Size-differential feeding in Pinna nobilis L. (Mollusca: Bivalvia): Exploitation of detritus,phytoplankton and zooplankton     

John Davenport  Daria Ezgeta-Balić  Melita Peharda  Sanda Skejić  Živana Ninčević-Gladan  Slavica Matijević 《Estuarine, Coastal and Shelf Science》2011

The endangered fan shell Pinna nobilis is a large bivalve mollusc (<120 cm shell length) endemic to the Mediterranean that lives one-third buried in soft substrata, generally in shallow coastal waters. We hypothesised that P. nobilis of different sizes would ingest different food sources, because small fan shells will inhale material from closer to the substratum than do large fan shells. We studied stomach contents and faeces of 18 fan shells, 6 small (mean 23.0 cm length), 6 medium-sized (mean 41.5 cm length) and 6 large (mean 62.7 cm length) living in a small area of a low-energy coastal detritic bottom characterised by mud, sand and macroalgae at Mali Ston Bay, Croatia. We found that all P. nobilis ingested copious quantities of undetermined detritus (probably at least 95% of ingested material), phytoplankton, micro and mesozooplankton and pollen grains. Large P. nobilis stomach contents showed a preponderance of water column calanoid copepods, while small fan shells had higher numbers of bivalve larvae. All fan shells took in high numbers of harpacticoid copepods that are benthonic, feeding on microbial communities of detritus and benthic vegetation. There was also a significant selection of phytoplankton species, some apparently occurring between inhalation and ingestion. The stomach contents of small P. nobilis had a higher organic matter content than either medium-sized or large fan shells; this indicated that small fan shells ingested detritus of higher organic content than did larger P. nobilis. As the faeces of all P. nobilis had similar organic matter content, this also indicates higher assimilation efficiencies in small fan shells. The demonstration of differential dietary selectivity by different sized animals has implications for future trophic studies of this endangered species. This study also provides the first demonstration of predation on zooplankton by P. nobilis.  相似文献   

Regional and temporal changes in bivalve diversity off the south coast of Portugal     

M.M. Rufino  M.B. Gaspar  F. Maynou  C.C. Monteiro 《Estuarine, Coastal and Shelf Science》2008,80(4):517-528

From 2000 to 2006, a total of 75 bivalve species were identified, varying from 29 (spring 2001) to 54 species (spring 2005) per year. Seasonal tendencies in diversity varied according the year, thus the interpretation of long-term and regional scales is essential before drawing any conclusions in other studies. Richness and diversity consistently decreased with depth and increased with sediment grain size (from low in very coarse sand to high in coarse silt). Diversity decreased progressively from 3 to 16 m depth, thus the harsher shallower environments (due to waves and tidal air exposure) showed greater diversity than the most stable areas. Communities in finer sediments were more diverse than those in coarser sand. Evenness showed patterns opposite to diversity, overall.Diversity and evenness maps (produced with multivariate universal kriging), showed that most geographic areas with greater diversity were farer from river outflows and wastewater treatment plants. Two types of geographic pattern were observed: areas with persistently greater bivalve diversity through time and areas that changed locally from year to year. This spatial analysis can be used to establish priority conservation areas for management purposes, and to analyse the persistency of regional diversity patterns. The area with most habitat heterogeneity (Sotavento) corresponded to greatest diversity.There was a positive relationship between Spisula solida and Chamelea gallina landings and bivalve diversity 2 years and 1 year later, respectively. Possibly, local fisheries, by selectively withdrawing the commercial numerically dominant species from the ecosystem, increased diversity 1 to 2 years later, as the ecological niches of the dominants are quickly filled by several other species thereby creating a more even community. On regional scales, no significant impact was found on long-term bivalve diversity in local fisheries,  相似文献   

Enhancement of jellyfish (Aurelia aurita) populations by extensive aquaculture rafts in a coastal lagoon in Taiwan   总被引：1，自引：0，他引：1  

Lo  Wen-Tseng; Purcell  Jennifer E.; Hung  Jia-Jang; Su  Huei-Meei; Hsu  Pei-Kai 《ICES Journal of Marine Science》2008,65(3):453-461

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湖北大冶沙田下三叠统菊石、双壳动物群的发现及其地层意义   总被引：3，自引：0，他引：3  

朱利东  丁梅华  刘华夏 《地球科学》1992,(3)

本文所研究的湖北大冶沙田下三叠统菊石、双壳动物群,包括菊石10属11种,双壳类4属9种。文中建立了5个菊石带:Lytophiceras带、Gyronites带、Flemingites带、Pseudosagece-ras—Xenodiscoides带和Anasibirites带;2个双壳动物带:Claraia griesbachi带和Cl.concentrica带,并依据动物群面貌,将原大冶群的时代详细划分为大冶组和观音山组。大冶组的时代相当于格里斯巴赫期至亭纳尔期,观音山组的时代相当于斯密斯期至斯派斯期。  相似文献   

