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  • 1
    Publication Date: 2012-12-28
    Description: The in situ reproductive activity of the copepods Centropages ponticus and Temora stylifera was investigated in autumn 2006 in the Bizerte Channel in relation to abiotic factors and phytoplankton composition. Egg production rate (EPR), hatching success (HS) and nauplii survival rate of both species were measured from samples taken daily over 45 days from September 28 to November 11 and then weekly over 8 supplementary weeks. Over this period, C. ponticus and T. stylifera had mean EPRs of 13.7 ± 0.3 and 35.2 ± 3.8 eggs f –1 day –1 , and mean HS of 24.4 ± 1.6 and 50.4 ± 5.5%, respectively. EPR and HS remained fairly stable for C. ponticus throughout the study period compared with T. stylifera in which reproductive traits fluctuated considerably. Changes in EPR and HS for both species resulted from environmental parameter variations and in particular, from phytoplankton composition, with slight decreasing EPR and HS observed after the important phytoplankton blooms. Centropages ponticus , a lagoon species, was able to withstand high turbidity, whereas T. stylifera , a marine species, had low EPR and HS under turbid conditions. The low HS recorded for C. ponticus , in particular in December, may be due to production of resting eggs.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
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  • 2
    Publication Date: 2012-02-23
    Type: Conference or Workshop Item , NonPeerReviewed
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  • 3
    Publication Date: 2021-05-19
    Description: La partie sud ouest de la baie de Tunis subit les apports de l’oued Méliane qui est le deuxième oued pérenne de la Tunisie. Afin de cerner le profil physicochimique de cette partie de la baie, des prélèvements mensuels ont été effectués au niveau de 22 stations dont 19 dans la partie Sud Ouest de la baie de Tunis et 3 en aval de l’oued Méliane pendant les deux saisons, estivale et automnale de l’année 2004. Les valeurs de la température étaient conformes aux normes saisonnières et la salinité était faible à l'embouchure de l'oued Méliane suite aux apports d'eau douce. Les teneurs en sels nutritifs (nitrates, phosphates et ammonium) étaient très élevées et ont classé la qualité des eaux de la partie sud ouest de la baie de Tunis dans la catégorie "médiocre" selon le calcul de l’indice TRIX. Ces résultats semblent indiquer que les apports de l’oued Méliane riches en matière minérale et organique favoriseraient l’eutrophisation de cette partie de la baie
    Description: inputs.The south western part of the Tunis bay receives flows from Meliane river. A grid of 22 stations was investigated monthly (19 in the bay and 3 in the the Méliane river) during the summer and the autumn 2004. Water samples were taken in order to check the physicochemical conditions in the bay. Temperature showed a normal seasonal variation and the salinity was low in the mouth of the Méliane river due to the continental imputs. The results showed that nutrient concentrations (nitrates, phosphates and ammonia) were very high, especially in the river mouth and suggested that the area a has high trophic level according to the TRIX index. This environment could be influenced by organic and mineral inputs from Méliane river that could lead to the eutrophication of the south western part of the bay.
    Description: Published
    Description: physicochemical quality, TRIX
    Keywords: Physicochemical properties ; River inflow ; Salinity ; Water samples
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 4
    Publication Date: 2021-05-19
    Description: The Tunis bay is located in the North Estern coast of Tunisia and receives in its Western part flows from Meliane River. Our study aims to describe the composition and the spatiotemporal distribution of planktonic copepods in the bay in order to identify the effect of the Meliane River supplies on the community. A grid of 19 stations was investigated monthly from July 2004 to December 2004 using a 160 μm mesh size plankton net, towed obliquely from the bottom to the surface. The planktonic copepod community was represented by 21 taxa of Calanoida, 4 taxa of Cyclopoida, 3 taxa of Poicilostomatoida and one species of Harpacticoida. The presence of freshwater taxa like Arctodiaptomus salinus, Microcyclops sp and Thermocyclops sp in the coastal stations indicated the meliane River flows. The copepod community dominated the mesozooplankton, they constituted 94% of total abundance. Two species (Oithona nana and Euterpina acutifrons) dominated the community showing a shift of the planktonic copepod community structure to smaller-sized copepods carrying egg sacs due to anthropogenic supply increase.
