نتایج جستجو برای: planktic foraminifera
تعداد نتایج: 4552 فیلتر نتایج به سال:
In this research systematics and biostratigraphy of the Cretaceous deposits foraminifera in Kerch section, southwestern Qayen, in the eastern margin of the Lut Block, were studied in detail. This section with 260 meters thickness, mainly formed by gray to cream color marl and shale, marly limestone and limestone laid on a light-colored limestone bed at the base. Seventeen genera and twenty two ...
Within the Porcupine Bank Canyon (NE Atlantic), cold-water coral (CWC) mounds are mostly found clustered along canyon lip, with individual disconnected occurring nearby on western Bank. Remotely operated vehicle-mounted vibrocoring was utilized to acquire cores from both of these sites. This study is first employ this novel method when aiming precisely sample two closely situated areas. Radiome...
Dockyards and harbors are recognized as being important locations where sediment-associated pollutants can accumulate, which constitutes an environmental risk to aquatic life due to potential uptake and accumulation of heavy metals in the biota. The aim of this paper is to assess the concentrations and the effects of some heavy metals in the benthic foraminifera assemblage in Niterói Harbor. Lo...
the larger benthic foraminifera gyroconulina columellifera schroeder & darmoian, 1977 (type-locality: maastrichtian aqra formation of iraq) is described for the first time from two sections of the maastrichtian tarbur formation of the zagros fold-thrust-belt, sw iran. new details on its wall microstructure are provided. the microfacies is represented by bioclastic wacke-/pack-/grainstones with ...
Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs) where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with (13)C and (15)N) by calcareous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern ...
We present stable isotope and geochemical data from four sediment cores from west of Prins Karls Forland (ca. 340 m water depth), offshore western Svalbard, recovered from close to sites of active methane seepage, as well as from shallower water depths where methane seepage is not presently observed. Our analyses provide insight into the record of methane seepage in an area where ongoing ocean ...
Three-dimensional modeling of lake morphometry enables the calculation of lake volume, planar surface area, and basin surface area, which are critical components of a conceptual model of how planktic and benthic habitat areas change with changing lake level. We have applied three-dimensional modeling to Foy Lake, Montana, and compared model results of changing ratios of planktic and benthic hab...
Cifelli, Richard. Textural Observations on Some Living Species of Planktonic Foraminifera. Smithsonian Contributions to Paleobiology, n u m b e r 45, 45 pages, 15 plates, 1982.—Wall textures of 11 species of spinose and quasi-spinose planktonic foraminifera collected in plankton tows from the Nor th and Equator ia l Atlantic have been studied with the scanning electron microscope. Il lustration...
Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing fo...
Molecular phylogenies of foraminifera are commonly inferred from the small subunit rRNA (SSU) genes, which can easily be obtained from single cells isolated from environmental samples. The SSU phylogenies, however, are often biased by heterogeneity of substitution rates, and their resolution of higher level relationships is often very low. The sequences of protein-coding genes provide an import...
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