Marine Biology Research Center

Tadjoura, Djibouti

Marine Biology Research Center

Tadjoura, Djibouti
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Sacco F.,University of Palermo | Marrone F.,University of Palermo | Lo Brutto S.,University of Palermo | Besbes A.,Institute National Des Science Et Technologies Of La Mer | And 6 more authors.
Fisheries Research | Year: 2017

The dolphinfish, Coryphaena hippurus Linnaeus, 1758, is an important target species for Mediterranean artisanal, recreational and commercial fisheries but to date only scarce genetic data are available for its Mediterranean population(s). The genetic variation of Mediterranean dolphinfishes was thus investigated through the sequencing of fragments of the cytochrome c oxidase subunit 1 (COI) gene and the NADH dehydrogenase subunit 1 (ND1) mitochondrial DNA markers with the explicit aims of (i) testing for significant genetic differentiation of the Mediterranean vs. non-Mediterranean populations of the species, and (ii) investigating the possible presence of molecular structuring within the Mediterranean basin. Performed analyses revealed significant genetic differentiation between Mediterranean and Atlantic dolphinfish population, while no significant geographically-based genetic differentiation was detected within the Mediterranean basin. The apparent lack of genetic structuring at the Mediterranean level is likely due to the highly mobile behaviour of the species, which is typical of large pelagic fishes and in agreement with the few tag data currently available. Based on presented results, the Mediterranean dolphinfishes are thus suggested to be considered a distinct management unit from those outside the Mediterranean. Conversely, in order to test for the presence of a single vs. multiple Mediterranean stock units, the fulfillment of further analyses implementing fast-evolving nuclear markers is advisable. © 2016 Elsevier B.V.

Ben-Abdallah A.,Alfateh University | Al-Turky A.,Marine Biology Research Center | Nafti A.,Marine Biology Research Center | Shakman E.,Alfateh University
Acta Ichthyologica et Piscatoria | Year: 2011

The Lessepsian invasive fish, Lagocephalus suezensis was recorded for the first time in the eastern part of the Libyan coast, adding a new invasive species to the 16 Lessepsian species recorded in the Libyan waters.

Fadhlaoui-Zid K.,National Institute of Marine science and Technologies | Knittweis L.,Capture Fisheries Section | Aurelle D.,Aix - Marseille University | Nafkha C.,National Institute of Marine science and Technologies | And 6 more authors.
Comptes Rendus - Biologies | Year: 2012

The polymorphism of the mitochondrial gene cytochrome oxidase III was studied in the Mediterranean octopus, Octopus vulgaris Cuvier, 1797. A total of 202 specimens from seven sampling sites were analysed with the aim of elucidating patterns of genetic structure in the central Mediterranean Sea and to give an insight into the phylogeny of the Octopus genus. Phylogenetic analyses showed that individuals from the central Mediterranean belong to the O. vulgaris species whose limits should nevertheless be clarified. Concerning genetic structure, two high-frequency haplotypes were present in all locations. The overall genetic divergence (ΦST = 0.05, P < 0.05) indicated a significant genetic structuring in the study area and an AMOVA highlighted a significant break between western and eastern Mediterranean basins (ΦCT = 0.094, P < 0.05). Possible explanations for the observed patterns of genetic structuring are discussed with reference to their relevance for fisheries management. © 2012 Académie des sciences.

Denaro G.,University of Palermo | Valenti D.,University of Palermo | La Cognata A.,University of Palermo | Spagnolo B.,University of Palermo | And 6 more authors.
Ecological Complexity | Year: 2013

In this paper, by using a stochastic reaction-diffusion-taxis model, we analyze the picophytoplankton dynamics in the basin of the Mediterranean Sea, characterized by poorly mixed waters. The model includes intraspecific competition of picophytoplankton for light and nutrients. The multiplicative noise sources present in the model account for random fluctuations of environmental variables. Phytoplankton distributions obtained from the model show a good agreement with experimental data sampled in two different sites of the Sicily Channel. The results could be extended to analyze data collected in different sites of the Mediterranean Sea and to devise predictive models for phytoplankton dynamics in oligotrophic waters. © 2012 Elsevier B.V.

