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1.
Marco Loia Paola La Valle Loretta Lattanzi Barbara La Porta Monica Targusi Luisa Nicoletti 《Marine Ecology》2020,41(6):e12615
Recolonization patterns of benthic assemblages after relict sand dredging were investigated in an area offshore of Capo d’Anzio (central Tyrrhenian Sea). Surveys were performed before, during, and after dredging in 2007. Sampling stations were located within and outside the dredging site in water depths between 40 and 56 m. Defaunation due to sand extraction was the main impact observed in the inner stations and in stations located in proximity of the dredging site. At the inner stations, 9 months after dredging, a significant increase in species richness and diversity was observed: the sediment removal led to an increase of the sandy sediment fraction, favouring the settlement of sabulicolous species. A decrease in number of individuals and species was also observed in most of the outer stations, probably due to fine sediment redeposition. Recolonization of macrobenthic assemblages was essentially achieved at inner stations both in terms of abundance and species richness, while at outer stations it was still in progress. Results of this study, providing a picture of recovery times and processes in the Tyrrhenian Sea, could be used to develop predictions of the effects of future offshore sand dredging projects in comparable areas. Monitoring programs and research have a key role to provide a more detailed overview of biological recovery processes and times in different regions and with different dredging intensity. 相似文献
2.
The San Clemente cold seep lies within 100–200 km of other reducing habitats in the NE Pacific, offering an opportunity to compare diversity and species overlap among reducing habitats (i.e. whale‐, kelp‐, and wood‐falls) at similar depths within a single region. Video observations from the research submersible Alvin at the San Clemente seep (1800 m depth) indicated clumps (‘thickets’) of vestimentiferans distributed as meter‐scale patches interspersed with vesicomyid clam beds and black sediments. Sediment‐core samples were collected at distances of 0 to 80–200 m along randomly oriented transects radiating outward from vestimentiferan thickets to evaluate changes in macrofaunal community structure from thickets into the background community. Macrofaunal abundance was elevated at distances of 0–1 m compared to 80–200 m (i.e. the ‘background’ community). The tube‐building frenulate worms Siboglinum spp., along with peracarid crustaceans, dominated sediments within 1 m of vestimentiferan thickets. Species diversity was depressed within 1 m of thickets but with high rates of species accumulation, suggesting that seep sites greatly increase sediment heterogeneity and facilitate colonization by non‐background macrofaunal species. Stable isotope data indicate chemosynthetic nutrition for some dominant macrofaunal species within 1 m of tubeworm thickets. The macrofaunal community near vestimentiferan thickets in San Clemente seep contains intermediate levels of species richness and diversity compared to other deep‐sea seep areas in the northeast Pacific. There was low species overlap between the San Clemente seep macrofauna and communities in reducing habitats near wood‐, whale‐, and kelp‐falls at similar depths within the region, suggesting that seeps harbor a distinct infaunal community. 相似文献
3.
Katerina Sevastou Nikolaos Lampadariou Anastasios Eleftheriou 《Journal of Sea Research》2011,66(3):205-214
Meiobenthic data from two microtidal sandy beaches of the eastern Mediterranean (Crete, Greece) were used to investigate patterns of both alpha and beta diversity in space and time. Copepod assemblages and environmental variables related to sediment characteristics, morphodynamics and food were studied over a year at four distinct habitats at each beach; the retention, resurgence and saturation zones of Salvat's intertidal scheme (midlittoral zone), and the surf zone of the sublittoral. Αlpha diversity analysis indicated similar species richness at both beaches when the whole 13-month data set was considered but was higher at the sheltered site when each sampling period was examined separately. Both beaches supported higher diversity in the sublittoral zone. Species richness increased seawards at the midlittoral zone of the sheltered site whereas, no pattern was evident at the exposed site, where the intense hydrodynamic conditions homogenized the sediments. Beta diversity increased markedly towards the sublittoral, indicating greater differences in alpha diversity between the sublittoral and the midlittoral zone. Species turnover was more variable at the exposed beach and at the most landward stations, where environmental conditions change often between extremes. A proportion of the variation in alpha diversity was explained by food availability at both beaches and additionally by grain size at the sheltered site. However, no environmental variable explained beta diversity patterns. Although the results of our study support the hypothesis of Multicausal Environmental Severity proposed for sandy beach macrofauna, we believe the classic Intermediate Disturbance Hypothesis is a more appropriate framework for the meiofauna communities of the studied sites. 相似文献
4.
