using the SevenGo (Duo) proTM/OptiOxTM meters
according to the manufacturer’s instructions (METTLERTOLEDO,
Switzerland). For oxygen measurement, signal
was in air saturation percentage, twenty-one percent oxygen
(air composition) representing 100 % of the saturation
scale and corresponding to 9 mg/L [O2]. The total salinity
was measured using a hand refractometer (ATAGO,
Japan). Redox potential was determined using a METTLER
TOLEDO probe (InPro 3253 SG) calibrated with a buffer
solution (METTLER TOLEDO, 427 mV at 25 C). Values
are given in mV versus reference electrode H?/H2. Solubilized
sulfide compounds (HS-/S2-) concentrations were
measured using the turbidimetric Cord-Ruwisch assay