FN Archimer Export Format
PT J
TI Temporal and spatial variations in benthic nitrogen cycling in a temperate macro-tidal coastal ecosystem: Observation and modeling
BT 
AF Ratmaya, Widya
   Laverman, Anniet M.
   Rabouille, Christophe
   Akbarzadeh, Zahra
   ANDRIEUX-LOYER, Francoise
   Barillé, Laurent
   Barillé, Anne-Laure
   Le Merrer, Yoann
   Souchu, Philippe
AS 1:1;2:2;3:3;4:4;5:5;6:6;7:7;8:1;9:1;
FF 1:PDG-ODE-LITTORAL-LERMPL;2:;3:;4:;5:PDG-ODE-DYNECO-PELAGOS;6:;7:;8:PDG-ODE-LITTORAL-LERMPL;9:PDG-ODE-LITTORAL-LERMPL;
C1 Ifremer , LER MPL, Rue de l'Ile d'Yeu, BP 21105, 44311, Nantes, Cedex 03, France
   Université de Rennes, CNRS, UMR 6553 ECOBIO, Campus Beaulieu, 263 avenue du Général Leclerc, Rennes F, 35042, France
   Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS UNMR 1572, Av. de la Terrasse, 91198, Gif sur Yvette, France
   Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada
   Ifremer, DYNECO PELAGOS, ZI Pointe du Diable, 29280, Plouzané, France
   Université de Nantes, Mer Molécules Santé EA 2160, Faculté des Sciences et des Techniques, BP 92208, 44322, Nantes, Cedex 3, France
   Bio-Littoral, Immeuble Le Nevada, 2 Rue du Château de l'Eraudière CS 80693, 44306, Nantes, France
C2 IFREMER, FRANCE
   UNIV RENNES, FRANCE
   CEA, FRANCE
   UNIV WATERLOO, CANADA
   IFREMER, FRANCE
   UNIV NANTES, FRANCE
   UNIV NANTES, FRANCE
SI NANTES
   BREST
SE PDG-ODE-LITTORAL-LERMPL
   PDG-ODE-DYNECO-PELAGOS
IN WOS Ifremer UPR
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
IF 2.3
TC 8
UR https://archimer.ifremer.fr/doc/00748/85996/91213.pdf
LA English
DT Article
DE ;DIN;DON fluxes;Diatom blooms;Hypoxia;anoxia;Monitoring station;Reactive transport model;Sediments
AB We used field observations, laboratory measurements and a reactive transport model (RTM) to investigate temporal and spatial variations in benthic nitrogen (N) cycling in the eutrophic temperate macro-tidal Vilaine Bay (VB), France. A time series of benthic flux measurements and pore-water profiles of dissolved inorganic N (DIN: ammonium, nitrate, nitrite) and dissolved organic N (DON) was conducted at a single station between April and September 2015 (six times). A spatial investigation of the benthic fluxes was performed in July 2016 at this station and three other stations in the VB. All measurements were accompanied by a large panel of physical, chemical and biological descriptors in the water column. In 2015, benthic ammonium fluxes at the monitoring station varied between 75 μmol m−2 h−1 in spring and were less than 10 μmol m−2 h−1 in summer. The benthic DON fluxes co-varied with the ammonium fluxes, ranging from 100 μmol m−2 h−1 in spring to zero in summer. In the summer of 2016, a phytoplankton bloom occurred and as a result the benthic ammonium and DON fluxes reached higher values than in the spring of 2015, accompanied by bottom water hypoxia at one measured station. Benthic nitrate and nitrite fluxes varied between −31 (towards the sediments) and 22 μmol m−2 h−1 and were explained by the bottom water concentration and nitrification rates. After fitting the existing pore-water profiles, the applied RTM correctly simulated the temporal and spatial variations in the benthic DIN fluxes and predicted that a large part of the deposited organic matter (OM) is remineralized aerobically at the sediment-water interface (SWI). The overall results showed a synthetic pattern of benthic N cycling in the VB, based on the occurrence of diatom blooms as the main source of OM in the sediments. The rapid decomposition of this deposited diatom material at the SWI releases large amounts of ammonium and DON to the water column and rapidly consumes oxygen at the sediment surface. When blooms occur in summer, their decomposition can be followed by hypoxia/anoxia in the bottom water. When blooms are absent, benthic N fluxes are weak and mainly fed by the diffusion from the pore-water. By integrating the present results in a 3D ecological model, it should be possible to more accurately predict the development of bottom water hypoxia in the VB. 
PY 2022
PD FEB
SO Continental Shelf Research
SN 0278-4343
PU Elsevier BV
VL 235
UT 000791947700002
DI 10.1016/j.csr.2022.104649
ID 85996
ER

EF