Showing papers by "Frans Jorissen published in 1999"
01 Jan 1999
TL;DR: Benthic Foraminifera do not live exclusively at the sediment-water interface, and can be found alive at considerable depths in marine sediments, in many cases down to 10 cm.
Abstract: Benthic Foraminifera do not live exclusively at the sediment-water interface, and can be found alive at considerable depths in marine sediments, in many cases down to 10 cm ( Fig. 10.1) . Within this depth interval, large changes take place in the natural environment, especially in the case of finegrained sediments, the surface layer and the deep sediment layers forming two very different worlds. At the sediment-water interface, the sea water may be rich (even saturated) in oxygen, high-quality organic matter is often available, and in the photic zone, there is l ight. Deep in the sediment, conditions are drastically different: often there is no oxygen, except in halos around metazoan burrows, but there may be toxic substances (e.g. instead. Furthermore, the remaining organic matter may be mostly refractory, with a low nutritional value (see chapter 11) . Apparently, the deeper sediment layers, with their poverty of resources and lack of oxygen, form an inhospitable or even hostile environment for many organisms, and as a consequence, animal life is generally scarce (Fenchel and Finlay, 1995). Nevertheless,
298 citations
TL;DR: Benthic foraminiferal records across Late Quaternary Mediterranean sapropels S6, S5 and S1 are reviewed and re-considered in the light of recent advances in foraminifereral ecology as discussed by the authors.
167 citations
TL;DR: In this article, a conceptual model is proposed to link the productivity variations to atmospheric circulation, in particular to the wind stress, direction and seasonality, and the authors show that the conditions of sedimentation during the last 5-6 thousend years on the upper slope (site 11K) are largely dominated by advection from the shelf, leading to strong sorting prior to deposition.
122 citations
TL;DR: In this article, a comparison of live and dead benthic foraminiferal faunas in a five-station sample transect off Cape Blanc suggests that interspecific differences in living/dead (L/D) ratios are to a large extent determined by seasonal differences in reproduction.
118 citations
15 Jun 1999-Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule A-sciences De La Terre Et Des Planetes
TL;DR: The phosphorus geochemistry on the Bay of Biscay margin shows that modern sediments represent a source of phosphate for overlying seawater as mentioned in this paper, however, particulate phosphorus leached with an ascorbate solution and 1 N HCl remains constant in the sedimentary column.
Abstract: The phosphorus geochemistry on the Bay of Biscay margin shows that modern sediments represent a source of phosphate for overlying seawater. However, particulate phosphorus leached with an ascorbate solution and 1 N HCl remains constant in the sedimentary column, which suggests that inorganic particulate phosphorus is trapped in the sediment. This is due to bioturbation, which carries iron oxides with high adsorption capacities for phosphate deep into the sediment, and also, to the precipitation of authigenic phosphate minerals in the anaerobic zone of the sediment.
18 citations
30 Aug 1999-Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule A-sciences De La Terre Et Des Planetes
TL;DR: In this article, the authors reconstructed the Late Quaternary productivity record of two cores of the NW Africa upwelling area, SEDORQUA 20bK and 17aK, down to isotopic stage 7 and showed the lateral variability of the palaeoproductivity signal.
Abstract: We reconstructed the Late Quaternary productivity record of two cores of the NW Africa upwelling area. Cores SEDORQUA 20bK and 17aK contain a continuous record down to isotopic stage 7 and show the lateral variability of the palaeoproductivity signal. Several palaeo-environmental proxies, using benthic foraminiferal compositions, have been applied and are confronted with geochemical proxies. In both cores the highest values of palaeoproductivity were registered in glacial stages. These differences between the two cores show that the intensity of upwelling cells descreased to the deeper location core and also that the quality of the input of organic flux becomes predominantly refractory.
17 citations