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The occurrence of the exotic Atlantic blue crab Callinectes sapidus Rathbun, 1896 (Crustacea: Decapoda: Portunidae) is reported for the first time from the Moroccan Atlantic coast. Working with local fishermen, we gathered 160 records of the Atlantic blue crab from several estuarine, coastal and marine areas, in the period between June and August 2021. These new records confirm its establishment in the Atlantic coasts of North Africa, suggesting a southern range expansion. These findings, likely exacerbated by growing populations along the Atlantic coast of Morocco and temperate coastal waters, provide new insights into the invasion dynamics of this species in the northeast Atlantic Ocean. info:eu-repo/semantics/publishedVersion

International audience; The commercial value of agar in the phycocolloid market depends mostly on the agar yield and quality. The present study investigates the agar content and characterization of two Gelidiales Gelidium corneum and Gelidium microdon from the Moroccan Atlantic coast. Spectroscopic and rheological characterization of extracted agar without and with alkali pretreatments were evaluated. The highest agar yield was detected for mild alkaline pretreatment (N2CO3). The native agar content in G. corneum was 16.21%, while those pretreated with NaOH and N2CO3 ranged from 6.2 to 20.50 %. The agar yields of G. microdon showed values of 12.23%, 14.87%, and 17.73%, corresponding respectively to native agar, NaOH, and Na2CO3 pretreatments. Agar with alkali pretreatments depicted the better gelling property with higher gel strength and elevated gelling and melting temperatures. 13C NMR spectroscopy showed that G. Corneum has a typical unsubstituted and weakly methylated agar pattern. However, G. microdon revealed the presence of methyl and sulfate groups at the C4 of 4-O-L-galactose residues, responsible for the low gelling ability of the native agar. The decline of sulfate groups after alkali pretreatments were proved by FTIR spectroscopy. This study demonstrates that G. microdon produces a quality of agar similar to that of G. corneum. Thus G. microdon could be regarded as a potential additional source of agar industry in Morocco.

International audience; The inhibition effect of the invasive brown seaweed Sargassum muticum extract (ESM), harvested from the Atlantic coast of Morocco, against the corrosion of carbon steel (CS) in 1 M HCl medium was studied for the first time using gravimetric, electrochemical and surface techniques. The methanolic crude extract of Sargassum muticum (ESM) is rich in alginate biopolymer. The evaluation corrosion tests showed that this algal extract acts as a good mixed corrosion inhibitor for CS substrate in 1 M HCl since inhibition efficiency of 97% was reached with 1 g/L of ESM at 303 K. AC impedance findings showed that the seaweed extract adding in the corrosive electrolyte increases the polarization resistance and conversely decreases the charge capacitance at the interface. Adsorption of ESM on the substrate surface followed the Langmuir adsorption isotherm. X-ray photoelectron spectroscopy analyses (XPS) demonstrated that the corrosion inhibition mechanism of CS substrate in 1 M HCl environment by the investigated algal extract is typical of the chemisorption process and the protective barrier is mainly formed by the adsorbed biological macromolecules.

In the present study, alginate yield and composition were investigated during the seasonal life cycle of the alien brown alga Sargassum muticum harvested from the Atlantic coast of Morocco. Alginate yield ranged from 11.14% in winter to 25.62% in spring/early summer, coinciding with maximum vegetative growth. Monthly monitoring of the alginate block structure showed that the highest mannuronate (M)/guluronate (G) ratio was recorded during the maximum development of S. muticum, before sexual maturity and during resumption of vegetative growth, giving maximum flexibility to the alga. The unusually high molar monad fractions (FG) and dyad fractions (FGG) of guluronic acid in late summer/early autumn appeared to be related to stiffness of senescent thalli. Rheological characterisation showed that the alginate of S. muticum exhibited pseudoplastic behaviour, with the highest apparent viscosities measured in late summer/early autumn when the G blocks dominated the alginate structure. This study suggests that S. muticum could be exploited as an alginophyte for commercial applications. The best harvest time is May-June, which corresponds to the highest alginate yield, maximum thallus growth, and largely completed sexual reproduction, ensuring sustainable exploitation of the species.

