Browsing by Author "Sabour, Brahim"
Now showing 1 - 8 of 8
Results Per Page
Sort Options
- A baseline assessment of beach macrolitter and microplastics along northeastern Atlantic shoresPublication . Velez, Nadja; Zardi, Gerardo, I; Lo Savio, Roberto; McQuaid, Christopher D.; Valbusa, Ugo; Sabour, Brahim; Nicastro, KatyMarine litter is widely dispersed throughout coastal environments. Assessing the distribution and accumulation of such contaminants is crucial to understand their environmental impacts. This study presents a baseline for the monitoring of litter and microplastics in intertidal sediments along the Atlantic shores of southern Portugal and Morocco and identifies potential sources of contamination. Although variable, distribution and composition of both litter and microplastics did not follow a latitudinal pattern. Most of the litter had an undifferentiated source. Within the identifiable sources of litter, food packaging, fishing and tobacco were the most abundant, with variable contributions among sites. Over 97% of marine litter retrieved was plastic. Fragments and filaments were the most abundant categories of plastics at sites with the highest and lowest microplastic abundance respectively. Filaments were mainly made of Polypropylene (PP,50%) and Polyethylene terephthalate (PET,29%) while the predominant polymers for fragments were Polyethene (PE, 75%) and PP (25%).
- DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae)Publication . Neiva, J.; Bermejo, Ricardo; Medrano, Alba; Capdevila, Pol; Milla-Figueras, David; Afonso, Pedro; Ballesteros, Enric; Sabour, Brahim; Serio, Donatella; Nóbrega, Eduardo; Soares, João; Valdazo, José; Tuya, Fernando; Mulas, Martina; Israel, Álvaro; Sadogurska, Sofia S.; Guiry, Michael D.; Pearson, Gareth; Serrao, EsterCystoseira sensu lato (s.l.) - encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria - is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a similar to 1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. phylogenetic signal of coxl was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered.
- Latitudinal incidence of phototrophic shell-degrading endoliths and their effects on mussel bed microclimatesPublication . Lourenço, Carla R.; R Nicastro, Katy; McQuaid, Christopher D.; Sabour, Brahim; Zardi, Gerardo I.Aggregations of organisms commonly benefit their members by mitigating the effects of predators and environmental stresses. Mussel aggregations also form important intertidal matrices that support associated infaunal communities, the structures of which are largely shaped by the conditions within the interstitial spaces. Intertidal mussels are frequently parasitized by phototrophic endoliths that infest the shell and have thermoregulatory effects on both solitary and aggregated mussels by changing shell albedo. A large-scale sampling was carried out May June 2016 along Portuguese and Moroccan shores to investigate a latitudinal gradient of endolithic infestation of the intertidal mussel Mytilus galloprovincialis. Endolithic infestation increased towards lower latitudes most likely as a response of greater light availability. Additionally, artificial beds of either 100% non-infested or infested biomimetic mussels were used to test whether infestation alters the temperature and humidity of the interstitial spaces within beds, and if mussels surrounded by infested mussels experience lower body temperatures than those surrounded by non-infested ones. Conditions within beds of infested mussels were significantly cooler and more humid than in non-infested beds and individuals in the centre of infested mussel beds experienced significantly lower body temperatures. Under a scenario of warming climate, endolithic infestation of mussel beds might thus represent an ecological advantage not only for M. galloprovincialis as a species but also for the associated communities.