The characteristics of the nematode faunas in subtidal sediments of a large microtidal estuary and nearshore coastal waters differ markedly 总被引：1，自引：0，他引：1
M. Hourston I.C. PotterR.M. Warwick F.J. Valesini 《Estuarine, Coastal and Shelf Science》2011,94(1):68-76
The present study examines traditional paradigms regarding the differences between faunas in estuaries vs coastal waters. The ecological characteristics of the free-living nematode faunas of nearshore, subtidal sediments in downstream and upstream areas of the large, microtidal Swan River Estuary are compared with those similarly recorded seasonally in subtidal sediments along an adjacent part of the coast of temperate south-western Australia. Overall, the nematode species richness recorded in the upstream (38) and downstream estuarine areas (58) and from throughout the estuary (61) were substantially less than in marine waters (75). In addition, the value for Simpson’s diversity index was marginally less in the estuary and the dominance of the most abundant species greater. In contrast, the mean nematode species richness and diversity in individual cores followed the reverse trend, reflecting a combination of less variability among the species compositions and far greater densities in the cores from estuarine sediments. Furthermore, the mean density (numbers 10 cm−2) was far higher in both upstream (341) and downstream (903) areas of the estuary than in marine waters (87). Although the compositions of the assemblages in upstream and downstream estuarine areas differed markedly from each other at the species, genus and family levels, these differences were less pronounced than those between either of these areas and marine waters. The trophic compositions at the moderately sheltered and fully exposed marine sites differed from that in both areas of the estuary, whereas that at the most sheltered marine site was similar to that in the downstream estuarine area, with both containing substantial proportions of epistrate-grazing species. The variations among the species richness, diversity, densities and taxonomic and trophic compositions of nematode assemblages in the sediments of the two estuarine areas and nearby marine waters appear to reflect differences in 1) salinity regimes, 2) extents of exposure to wave action and its related effects and 3) amounts and types of food available to nematodes. 相似文献
5.
2010年夏季雷州半岛沿岸海域浮游动物群落结构特征 总被引：4，自引：1，他引：3
2010年7月对雷州半岛海岸带的浮游动物群落结构及相关环境因子进行了调查,共鉴定出浮游动物87种和34类浮游幼体,其中原生动物4种,占总种类数的4.6%;腔肠动物20种,占总种类数的23.0%;介形类1种,占总种类数的1.1%;枝角类2种,占总种类数的2.3%;桡足类37种,占总种类数的42.5%;十足类2种,占总种类数的2.3%;毛颚动物7种,占总种类数的8.0%;被囊动物6种,占总种类数的6.9%;浮游软体动物8种,占总种类数的9.2%。优势种有13种和3类浮游幼体,孔雀强额哲水蚤和小毛猛水蚤是该海域重要的优势种群,几乎在全海域均为优势种,桡足类幼体为全海域优势类群。半岛沿岸海域浮游动物种类数由近岸往远岸逐渐增多,浮游动物丰度分布则相反。浮游动物种类数由多到少的顺序为东北部、东南部、西北部和西南部、南部,丰度由大到小的顺序为西北部、西南部、东北部、东南部、南部,生物量由大到小的顺序为东北部、西南部、西北部、东南部、南部,浮游动物丰度和生物量的平面分布反映了人类对海岸带开发利用的活动概貌。多样性指数和均匀度平均值分别为2.96和0.57。相关分析表明:浮游动物丰度与水温、细菌总数、浮游动物生物量均呈极显著的正相关关系,与磷酸盐呈显著的负相关关系;浮游动物生物量与TOC、细菌总数、叶绿素a、浮游植物丰度均呈极显著的正相关关系,与pH呈显著的正相关关系,与盐度呈显著的负相关关系。 相似文献
6.
