نتایج جستجو برای: planktonic and benthic foraminifera
تعداد نتایج: 16831487 فیلتر نتایج به سال:
The discovery that foraminifera are able to use nitrate instead of oxygen as an electron acceptor for respiration has challenged our understanding of nitrogen cycling in the ocean. It was thought before that only prokaryotes and some fungi are able to denitrify. Rate estimates of foraminiferal denitrification have been very sparse and limited to specific regions in the oceans, not comparing sta...
Marine protist diversity inventories have largely focused on planktonic environments, while benthic protists have received relatively little attention. We therefore hypothesize that current diversity surveys have only skimmed the surface of protist diversity in marine sediments, which may harbor greater diversity than planktonic environments. We tested this by analyzing sequences of the hyperva...
A dynamic global model for planktonic foraminifera I. Fraile, M. Schulz, S. Mulitza, and M. Kucera Department of Geosystem modelling, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany DFG Research Center Ocean Marigins, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany Institute of Geosciences, Eberhard Karls University of Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germa...
the investigated section cropping out in kuh-e-banesh, zagros basin (southern iran) is represented by limestone, cherty beds and marllevels bearing abundant planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. for the first time, well to moderatelypreserved forms of planktonic foraminifera have been extracted from black shale and marls levels. extracted biota was studied wit...
Micropaleontological analysis of sixty (62) ditch cuttings rock samples collected from interval, 7800 feet to 12,002 well AD, located offshore western Niger Delta was carried out for the investigation their age and paleodepositional environment. Standard methods techniques foraminiferal sample processing were followed disaggregate microfauna matrix. The studied interval is predominantly made up...
Major negative oxygen isotopic anomalies in planktonic foraminifera are associated with deep-sea anoxic mud layers (sapropels) deposited 9000 and 80,000 years ago in the eastern Mediterranean. The isotopic depletion in surface-dwelling foraminifera is significantly greater than in mesopelagic foraminifera. This difference in isotopic response suggests that surface-water salinities were drastica...
The Asmari Formation was deposited in the foreland basin of southwest Iran (Zagros Basin). Carbonate sequences of the Asmari Formation consist mainly of large benthic foraminifera along with other skeletal and non-skeletal components. Three assemblage zones have been recognized by distribution of these large foraminifera in the study area that indicate Oligocene age (Rupelian-Chattian). Absence...
[1] We studied the seasonality of planktonic foraminifera during the Last Glacial Maximum using a foraminifera model coupled to an ecosystem model. The model suggests that the timing of the maximum seasonal production of planktonic foraminifera during the Last Glacial Maximum occurred at a different time of the year from present day. The assumption of ‘‘stable’’ seasonality through time, one of...
Stable isotopic measurements have been made on both planktonic foraminifera and coccolithic matrix of Middle Cretaceous (Late Albian–Cenomanian) age from two Pacific low latitude sites. The degree of alteration of the foraminifera has been assessed through the application of chemical analyses, cathodoluminescence and Scanning Electron Microscopy (SEM). The rotaliporid foraminifera display an in...
[1] We present a high-resolution climate record from a sediment core spanning an 80-kyr interval of time during the mid-Pliocene epoch, when warmer conditions and lower global ice volume prevailed worldwide. Oxygen and carbon isotope analyses were made on benthic and planktonic foraminifera from ODP Site 981 in the North Atlantic. The amplitude and approximate recurrence interval of suborbital ...
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