Placenti F.,CNR Institute for Coastal Marine Environment | Schroeder K.,CNR Marine Science Institute | Bonanno A.,CNR Institute for Coastal Marine Environment | Zgozi S.,Marine Biology Research Center | And 12 more authors.
Journal of Marine Systems | Year: 2013

This paper analyzes for the first time the water masses circulation in the Gulf of Syrte (Libya) and along a Sicily-Libya transect (central Mediterranean Sea) based on a new dataset of hydrological and nutrients data. The collected dataset highlights the presence of three main water masses with different chemical-physical features: Atlantic Water, Levantine Intermediate Water and Deep Water. Atlantic Water shows an intrusive low-salinity water near the Sicilian (≤. 37.6) and Libyan coasts (≤. 37.8), linked to the Atlantic Ionian Stream and the Atlantic Libyan Current respectively. The surface circulation evidences meandering structures throughout the area and the presence of an anti-cyclonic vortex in the central part of the Gulf of Syrte. In this latter area no coastal surface current is recognized, suggesting a seasonal character for such coastal circulation. In the Gulf the anti-cyclonic pattern characterizes also the intermediate water circulation. The nutrient distribution confirms the oligotrophic character of the area with a strong reduction in concentration in the surface layer due to the assimilation of phytoplankton in the euphotic zone. Furthermore, there is an evident increase in the deep water caused by the re-mineralization of organisms. The nitrate:phosphate ratio is ~. 10 and ~. 30 in the surface waters and deep waters, respectively, the latter being far in excess of the Redfield ratio (16:1) found in the oceans' deep waters. Nutrients data close to the Libyan coast do not show any enrichment pattern as a potential effect of the input of Saharan dust. © 2013 Elsevier B.V.

Denaro G.,University of Palermo | Valenti D.,University of Palermo | Spagnolo B.,University of Palermo | Bonanno A.,CNR Institute for Coastal Marine Environment | And 4 more authors.
Acta Physica Polonica B | Year: 2013

A stochastic reaction-diffusion-taxis model is analyzed to get the stationary distribution along water column of two species of picophytoplankton, that is picoeukaryotes and Prochlorococcus. The model is valid for weakly mixed waters, typical of the Mediterranean Sea. External random fluctuations are considered by adding a multiplicative Gaussian noise to the dynamical equation of the nutrient concentration. The statistical tests show that shape and magnitude of the theoretical concentration profile exhibit a good agreement with the experimental findings. Finally, we study the effects of seasonal variations on picophytoplankton groups, including an oscillating term in the auxiliary equation for the light intensity.

Denaro G.,University of Palermo | Valenti D.,University of Palermo | Spagnolo B.,University of Palermo | Basilone G.,CNR Institute for Coastal Marine Environment | And 4 more authors.
PLoS ONE | Year: 2013

A stochastic advection-reaction-diffusion model with terms of multiplicative white Gaussian noise, valid for weakly mixed waters, is studied to obtain the vertical stationary spatial distributions of two groups of picophytoplankton, i.e., picoeukaryotes and Prochlorococcus, which account about for 60% of total chlorophyll on average in Mediterranean Sea. By numerically solving the equations of the model, we analyze the one-dimensional spatio-temporal dynamics of the total picophytoplankton biomass and nutrient concentration along the water column at different depths. In particular, we integrate the equations over a time interval long enough, obtaining the steady spatial distributions for the cell concentrations of the two picophytoplankton groups. The results are converted into chlorophyll a and divinil chlorophyll a concentrations and compared with experimental data collected in two different sites of the Sicily Channel (southern Mediterranean Sea). The comparison shows that real distributions are well reproduced by theoretical profiles. Specifically, position, shape and magnitude of the theoretical deep chlorophyll maximum exhibit a good agreement with the experimental values. © 2013 Denaro et al.

Galgani F.,French Research Institute for Exploitation of the Sea | Chiffoleau J.F.,French Research Institute for Exploitation of the Sea | Barrah M.,Marine Biology Research Center | Drebika U.,Marine Biology Research Center | And 2 more authors.
Environmental Science and Pollution Research | Year: 2014