基于历史海图、历史时期卫星遥感影像、2019年实测水下地形和潮流、波浪数值模拟成果,研究该海域岸滩的发育演变背景、海床和岸线自然冲淤动态、动力泥沙环境及岸滩冲淤动力机制。采用LITLINE岸线演变数学模型,模拟计算了不同离岸距离和不同平面形态人工岛布置型式对近岸岸线变形的影响,岸滩泥沙动力机制和岸滩演变趋势表明,人工岛实施后近岸最大潮流流速小于近岸泥沙起动流速,不具备起动近岸岸滩泥沙的基本条件; SSE向波浪作用时,人工岛西北侧波高明显减弱,波向西偏; S向波浪作用时,人工岛北侧波高明显减弱; SSW向波浪作用时,人工岛东北侧波高明显减弱,波浪传播方向东偏;波浪场改变后人工岛掩护区东西两侧岸滩附近泥沙分别具有向东和向西运移至人工岛掩护区的趋势,形成掩护区的淤积和东西两侧岸线冲刷。 相似文献
7.
《Deep Sea Research Part II: Topical Studies in Oceanography》2010,57(15):1396-1405
Temporal variability in deep-sea polychaete assemblages was assessed at the Porcupine Abyssal Plain Sustained Observatory, NE Atlantic, over a 9-year period (eight cruises between August 1989 and September 1998). The polychaete communities were characterized by large number of individuals (abundance) and high family richness. The highest abundances occurred in the upper 1 cm sediment layer (53.2% of total abundance). The most abundant families were the Cirratulidae, Spionidae, Opheliidae and Paraonidae. Surface deposit feeders were the dominant trophic group (67.4% of total abundance). Significant temporal variability was evident in polychaete abundance with significant differences in polychaete abundance between sampling periods (cruises; p<0.01). Stepwise increases in abundance in September 1996 and March 1997 coincided with similar increases in abundance in large invertebrates (megafauna) in the same area (known as the ‘Amperima Event’ after a species of holothurian that increased in abundance by over three orders of magnitude). Similar patterns were observed for abundances across different layers of the sediment, main families and trophic groups showing significant differences between cruises (p<0.05). A comparison of samples taken (1) before the ‘Amperima Event’ (1989–1994) and (2) during the ‘Amperima Event’ (1996–1998) showed significant differences in the polychaete abundance in the upper 3 cm of the sediment. There were significant differences in some trophic groups (predators, deposit feeders and burrowers) and the dominant families (Cirratulidae, Spionidae and Opheliidae). Not all elements of the polychaete community showed a response (e.g. the Paraonidae). Changes in surface deposit feeders were particularly evident. The temporal variability is likely to be related to seasonal and interannual variability in organic matter input. Greater food supply in some years may allow the growth and development of deposit-feeding polychaetes. 相似文献
8.
Multidimensional statistical analysis was used to study the polychaete distribution in soft-bottoms of two coastal areas of the Tyrrhenian Sea (Italy), which are influenced by the discharges of the rivers Tiber and Ombrone. In both areas the distributional patterns of these organisms are determined mainly by sediment types and related factors such as hydrodynamics, river input, and sedimentation. The grain-size gradient from the coast to the open sea affects not only species composition, but also species richness, diversity and abundance.In both areas three main communities have been identified: a sandy biocoenosis, a mixed-sediment biocoenosis and a muddy biocoenosis. The sandy coastal community is characterized by only a few species, while the intermediate zone of sandy-mud sediments presents the highest species richness and diversity. At the mouth of the River Tiber the influence of the river is more evident than at the mouth of the River Ombrone. This is due to the Tiber's greater river flow, which determines an environmental uniformity and a ‘cenotic continuum’ from sandy to muddy communities. This does not occur at the mouth of the Ombrone, where the river flow is less important and the polychaete communities are better defined. 相似文献
9.
