Intertidal macroalgae and macroinvertebrates: Seasonal and spatial abundance patterns along an estuarine gradient     

Morgan N. Hardwick-Witman  Arthur C. Mathieson 《Estuarine, Coastal and Shelf Science》1983,16(2):113-129

Quantitative sampling of the dominant intertidal epibiota was conducted seasonally along an estuarine gradient within the Great Bay Estuary System, New Hampshire, U.S.A. The abundance and zonation of the dominant macroorganisms varied with distance into the estuary. Replacement of marine by estuarine species occurred, and overall abundance and species richness decreased along the estuarine gradient. Zonation patterns within the inner estuary were primarily allied with substrata. Maximum abundance of invertebrates occurred in the mid-intertidal zone where a dense fucoid canopy provided habitat heterogeneity. Densities of epibiotic organisms decreased toward low water, especially in the inner estuary where hard substratum was limiting. Settlement blocks, introduced into the low intertidal zone, were dominated by barnacles and fucoid algae; after 16 months, the species composition on the settlement blocks resembled the adjacent community. Semibalanus balanoides settled in the spring, while Fucus vesiculosus var. spiralis exhibited low but constant settlement. Despite the physical rigors of the estuarine environment, only Semibalanus balanoides, Ilyanassa obsoleta and Spartina alterniflora showed significant seasonal changes in density. Thus, there are predictable and persistent epibiotic species assemblages within the intertidal zone of the Great Bay Estuary System.  相似文献   

¹³⁴Cs: ¹³⁷Cs and ¹⁰⁶Ru: ¹³⁷Cs ratios in intertidal sediments from the Cumbria and Lancashire coasts England     

D.A. Stanners  S.R. Aston 《Estuarine, Coastal and Shelf Science》1981,13(4):409-417

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Food supply and dispersal in the determination of wintering population levels of oystercatchers, Haematopus ostralegus     

William J. Sutherland 《Estuarine, Coastal and Shelf Science》1982,14(2):223-229

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Structure and seasonality in a Malaysian mudflat community     

M.J. Broom 《Estuarine, Coastal and Shelf Science》1982,15(2):135-150

An assessment of community composition and the functional roles of the dominant species has been carried out in two intertidal areas of Malaysian mudflat dominated by natural populations of the arcid bivalve mollusc Anadara granosa.In addition to A. granosa, organisms of numerical importance are the venerid bivalve Pelecyora trigona, the neogastropod Plicarcularia leptospira, the mesogastropods Stenothyra glabrata and Cerithidea cingulata and the hermit crab Diogenes sp. The mesogastropod Natica maculosa and the neogastropod Thais carinifera may be of some importance to community organization but they are not numerically dominant. Annelids are conspicuous by their absence.The following trophic roles are ascribed to specific members of the community: A. granosa—facultative surface deposit feeder; P. trigona—suspension feeder; P. leptospira—scavenger; C. cingulata—deposit feeder/grazer; S. glabrata—deposit feeder/grazer; N. maculosa—predator; T. carinifera—predator; Diogenes sp.—scavenger/predator. S. glabrata is of particular interest because it appears to fill the niche occupied by mud snails of the genus Hydrobia in temperate mudflat systems.There is evidence of seasonality on the mudflats which points to a spawning of certain forms triggered by the major annual salinity depression at the time of the onset of the north-east monsoon in October/November. Concentrations of benthic chlorophyll a show no obvious signs of a seasonal fluctuation and the seasonality of the primary consumers is not thought to be related to food abundance. However there is some evidence of seasonality of reproduction in N. maculosa which preys on the seasonally reproducing bivalves.  相似文献   

Enteromorpha and the cycling of nitrogen in a small estuary     

N.J.P. Owens  W.D.P. Stewart 《Estuarine, Coastal and Shelf Science》1983,17(3):287-296

The nitrogen relations of Enteromorpha spp. growing on intertidal mud flats have been examined over a twelve-month period. Nitrogen assimilation rates using ¹⁵N have been used to calculate the production of the alga and were between 0·046 and 0·217 mg $\text{NH}{}_4{}^{\mathrm{+}}\text{N}$ (g dry wt alga)^?1 h^?1 A considerable quantity of the alga was buried beneath the sediment over the growth season and was calculated to be equivalent to an input of up to 9·52 g N m^?2 per month and 32 g N m^?2 over one complete growth season. Based on carbon, this latter value represented an input of approximately 320 g C m^?2 annually. Low rates of nitrogenase activity (acetylene reduction) were found to be associated with the Enteromorpha. The organisms responsible for the nitrogenase activity were probably heterotrophic bacteria but they did not contribute significant quantities of nitrogen to the alga.  相似文献   

拟建宁海电厂附近潮间带底栖生物群落生态   总被引：3，自引：0，他引：3  

杨俊毅  高爱根  陈全震  胡锡钢  杨关铭 《海洋学研究》2004,22(3):48-55

2002年12月对拟建宁海电厂附近海域3条潮间带断面的底栖生物生态进行了调查,共鉴定出潮间带大型底栖生物71种,平均生物量为1753.92g/m2,平均栖息密度为839个/m2。生物多样性指数和K-优势曲线都显示了位于拟建电厂选址区内的潮间带底栖生物群落已经受到了扰动。  相似文献   

Geoheritage at the small scale: tidal-zone bubble-sand structures as diagnostic paleo-environmental indicators,and their geoheritage significance     

