Live benthic foraminiferal faunas from the Bay of Biscay: faunal density, composition, and microhabitats

Abstract

In the meso-oligotrophic Bay of Biscay, a diminishing downward organic matter flux with depth is accompanied by an important decrease of the live foraminiferal density. Although bottom water oxygenation is not directly influenced by organic matter input, the oxygenation of interstitial waters and the primary redox fronts do change in response to variations of the organic matter flux. The occurrence of deep and intermediate infaunal taxa can be linked to fundamental redox fronts and putative associated bacterial consortia. Our data are in agreement with the TROXmodel, which explains the benthic foraminiferal microhabitat as a function of organic flux and benthic ecosystem oxygenation. Both the depth of the principle redox fronts and the microhabitat of deep infaunal species show important increases with depth. At the deepest oligotrophic stations, deep infaunal faunas become relatively poor. Therefore, the exported flux of organic matter appears to be the main parameter controlling the composition and the vertical distribution of benthic foraminiferal faunas below the sediment-water interface. The oxygenation of pore waters plays only a minor role. A species-level adaptation of the TROX-model is presented for the Bay of Biscay. r

Recostruction of the unusual Mid Miocene (Badenian) palaeoenvironment of the Carpathian Foredeep (Lomnice/Tišnov denudational relict, Czech Republic)

“…How ever, Abu-Zied et al (2008) sug gested that Bolivina, Bulimina and Uvigerina are de pend ent on a rather con tin u ous abun dance of or ganic mat ter, that may be of a lower qual ity. More over, Jorissen et al (1995) and Fontanier et al (2002) ques tioned the high-nu tri ent pref er ence of Melonis when re cord ing that, with a de creas ing or ganic in put, the ox y gen ated layer ex pands, and un der such con di tions, in ter me di ate infaunal taxa (such as Melonis) may be come very suc cess ful. In any case, the sub sti tu tion of Bulimina, Uvigerina and Melonis re flects vari a tion in ox y gen con tent and in quan tity and qual ity of nu tri ents.…”

Messinian paleoenvironmental evolution in the lower Guadalquivir Basin (SW Spain) based on benthic foraminifera

“…5 and 11). Nonion fabum is usually associated with eutrophic environments with high organic matter of low quality and significant oxygen depletion (Fontanier et al, 2002;Duchemin et al, 2008;Mojtahid et al, 2010aMojtahid et al, , 2010b.…”

“…Uvigerina peregrina s.l. is an opportunistic taxon commonly present in fine grained sediments deposited in environments with significant fluxes of labile organic matter and moderate oxygen depletion (Schmiedl et al, 1997(Schmiedl et al, , 2000Fontanier et al, 2002;Koho et al, 2008).…”

“…Cibicidoides pachyderma is a suspension feeder that inhabits oligo-to mesotrophic environments with high oxygenation contents (Gebhardt, 1999;Schmiedl et al, 2000Schmiedl et al, , 2003. This species feeds from episodic inputs of labile organic matter (Fontanier et al, 2002;Melki et al, 2009). The presence of Cibicidoides sp.…”

Paleoecology of the Maastrichtian and Danian sediment at North of Central Alborz, Iran, based on Planktonic foraminifera

“…Corliss, 1985;Corliss and Chen, 1988;Jones and Charnock, 1985), allows us to infer probable microhabitat preferences and environmental parameters such as the nutrient supply and oxygenation sea floor (e.g. Bernhard, 1986;Fontanier et al, 2002;Murray, 2001), Corliss (1985Corliss ( , 1991, Jones and Charnock (1985), Corliss and Chen (1988) and Alegret et al 2003. Subdivided benthic foraminifera to two morphotypebenthic foraminifera with planoconvex, biconvex and rounded trochospiral tests, tubular and coiled flattened milioline and palmate tests, have an epifaunal mode of life, these living at the sediment surface or in its upper few centimeters. Infaunal morphogrup , living in the deeper layers of the sediment.…”