FN Archimer Export Format PT J TI Two dimensional mapping of iron release in marine sediments at submillimetre scale BT AF THIBAULT DE CHANVALON, A. METZGER, E. MOURET, A. KNOERY, Joel GESLIN, E. MEYSMAN, F. J. R. AS 1:1,2;2:1;3:1;4:2;5:1;6:3; FF 1:;2:;3:;4:PDG-RBE-BE-LBCM;5:;6:; C1 Univ Angers, LPG BIAF, UMR CNRS 6112, F-49025 Angers, France. IFREMER, LBCM, F-44300 Nantes, France. Netherlands Inst Sea Res NIOZ, Dept Ecosyst Studies, NL-4401 NT Yerseke, Netherlands. C2 UNIV ANGERS, FRANCE IFREMER, FRANCE INST SEA RESEARCH (NIOZ), NETHERLANDS SI NANTES SE PDG-RBE-BE-LBCM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-europe copubli-univ-france IF 3.337 TC 23 UR https://archimer.ifremer.fr/doc/00332/44365/43970.pdf LA English DT Article AB Coastal and shelf sediments are considered as an important source of dissolved iron to the ocean. Here, we present a new numerical approach to estimate geochemical fluxes and production rates in an estuarine sediment at sub-millimetre resolution. This approach is based on application of Savitsky–Golay filter (SGF) procedure to two-dimensional concentration distributions of dissolved iron. We verified the procedure by applying it to artificial data of known production rates, and analysed the resulting uncertainty on production rates and fluxes across the water–sediment interface. This SGF procedure was applied to data from an intertidal mudflat that is densely inhabited by macrofauna (e.g. 630 ind m− 2 of Hediste diversicolor, I. Métais, pers.com.). Our analysis reveals an apparent recycling rate of 3780 ± 1399 μmol m− 2 d− 1 and a mean residence time of iron in the dissolved phase of 2.3 days. Visual identification of burrows permitted to calculate separately the diffusive flux across the sediment–water interface (104 ± 20 μmol m− 2 d− 1) and the bio-irrigational flux (410 ± 213 μmol m− 2 d− 1). Reactive iron particles will undergo on average 7.4 cycles of dissolution/precipitation before being released to the water column. These results show that estuarine sediments support intensive iron recycling that has probably a large impact on terrigeneous particles before being released into the ocean. PY 2017 PD APR SO Marine Chemistry SN 0304-4203 PU Elsevier Science Bv VL 191 UT 000399865800005 BP 34 EP 49 DI 10.1016/j.marchem.2016.04.003 ID 44365 ER EF