The present study focused on the dynamics of the phenology and life cycle of the Phaeophyceae invader Sargassum muticum at three sites on the Atlantic coast of Morocco over a period of two years (2013 and 2014). The results showed that S. muticum has two distinct growth phases; one with slower growth in winter followed by one with faster growth in spring-early summer, when the species exhibited high elongation and branching activities with thalli length ranging from 1 to more than 5 m depending on the study site. The site S1, with a rocky substratum covered by submerged sands, promotes thalli elongation, with maximum lengths of 643.33 11.10 cm recorded in July. At the rocky sites (S2 and S3), the maximum length of the seaweed depends on the pools’ depth. Although the elongation of thalli is enhanced by the water body depth, the settlements’ density (5-48 ind. m–2) seems to be mainly related to the nature of the substrate. The maturity index progressively increases from spring to early summer, when it reaches the highest values. S. muticum seems to be more abundant and more easily acclimated in shallow rockpools (sufficiently lighted and semi-exposed to wave action at the mid and lower tidal levels) than in protected sandy bottom sites with low hydrodynamic forces., El presente trabajo se centró en el estudio de la fenología y el ciclo de vida del alga parda invasoraSargassum muticumen tres localidades de la costa atlántica de Marruecos durante dos años (2013 y 2014). Los resultados mostraron queS. muticumtiene dos fases de crecimiento distintas; la primera se caracteriza por un crecimiento más lento y ocurre durante el invierno, y la segunda fase caracterizada por un crecimiento más rápido ocurre durante la primavera y principios del verano, cuando la especie mostró una alta tasa de elongación y ramificación alcanzando longitudes entre 1 y más de 5 m dependiendo del sitio de estudio. El sitio S1, donde el sustrato rocoso estuvo cubierto por arena, los talos presentaron una mayor elongación con longitudes máximas de 643.33±11.10 cm registradas en julio. En los sitios rocosos (S2 y S3), la longitud máxima de las algas dependió de la profundidad de las piscinas. Aunque el alargamiento de los talos fue mayor con la profundidad, la densidad de los asentamientos (5-48 ind. m-2) parece estar principalmente relacionada con la naturaleza del sustrato. El índice de madurez aumentó progresivamente desde la primavera hasta principios del verano alcanzando los valores más altos durante el verano.S. muticumparece ser más abundante y se aclimata mejor en pozas rocosas poco profundas (suficientemente iluminadas y semi-expuestas a la acción del oleaje en los niveles medios e inferiores del intermareal), que en sitios protegidos de fondos arenosos con bajas fuerzas hidrodinámicas.

Alginates are widely used as gelling agents in textile print pastes, medical industries, impression material in dentistry, and anticoagulant material in toothpaste. In the present study, the content and spectroscopic characterization (1H NMR and FT-IR) of the sodium alginates were investigated in the eight brown seaweeds Sargassum muticum, Fucus vesiculosus f. volubilis, Carpodesmia tamariscifolia, Bifurcaria bifurcata, Laminaria ochroleuca, Cystoseira humilis, Saccorhiza polyschides, and Fucus guiryi harvested from the NW Atlantic coast of Morocco. The results proved that the most studied algae depicted alginate yields higher than 18% dry weight. The FT-IR analysis showed that the spectra of the extracted alginates exhibited significant similarities to the commercial alginate from Sigma-Aldrich. The 1H NMR spectroscopy indicated that the extracted alginates have a high content of &beta, d-mannuronic (M) than &alpha, l-guluronic acid (G) with M/G ratio values ranging from 1.04 to 4.41. The homopolymeric fractions FMM are remarkably high compared to the FGG and heteropolymeric fractions (FGM = FMG) especially for F. guiryi, C humilis, C. tamariscifolia, L. ochroleuca, and S. polyschides. Nevertheless, the heteropolymeric fractions (FGM/FMG) are quite abundant in the alginates of S. muticum, F. vesiculosus f. volubilis, and B. bifurcata accounting for more than 52% of the polymer diads. Based on these results, the investigated algal species (except Fucus guiryi and Bifurcaria bifurcata) could be regarded as potential sources of alginates for industrial uses.

