Institute National Des Science Et Technology Of La Mer

La Goulette, Tunisia

Institute National Des Science Et Technology Of La Mer

La Goulette, Tunisia
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Drira Z.,University of Sfax | Bel Hassen M.,Institute National Des Science Et Technology Of La Mer | Ayadi H.,University of Sfax | Aleya L.,University of Franche Comte
Environmental Science and Pollution Research | Year: 2014

The spatial and temporal variations in copepod communities were investigated during four oceanographic cruises conducted between July 2005 and March 2007 aboard the R/V Hannibal. A close relationship was observed between the temperature, salinity, hydrographic properties and water masses characterising the Gulf of Gabes. Indeed, water thermal stratification began in May-June, and a thermocline was established at a 20-m depth, but ranged from 25 m in July to more than 30 m in September. The zooplankton community is dominated by copepods representing 69 % to 83 % of total zooplankton. Spatial and temporal variation of copepods in relation to environmental factors shows their close relationship with the hydrodynamic features of the water column. Thermal stratification in the column, established in summer, supports copepod development. In fact, copepod abundance increases gradually with rising water temperature and salinity, starting from the beginning of thermal stratification (May-June 2006) and lasting until its completion (July 2005 and September 2006). When the water column is well mixed (March 2007), copepod abundance decreased. Our finding shows that temperature and salinity seem to be the most important physical factors and thus strongly influence the taxonomic diversity and distribution of the copepod population. They are characterised by the dominance of Oithona nana, representing 75-86 % of total cyclopoid abundance. The most abundant species during the stratification period were O. nana, Acartia clausi and Stephos marsalensis in July 2005 and September 2006. However, during the mixing period, Euterpina acutifrons was more abundant, representing 21 % of the total. Unlike the copepod community, which is more abundant during the period of high stratification, phytoplankton proliferates during semi-mixed conditions. © 2013 Springer-Verlag Berlin Heidelberg.


Mounir B.B.,Institute National Des Science Et Technology Of La Mer | Asma H.,Institute National Des Science Et Technology Of La Mer | Sana B.I.,Institute National Des Science Et Technologies Of La Mer Instm | Lotfi M.,Institute National Des Science Et Technology Of La Mer | And 2 more authors.
Marine Pollution Bulletin | Year: 2013

A hierarchical sampling design was used during two seasons (spring (May) and summer (August) 2006). Using this design, three regions of the Kerkennah Islands (Tunisia) were analyzed for the distribution of microalgal, protozoan and metazoan assemblages in two different habitats: (1) the water column; and (2) on Posidonia oceanica (L.) Delile (P. oceanica) leaves in shallow meadows. A total of 85 species were obtained. In particular, the diatom family Naviculacea consistently dominated (both numerically and in their diversity) the micro-algae in all regions for the two seasons of the study and in both habitats. In the Chergui region, which is the closest area to a source of impact, fast growing centric diatoms (such as Thalassionema, Rhizosolenia, Striatella, and Skeletonema) were identified as indicators of high organic matter and nutrient enrichment in water bodies. Protozoan and metazoan species abundance in the different regions indicate a non-random spatial and temporal distribution of the epiphytic organisms on leaves of P. oceanica that correlated with phytoplankton. The results also indicate that (1) the abundance of micro- and macroorganisms in the three regions were higher on P. oceanica leaves than in the water column for the two seasons; (2) environmental factors such as currents and tide influenced assemblages; and (3) the highest abundance was due to direct exposure to the polluted coast of Sfax and the effect of tidal asymmetries generating nutrient-rich inputs from the city. © 2013 Elsevier Ltd.


Mzoughi N.,Institute National Des Science Et Technology Of La Mer | Chouba L.,Institute National Des Science Et Technology Of La Mer | Lespes G.,University of Pau and Pays de l'Adour
Soil and Sediment Contamination | Year: 2010

