest communities. Macrocysiis pyrifera was found at all four sites. Nereucyslis tuelkeana only at the most exposed site. The understory kelps Laminaria setchellii and Pterygopltora californica were also characteristic of exposed sites. Articulated coralline algae were more abundant at exposed sites than protected, while fleshy red algae showed the opposite pattern. All four study sites were located along 8.5 km of coastline, and thus were assumed to have available to them the same species pool for colonization. The substrate composition was the same and the amount of unconsolidated substrate was similar at all four sites. We suggest that exposure to wave-generated water motion, through its influence on the surface canopy and therefore on the amount of light reaching the bottom, is responsible for these between-site differences.     

Sublittoral meiofauna with particular reference to nematodes in the southern Yellow Sea, China

Densities of major meiofaunal taxa were investigated at 34 sampling stations during six cruises by R/V Beidou to the southern Yellow Sea, China from 2000 to 2004, and the community structure of free-living marine nematodes was studied during one of the cruises in 2003. Meiofauna abundance ranged from 487.4 to 1655.3 individuals per 10 cm². Nematodes and harpacticoid copepods were the two most dominant groups, contributing 73.8–92.8% and 3.5–18.7%, respectively, to the total meiofauna abundance. One-way ANOVA showed no significant annual fluctuation of meiofauna and nematode abundances from 2000 to 2004 in the southern Yellow Sea. However, two-way ANOVA based on six stations sampled in 4 years (2001–2004) showed that there were significant differences among the six stations and the 4 sampling years for meiofauna, nematode and copepod abundance. Correlation analysis demonstrated that meiofauna abundance was mainly linked to chloroplastic pigments. Other environmental factors could not be ruled out, however. A total of 232 free-living marine nematode species, belonging to 149 genera, 35 families and 4 orders, were identified. The dominant species in the sampling area were the following: Dorylaimopsis rabalaisi, Microlaimus sp.1, Prochromadorella sp., Promonohystera sp., Cobbia sp.1, Daptonema sp.1, Leptolaimus sp.1, Halalaimus sp.2, Aegialoalaimus sp., Chromadorita sp., Parodontophora marina, Parasphaerolaimus paradoxus, Quadricoma sp.1, Campylaimus sp.1, Halalaimus gracilis, Paramesacanthion sp.1, Paramonohystera sp.1, and Metalinhomoeus longiseta. CLUSTER and SIMPROF analyses revealed three main types of nematode community (or station groups) in the sampling area, including I: coastal community, II: transitory community between coastal and YSCWM (Yellow Sea Cold Water Mass), and III: YSCWM community. Each community was indicated by a number of dominant nematode species. Bio-Env correlation analysis between the nematode community and environmental variables showed that water depth, sediment water content, organic matter, chlorophyll a (Chl-a) and phaeophorbide a (Pha-a) were the most important factors to determine the community structure.     

Influence of stratification and irradiance regime on summer phytoplankton composition in coastal and shelf seas of the British Isles

The effect of interaction between stratification and irradiance regimes on phytoplankton community structure was investigated in three shelf/coastal regions of the British Isles, each of which displayed ranges of vertical stability and light attenuation. Relationships between vertical stability, light penetration and community structure were indicated by the ordination of dominance (assessed using cell volume) of the main phytoplankton phyletic groups—diatoms, dinoflagellates and microflagellates—on a surface defined by a bulk stratification index () and water column depth, scaled by transparency (λh). Diatom- and dinoflagellate-dominated communities occupied distinctly different domains on the - λh surface, diatoms being favoured in well-mixed water columns with high values for λh and dinoflagellates dominating where stratification was strong and λh was low. Microflagellates were not abundant in any of the study areas and showed no clear ordination on the - λh surface. The domain of co-dominance of diatom and dinoflagellates on the - λh surface was narrow with small changes in the irradiance or stratification regime resulting in a switch to diatom or dinoflagellate dominance. It is suggested that loss of non-motile diatom communities in strongly stratified water columns might be a strong selective force in favour of dinoflagel-lates. However, in water columns with intermediate stratification and optical properties, the outcome of competition may be decided by physiological attributes of the two groups with respect to growth in low and fluctuating irradiances.     

Ecology of beach wrack in northern New England with special reference to Orchestia platensis

The northern New England beach wrack community with special reference to the cosmopolitan amphipod crustacean, Orchestia platensis, was examined at estuarine and open coastal habitats. Beach wrack was dominated by the plant genera Ascophyllum, Zostera, Spartina and Chondrus, and was most abundant during spring and late summer. Animal community numbers, biomass and frequency in fresh to moderately decomposed wrack were dominated by O. platensis throughout the year at all habitats; oligochaetes and Collembola were also important. The abundance of O. platensis showed high spatial and temporal variability, with low abundance generally associated with decreased amounts of wrack during colder months. An exception was the winter presence of the species at one estuarine habitat, in patchy aggregations within gravel-cobble refuges. The abundance of O. platensis averaged 1280 (0.04 m²)⁻¹, with a maximum of 7040 (0.04 m²)⁻¹. The life cycle of O. platensis is bivoltine, with summer-hatched young reaching maturity within 1 month. Laboratory studies indicate females with up to 4 broods (30 days)⁻¹, averaging 18 eggs brood⁻¹.Orchestia platensis is omnivorous, eating fresh plant tissue, live oligochaetes, Limulus eggs and diatom ‘fuzz’. The rate of laboratory consumption of algae and Zostera was 0.05 mg plant mg⁻¹ wet body weight day⁻¹. Presumptive predators of O. platensis are juvenile green crab, Carcinus maenus, and the earwig. Anisolabis maritima. The mobility, aggregation and aggressiveness of O. platensis assist the species in establishing and maintaining populations in the rigorous wrack habitat. The general competitive superiority of O. platensis over its congener, O. gammarella, and the co-occurrence of these species on both eastern and western Atlantic shores is discussed.     

A study on benthic community structure in west of the Taiwan Strait and near the Taiwan Shoals

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广西崇左三合巨猿大洞早更新世小哺乳动物群

最近在广西崇左三合大洞发现了步氏巨猿和似人似猿共生的新层位,与之伴生的有52种小哺乳动物,占三合大洞巨猿动物群总数的62%,其中苏门答腊兔（Nesolagus）是东南亚地区首次发现的化石。小哺乳动物群以南方早更新世常见的偏皮氏毛耳飞鼠（Belomys parapearsoni）、中间猪尾鼠（Typhlomys intermedius）、拟低冠竹鼠（Rhizomys brachyrhizomyoides）、硕豪猪（Hystrix magna）、先社鼠（Niviventer preconfucianus）、拟爱氏巨鼠（Leopoldamysedwardioidesi）等为代表,根据小哺乳动物群性质和与其他动物群对比以及磁性地层年代测定,表明其时代应是早更新世中期（约距今120¹60万年前）。该动物群由树鼩、扁颅蝠、小彩蝠、飞松鼠、笔尾树鼠、猪尾鼠等几乎是旧大陆热带-亚热带森林型动物组成,缺少北方类型,基本上属于热带森林动物群,这表明了当时的自然景观为温暖湿润的热带雨林环境。三合大洞小哺乳动物群是广西地区的首次发现,对华南早更新世巨猿动物群详细划分,探讨步氏巨猿演化和早期人类环境背景等目前科学界关注的问题具有重要的意义。