湄洲湾海域甲藻孢囊的时空分布初步调查 总被引：1，自引：1，他引：0
为了解湄洲湾海域表层沉积物中甲藻孢囊的时空分布特征，于2018年5月(春)、8月(夏)、11月(秋)和2019年2月(冬)采集湄洲湾海域7个站位表层沉积物样品，进行甲藻孢囊分析，共鉴定出甲藻孢囊6大类42种和2种未知种。异养型甲藻孢囊种类数和丰度均高于自养型甲藻孢囊，其中又以原多甲藻类孢囊的种类和丰度最高。季节间差异不明显:种类数介于34～38种之间，丰度则在397.8～569.5 cysts/g之间变化，全年平均丰度448.0 cysts/g。工业区附近的站位种类数和丰度均低于养殖区附近的站位和对照点。优势种高达16种，原多甲藻类占绝对优势，但全部优势种优势度均不大。多样性指数、丰富度指数和均匀度指数均较高，全年的平均值分别为3.45、1.55和0.92。与历史资料对比，新发现19种孢囊，但丰度相差不大。另需注意的是，在湄洲湾海域共发现6种有毒甲藻孢囊，虽然全年丰度均不高，但仍有暴发有毒赤潮的危险，需引起重视。 相似文献
10.
海草床是海岸带最富生产力的生态系统之一，支撑着各种各样的伴生生物。热带的印度和太平洋地区被认为拥有海草植物种类多样性最高，且分布面积最广，然而，这个区域的海草床大型底栖生物我们知之甚少。为了填补认知的空白，我们在该区域开展了一项生态调查，旨在描述该区热带海草床大型底栖生物的丰度和多样性，以及确定大型底栖生物丰度、物种丰富度和群落结构是否明显存在断面内的站间变化和样地间变化。2014年5月和2015年10月我们分别在北苏拉威西省东海岸和西海岸开展野外工作，使用柱状取样器采集海草床大型底栖生物样品。所得样品共计鉴定14大类149种底栖生物，种类最为丰富的类别为多毛类（56种，占26%的总个体数），十足类（20种，占9%的总个体数）和端足类（18种，占35%的总个体数）。东、西海岸海草床大型底栖生物表现出不同的空间分布模式。在东海岸，同一断面的大型底栖生物和端足类的丰度存在显著的站间差异；而在西海岸，大型底栖生物和多毛类的种类丰富度和丰度都表现出明显的站间变化，这可能归结于同一断面底质不均所造成。单因素ANOSIM以及MDS排序表明了北苏拉威西省东海岸和西海岸海草床大型底栖生物群落结构存在显著不同，正好对应于将海草床分成两大类型的栖息地，即西海岸的红树林-海草床-珊瑚连续体和东海岸的海草床-珊瑚连续体。与在热带海区开展的其他研究相比，本研究的大型底栖生物丰度和多样性处于中等水平。东、西海岸海草床大型底栖生物群落存在显著区别，其原因可能源于多方面，包括了沉积物模式，海草床结构和时间变化。 相似文献
11.
Unravelling the complex structure of a benthic community: A multiscale-multianalytical approach to an estuarine sandflat 总被引：1，自引：0，他引：1
Luis Gimnez Caterina Dimitriadis Alvar Carranza Ana Ins Borthagaray Marcel Rodríguez 《Estuarine, Coastal and Shelf Science》2006,68(3-4):462
We evaluated scale-dependent patterns of distribution of sandflat macroinfauna of a coastal lagoon, using different analytical approaches. The sampled area was divided into three sectors (outer, inner-north, inner-south) containing small promontories. At each side of the promontories we defined stations in a line transect across the sandflat. Thus, we evaluated sediment characteristics and macroinfaunal responses to sectors, orientations and intertidal levels; animal–sediment relationships were also studied. At a large scale, there was a clear pattern of sediment composition and macroinfaunal abundance. While the outer sector had medium to coarse sands, reflecting the high hydrodynamic conditions existing near the lagoon entrance, the inner sectors showed sandy and muddy sediments. Most species were in low abundances at the outer sector. At small scale, macroinfaunal abundance and species richness decreased sharply towards the upper sandflat level. Also at small scale, sediment composition limited the maximal densities reached by all species, with exception of the deposit-feeding polychaetes. Thus, the macroinfaunal community at muddy sediments was dominated by burrowing deposit-feeders, while all species peaked in sandy sediments. Our results suggest that physical factors shaping macroinfaunal communities operate at different scales and are better detected using several analytical approaches. Large scale patterns, associated with along-shore variations in disturbance by currents, were detected as changes in the mean abundance of macroinfauna. Small scale patterns, related to sediment characteristics, were observed as changes in maximal densities of macroinfauna. Small scale patterns, associated with the level of inundation of the sandflats, were detected through changes in the abundance and presence of macroinfauna. The evaluation of the role of the physical conditions on communities must involve the use of several sampling and analytical approaches. 相似文献
12.