The age determination and growth rate of the European flat oyster, Ostrea edulis, in British waters determined from acetate peels of umbo growth lines     

Richardson  C. A.; Collis  S. A.; Ekaratne  K.; Dare  P.; Key  D. 《ICES Journal of Marine Science》1993,50(4):493-500

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First record of a middle Cenomanian caprinuloideid rudist (Hippuritida,Bivalvia) from Montana,USA, and its geographical and stratigraphical significance     

《Cretaceous Research》2013

The new caprinoidean rudist bivalve Cobbanicaprina bighornensis gen. nov., sp. nov. is described from the upper middle Cenomanian of Big Horn County, Montana, USA. Cobbanicaprina gen. nov. is closely related to Mexicaprina and differs from that form in the absence of an external ligamental groove. The presence of Cobbanicaprina gen. nov. in the middle Cenomanian indicates that the Caprinuloideidae did not become extinct at the top of the Albian and persisted into the Cenomanian. The presence of this specimen so far north in the Western Interior Seaway is attributed to a dried-out individual specimen having been transported post-mortem by currents.  相似文献   

鸡西群城子河组时代的进一步探讨   总被引：9，自引：1，他引：9  

姜宝玉  冯金宝 《地层学杂志》2001,25(3):217-221,240

近年来 ,古生物工作者在鸡西群城子河组及其相当地层的生物化石研究方面取得了巨大的进展。在总结这些新的材料的基础上 ,通过与国外的化石组合进行对比 ,从海相双壳类、植物、孢粉及海相沟鞭藻化石等多方面的证据 ,尤其是根据 Thracia rotundata、Vectianella、Pseudaphrodina ricordeana等欧洲 Aptian阶重要的双壳类化石、被子植物及三沟类被子植物花粉的出现 ,城子河组的时代应为 Aptian期 - Albian期早期  相似文献   

贵州紫云四大寨早三叠世地层初步研究     

胡艳霞  徐东来  童金南 《地层学杂志》2006,30(2):T0001-T0002

贵州紫云四大寨剖面下三叠统发育较齐全,化石较丰富。在此剖面上发现了大量牙形石、双壳类、菊石等生物化石,其中牙形石在该剖面上为首次发现,并识别出了早三叠世Neospathodusdieneri带、Neospathoduscrista-galli带、Neospathoduswaageni带和Neospathodushomeri-Neospathodustriangularis带的重要牙形石分子或带化石,可与国际同期地层中相应的牙形石化石带进行较好的对比;同时还发现了Claraiagriesbachi-C.concentrica组合和Claraiastachei-Claraiaaurita组合带的双壳类代表性分子。通过对这些化石综合分析,大致拟定了本剖面下三叠统格里斯巴赫亚阶(Griesbachian)、亭纳尔亚阶(Dienerian)、斯密斯亚阶(Smithian)和斯派斯亚阶(Spathian)的年代地层单位界线。  相似文献   

莺歌海盆地上新统双壳类贝壳的锶含量及其意义   总被引：1，自引：0，他引：1  

王子玉  蓝秀 《地层学杂志》1998,22(2):149-153

锶（Ｓｒ）是碳酸盐沉积物及软体动物介壳中的重要微量元素之一,Ｓｒ含量和Ｓｒ／Ｃａ比值的变化明显受沉积相的控制。因此,锶作为地球化学指标具有一定的环境意义。通过对南海北部莺歌海盆地莺６井上新统双壳类贝壳中的Ｓｒ含量和Ｓｒ／Ｃａ比值的变化与环境、成岩作用关系的研究,发现莺歌海盆地上新世沉积环境为上陆坡→潮下带→潮间带,所得结论与双壳类的生态环境和地层沉积相的综合分析结果一致。  相似文献   

Observations on shell growth and morphology of the bivalve Ruditapes philippinarum     

范德江  张爱滨  杨作升  孙效功 《中国海洋湖沼学报》2007,25(3):322-329

The bivalve Ruditapes philippinarum is not only one of the main mollusc species in the west Pacific Ocean, but also one of the main species for aquaculture in China. Knowledge of growth of the R. philippinarum shell will improve our understanding of the shell as an environmental archive. It is also useful for the aquaculture of R. philippinarum. In this research, a hanging box culture method was introduced in the culture of R. philippinarum. The bivalves were cultured for 126 days, from March 31 to August 3, 2002. The average growth rates of shell width, height, and thickness were 0.069, 0.046, and 0.032 mm/d, respectively. The mean increase of average individual wet mass was 0.028 g/d. The largest growth rates of both shell and average individual wet mass occurred in June, indicating that water temperature and bivalve reproduction were 2 important factors. The shell morphology underwent significant changes with shell growth. The ratio of height to thickness (value of B/C) shifted 1.58 in the first 60 days to 1.54 in the last 30 days, which was resulted from the change in major shell growth direction. Periodic changes in the B/C ratio led to corrugated shell form, which could be used to determine the age of the shell.  相似文献