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Semeniuk T A. Journal of Foraminiferal Research,2000, 30(2): 99-109 1 图 版 .Density of epiphytic foraminifera varies spatiallyfrom sub-leaf to regional scales withinPosidonia australis meadows of south WesternAustralia. Foraminiferal populations on individualseagrass leaves show compositional zoningand aggregation around algae and serpulid wormtubes. Such microscale spatial heterogeneitycould reflect microhabitat, leaf growth history,food source and recruitment patterns. Most foraminiferahave homogeneous densities on individualplants, and are distributed evenlythroughout seagrass samples from meadows at agiven geographic site. Only species associatedwith patchy epiphytic algae within the meadowsshow spatial heterogeneity at the local scale.Spatial homogeneity within the seagrassmeadow reflects repetition of seagrass leaf substrateand microhabitats, and the uniformity ofambient environmental variables at scales largerthan the seagrass leaves. Spatial homogeneity inthis environment permits characterization of agiven geographic site based on three samples. Atregional scales, foraminifera may have homogeneousand heterogeneous distributions. Abundanceof individual species is uniform, sporadic,or shows a gradient pattern along the coast. Patternsof variation in foraminiferal populationsregionally, partly reflect the climate gradient, butalso factors operating at micro- and local scales.Regionally distinct assemblages could be definedfor different climatic regions along thecoast. Thus, populations of the various foraminiferalspecies are regulated by environmentalor biotic variables at different scales.This study shows how sample composition ateach site reflects spatial variation of species atmicro-, local and regional scales and how thesedifferences can be used to define assemblageswhich characterize microhabitats, localities andregions.2008040261意 大 利 北 部 特 兰 托 地 台 Calcari Grigi 地 区 威尼 斯 早 三 叠 世 有 孔 虫 EverticyclamminaRedmond 1964( 新 种 E. praevirguliana) 的首 次 记 录 = First record of EverticyclamminaRedmond 1964(E.praevirguliana n. sp., foraminifera)from the early jurassic of the venetianprealps (Calcari Grigi,Trento platform,northern Italy). ( 英 文 ). Fugagnoli A. Journal ofForaminiferal Research, 2000, 30(2): 126-134 3图 版 .The rich fossil content of the Lower Jurassiccarbonate successions of the Trento Platform(northeastern Italy) have been studied since thebeginning of the nineteenth century. This detailedstudy on several stratigraphic sectionscropping out in this area, all spanning the LiassicRotzo Member (Calcari Grigi formation, VenetianPrealps), provides us new biostratigraphicdata about the genus Everticyclammina Redmond1964. A new species of Everticyclammina,E. praevirguliana n. sp., is formally describedfrom the Calcari Grigi, where it occurs in levelsattributed to the late Sinemurian to Domerianage. Everticyclammina praevirguliana n. sp.thus becomes the first representative of the genusin the Early Jurassic; this record consequentlyenables the stratigraphic distribution ofthe genus to be lowered to the Liassic. Hence theplexus of Everticyclammina evolving communitiesnow bridges the Liassic (late Sinemurian) toEarly Cretaceous (Aptian) interval.2008040262变 形 虫 Arcellaceans 作 为 印 度 尼 西 亚 IrianJaya 岛 Sentani 热 带 湖 中 的 湖 泊 指 示 物 的 初步 调 查 = Preliminary survey of Arcellaceans(Thecamoebians)as limnological indicators intropical lake Sentani, Irian Jaya, Indonesia. ( 英文 ). Dalby A P; Kumar A. Journal of ForaminiferalResearch, 2000, 30(2): 135-142 1 图版 .Arcellacean (thecamoebian) assemblages recoveredfrom Lake Sentani, a large tropical lakesouthwest of Jayapura, Irian Jaya, Indonesia, arecharacterized by low diversity and low abundances.Dominated by Centropyxis aculeata andArcella vulgaris, this fauna is similar to thoseindicative of stressed environments (brackishconditions, high levels of industrial contaminants)in temperate regions. However, neithercondition exists in Lake Sentani. Previous workhas determined that the lake is oligomictic, characterizedby weak circulation with turnover occurringonly every few years. Prolonged isolationof the lake bottom produces progressivelyreduced oxygen levels and results in reducedproductivity among benthic organisms. The feeblestratification that exists here creates reducedoxygen levels at depth providing a likely explanationof the stressed arcellacean fauna. The oligomicticconditions observed here and the resultantfauna are widespread and are characteristicof a large proportion of tropical lakes around theworld. As the low bottom water oxygen conditionswill have a serious impact on most benthicorganisms in these lakes, other limnological signalsincluding anthropogenic contamination willbe masked. This is a disappointing result as theutility that has been developed for the group as alimnological indicator in temperate lakes doesnot appear to apply in a significant proportion oflow latitude lakes.200804026384