نتایج جستجو برای: foraminifera
تعداد نتایج: 4350 فیلتر نتایج به سال:
Accurate and precise estimation of divergence times during the Neo-Proterozoic is necessary to understand the speciation dynamic of early Eukaryotes. However such deep divergences are difficult to date, as the molecular clock is seriously violated. Recent improvements in Bayesian molecular dating techniques allow the relaxation of the molecular clock hypothesis as well as incorporation of multi...
in order to study the biostratigraphy and paleoecology of the early miocene in south west of kerman province, one section (gefriz) has been chosen, measured and sampled. the thickness of measured section is about 67 m. it consists mainly of thin to thick bedded limestone and marl. at this section, the early miocene deposits nonconformably lie between volcano sedimentary eocene at the base, and ...
The distribution and abundance of live (rose Bengal stained) and dead, shallow infaunal (0–1 cm depth) and deep infaunal (>1 cm depth) benthic foraminifera have been documented at three locations representing different salinity settings on the fringing marshes along the Pamlico Sound and Currituck Sound coasts of North Carolina’s Outer Banks. Two cores taken at each site represent the lower and...
Large benthic foraminifera (LBF) are important for reef sediment formation, but sensitive to elevated temperature and nutrients. However, it is possible that conspecific foraminifera living in different reef sites present divergent response to environmental shifts. We investigated how populations of Amphistegina lobifera from reef sites located along a temperature and nutrient gradient of the n...
Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Hence, their response to an acidifying ocean may have important consequences for future...
This paper describes and characterises the co-occurrence of ammonite and benthic foraminiferal assemblages across the São Gião outcrop (Central Portugal), a reference section for the Lower-Middle Jurassic boundary in the Lusitanian Basin. The upper Toarcian-lower Aalenian marls and marly-limestones in this section provide a precise and detailed ammonitebased biostratigraphic zonation, with a mi...
Monothalamous (single-chambered) foraminifera comprise a poorly known group, the diversity of which is strongly underestimated according to environmental DNA surveys. The gross morphology of monothalamids offers few distinguishing features; their organic-walled or agglutinated tests are often very delicate and make isolation difficult. Here, we use an integrated taxonomic approach, including mo...
Planktonic foraminifera from a continuous Oligocene succession with clear magnetochronology and sediment cycles at Ocean Drilling Program Site 1218 (equatorial Pacific Ocean) were studied in the interval from 27 to 30 Ma. Paragloborotalia taxa are common and we examined their size, relative abundance, and stable isotopes. Multispecies stable isotope data indicate the depth habitats of Oligocene...
A thorough review of literature showed that very little work has been carried out on foraminifera from the Muthupet Lagoon. The most notable research in this aspect has been the recent findings by Rajeshwara Rao et al. (2013), who provided an insight into the ecology of one particular species, Asterorotalia trispinosa (Thalmann, 1933). Infaunal habitat preferences of benthic foraminifera, howev...
We present an expanded training set of salt-marsh foraminifera for reconstructing Holocene relative sea-level change from 12 sites in New Jersey that represent varied physiographic environments. Seven groups of foraminifera are recognized, including four highor transitional-marsh assemblages and a low-salinity assemblage. A weighted-averaging transfer function trained on this dataset was applie...
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