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Accueil du site → Master → Tunisie → Mastère → Etude de la qualité des sédiments de la lagune côtière de Kalaât Andalous (golfe de Tunis) : impact sur l’écosystème marin.

Université de Tunis el Manar (2017)

Etude de la qualité des sédiments de la lagune côtière de Kalaât Andalous (golfe de Tunis) : impact sur l’écosystème marin.

Khsiba, Samia

Titre : Etude de la qualité des sédiments de la lagune côtière de Kalaât Andalous (golfe de Tunis) : impact sur l’écosystème marin.

Auteur : Khsiba, Samia

Université de soutenance  : Université de Tunis el Manar

Grade : Mastère de Recherche en Ecologie et Environnement 2017

Résumé pàartiel
Lagoon ecosystems have a major component in the balance of coastal wetlands. These systems, which were heavily relied on by port activities, experienced a disruption of their dynamic. The objective of this study is the qualitative characterization of the sediments at Kalaât Andalous harbor lagoon. The investigations were based on the study of the sedimentological facies (Grain size indexes, Folk and ward, 1957), a floristic (EXCLAME) and faunistic identification. Preliminary results showed that sediments are predominantly silty (70%). The mean grain size D50 ranges from 3,395 μm (P6) to 20,975 μm (P8) with a logarithmic facies indicating an excess load deposition zone, following a decrease in transport agent skill (El Arrim, 1996) . The sandy sediments are unimodal (100%) with modes ranging from 160 μm to 200 μm. The sandy distribution is characterized by a fine sand (MZ = 2, 03 Φ to 2.96 Φ ; Md 0.15 mm to 0.24 mm), which is predominantly well sorted (σ = 0.28 Φ, 0.39 Φ).KI indexe shows fine sands, asymmetric both towards fine sands (positively skewed) (P 12 – p13) and towards coarse sand (P14).The spatial representation of the lagoon sediments shows that the silty facies predominate the central area (quay) of the harbor. The sandy sediments line both at the inner side of the northern sandy spit of the Foum El Oued (P10, P12) and its southern side (P13 and P14)². The lagoon floristic investigation reveals the presence of 21 species, with the dominance of green algae (52.38 %). In addition, 6 reference species detected with the presence of Cymodocea nodosa at all radials. According to the ratio between reference Species number and RS, the radial 3 located southward of the lido channel, is the least eutrophic radial with a ratio equal to 0.66 (3 reference species, RS = 5). The microorganisms harvested and identified correspond essentially to benthic forminifiera of genus ; Ammonia, Elphidium, Uvigirina, Rosalina, Quinqueloculina , Triloculina, Spiriculina, Plantonoc Foraminifera (Globigerina and Orbulina ), ostracods (Smooth and crosslinked) , molluscs (Lamellibranchs and gastropods) , Echinoderm (spicules ) and Annelids .

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Page publiée le 1er juin 2021