scholarly journals Seasonal variation of microplastics density in Algerian surface waters (South-Western Mediterranean Sea)

2021 ◽  
Author(s):  
SKANDER SETITI ◽  
BOUALEM HAMDI ◽  
SAFIA CHERNAI ◽  
FOUZIA HOUMA BACHARI ◽  
SAMIR BACHOUCHE ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Temporal Distribution ◽  
Western Mediterranean ◽  
Additional Information ◽  
Western Mediterranean Sea ◽  
Wide Range ◽  
Algerian Coast ◽  
Spatio Temporal ◽  
Few Data ◽  
Harmful Effects

Coastal waters worldwide are widely contaminated with various-size plastics, whose presence in aquatic ecosystems has been shown to produce a wide range of economic and social impacts and harmful effects on marine ecosystems. While microplastics have been reported from many regions of the Mediterranean Sea, very few data exist regarding microplastics concentration in Algerian waters. In this study, we used a Manta trawl (330 µm) at six sampling stations in Bou-Ismail Bay, Algeria (South-West Mediterranean Sea) in order to provide novel information about the occurrence and composition of microplastics along the Algerian coast. Sampling was performed seasonally at six different sampling stations in 2018, providing additional information about the spatio-temporal variability of microplastics concentrations at the sea surface. Microplastics were found in all collected samples, with highly variable concentrations of 0.95, 0.88, 1.26, and 0.36 items/m3 in Autumn, Winter, Spring and Summer, respectively, and an overall mean concentration of 0.86 ± 0.35 items/m3. A classification based on the shape and appearance of microplastics indicated the predominance of fibers (32%), followed by fragments (27%), films (16%), foams (13%), and granules (12%). A qualitative microplastics analysis through Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) revealed that microplastics were mainly composed of polyethylene (68.2%), polypropylene (24.7%), polystyrene (4.1%) and other polymers (3%). These data provide an initial overview of the quantity, characteristics, and spatio-temporal distribution of floating microplastics in Bou-Ismail Bay (Algeria).

scholarly journals Spatio-temporal distribution of the dominant Diatom and Dinoflagellate species in the Bay of Tunis (SW Mediterranean Sea)

2005 ◽  
Vol 6 (1) ◽  
pp. 17 ◽  
Author(s):  
O. DALY YAHIA-KEFI ◽  
S. SOUISSI ◽  
F. GOMEZ ◽  
M.N. DALY YAHIA
Keyword(s):  
Mediterranean Sea ◽  
Chlorophyll Concentration ◽  
Temporal Distribution ◽  
Late Summer ◽  
Clear Correlation ◽  
Red Tides ◽  
Nutrient Inputs ◽  
Wide Range ◽  
Spatio Temporal ◽  
Diatom Blooms

Microphytoplankton composition and its relationships with hydrology and nutrient distributions were investigated over 24 months (December 1993 - November 1995) in the Bay of Tunis ( SW Mediterranean Sea). A new index, the ‘Specific Preference Index’ (SPI) obtained by computing the median value of each parameter weighed by the numerical value of each species density was developed. Using this index, the relationships between each species and temperature, salinity and major nutrients were analysed. The distribution of chlorophyll a did not show a clear correlation with microplankton abundance suggesting that other factors contribute to chlorophyll concentration, such as smaller phytoplankton size fractions or detritus. The winter-spring diatom blooms did not show a regular pattern during both years. High nutrient inputs in late summer, associated with mild meteorological conditions, contributed to the development of a large diatom bloom in autumn 1995 where significant silicate depletion was witnessed. Generally, diatoms were more stenotherm than dinoflagellates in the Bay, whereas dinoflagellates were more stenohaline than diatoms. The statistical analyses showed that the two species, Bellerochea horologicalis , and Lithodesmioides polymorpha, var., tunisiense, appeared in a wide range of environmental conditions. An excess of phosphateversus nitrate appeared to be associated with red tides of, Gymnodinium spp, whereas Peridinium quinquecorne, showed the opposite. Phosphate concentrations appear to be crucial in this coastal environment, where diatom blooms are often limited by low silicate availability.

scholarly journals Inventory and the biogeographical affinities of Annelida Polychaeta in theAlgerian coastline (Western Mediterranean)

2020 ◽  
Vol 21 (1) ◽  
pp. 157
Author(s):  
ALI BAKALEM ◽  
PATRICK GILLET ◽  
JEAN-PHILIPPE PEZY ◽  
JEAN-CLAUDE DAUVIN
Keyword(s):  
Mediterranean Sea ◽  
World Ocean ◽  
Aegean Sea ◽  
Western Mediterranean ◽  
The Black Sea ◽  
Polychaete Species ◽  
Western Mediterranean Sea ◽  
Atlantic Origin ◽  
Algerian Coast ◽  
The Mediterranean

