FN Archimer Export Format
PT J
TI Impact of anoxia and oyster mortality on nutrient and microbial planktonic components: A mesocosm study
BT 
AF LE RAY, Julie
   BEC, Beatrice
   FIANDRINO, Annie
   LAGARDE, Franck
   CIMITERRA, Nicolas
   RAIMBAULT, Patrick
   ROQUE, Cécile
   RIGAUD, Sylvain
   Regis, Julie
   Mostajir, Behzad
   Mas, Sébastien
   RICHARD, Marion
AS 1:1,2;2:2;3:3;4:1;5:1;6:4;7:2;8:5;9:5;10:2;11:6;12:1;
FF 1:PDG-ODE-LITTORAL-LERLR;2:;3:PDG-ODE;4:PDG-ODE-LITTORAL-LERLR;5:PDG-ODE-LITTORAL-LERLR;6:;7:;8:;9:;10:;11:;12:PDG-ODE-LITTORAL-LERLR;
C1 MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, Sète, France
   MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, Montpellier, France
   MARBEC, Univ Montpellier, CNRS, IRD, Ifremer, La Seyne/mer, France
   Aix Marseille Univ., Université de Toulon, CNRS, IRD, MIO, Marseille, France
   Univ. Nîmes, EA 7352 CHROME, Rue Du Dr Georges Salan, F-30021 Nîmes, France
   MEDIMEER (Mediterranean platform for Marine Ecosystems Experimental Research), Observatoire de Recherche Méditerranéen de l’Environnement, Univ Montpellier, CNRS, IRD, INRAE, Sète, France
C2 IFREMER, FRANCE
   UNIV MONTPELLIER, FRANCE
   IFREMER, FRANCE
   UNIV AIX MARSEILLE, FRANCE
   UNIV NIMES, FRANCE
   UNIV MONTPELLIER, FRANCE
SI SETE
   TOULON
SE PDG-ODE-LITTORAL-LERLR
   PDG-ODE
UM MARBEC
IN WOS Ifremer UMR
   WOS Cotutelle UMR
   copubli-france
   copubli-univ-france
IF 4.5
TC 1
UR https://archimer.ifremer.fr/doc/00813/92491/99420.pdf
LA English
DT Article
DE ;Anoxia;Crassostrea gigas;Oxygen;Community shift;Phytoplankton;Microbial loop
AB The Thau lagoon is a Mediterranean coastal lagoon used for shellfish farming. It is periodically affected by anoxia events that trigger oyster mortality. To investigate the effects of an anoxia event focussed on nutrient dynamics and the responses of the microbial planktonic communities a 13-day in situ experiment was performed in September 2020. Transparent mesocosms (270 L) were placed at a depth of 4 m, inserted in the sediment, and kept closed throughout the experiment. The experiment comprised three treatments: i) Natural environment (N), i.e. in the natural water outside the mesocosms containing a rope of 30 oysters (Crassostrea gigas), ii) Control mesocosm (C) filled with natural water with no oysters, and iii) Oyster mesocosm (O) filled with natural water containing a rope of 30 oysters. Oyster respiration in the oyster mesocosm depleted oxygen after 54 h. All the oysters from O mesocosm were dead after nine days and decomposition of their flesh combined with releases from the water-sediment interface increased dissolved inorganic nitrogen (dominated by ammonium), phosphates, and ∑H2S up to 390, 17 and 295 μmol·L−1, respectively. Phytoplankton biomass consequently increased by 20 (11.8 μg chlal −1) and abundance by 4.5 (186 × 106 cells·L1) dominated largely by green algae <5 μm. During the oyster mortality period (day 6 to day 9) high abundances of heterotrophic flagellates and large ciliate specimens were observed. This shift in the community towards small phytoplankton favours the microbial loop and is detrimental to shellfish farming. In a context of global warming in which the risk of anoxia is higher, the results of the present investigation demonstrate that anoxia triggers shellfish mortality and that the change in the plankton community disrupts the normal functioning of the ecosystem, causing serious financial losses. In this context, it is crucial to predict possible hypoxia and anoxia events using high frequency measurements of dissolved oxygen, by avoiding using shallow zones for oyster production and by reducing shellfish stocks, or by mechanically lifting the oysters out of the water during the night to reduce oxygen respiration in the ecosystem 
PY 2023
PD MAR
SO Aquaculture
SN 0044-8486
PU Elsevier BV
VL 566
UT 000909801800001
DI 10.1016/j.aquaculture.2022.739171
ID 92491
ER

EF