This investigation represents the extensive study of the spatial distribution and sources of hydrocarbons in the Gulf of Tunis. Sediments and fish were sampled within the open sea of the Gulf of Tunis during August 2004. All samples were extracted with organic solvents, separated by silica/alumina column chromatography, and analyzed by spectrofluorometry for the determination of total aromatic hydrocarbons (TAH) and gas chromatography coupled with flame ionisation detector (GC-FID) for the determination of aliphatic hydrocarbons (AH) and polycyclic aromatic hydrocarbons (PAHs). Analysis of AH and PAH was confirmed with gas chromatography coupled with mass spectrometry (GC-MS). Sediments and fish samples have variable concentrations of TAH ranging from 0.8 to 9 μg g-1 and from 0.1 μg g-1 to 0.8 μg g-1 in tissues, respectively. The highest hydrocarbons levels (0.1 to 1.6 μg g-1) were found in liver in all fish species. Concentrations of sum AH and PAH in tissue of different fish species varied, respectively, from 0.28 to 1.05 μg g-1 dry weight and from 0.1 to 0.35 μg g-1 dry weight, respectively. In sediment concentrations of sum AH and PAH varied between 0.04 and 2.94 μg g-1 dry weight and between 0.01 and 2.6 μg g-1 dry weight, respectively. © 2010 Institut National des Sciences et Technologies de la Mer (INSTM).


Armi Z.,Institute National Des Science Et Technology Of La Mer | Armi Z.,Institute National Agronomique Of Tunis | Turki S.,Institute National Des Science Et Technology Of La Mer | Trabelsi E.,Laboratoire Des Analyses Of Leau Of Mer | Ben Maiz N.,Laboratoire Des Analyses Of Leau Of Mer
Environmental Monitoring and Assessment | Year: 2010

Coolia monotis is a potentially toxic epiphytic dinoflagellate widespread along the Mediterranean coasts, where it is frequently detected year round at low concentrations. However, it only proliferates recurrently in some localities. The North Lake of Tunis is one of the affected areas in the southwestern part of the Mediterranean Sea. This site is one of the most productive aquatic Tunisian areas (Recreational Fisheries and shellfish collecting). In the south part of this area of study, recurrent C. monotis proliferation (5 ×10 5 cells per liter) took place in late spring and early summer of 2006. During this proliferation, the spatial distribution of C. monotis species, phytoplankton community, and abiotic factors were studied. The composition of the phytoplankton community exhibited a clear dominance of dinoflagellates over other genera. We suggest that proliferation development of C. monotis was linked to climatic conditions, water temperature (r=0.24, p<0.05) and high concentrations of nitrogenous nutrients, essentially NH 4 + (r=0.18, p<0.05) and NO 3 - (r=0.21, p<0.05). © 2009 Springer Science+Business Media B.V.


Chouba L.,Institute National Des Science Et Technology Of La Mer | Mzoughi N.,Institute National Des Science Et Technology Of La Mer
International Journal of Environmental Science and Technology | Year: 2013

La Goulette, Rades and Sidi Bou Said harbours are considered as the most important commercial and tourist ports in the Gulf of Tunis. They are located on the northeast coast of Tunis and receive industrial and municipal wastewaters from Tunis city. The contamination level of copper, lead, zinc, cadmium, manganese, iron, total nitrogen and total organic carbon in the surface sediments was assessed on the basis of the enrichment index factors and corresponding to sediment quality guidelines. The results revealed moderate to highly elevated concentrations near to the sites of intense industrial, shipping and/or commercial activities suggesting a direct influence of these sources. In winter and summer, concentrations varied for cadmium, 0.28-1.40 mg kg-1; lead, 18-217 mg kg-1; zinc, 87-459 mg kg-1; copper, 8-121 mg kg-1; manganese, 208-254 mg kg-1; and for iron, 24-40 g kg-1. Furthermore, in summer the concentration of the total organic carbon and the total nitrogen contents range between 4.3-6.5 % and 0.06-0.49 % with an average value of 5.9 and 0.15 %, respectively. Whereas, in winter, total organic carbon and the total nitrogen concentrations varied between 2.3-9.6 % and 0.03-0.22 % with an average value of 6.1 and 0.14 %, respectively. The levels of lead, copper, zinc and iron in suspended particulate matter content range between 3.1-27.5 mg kg-1; 0.4-11.7 mg kg-1; 1-1.5 mg kg-1; 1.2-1.7 g kg-1, respectively. This study revealed that heavy metals pollution is mainly localized in the commercial (Rades) and fishing (La Goulette) harbours and not in the yachting (Sidi Bou Said) harbour. © 2013 Islamic Azad University (IAU).