13.
Mahsa Haghi Ahmad Savari Preeta Kochanian Mohammad Bagher Nabavi Mohammad Hasan Nami Mohammad Zakeri Mohammad Bodaghi 《Marine Ecology》2012,33(4):460-469
Mapping surveys of coastal benthic habitat in Qeshm Island Geopark, Persian Gulf, were conducted using a combination of biological, sedimentological and echo‐sounding data. The survey area covered approximately 233 km2 in a depth range of 5–25 m, and the data were acquired from a single beam echo sounder, grab, video and still photography. Sediment and macrofauna samples were collected by grab at 76 stations and subjected to classification and ordination analyses. Two acoustic classes were identified differentiating along the near/offshore axis. Sediment texture was dominated by fine grain sizes, with five distinct sub‐sediment types. In total, 214 macrobenthic taxa were identified, of which polychaetes accounted for 60%. Other dominant groups included young sponges, nematodes, malacostracan crustacean, bivalves, ostracods and ophiuroids. Underwater videos and still photos integrated the macrofaunal and sedimentary data and revealed a range of biogenic sedimentary features such as burrows and tubes. The biological data identified six main biological assemblages showing an inshore/offshore pattern. The macrobenthic abundance did not demonstrate a significant difference with depth, although polychaetes were positively correlated with depth. The highest abundance and species richness were observed at median depths. Species distribution and diversity did not show any correlation with sediment type. A preliminary habitat mapping of the south coast of the Qeshm Island Geopark has been carried out, integrating acoustic, sediment and biological data. 相似文献
14.
为了解舟山市小干岛附近海域渔业资源状况,并为其可持续开发利用提供科学依据,文章于2016年5月(春季)在该海域设置15个站位,进行渔业资源定点拖网调查;采用相对重要性指数以及Shannon-Weaver指数、均匀度指数和丰富度指数,分析该海域的生物种类和生物多样性。研究结果表明:研究区生物种类有47种,为12目31科40属,优势种包括六丝钝尾虾虎鱼等3种,常见种包括日本鼓虾等9种;鱼类在质量和尾数方面都占绝对优势,虾类和蟹类也较多,渔业资源个体较小、经济价值较低;各调查站位的生物量和尾数分布有所不同;与其他海域渔业资源相比,研究区的生物多样性处于中等水平,应加强保护和恢复。 相似文献
15.
David C. Hockin 《Marine environmental research》1983,10(1):45-58
A nutrient enrichment experiment was conducted on an estuarine intertidal beach. A nutrient suitable for marine heterotrophic bacteria, derived from acid-hydrolysed casein, was applied to areas of sediment at low tide, at two frequencies. At the greater frequency of application the numbers of species of harpacticoid copepod comprising the community increased, as did the logarithmic series index of diversity. Displacement, presumably competitive, of the numerically dominant species by two confamilial species, formerly of less abundance, occurred and resulted in a decrease in the Berger-Parker dominance diversity. As the community converged to an equilibrium, due to the rapid growth rates of two species, it was predicted that the species richness and ecological diversity of the community would decrease, as some species underwent competitive exclusion, and in so doing would raise the dominance diversity. Before harpacticoid copepod communities can be used satisfactorily in biological monitoring programmes more basic research is needed to assess the response of a variety of meiobenthic communities to various loads of organic pollution. 相似文献
16.
依据2007年5月(春)、8月(夏)辐射沙脊群南部所获得的浮游动物样品,分析了该海域浮游动物的分布、时空变化及其与生态环境因子的关系。结果表明,调查海域浮游动物66种(不含鱼卵和仔鱼),生态属性以暖温性、近岸低盐种类为主;浮游动物总丰度春季(1 558.57 ind/m~3)>夏季(305.79 ind/m~3);饵料浮游动物生物量春季(2 923.75 mg/m~3)>夏季(335.46 mg/m~3);水平分布均呈现中北部高、南部低的特点。调查海域中部(4～5断面)多样性指数(H’)、丰富度指数(d)及均匀度指数(J)值较其他断面要低。相关性分析表明,春季浮游动物丰度和饵料浮游动物生物量的分布变化与浮游植物的丰度密切相关,夏季则与海水平均盐度的变化相关性显著;春、夏季浮游动物总丰度分布分别取决于优势种短尾类大眼幼体(Brachyura megalopa)和小拟哲水蚤(Paraca/anus parvus)的分布。 相似文献
17.