V. Semeniuk  M. Brocx 《Australian Journal of Earth Sciences》2019,66(6):913-922

In identifying sites of geoheritage significance, commonly there has been an emphasis on the larger-scale features. However, the story of geology and the significant features that are critical to unravel geological processes and geological history are commonly small in scale. This contribution focuses on bubble sand and bubble-sand structures as features that are small-scale but nonetheless important to geology, and hence are of geoheritage significance. Bubble sand and bubble-sand structures are ubiquitous on modern beaches and tidal flats, occurring in the uppermost tidal zone of sandy beaches, as a distinct layer in a shoaling beach-to-dune stratigraphy, and are a diagnostic indicator of upper-tidal conditions where a rising tide and a concomitantly rising water-table interacts with the upper swash-zone wave processes. On sandy tidal flats, bubble sand and bubble-sand structures may occur in the mid- to upper-tidal zones; here they are also diagnostic indicators of tidal conditions, forming during a rising tide where a rising water-table forces air upwards to be trapped in moist sand. If found in ancient sequences, bubble-sand structures are a powerful environmental indicator of tidal conditions and, for beach sequences, an indicator of the high-tide level and sea level. Bubble-sand structures have been found in a number of ancient sequences throughout the geological record as far back as the Neoproterozoic, e.g. within beach-to-dune stratigraphy in Pleistocene limestones of the Perth Basin and in southeastern USA, and in tidal-flat sands of the Mesozoic Broome Sandstone of the Canning Basin. The bubble-sand structure is a significant geological tool for use in paleo-environmental and paleo-oceanographic reconstructions, and determination of the position of a paleo-water-table. Given the rarity of their preservation, these occurrences of bubble-sand structures are of geoheritage significance in their own right and, depending on age of sequence and how common they are in the region, they may be nationally significant or globally significant.  相似文献   

Integrating field and laboratory approaches for ripple development in mixed sand–clay–EPS     

Jaco H. Baas  Megan L. Baker  Jonathan Malarkey  Sarah J. Bass  Andrew J. Manning  Julie A. Hope  Jeffrey Peakall  Ian D. Lichtman  Leiping Ye  Alan G. Davies  Daniel R. Parsons  David M. Paterson  Peter D. Thorne 《Sedimentology》2019,66(7):2749-2768

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基于遥感的江苏省大陆岸线岸滩时空演变   总被引：2，自引：0，他引：2  

陈玮彤  张东  崔丹丹  吕林  谢伟军  施顺杰  侯泽宇 《地理学报》2018,73(7):1365-1380

基于江苏省1984-2016年61景多源遥感影像数据和部分实测潮位、坡度数据,利用遥感技术结合改进的水边线方法提取了多时相的海岸线和平均大潮低潮线,研究了江苏省绣针河口至连兴河口大陆岸线岸滩的时空演变特征。结果表明：1984-2016年,由于海岸带开发,江苏省的海岸线整体以向海推进为主,自然岸线由458.24 km逐渐减少至166.74 km,人工岸线由163.66 km快速增加至598.74 km,大陆岸线长度由621.90 km增加至765.48 km。发生位置和长度变化的岸段中,淤长岸段长127.62 km,年均向海推进83.03 m;围垦岸段长401.21 km,年均向海推进87.63 m;冲刷岸段长71.17 km,年均离海后退10.81 m;围垦被侵蚀岸段长25.95 km,年均离海后退8.64 m。海岸线的空间变化导致江苏省沿海陆地面积净增加104332 hm²,其中由于围垦增加的陆地面积98520 hm²,围垦是陆地面积增加的主要原因。海岸线的离海后退主要发生在废黄河三角洲岸段,但是到2008-2016年,岸线的侵蚀范围已向南扩大至新洋河口至斗龙港岸段。受围垦活动及岸线侵蚀影响,江苏省潮间带坡度不断变陡,统计断面的平均坡度由1.4‰增加至1.9‰,其中废黄河三角洲岸段的中山河口至扁担河口岸段坡度最陡,基本在3~14‰之间;辐射沙洲陆岸岸段坡度最为平缓,但坡度也在逐渐陡化,由0.9‰增加至1.5‰。潮间带面积由271747 hm²减少至168645 hm²,减幅38%;潮间带平均宽度由5064 m减少至3096 m,减幅39%。  相似文献   

基于潮汐动态淹没过程的长江口潮滩地形信息反演研究     

章敏  吴文挺  汪小钦  孙玉 《地球信息科学学报》2022,24(3):583-596

潮滩是陆地与海洋之间重要的生态过渡地带,具有复杂的生态过程和重要的服务功能。受陆海交互作用及人类活动的影响,潮滩处于高度动态变化过程中,而传统测绘技术受到潮滩可达性影响无法快速获取潮滩地形信息。为解决潮滩高程数据获取困难的问题,本文提出一种基于潮汐动态淹没过程和时序遥感影像的潮滩地形信息提取算法,利用K-means++聚类方法实现水域提取,并通过时序淹没特征计算潮滩淹没频率提取潮滩范围信息,最终综合区域潮汐特征反演潮滩地形。研究以崇明东滩为例,利用2016—2020年所有可用Sentinel-2和Landsat-8时序遥感影像,实现潮滩范围提取与高程反演,并通过实测高程数据进行精度验证。研究结果表明,潮滩范围提取总体精度为97.73%,F1_score为0.98;高程反演平均绝对误差为0.15 m,潮滩高程的反演精度与可用影像的数量呈正相关。研究利用该算法进一步反演长江口地区主要潮滩地形特征,结果表明区域内潮滩面积为346.93 km²,高程范围为1.00~3.84 m,且与现有潮滩范围数据集相比,本研究提取的长江口潮滩范围更为完整。该算法为潮滩地形的快速反演提供了可能,对潮滩资源动态监测和管理具有重要意义。  相似文献