Mzoughi N.,Institute National Des Science Et Technology Of La Mer | Chouba L.,Institute National Des Science Et Technology Of La Mer
Environmental Technology | Year: 2011

Under the framework of the IAEA's Technical Co-operation project RAF7/004, international research cruises were carried out in 2004 to assess the distribution of radionuclides and micropollutants in the south-western Mediterranean Sea. Sediments samples had variable concentrations of total aliphatic hydrocarbons and polycyclic aromatic hydrocarbons ranging from 0.2 to 1.8 μg g-1 and 26.9 to 364.4 ng g-1, respectively, in the Sicily Channel and from 0.7 to 2.8 μg g-1 and 14.7 to 618.1 ng g-1, respectively, in the open sea of the Gulf of Tunis. Hydrocarbon concentrations changed with depth and were relatively high at 3 cm and 10 cm depths. The use of 'fingerprint' ratios of certain isomeric pairs of polycyclic aromatic hydrocarbons (PAH) and the proportion of 2-3 ring and 4-5 ring PAH concentrations showed that the main origins are characteristic of petroleum sources. The ranges of trace metal concentrations, expressed in gg-1, in the Sicily Channel and in the Gulf of Tunis, respectively, were: Hg 0.009-0.2 and 0.02-0.1; Pb 9.9-26.1 and 21.2-32.5; Cd 0.06-0.1 and 0.07-0.33; Fe 23.7-28.1 and 29.9-36.2p; Zn 83-99.5 and 83-104; Mn 309.2-752.5 and 651-814; Cu 17.1-18.5 and 33.5-51.3. Sediment metal abundances were in the order: Mn > Zn > Fe > Cu > Pb > Cd > Hg. The results showed significant differences (p < 0.001) for trace metal and hydrocarbon mean concentrations between the two cores. These concentrations are generally similar to the background levels from the Mediterranean Sea and could be affected by physico-chemical conditions and sedimentation rate as well as biodegradation. © 2011 Taylor & Francis.


Fadhlaoui-Zid K.,Institute National Des Science Et Technology Of La Mer | Curiel J.A.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan | Landeta G.,Institute Ciencia Y Tecnologia Of Alimentos Y Nutricion Ictan | Fattouch S.,Institute National Des Science Et Technology Of La Mer | And 4 more authors.
Food Control | Year: 2012

The occurrence of in vitro production of biogenic amines in bacteria isolated from ice-preserved sardine and mackerel was studied. Biogenic amine production was investigated by means of amino acid decarboxylation by growth on decarboxylase differential medium, biogenic amine detection by thin-layer chromatography (TLC) and decarboxylase gene detection by PCR. Decarboxylase medium overestimate the number of biogenic amine-producer strains, as the production of amine was confirmed by TLC in only five out the 17 presumptive strains. On the producer strains, PCR was used to confirm the presence of the genes encoding the amino acid decarboxylase responsible for the synthesis of these amines. Moreover, biogenic amine-producer bacteria were molecularly identified by sequencing their 16S rRNA. Form sardine, enterobacteria producing simultaneously several biogenic amines were isolated. A Kluyvera intermedia strain producing histamine, putrescine and cadaverine, and an Enterobacter asburiae strain producing only the diamines cadaverine and putrescine were identified. From mackerel, lactic acid bacteria from the Enterococcus durans species producing tyramine were isolated. This study constitutes the first description of the presence on these putatively harmful species on ice-preserved sardine and mackerel. © 2011 Elsevier Ltd.


Mzoughi N.,Institute National Des Science Et Technology Of La Mer | Chouba L.,Institute National Des Science Et Technology Of La Mer
Journal of Environmental Monitoring | Year: 2011

