نتایج جستجو برای: large benthic foraminifera

تعداد نتایج: 1043693  

2015
S. V. Petersen D. P. Schrag

Across the Eocene-Oligocene transition, the oxygen isotopic composition (δO) of benthic and planktonic foraminifera increased by over 1‰. This shift is thought to represent a combination of global cooling and the growth of a large ice sheet on the Antarctic continent. To determine the contribution of each of these factors to the total change in δO, we measured the clumped isotopic composition o...

2011
Yair Rosenthal Audrey Morley Christine Barras Miriam E. Katz Frans Jorissen Gert‐Jan Reichart Delia W. Oppo Braddock K. Linsley

[1] Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and dO in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4°C and 13°C. This shallow infaunal species is primarily abundant in neritic to upper bathyal sediments (<600 m). Both linear and exponential calibrations suggest a temperature sensitivi...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Laia Alegret Ellen Thomas Kyger C Lohmann

An asteroid impact at the end of the Cretaceous caused mass extinction, but extinction mechanisms are not well-understood. The collapse of sea surface to sea floor carbon isotope gradients has been interpreted as reflecting a global collapse of primary productivity (Strangelove Ocean) or export productivity (Living Ocean), which caused mass extinction higher in the marine food chain. Phytoplank...

Journal: :international journal of environmental research 0
m. c. m. blettler ciudad universitaria, argentina m. l. amsler ciudad universitaria, argentina i. ezcurra de drago ciudad universitaria, argentina e. drago ciudad universitaria, argentina a. paira ciudad universitaria, argentina l. a. espinola ciudad universitaria, argentina e. eberle

several studies suggest that invertebrate abundance and richness are disrupted and reset at confluences. thus, junctions contribute disproportionately to the overall aquatic biodiversity of the river. in general terms, authors have reported high abundance and diversity due to the major physical heterogeneity at junctions. however, data are still scarce and uncertainties are plentiful.the impact...

2016
Heather S. Birch Helen K. Coxall Paul N. Pearson Dick Kroon Daniela N. Schmidt

The impact of an asteroid at the end of the Cretaceous caused mass extinctions in the oceans. A rapid collapse in surface to deepocean carbon isotope gradients suggests that transfer of organic matter to the deep sea via the biological pump was severely perturbed. However, this view has been challenged by the survival of deep-sea benthic organisms dependent on surface-derived food and uncertain...

Journal: :Revista de biologia tropical 2002
Patricia Sánchez Rueda

A year-long research on the Mugil cephalus and M. curema diet was conducted. The food content in the cardiac portion of 192 stomachs revealed a great similarity in both species leading to two conclusions: sediments are their basic food and high levels of benthic diatoms are dominant. A total of 130 taxa were found (Nitzschia, Navicula, Amphora, and Cocconeis dominated). Other food components we...

2007
Richard E. Zeebe

I present a numerical diffusion–advection-reaction model to simulate CO2 chemistry, d C, and oxidation of organic carbon and methane in sediment porewater. The model takes into account detailed reaction kinetics of dissolved CO2 compounds, H2O, H , OH , boron and sulfide compounds. These reactions are usually assumed to be in local equilibrium, which is shown to be a good approximation in most ...

2017
G. Sreenivasulu N. Jayaraju B.C. Sundara Raja Reddy T. Lakshmi Prasad K. Nagalakshmi B. Lakshmanna

Fourier Transform Infrared Spectroscopy (FTIR) was used to study the variations in organic matters of benthic foraminifera (Ammonia beccarii) from four samples collected from beach environments from brackish environments along Tupilipalem coast (South east coast of India). Common absorption bands were observed as peaks in the range of 3600-3400 cm-1, 3000-2850 cm-1, 1750-1740 cm-1, 1640-1600 cm...

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