黄河口大型底栖动物群落结构特征及其与环境因子的耦合分析 总被引：6，自引：4，他引：2
为探究复杂环境下的河口大型底栖生物群落结构特征,研究了黄河口及其毗邻海域内14个站位的底栖生物群落结构及其与主要环境因子的耦合关系。研究结果表明调查海域底栖生物群落组成和结构的空间异质性较高。底栖生物优势度不明显,优势物种集中于河口附近站位。生物多样性随离河口距离增加而增加,物种丰富度和生物多样性指数等的高值区均出现在远离河口的渤海湾和渤海中部站位,低值区位于近河口站位。对底栖生物群落的非参数多维排序(nMDS)和等级聚类分析显示,底栖生物群落结构相似性较低。丰度/生物量曲线(ABC曲线)分析显示,黄河口底栖生物群落整体上处于稳定状态,但近河口和莱州湾中西部站位受到干扰影响,群落结构不稳定。研究还表明生物量大的底栖生物(软体动物)倾向于向重金属含量较高的站位聚集。综合沉积物化学、预测毒性和底栖生物群落结构变化的评价结果可知,远离黄河口的沉积物环境质量普遍较好,而河口附近的沉积物环境质量较差。 相似文献
18.
Abstract. Small-scale patterns of low-, mid- and high-shore intertidal species density, richness and abundance were systematically examined to assess the potential influence of 'mobility' on spatial community dynamics and diversity. Mobile taxa outnumbered sessile species by approximately 2:1, whereas sessile individuals were over 12 times as numerous as mobile ones over the entire study site. Patterns of density, richness and abundance differed with shore level and substratum. The results also highlighted the importance of clearly distinguishing between species density and species richness when examining spatially quantitative data. The rank order of habitats from highest to lowest species density was not the same when analysed in order of species richness. The potential for the mobile proportion of assemblages to influence small-scale diversity assessment through movement was greater at mid- and high-shore zones because the ratio of mobile species was higher and abundance (relative to the lower shore) was low. These observations might reflect the relative influence of the land–sea gradient of immersion on diversity and mobility in intertidal communities. The influence of mobile organisms on marine ecosystem function may be significant because small-scale patterns of movement are known to positively influence biodiversity. High richness paired with low abundance, however, may result in underestimating the functional role of mobile intertidal species. 相似文献
19.
胶州湾底栖生物多样性初探 总被引：21，自引：5，他引：21
用１９９１－１９９５年胶州湾１０个监测站的资料，采用Ｓｈａｎｎｏｎ－Ｗｅａｖｅｒ指数，Ｐｉｅｌｏｕｓ均匀度指数，种的丰盛度指数以及Ｓａｎｄｅｒｓ稀疏曲线进行大型底栖生物多样性比较。结果表明，在胶州湾，粉砂－粘土混合型的沉积环境中大型底栖生物多样性高于匀质的粗砂底质。 相似文献
20.
多样性指数在海洋浮游植物研究中的应用 总被引：109，自引：12，他引：97
对海洋浮游植物群落分析中常用的多样性指数进行了比较研究.对物种丰富度依赖型、丰度依赖型和实测浮游植物群落中物种丰富度、Shannon指数(以2或e为底)、Pielou均匀度指数、Simpson指数(1-D或1/D形式)、Margalef指数、Berger-Parker指数、McIntosh指数、McIntosh均匀度指数、Brillouin指数、Brillouin均匀度指数、Fisher α指数和Q统计指数等不同多样性指数计算结果进行了比较,发现不同多样性指数对浮游植物群落多样性的分析存在明显差异.对于一般情况下浮游植物群落多样性的研究,物种丰富度、Margalef指数、Fisher α指数、Shannon指数、Simpson相遇指数和Pielou指数的综合使用是较合适的,但对Margalef指数和Fisherα指数的结果要谨慎解释.并在综合应用各指数的基础上提出了浮游植物群落多样性分析的一般步骤. 相似文献