FN Archimer Export Format PT J TI Dynamics of phytoplankton productivity and exopolysaccharides (EPS and TEP) pools in the Seine Estuary (France, Normandy) over tidal cycles and over two contrasting seasons BT AF MORELLE, Jerome SCHAPIRA, Mathilde CLAQUIN, Pascal AS 1:1,2;2:3,4;3:1,2; FF 1:;2:PDG-ODE-LITTORAL-LERMPL;3:; C1 Univ Caen Normandie, Normandie Univ, F-14032 Caen, France. UPMC, UCBN, UMR BOREA, CNRS 7208,IRD 207,MNHN, F-14032 Caen, France. IFREMER, LER N, Ave Gen Gaulle, F-14520 Port En Bessin, France. IFREMER, LER, MPL, NT, Rue Ile Yeu BP 21105, F-44301 Nantes 03, France. C2 UNIV CAEN NORMANDIE, FRANCE UNIV PARIS 06, FRANCE IFREMER, FRANCE IFREMER, FRANCE SI NANTES SE PDG-ODE-LITTORAL-LERMPL IN WOS Ifremer jusqu'en 2018 copubli-france copubli-univ-france IF 3.159 TC 14 UR https://archimer.ifremer.fr/doc/00400/51132/51898.pdf LA English DT Article DE ;Phytoplankton;Microphytobenthos;PAM fluorometer;Electron transport rate AB Exopolysaccharides (EPS) play an important role in the carbon flux and may be directly linked to phytoplankton and microphytobenthos production, most notably in estuarine systems. However the temporal and spatial dynamics of estuarine EPS are still not well understood, nor how primary productivity triggers this variability at these different scales. The aim of this study was to investigate the primary productivity of phytoplankton and EPS dynamics in the Seine estuary over a tidal cycle in three different haline zones over two contrasted seasons. The other objectives was to investigate the origin of pools of soluble carbohydrates (S-EPS) and transparent exopolymeric particles (TEP) in phytoplankton, microphytobenthos or other compartments. High frequency measurements of productivity were made in winter and summer 2015. Physical and chemical parameters, biomass and EPS were measured at hourly intervals in sub-surface waters and just above the water sediment-interface. Our results confirmed that high frequency measurements improve the accuracy of primary productivity estimations and associated carbon fluxes in estuaries. The photosynthetic parameters were shown to be strongly controlled by salinity and by the concentrations of suspended particle matter at the smallest temporal and at spatial scales. At these scales, our results showed an inverse relationship between EPS concentrations and biomass and productivity, and a positive relationship with sediment resuspension. Additionally, the distribution of EPS appears to be linked to hydrodynamics with the tide at daily scale and with the winter at seasonal scale. At spatial scale, the maximum turbidity zone played an important role in the distribution of TEP. Our results suggest that, in the Seine estuary, between 9% and 33% of the S-EPS pool in the water column can be attributed to phytoplankton excretion, while only 0.4%–1.6% (up to 6.14% in exceptional conditions) originates from the microphytobenthos compartments. Most EPS was attributed to remobilization of detrital carbon pools in the maximum turbidity zone and in the sediment or allochthonous origin. PY 2017 PD OCT SO Marine Environmental Research SN 0141-1136 PU Elsevier Sci Ltd VL 131 UT 000418222400016 BP 162 EP 176 DI 10.1016/j.marenvres.2017.09.007 ID 51132 ER EF