Fig 1.
a) Study area in the Bizerte Lagoon (adapted from OTC, 1992, Map of Bizerte Lagoon office de la topographie et de la cartographie de Tunisie). The studied stations are labeled with numbers. The main towns and streams are indicated. b) Photo of the surface water column showing the cnidarian bloom. c) Photo showing suspended structures used in mollusks culture.
Fig 2.
Distribution maps of: a) pH; b) redox potential (Eh) (mV); c) dissolved oxygen (DO) content in surface sediments (mg/l); d) sediment mean grain size (SMGS; μm); e) phyllosilicates (%); f) ferrous berthierine (f.; %); g) kaolinite (%); h) magnetic susceptibility (SI unities).
Table 1.
Selected sedimentological data.
Fig 3.
Distribution maps of: a) total organic carbon (TOC; %); b) calcium carbonate content (CaCO3; %); c) acid volatile sulfides concentrations (AVS; μg/g); d) simultaneous extracted metals and AVS ratio (SEM/AVS).
Fig 4.
Distribution maps of: a) Cha—Chlorophyll a (Cha; mg/m3) and; b) δ13C (‰) values.
Fig 5.
Distribution maps of bacterial counts: a) total coliforms (TC; net primary production per 100 mg or NPP/100 mg); b) fecal enterococci (FE; NPP/100 mg), and c) total mesophilic counts (TMC; colony-forming units per gram—cfu/g).
Table 2.
Selected biotic data.
Fig 6.
Distribution maps of: a) FD: foraminiferal density (n°/g); b) H’: Shannon Index; c) Ammonia parkinsoniana (%); d) Hopkinsina atlantica (%); e) Bolivina striatula (%); and; f) Bolivina ordinaria (%).
Fig 7.
Principal components analysis based on the main benthic foraminifera species/taxa and: a) sedimentological data (grain size, mineralogical, geochemical and geophysical data); b) quantity and quality of organic matter and bacteria.
Legend: Sand–sand fraction (>63μm); Mud–fine fraction (<63μm); clay–clay fraction (<2μm); total organic carbon–TOC; Chl–chlorite; Kaol–kaolinite; Berth–berthierine; Phyl–phyllosilicates; MS–magnetic susceptibility; AVS–acid volatile sulfides; SEM/AVS–simultaneous extracted metals and AVS ratio; FE—fecal enterococci; TC–total coliforms; TMC–total mesophilic counts; TBP—total of biopolymers; LIP–lipids; PTN–proteins; CHO–carbohydrates; Chla–Chlorophyll a; FD–foraminiferal density (n°/g); b) SI–Shannon Index; S–species richness; J–equitability.
Fig 8.
Results of Q-mode cluster analysis.