- Population level variation in reproductive development and output in the golden kelp Laminaria ochroleuca under marine heat wave scenariosPublication . Strasser, Fiona-Elaine; Barreto, Luis M.; Kaidi, Soukaina; Sabour, Brahim; A, Serrão; Pearson, Gareth; Martins, NeusaThermal tolerance is often interpreted as a species-wide thermal niche in the absence of studies focusing on the adaptive potential of populations to exhibit differential thermal tolerance. Thus, considering intraspecific thermal plasticity, local adaptation or both between populations along distributional gradients when interpreting and predicting species responses to warming is imperative. Removing the effect of environmental histories by raising kelp gametophyte generations in vitro under common garden conditions allows unbiased comparison between population-specific adaptive variation under different environmental conditions. Following this approach, this study aims to detect (potentially) adaptive differentiation in microscopic life-stages (gametophytes) between populations of a temperate forest forming kelp, Laminaria ochroleuca from locations with distinct thermal conditions. Gametophytes from four geographically distinct populations were subjected to different temperature treatments (17, marine heat waves of 23, 25 and 27 degrees C) and gametophyte survival during thermal stress as well as reproductive success and photosynthetic responses during recovery were investigated. Intraspecific variation in resilience and reproductive output to thermal stress was found in L. ochroleuca; gametophytes from the most northern population (Brittany, France) were the most thermally sensitive, with mortality onset at 23 degrees C, whereas mortality in the remaining populations was only apparent at 27 degrees C. Gametophytes from northern Spain and Morocco exhibited very low reproductive success during recovery from 23 and 25 degrees C. However, when recovering from the highest thermal treatment (27 degrees C) the reproductive development and sporophyte output was higher than in the gametophytes from France and Italy (Mediterranean). The population-specific responses of gametophyte resilience and reproductive success to temperature stress suggest genetic differentiation in response to variation in local thermal regimes.
- Record of the first Pleonexes species (Crustacea: Amphipoda: Ampithoidae) in Moroccan waters: Pleonexes gammaroides Spence Bate, 1857Publication . Kaid, Soukaina; Chaouti, Abdellatif; Mateus, M.; Belattmania, Zahira; Serrao, Ester; Engelen, Aschwin H.; Reani, Abdeltif; Sabour, BrahimThe ampithoid amphipod crustacean Pleonexes gammaroides Spence Bate, 1857 is reported from Morocco (northeastern Atlantic Ocean) for the first time, where it is the only representative of the genus Pleonexes Spence Bate, 1857 so far. Specimens were collected from the upper fringe of the infralittoral zone (including low intertidal) of El Jadida coastline associated with the holdfasts of the kelp Saccorhiza polyschides (Lightfoot) Batters (Phaeophyceae), colonising the sublittoral fringe in the southernmost distribution limit (Morocco). This finding updates the known geographical distribution of P. gammaroides in northern Africa and northeastern Atlantic. Some ecological and distributional details of this amphipod species are briefly discussed here.
- Spatiotemporal patterns of phenology of the alien Phaeophyceae Sargassum muticum on the Atlantic coast of MoroccoPublication . Elatouani, Samir; BELATTMANIA, ZAHIRA; Kaidi, Soukaina; Engelen, Aschwin; Serrao, Ester; Chaouti, Abdellatif; REANI, Abdeltif; Sabour, BrahimThe present study focused on the dynamics of the phenology and life cycle of the Phaeophyceae invader Sar-gassum 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 ma-turity 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.
- Spatiotemporal variation of the epifaunal assemblages associated to Sargassum muticum on the NW Atlantic coast of MoroccoPublication . Belattmania, Zahira; Chaouti, Abdellatif; Engelen, Aschwin; Serrao, Ester; Machado, Margarida; Reani, Abdeltif; Sabour, BrahimEpifaunal assemblages inhabiting the non-indigenous macroalga Sargassum muticum (Yendo) Fensholt were investigated on two physically distinct intertidal rocky (S1) and sandy (S2) sites along the Atlantic coast of Morocco. The objective of this study was to test whether the habitat-forming marine alga S. muticum invasive in these sites supported different epifaunal assemblages under different environmental conditions and through time. The gastropods Steromphala umbilicalis, S. pennanti, and Rissoa parva and the isopod Dynamene bidentata were the most contributive species to the dissimilarity of epifaunal assemblage structure between both sites throughout seasons. SIMPER analysis showed a dissimilarity of 58.3-78.5% in the associated species composition of S. muticum between study sites with respect to sampling season. Species diversity and total abundance were significantly higher at the rocky site compared to the sandy site. PERMANOVA analyses showed significant differences of associated epifaunal assemblage structure for the season and site interaction. Accordingly, site and season were determinant factors conditioning the role of habitat in structuring epifaunal assemblages.
- The invasive Atlantic blue crab Callinectes sapidus Rathbun, 1896 expands its distributional range southward to Atlantic African shores: first records along the Atlantic coast of MoroccoPublication . Chaouti, Abdellatif; Belattmania, Zahira; Nadri, Amal; Serrao, Ester; Encarnação, João; Teodosio, Maria; Reani, Abdeltif; Sabour, BrahimThe 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.