The data analyzed to inventory of all polychaetes in Algerian waters make it possible to estimate the diversity of this group to 534 species. The most diversified families are Syllidae (66 species), Spionidae (37 species) and Terebellidae (27 species).The presence of these listed species along the Algerian coast is compared with their occurrence in nine other areas of the Mediterranean Sea, in the Black Sea and in four other areas of the World Ocean. Comparison are also made with respect to the indications of the biogeographical origin for each species. The polychaete fauna of the Algerian coast is among the richest of the Mediterranean Sea and comparable to that reported for the French Mediterranean continental shelf  and the Aegean Sea, but higher that that found in the bordering coastlines of Morocco and Tunisia. Most of the species have an Atlantic origin and are present in the western Mediterranean Sea; this inventory includes eight Non-Indigenous Polychaete Species in the Algerian waters.

scholarly journals DISTRIBUTION OF SPAWNING AND NURSERY GROUNDS FOR DEEP–WATER RED SHRIMPS IN THE CENTRAL WESTERN MEDITERRANEAN SEA

2014 ◽  
Vol 16 (1) ◽  
pp. 117 ◽  
Author(s):  
F. PALMAS ◽  
P. ADDIS ◽  
S. CABIDDU ◽  
D. CUCCU ◽  
M. C. FOLLESA ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Temporal Distribution ◽  
Relevant Information ◽  
Western Mediterranean ◽  
Physical Habitat ◽  
Nursery Areas ◽  
Nursery Grounds ◽  
Habitat Features ◽  
Western Mediterranean Sea ◽  
Partial Overlap

The presence of spawning and nursery grounds of Aristeids in the central western Mediterranean Sea were investigated using fishery-independent data (trawl surveys, 1994–2012). Spatial distributions were generated for mature animals and recruits, for both spring/summer and autumn data, using an inverse distance weighted deterministic interpolation. The persistence index was used to identify stable spawning and nursery grounds in the Sardinian slope region for Aristaeomorpha foliacea and Aristeus antennatus. Areas of aggregation for recruits and mature females appear connected with important physical habitat features. The analysis also suggests a seasonal bathymetric distribution for nursery areas. The recruits of A. foliacea are located in the upper part of the continental slope (377-450 m) in spring-summer and reach greater depths (468-628 m) in autumn. For A. antennatus, for which nursery areas only emerge in autumn, there is presumably an opposite ontogenic migration, from deep sea to upper slope, during the summer (575-681 m). Results indicate also a partial overlap between the nursery and spawning grounds of both species. In this particular areas, local environmental conditions such as upwelling events or the presence of canyons and seamounts seem to play an important role in their distribution. This study generated also relevant information on the spatial and temporal distribution of seasonal or persistent aggregations of spawners and recruits, providing scientific elements to suggest the feasibility of protecting these important resources.

scholarly journals Using opportunistic sightings to infer differential spatio-temporal use of western Mediterranean waters by the fin whale

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6673
Author(s):  
Estefanía Torreblanca ◽  
Juan Antonio Camiñas ◽  
David Macías ◽  
Salvador García-Barcelona ◽  
Raimundo Real ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Low Cost ◽  
Temporal Distribution ◽  
Western Mediterranean ◽  
Long Distance ◽  
Cetacean Species ◽  
Fin Whale ◽  
Gulf Of Lion ◽  
Fin Whales ◽  
Spatio Temporal

The fin whale (Balaenoptera physalus) is a cosmopolitan species with a resident population in the Mediterranean Sea. Due to its habitat, open seas often far from ports and airfields, and its long-distance migratory behaviour, studying and monitoring its distribution is costly. Currently, many opportunistic sightings (OS) reports are available, which provide a source of potentially useful, low-cost information about the spatio-temporal distribution of this species. Since 1993, the Spanish Institute of Oceanography has compiled a dataset comprising 874 records of OS of nine species of cetaceans in the western Mediterranean Sea and adjacent waters. The aim of this study was to use this dataset to investigate the differential use of these waters by the fin whale when compared with other cetaceans. We compared the presence of fin whales with the presence of any other cetacean species in the dataset. Binary logistic regression was then used to model these occurrences according to several spatio-temporal variables expected to reflect their habitat use. Several significant models reveal that fin whales are more prone than other cetaceans to use the waters over the slope of the Gulf of Lion in summer. This finding confirms that the Gulf of Lion is an area of importance for this species and suggests that the slope of the continental shelf could be particularly important. Our study shows how OS can be a source of useful information when appropriately analyzed.

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