Biomass of the invasive seaweed Sargassum muticum harvested from the Atlantic coast of Morocco was investigated as a natural biosorbent for the removal of methylene blue (MB) dye from aqueous solutions. FTIR spectroscopy was used to examine the variability of functional groups participating in the interaction between MB and biosorbent. The zero point charge (pHZPC) of the biomass was about 5.45. The factors affecting the efficiency of the biosorption process such as the biosorbent dose, the initial solution pH, the initial dye concentration and the contact time were investigated. The theoretical monolayer saturation capacity was estimated to be 191.38 mg/g. The biosorption process was generally not dependent on pH for values ranging from 2 to 10. The biosorption occurs very fast in the first 5 min and reaches the equilibrium within 60–90 min. The pseudo-second-order model was found to explain the adsorption kinetics most effectively. Four conventional isotherm models were applied to describe the biosorption equilibrium data and classified according to their correlation coefficients in the following order: Temkin model (R2 = 0.989) > Dubinin–Radushkevich (R2 = 0.982) > Langmuir (R2 = 0.938) > Freundlich (R2 = 0.934). The Temkin constants (KT = 0.825 L/g, bT = 43.165 J/mol) and the Dubinin–Radushkevich mean free energy (ED= 0.731 kJ/mol) indicated that the adsorption of MB onto the biomass of the invasive seaweed could be a physisorption process. The values of the thermodynamic parameters showed that adsorption is a spontaneous and exothermic process. This study suggests that biomass of the invasive seaweed Sargassum muticum has a good potential capacity to remove MB dye and it could offer promising opportunity, as a low-cost biosorbent for the treatment of cationic dye industrial wastewaters.

The littoral paranthurid isopod crustacean Paranthura nigropunctata (Lucas, 1846) is recorded for the first time from the littoral of El Jadida located on the Atlantic northwest coast of Morocco. Specimens were obtained from the invasive brown seaweed Sargassum muticum and the natives Bifurcaria bifurcata and Cystoseira tamariscifolia in January 2015. This new record further confirms a significant southward distribution of P. nigropunctata and contributes to the knowledge of the biogeography of this isopod. Heretofore, the species was only known from the western and eastern Mediterranean and some Atlantic coasts. The present finding is the first of the species from Moroccan Atlantic shores, and suggests that the species may also be present in other coastal localities from Morocco and Africa. Some data on morphology, ecology and spatial distribution of the species are provided.

The diversity and structure of epiphytic macrofaunal assemblages on the introduced invasive brown macroalga Sargassum muticum and native fucoids (Bifurcaria bifurcata, Cystoseira humilis, Cystoseira tamariscifolia and Sargassum vulgare) were compared over a 1-year period in intertidal rockpools on the Atlantic coast of Morocco. In comparison with the epiphytic fauna associated to other macroalgae from European shores, we found that the associated epiphytic macrofauna was moderately diverse (H'

Silver nanoparticles (AgNPs) were synthesized using sodium alginate extracted from the invasive macroalga Sargassum muticum harvested from the Atlantic coast of Morocco. The characterization of silver nanoparticles was determined by various analytical techniques (UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA)). The X-ray diffraction patterns proved the crystal phase of AgNPs. The interaction of the functional groups of sodium alginate in the AgNPs was confirmed by FTIR analysis. They were spherical in shape with average size around 21.95 ± 0.96 nm and they exhibit important thermal stability. The in vitro antimicrobial activity of the synthesized nanoparticles exhibited high antibacterial activity against the tested human pathogenic bacteria Bacillus cereus, Micrococcus luteus, Staphylococcus aureus, and Pseudomonas aeruginosa. These eco-friendliness alginate-mediated silver nanoparticles may serve as antibacterial agents for pharmaceutical applications.