    Description: La baie de Tunis se situe au niveau des côtes Nord Est de la Tunisie et est sujette à des apports d’eau continuels par le biais de l’Oued Meliane. Cette étude vise à décrire la composition et la distribution spatiotemporelle des copépodes planctoniques dans cette partie de la baie afin de déceler l’effet des apports de l’oued. Dix neuf stations ont été prospectées mensuellement de juillet 2004 à décembre 2004, le mésozooplancton a été prélevé à l’aide d’un filet de 160 μm de vide de maille selon des traits obliques fond surface. La communauté des copépodes planctoniques était formée de 21 taxa de Calanoides, 4 taxa de Cyclopoides, 3 taxa de Poecilostomatoides et une espèce d’Harpacticoides. La présence de taxa indicateurs d’eau saumâtre tels que Arctodiaptomus salinus, Microcyclops sp and Thermocyclops sp confirme les apports de l’oued. Les copépodes ont contribué à 94% au mésozooplancton total. Deux espèces (Oithona nanaetEuterpina acutifrons) ont dominé la communauté, elles témoignent d’un changement de la structure de la communauté à cause de la pression anthropiqueque subit cette partie de la baie, favorisant les copépodes de petite taille portant des sacs ovigères.
    Description: Published
    Description: Composition
    Description: Copepods
    Keywords: Plankton ; Distribution ; Crustaceans ; Freshwater-seawater interface
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 5
    Publication Date: 2021-05-19
    Description: Les bio-salissures marines intéressent toute structure immergée en mer. Les dommages engendrés par ce phénomène sont économiquement importants. Les peintures utilisées pour prévenir du biofouling, utilisent des biocides organostaniques qui se sont avérés très toxiques et posent un problème environnemental important. Le présent travail s'intègre dans le cadre de la valorisation des macroalgues des côtes tunisiennes par la recherche de molécules naturelles antifouling pouvant se substituer aux substances déjà utilisées. Dans cette étude, nous avons analysé le potentiel anti-microfouling d’extraits organiques de 10 espèces d’algues vertes: Ulva linza, Ulva rigida, Chaetomorpha linum, Cladophora laetivirens, Codium bursa, Codium fragile, Caulerpa prolifera, Caulerpa racemosa var. cylindracea, Halimeda tuna et Bryopsis muscosa. L’activité antibactérienne des extraits bruts a été testée vis-à-vis de 12 espèces de bactéries de référence Gram (-) et Gram (+) (majoritairement isolées du milieu marin) et de 8 bactéries foulantes. Bryopsis muscosa est l'espèce qui a montré l'activité antibactérienne la plus importante sur différentes souches bactériennes et notamment celles foulantes. L’activité algicide des extraits a été testée sur la croissance de 3 microalgues : une diatomée, une haptophyceae et une chlorophyceae. L’inhibition de la croissance, par les extraits de macroalgues, a été plus importante sur la diatomée Chaetoceros calcitrans. L’extrait de Codium fragile est l'espèce qui a montré l'activité algicide la plus importante.
    Description: Marine biofouling interests any immersed structure leading to economically important damages. Paints used to warn biofouling, use organostanic biocides which turned out to be very toxic and raise important environmental problems. The present work aimed to assess Tunisian seaweeds use for natural products extraction as substitute to toxic antifouling substances. Thus, anti-microfouling potential of organic extracts of 10 species of green seaweeds: Enteromorpha linza, Ulva rigida, Chaetomorpha linum, Cladophora laetivirens, Codium bursa, fragile Codium, Caulerpa prolifera, Caulerpa racemosa var. cylindracea , Halimeda tuna and Bryopsis muscosa , were analysed. Antibacterial activity was tested towards 12 bacteria strains: Gram (-) and Gram (+) (mainly marine species) and 8 fouling bacteria. The seaweed Bryopsis muscosa showed a large spectrum of antibacterial activity and particularly on fouling bacteria. In second step, algicidal activity of crude extracts was tested against 3 microalgae species: a Diatom, an Haptophyceae and a Chlorophyceae. Results revealed seaweeds extracts inhibition mainly against the diatom Chaetoceros calcitrans. Codium fragile extract showed the highest algicidal activity
    Description: Published
    Description: dichloromethane, microalgae, marine bacteria, antifouling
    Keywords: Green algae ; Bacteria ; Algae ; Seaweeds
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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