Floating plastic debris in the Central and Western Mediterranean Sea.

In two sea voyages throughout the Mediterranean (2011 and 2013) that repeated the historical travels of Archduke Ludwig Salvator of Austria (1847-1915), 71 samples of floating plastic debris were obtained with a Manta trawl. Floating plastic was observed in all the sampled sites, with an average weight concentration of 579.3 g dw km(-2) (maximum value of 9298.2 g dw km(-2)) and an average particle concentration of 147,500 items km(-2) (the maximum concentration was 1,164,403 items km(-2)). The plastic size distribution showed microplastics (<5 mm) in all the samples. The most abundant particles had a surface area of approximately 1 mm(2) (the mesh size was 333 μm). The general estimate obtained was a total value of 1455 tons dw of floating plastic in the entire Mediterranean region, with various potential spatial accumulation areas.

Ruiz-Orejón LF ，Sardá R ，Ramis-Pujol J 《-》

Now, you see me: High concentrations of floating plastic debris in the coastal waters of the Balearic Islands (Spain).

Coastal ecosystems are under significant human pressure, partly due to the proximity of pollution sources. In this study, a total of 20 samples were taken in summer around the coastal waters of the Balearic Islands (Spain) using a manta trawl net to examine the concentrations of floating plastic debris through the NIXE III project campaign. Although plastic concentrations showed high variability along the coast, the higher particle concentration (max: 4,576,115 items ⋅ km-2) and weight (max: 8,102.94 g(DW) ⋅ km-2) values were located at the north of the Balearic Promontory. The particle size analysis showed the high prevalence of microplastics (< 5 mm) in these waters, where particles of approximately 0.7 mm and 1 mm2 were the most frequent in the range analyzed. The high plastic concentration values in the N-NW coast of Ibiza and Mallorca in sparsely populated locations suggest that the plastic particle distribution was mostly conditioned by the hydrodynamic surface conditions.

Ruiz-Orejón LF ，Sardá R ，Ramis-Pujol J 《-》

Floating debris in the Mediterranean Sea.

Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km(2)) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km(2). According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin.

Suaria G ，Aliani S 《-》

Quarterly variability of floating plastic debris in the marine protected area of the Menorca Channel (Spain).

Plastic pollution is widespread in all the oceans and seas, representing a significant threat to most of their ecosystems even in marine protected areas (MPAs). This study determines the floating plastic distribution in four different periods between 2014 and 2015 in the recently approved Menorca Channel MPA (Balearic Islands). Plastic debris were persistent during all sampling periods on the surface of the Channel, composed mainly by the microplastic sizes. Average particle abundances ranged from 138,293 items⋅km-2 in autumn to 347,793 items⋅km-2 during the spring, while weight densities varied from 458.15 g(DW)⋅km-2 in winter to 2016.67 g(DW)⋅km-2 in summer. Rigid plastics were the most frequent particles in all the periods analysed (from 89.40%-winter to 94.54%-spring). The high-resolution and particle distribution models corroborated that the oceanographic variability shapes different patterns of presence of plastics, and in particular the existence of areas with almost no plastics.

Ruiz-Orejón LF ，Mourre B ，Sardá R ，Tintoré J ，Ramis-Pujol J ... -  《-》

Abundance and composition of floating marine macro litter on the eastern sector of the Mediterranean Sea.

Floating marine litter is known to be currently a widespread pollution problem, especially in the Mediterranean basin, but records on the levels of floating debris in the eastern part are less known. By using an observation platform (32 days, 137 transects, 1784 km), this study provides evidence of a high amount of floating debris in the Levantine sub-basin, within the eastern Mediterranean Sea. The density of floating litter varied between 18 and 1593 items km-2 (average 232 ± 325 items km-2), and small plastic debris accounted for >90% of the items surveyed. These values tend to be higher than densities reported for the central and western Mediterranean areas, which may be related to the circulation patterns and inputs from coastal sources. Significant correlations of floating macro litter density with wind force and sea state were found, thus strengthening the need to standardise protocols (including oceanographic variables) of visual surveys of floating debris.

Constantino E ，Martins I ，Salazar Sierra JM ，Bessa F ... -  《-》