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| Barras, C.; Duplessy, J. -c.; Geslin, E.; Michel, Elisabeth; Jorissen, F. J.. |
| The geochemical composition of deep-sea benthic foraminiferal calcite is widely used to reconstruct sea floor paleoenvironments. The calibration of the applied proxy methods has until now been based on field observations in complex natural ecosystems where multiple factors are interfering. However, laboratory experiments with stable physico-chemical conditions appear to be the ideal way to evaluate the influence of a single parameter. In this paper, we present the oxygen isotopic composition of deep-sea benthic foraminiferal shells entirely calcified under controlled experimental conditions over a large temperature range (4 to 19 degrees C). The new laboratory protocols developed for this study allowed us to produce large quantities of shells in stable... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00241/35177/33738.pdf |
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| De Chanvalon, A. Thibault; Metzger, E.; Mouret, A.; Cesbron, F.; Knoery, Joel; Rozuel, Emmanuelle; Launeau, P.; Nardelli, M. P.; Jorissen, F. J.; Geslin, E.. |
| We present a new rapid and accurate protocol to simultaneously sample benthic living foraminifera in two dimensions in a centimeter scale vertical grid and dissolved iron in high resolution (200 μm). Such an approach appears crucial to study foraminiferal ecology in heterogeneous environments. The foraminiferal faunas of the main intertidal mudflat of the Loire estuary are dominated by Ammonia tepida, which accounts for 92 % of the living assemblage (CTG-labeled). Its vertical distribution shows a first density maximum at the surface, a sharp decrease in the next two centimeter followed by a well defined second maximum between 3 and 8 cm depth. The heterogeneity of A. tepida in this 3–8 cm depth layer was calculated by the Moran's Index and reveals lateral... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00277/38786/37335.pdf |
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| Wit, J. C.; De Nooijer, L. J.; Barras, C.; Jorissen, F. J.; Reichart, G. J.. |
| The reconstruction of past temperatures is often achieved through measuring the Mg/Ca value of foraminiferal test carbonate. The diversity in foraminiferal Mg/Ca-temperature calibrations suggests that there is also a biological control on this proxy. This study presents a new Mg/Ca-temperature calibration for the benthic foraminifer Bulimina marginata, based on cultures under a range of temperatures (4-14 degrees C). Measured Mg/Ca values for B. marginata correlate with temperature (Mg/Ca = (1.10+/-0.10) e((0.045+/-0.009)) T, R-2 = 0.28 p < 0.01). The inter-individual variability is, however, also significant (standard deviation is 10-35% of the average). Before applying this or any calibration, the effect of the inter-individual variability on the... |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00249/36045/34589.pdf |
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| Caulle, Clemence; Mojtahid, M.; Gooday, A. J.; Jorissen, F. J.; Kitazato, H.. |
| Rose-Bengal-stained foraminiferal assemblages (> 150 mu m) were analysed along a five-station bathymetric transect across the core and the lower part of the oxygen minimum zone (OMZ) on the Indian margin of the Arabian Sea. Sediment cores were collected using the manned submersible Shinkai 6500 during the RV Yokosuka cruise YK08-11 in the post-monsoon season (October 2008) at water depths ranging from 535 to 2000 m, along a gradient from almost anoxic to well-oxygenated (0.3 to 108 mu M) bottom waters. Stained benthic foraminifera were investigated from two different size fractions (150-300 mu m and > 300 mu m). Stained foraminiferal densities were very high in the core of the OMZ (at 535 and 649 m) and decreased at deeper sites. The faunas (> 150... |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00279/39027/37583.pdf |
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| Jorissen, F. J.; Bicchi, E.; Duchemin, G.; Durrieu, J.; Galgani, Francois; Cazes, L.; Gaultier, M.; Camps, R.. |
| In order to assess the possible environmental impact of oily cuttings discharged during oil exploration activities, we studied the benthic foraminiferal faunas in a five-station, 4-km-long sampling transect around a cuttings disposal site at about 670 m depth offshore Angola (W Africa). where drilling activities started 1.5 years before sampling. Living (Rose Bengal stained) and dead foraminiferal faunas were sampled in March 2006. The faunal patterns mirror the spatial distribution of hydrocarbons, which are dispersed into a southeastern direction. Four different areas can be distinguished on the basis of the investigated faunal parameters (density, diversity and species composition of the living fauna, and comparison with subrecent dead faunas). The... |
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Palavras-chave: W Africa; Upper continental slope; Offshore Angola; Drill cuttings; Bio indicators; Benthic foraminifera. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7301.pdf |
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