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41.
九龙江口红树林上附着动物的生态   总被引:12,自引:2,他引:12  
周时强  洪荣发 《台湾海峡》1993,12(4):335-341
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  相似文献   
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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.  相似文献   
44.
Abstract. We describe the basic ecology of two key-hole limpets, Fissurella crassa and Fissurella limbata , which are heavily harvested by coastal shellfishermen (mariscadores) at the rocky intertidal of central Chile. The ecological role of human predation on these species was assessed. Anthropic exclusion from a stretch of the rocky intertidal at Las Cruces (non-harvested area) for about two and a half years resulted in changes of the densities and size distributions of these fissurelid species as compared to populations in control zones (harvested area). Differential human predation generates, on key-hole limpets, responses of different intensities related to the accessibility of man to the mesohabitats (sheltered platforms, exposed platforms and vertical walls) and fringes of the intertidal (mid-low intertidal and Lessonia nigrescens fringe). Thus, size distributions and mean densities of both fissurelids differ widely between the harvested and non-harvested areas on both platform habitats but not on vertical walls. In the mid-low intertidal fringe, differences are greater than in the less accessible L. nigrescens intertidal fringe. Moreover, we discuss the way in which other species, directly harvested by mariscadores (i. e., the mollusc Concholepas concholepas) can affect the keyhole limpet populations of central Chile rocky shores. Finally, we highlight the ecological role of these limpets on the dynamics of intertidal ecosystems and how they can modify community landscape.  相似文献   
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46.
厦门地区软相潮间带多毛类的生态   总被引:1,自引:0,他引:1  
鲁琳 《台湾海峡》1996,15(3):286-292
根据厦门地区1990年2月至1992年1月调查软相潮间带所获资料,研究了该区多毛类的种类组成,数量与分布,结果表明,该区多毛类种类丰富,共鉴定出118种,隶属于37科83属。其中,高潮区40种,中潮区90种,低潮区83种。多毛类平均栖息密度87个/m^3,平均生物量3.33g/m^2。  相似文献   
47.
福建红树林上钻孔动物的生态   总被引:1,自引:0,他引:1  
黄戚民  周时强 《台湾海峡》1996,15(3):305-309
福建红树林上的钻孔动物共发现了5种,其中软体动物的龙骨节铠船蛆Bankia carinata、裂铠船蛆Teredo manni和甲壳动物的光背团水虱Sphaeroma retrolaevis是破坏红树林的主要的钻孔动物。钻孔动物钻凿红树茎的基部和裸露的根部,垂直分布受潮汐水位制约,在红树林区的纵深分布与水流畅通程度有关。  相似文献   
48.
The influence of large-scale natural disturbance from winter storms (‘northers’) and river runoff on the macrobenthic community structure of the southern Gulf of Mexico was investigated in both carbonate and transitional carbonate–terrigenous sedimentary environments. Samples of the infauna were obtained in three seasons from 13 stations from two 250 km transects along 80–170 and 20–50 m water depth. Samples after the northers season had the lowest total number of families and individuals, 114 and 2940, respectively, compared to the dry and rainy seasons with 129 and 132 families and 11580 and 15266 individuals, respectively. Spatial patterns of macroinfauna composition varied across and along the shelf as a response to sedimentary environments and depth. Coarser sediments from the carbonate area harboured the highest mean densities per station with 500–24,000 individuals m−2 and 108–122 families in total, compared to the transitional sediment with 500–8200 individuals m−2 and 56–74 families across the three seasons. Univariate and multivariate statistical techniques demonstrated that low densities and number of taxa were associated with winter storms, but storm influence was dependent on depth and sediment type. Multiple linear regression analysis and BIOENV analysis indicated that sediment mean grain size, percentage of clay and organic matter best explained the macroinfauna spatial patterns, although BIOENV indicated that depth has an overriding role. An increase in densities of opportunistic taxa (numerous polychaetes of small sizes) was observed four months after the ‘northers’ and this was more evident in the area of carbonate sediment. Additionally a combined disturbance from northers and river runoff is suspected to be responsible for a naturally impoverished macroinfauna community in the transitional sedimentary environment.  相似文献   
49.
A sedimentary record spanning 5792–5511 cal yr BP and 3188–2854 cal yr BP was recovered at 36° 45′ 43″ S–56 ° 37′ 13″ W, south-west South Atlantic. The sedimentological features and micropaleontological (benthic foraminifera and ostracoda) content were analyzed in order to reconstruct paleoenvironmental conditions. Considerable environmental fluctuations are indicated by all these proxies. Five different stages were distinguished: Stage 1 (ca. 5800–5000 cal yr BP) consists of muddy sand with abundant microfossils. In this interval, species typical for inner marine shelf environments maintained a high abundance. Stage 2 consists of plastic light greenish grey clays barren of microfossils, and probably represents fluvial input from the de la Plata River to the shelf contemporaneous of a lowering of sea level. Stage 3 is composed of brownish yellow sandy silts, and represents increasing marine conditions in the area as reflected by higher faunal diversity and typical foraminifera of inner shelf environments. Stage 4 is made of homogeneous mud, barren of microfossil, which represents a new pulse of fluvial input to the shelf in consequence of a new fall in sea level. The final part of the core (Stage 5) is a coarsening upward sequence, grading from greeny brown clayey sandy silts to coarse shelly sands and represents the modern sedimentation in the area. This interpretation strengthens the stepped model of late-Holocene sea-level fall between 5511–5792 cal yr BP and 2854–3188 cal yr BP in Buenos Aires coast, and agrees with the relative sea-level history previously proposed by some authors from western South Atlantic coasts.  相似文献   
50.
何德华 《海洋学研究》1991,9(2):119-123
本文综述了1989年4月至1990年1月秦山核电站邻近水域生态调查结果,认为,该水域具暖温带强潮河口区生态特征。水体虽含丰富营养盐和充足溶解氧,由于同时存在着各种不利于生物繁殖生长的环境因子,表现为生物资源贫瘠、种类组成简单,测区所代表的强潮河口湾顶区属低生产力水域。  相似文献   
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