Living (stained) deep-sea foraminifera from the Sea of Marmara : a preliminary study Fontanier C. auteur aut IRD Dissard Delphine auteur aut IRD Ruffine L. auteur aut IRD Mamo B. auteur aut IRD Ponzevera E. auteur aut IRD Pelleter E. auteur aut IRD Baudin F. auteur aut IRD Roubi A. auteur aut IRD Chéron Sophie auteur aut IRD Boissier A. auteur aut IRD Gayet N. auteur aut IRD Bermell-Fleury S. auteur aut IRD Pitel M. auteur aut IRD Guyader V. auteur aut IRD Lesongeur F. auteur aut IRD Savignac F. auteur aut IRD text journalArticle eng text/pdf born digital access In this preliminary study, we investigate living (stained) foraminifera from the Sea of Marmara. We focus on the faunal composition and geochemical signatures (trace elements, carbon and oxygen stable isotopes) in foraminiferal tests at two deep-sea sites (329 and similar to 1240 m depth respectively). Documented by ROV observations and sampling, both study areas are heterogeneous (including bacterial mats and carbonate concretions), proximal to cold seeps and consist of dysoxic bottom water (O-2 < 20 mu mol/L). The prevailing dysoxia at both study areas restricts foraminiferal diversity to very low values (S < 9, H' < 0.97). Stress-tolerant species Bolivina vadescens and Globobulimina affinis dominate living faunas at both sites. The highest foraminiferal standing stock is recorded at the shallowest site underneath a spreading bacterial mat. No benthic foraminifera from either site possess geochemical signatures of methane seepage. Our biogeochemical results show that use of foraminiferal Mn/Ca ratios as a proxy for bottom water oxygenation depends strongly on regional physiography, sedimentary processes and water column structure. specialized Living (stained) benthic foraminifera Sea of Marmara Extreme ecosystems Trace elements Stable isotopes TURQUIE 032 036 064 Fluids and geochemical processes at the seismically active fault zone in the Sea of Marmara Çagatay N. ed. edt IRD Géli L. ed. edt IRD Ruffine L. ed. edt IRD Deep-Sea Research Part II :Topical Studies in Oceanography 153 No spécial 61-78 2018 0967-0645 https://www.documentation.ird.fr/hor/fdi:010074392 10.1016/j.dsr2.2017.12.011 0967-0645 [F B010074392] https://www.documentation.ird.fr/hor/fdi:010074392 https://www.documentation.ird.fr/intranet/publi/2018/11/010074392.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2018-12-06 2023-07-11 fdi:010074392 fre