Fig 1.
Maps of the study area showing the sampling sites.
(A) Maps of Tunisia showing the location of the coastal station CST-01. (B) Localities of the Gabes and, Djerba transects and other coastal stations inside the Gulf of Gabes. This figure is similar but not identical to the original image, and is therefore for illustrative purpose only.
Table 1.
Geographical coordinates of stations of Gabes and Djerba transects and coastal stations.
Table 2.
Bottom water parameters from stations of Gabes and Djerba transects.
Fig 2.
Variation in mineralogical composition and seawater parameters.
(A) Gabes Transect. (B) Djerba transect.
Fig 3.
Isosurface in the Gulf of Gabes.
Water parameters, TOC, carbon isotope composition of sedimentary organic matter, phosphorus reservoir concentrations are plot on a 2D Maps of the Gulf of Gabes. The maps are drawn by using the Ocean Data View software [47].
Fig 4.
Illustration of the sedimentary facies.
Images of seafloor and relative Box-Cores representing the sedimentary facies of (A) the Gabes and (B) the Djerba transects.
Fig 5.
(A) Gabes transect. (B) Djerba transect.
Table 3.
Mineralogical composition of surface sediment from Gabes and Djerba transects.
Fig 6.
Thin section images of carbonate nodules.
(A) Dolomite nodule from station GBS-03. (B) Nodule from station GBS-03 with bioclasts (foraminifera), quartz grains embedded in micrite. (C) Nodule from station GBS-03 with coral fragments and micrite. (D) Nodule from station GBS-04 with bioclasts, quartz grains into micrite. (E) Nodule from station GBS-04 with bioclasts, quartz grains embedded in micrite.
Fig 7.
Origin of organic matter from surface sediments in the Gulf of Gabes.
(A) S2 versus TOC diagram. (B) HI versus T max diagram. (C) The three clusters based on OM δ13C value.
Table 4.
Geochemical data of OM and elemental composition of sediment.
Fig 8.
Phosphorus content and proportion in surface sediments from the Gulf of Gabes.
(A) Phosphorus concentrations along the Gabes transect with the average phosphorus reservoirs. (B) Phosphorus concentrations along the Djerba transect with the average phosphorus reservoirs. (C) Phosphorus concentrations at coastal stations and phosphogypsum and phosphorus reservoirs of coastal stations from the Gulf of Hammamet, Gulf of Gabes and from phosphogypsum.
Table 5.
Phosphorus reservoirs distribution in surface sediments.
Fig 9.
(A) Gabes transect. (B) Djerba transect. (C) Coastal stations.