SUMMARY The Japanese brown seaweed Sargassum muticum, recently invaded several shorelines worldwide including the Atlantic coast of Morocco with large well-established populations. Within the framework of a sustainable strategy to control this invasive seaweed, we report on extraction yield, spectroscopic characterization and rheological properties of alginate, a commercially valuable colloid, from harvested biomass of S. muticum. Extraction yield was about 25.6% on dry weight basis. Infrared spectroscopy analysis shows that the obtained Fourier transform infrared spectra of the extracted biopolymer exhibit strong similarities with that of the commercial alginate. Furthermore, Proton nuclear magnetic resonance spectroscopy revealed that S. muticum alginate has almost equal amounts of β-D-mannuronic acid (M; 49%) and α-L-guluronic acid (G; 51%) with an M/G ratio of 1.04 and a high content of heteropolymeric MG GM diads suggesting a sequence distribution of an alternated polymer type. Rheological measurements were performed at different sodium alginate concentrations, temperatures and shear rates. The hydrocolloid exhibited pseudoplastic behavior and showed shear thinning, particularly at high solution concentration and low temperature which is consistent with the rheological behavior reported for commercial alginates. Considering the abundance of S. muticum in the Northwestern Atlantic coast of Morocco and the quality of the extracted hydrogel, this invasive species could be considered as a potential source of alginates.

Background This study reports for the first time the presence of the Lusitanian ampeliscid amphipod Ampelisca lusitanica Bellan-Santini & Marques, 1986 in the northwestern Atlantic coast of Morocco. Methods Specimens were collected in January 2015 from intertidal rock pools along the El Jadida shoreline associated with the brown algae Bifurcaria bifurcata and Sargassum muticum. Results Systematic description of the species is presented, as well as a discussion of its ecological and geographical distribution. Conclusion This new finding extends the geographical distribution from the Lusitanian (Europe) to the Mauritanian (Africa) region and increases knowledge of the ecology and the global distribution of A. lusitanica found, previously, only on Portuguese and Spanish coasts. info:eu-repo/semantics/publishedVersion

The Japanese brown seaweed Sargassum muticum (Yendo) Fensholt (Fucales, Phaeophyta) is reported for the first time in Atlantic Morocco, along the shoreline of Doukkala (S of Casablanca). This record, the first in the African continent, represents a remarkable range expansion of this invasive marine species. Indeed, it is the southern-most occurrence of the species in the Atlantic. Preliminary phenological and ecological data of this non-native species were provided from the Doukkala coast. The major effects on benthic structure and composition of this invasive brown macroalga were also evaluated from published data. Oyster transfers from the French coast were the most likely primary

Raw biomass of the invasive Japanese brown seaweed Sargassum muticum, recently introduced to the Atlantic coast of Morocco, has been applied for the removal of hexavalent chromium Cr(VI) from aqueous solutions. Various parameters such as biomass dose, initial pH, contact time and initial Cr(VI) concentration were studied to reveal their effects on the biosorption process. At optimum values of the above mentioned parameters, total removal of Cr(VI) can be achieved within 10 min at pH 2, adsorbent dose of 0.5 g/100 mL for initial chromium ions concentration of 50 mg/L. Cr(VI) biosorption follows pseudo second-order kinetics. Adsorption isotherms were determined at room temperature and the experimental data were modelled with the Langmuir, Freundlich and Temkin isotherm equations. The isotherm data were found to be well fitted by linear Langmuir equation. The maximum sorption capacity calculated from Langmuir isotherm was estimated to be about 143 mg per gram of dry biosorbent. Thus, the biomass used in this study can be considered a promising and valuable natural adsorbent for the treatment of aqueous solution containing toxic hexavalent chromium ions.