Within the framework of the MYTIOR project in 2009, heavy metals and organic compounds contaminations were assessed in transplanted mussels in 16 different stations along the coasts of Libya. These stations were located at miles offshore industrial/urban sources but in open sea providing original results related to the background contamination rather than linked to a specific coastal source of pollutants. Results indicated mercury (Hg, 0.045–0.066 mg/kg dry weight (dw)), lead (Pb, 0.44–0, 71 mg/kg dw) and copper (Cu, 3.56–4.21 mg/kg dw) were in the same range or at lower value than control for all stations. Chromium (Cr) in Meleta (3.08 mg/kg dw) and Bomba (3.80 mg/kg dw) and Cadmium values in all stations (1.21–2.41 mg/kg dw) were above control. Meleta, stations from the gulf of Syrt and the three eastern stations were the most affected stations by nickel (max at 5.83 mg/kg dw in Syrt) when zinc was in the same range (141–197 mg/kg dw) and above the control (92 mg/kg dw) at all stations. Polycyclic aromatic hydrocarbon (PAH) levels were found in the range of 16.8–42.8 mg/kg (dry weight) indicating low levels along the Libyan coast with acenaphthene and benzo (a, b, k) pyrenes detected mainly in western Libya. The study of PAH ratios indicated a mixed petrogenic/pyrolytic origin. The only polychlorinated biphenyls (PCBs) found in Libya were PCB 101 in one location and PCB 153 in Tripoli, Garrapoli, Syrt, Ras Lanuf and Benghazi (1.2–1.9 μg/kg dw). Insecticides were lower than control in all stations except DDT, only detected in Misratah (3.5 μg/kg dw). Overall, the results indicated a low background contamination and a low pollution extent according to the environmental pressure occurring offshore the Libyan coast. © 2014, Springer-Verlag Berlin Heidelberg.

Elhajaji A.,Liverpool John Moores University | Al Khaddar R.,Liverpool John Moores University | Haddoud D.,Marine Biology Research Center | Durr S.,Liverpool John Moores University
World Environmental and Water Resources Congress 2015: Floods, Droughts, and Ecosystems - Proceedings of the 2015 World Environmental and Water Resources Congress | Year: 2015

Seawater desalination has become a rapidly growing industry in Mediterranean countries due to the water scarcity. This activity results in environmental problems chiefly generated by brine discharged into the sea, which alters the physico-chemical parameters of the receiving water and threatens its marine biota. This paper has examined data from the field study survey carried out in Libya to investigate the changes in physico-chemical parameters of the receiving water due to brine emitted from the Zwuarah Desalination Plant. 19 seawater samples near the outfall of ZWDP were collected and analysed. The results of the data collection are characterized by principal-component analysis (PCA) and it is indicated that the pattern is best explained in PC1, PC2, PC3, PC4 and PC5 with 67.6%, 81.4%, 88.2%, 92.4% and 94.9% of the total variance respectively. Wide variations in the physico-chemical parameters of the receiving seawater near the ZWDP outfall have been observed between total hardness, calcium and magnesium hardness, sulfate, potassium, sodium, chloride, phosphate, iron and nitrate ions, sea bed and the sea surface temperature, pH, dissolved oxygen levels and Salinity. These were scattered in ranges (-500 to + 9,071 mgl-1), (-800 to + 361 mgl-1), (+ 5300 to + 1370 mgl-1), (-306 to-216 mgl-1), (+ 37 to + 1,900 mgl-1), (-1,400 to + 1,183 mgl-1), (-408 to-570 mgl-1), (+ 945 to + 6,550 mgl-1), (-1,626 to + 2,625 mgl-1), (+ 0.089 mgl-1), (+ 0.6966 mgl-1), (+ 0.15 mgl-1), (+15.4°C to + 3°C), (-0.14 to + 0.06) (-4.67 to-2.1 mgl-1) and (+9.2 psu) respectively. The results revealed that physico-chemical parameters at the study site were different in ambient seawater and that indicated there is a threat to the marine ecosystem. © 2015 ASCE.

Elhajaji A.,Liverpool John Moores University | Al Khaddar R.,Liverpool John Moores University | Durr S.,Liverpool John Moores University | Haddoud D.,Marine Biology Research Center
World Environmental and Water Resources Congress 2014: Water Without Borders - Proceedings of the 2014 World Environmental and Water Resources Congress | Year: 2014

In Libya, as water resources are rapidly being exhausted due to an increase in both population growth and water consumption in various sectors, the Libyan government has turned to integrating nonconventional water resources such as multieffect distillation (MED and MED with TVC) to compensate for the water deficit. This paper has determined that the cost of desalinated water by thermal desalination plants is about $0.47/m3, thus seeing this as the best option for providing water resources, due to unlimited seawater sources, compared with the cost per cubic meter produced by the Great Man-Made River Project, which is estimated to cost 0.83$/m3. Moreover, the results indicate that the highest annual water deficit in Libyan water regions was in Jabal Nafusah and Jifarah plain, Middle Zone, and Aljabal Alakhdar Region in the north and middle of the country equaling 1,450 million m3, 250 million m3, and 60 million m3 respectively. © 2014 American Society of Civil Engineers.

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