Harbours of La Goulette, Rades and Sidi Bou Said are considered as the principal largest and most important port in the Gulf of Tunis characterised by a direct influence of different activities (sailing, industry and fishing) to the Mediterranean Sea. Due to their social and economic impact, a comprehensive assessment of the spatial distribution and partitioning of 24 polycyclic aromatic hydrocarbons (PAHs) and 18 aliphatic hydrocarbons (AHs) in summer and in winter among overlying water, suspended particulate matter (SPM) and surface sediments is essential. Distribution of hydrophobic organic contaminants in abiotic compartments is important for describing their transfer and fate in aquatic ecosystems and to identify the potential danger due to mobilization of contaminants produced by managing of the same sediments. Total organic carbon (TOC) contents range between 4.3% and 6.5%, with an average value of 5.9% in summer, and between 2.3% and 9.6%, with an average value of 6.1% in winter. The average concentrations of ΣPAH in winter and in summer were respectively 703.1 ng L -1 and 378.4 ng L -1 in seawater, 4599.1 ng g -1 and 3114 ng g -1 in SPM, and 1507.6 ng g -1 dw (dry weight) and 1294.6 ng g -1 dw in surface sediment. For ΣAH the average concentrations in winter and in summer were respectively 701 ng L -1 and 741.7 ng L -1 in seawater, 6743.5 ng g -1 and 6282.9 ng g -1 in SPM, and 4971.3 ng g -1 and 4588.1 ng g -1 in surface sediment. Higher PAH and AH concentrations were observed in SPM than in surface sediment. SPM and water were dominated by PAH with low molecular weight, while for sediment low and high molecular weight PAHs were present. PAH and AH fingerprint ratios, such as pristane to phytane (Pr/Ph), phenanthrene to anthracene (Phe/An) and fluoranthene to pyrene (Fl/Py), suggest that hydrocarbons in all harbours may originate from both pyrolytic and petrogenic sources derived from discharge of untreated sewage and wastewater or from direct input by ship traffic in the area. The results showed significant difference (ANOVA, p < 0.05) for hydrocarbon mean concentrations between all harbours studied and between different matrixes. © 2011 The Royal Society of Chemistry.


Mzoughi N.,Institute National Des Science Et Technology Of La Mer | Chouba L.,Institute National Des Science Et Technology Of La Mer
International Journal of Environmental Research | Year: 2012

In the framework of the Mytilos project (Interreg IIIB Medocc), international research cruises were carried out in 2006 in order to evaluate the level of Heavy metals and polycyclic aromatic hydrocarbons (PAH) along the coast of the western basin of the Mediterranean Sea. Caged mussels (Mytilus galloprovincialis) were placed in situ at six sites in the North coast of Tunisia. Results showed total PAH levels were in the range 45.6-241.6 ng/g dry weight (dw). The ranges of trace metals concentrations expressed in μg/gdw are: Hg (0.1- 0.2), Pb (0.4-0.7), Cd (0.9-2.9), Cu (2.9-3.9), Fe (117-248) and Zn (250-426). Higher concentrations were observed at Rades, La Galite and Tabarka which can be attributed to the industrial activities implanted in the coast of Algeria and in the city of Rades. Concentrations of PAH, Cd, Pb, Fe and Zn are generally different from initial concentrations (before caging), depending on the adaptability of transplanted mussels to be used as bio-indicator of contaminants. Yet bio-monitoring using mussels give information on compound bioavailability which depends on their ability to accumulate contaminants in its tissue.


Attouchi M.,Institute National Des Science Et Technology Of La Mer | Sadok S.,Institute National Des Science Et Technology Of La Mer
Food Chemistry | Year: 2010

The effect of powdered thyme sprinkling on the quality characteristics of fresh and ice-stored wild and farmed gilthead sea bream fillets was assessed. Initially, significant differences in proximate composition and quality attributes were found between wild and farmed fresh sea bream flesh. Throughout ice storage, biochemical alteration appeared more pronounced in farmed fish fillets with significantly higher levels of TVB-N, TMA-N, and TBA; and a lower liquid-holding capacity (LHC). Thyme powder addition (1% w/w) exhibited a preservative effect in both fish lots since significant lower levels of TVB-N, TMA-N, free amino acids (NPS), TBA and LHC were observed in thyme-treated fillets during ice storage. However, thyme inhibitory effect was more marked in wild than farmed fish. As revealed by partial least square regression, LHC in both groups was positively influenced by storage time and trimethylamine accumulation factors, while it was negatively influenced by thyme treatment and fish origin. Hence, LHC was suggested to be related to spoilage bacterial growth. The use of dried thyme extended the shelf life of fish fillets by about 5 days and appeared to be highly valuable to the fish industry as a natural preservative. © 2009 Elsevier Ltd. All rights reserved.

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