Nearshore sea-surface manta trawls were carried out monthly at seven sites along the coastline of Mallorca in the Balearic Islands in the Western Mediterranean Sea. Plastic marine debris was present in all trawls (n = 63) with an overall average abundance of 858,029 ± 4,082,964 items/km2 (mean ± standard deviation) and weight of 4,520 ± 22,806 g(DW)/km2 and the micro-plastic fraction (74%) dominating the size class. Polyethylene (LDPE and HDPE) was the most common polymer (70%) with high spatial heterogeneity, especially along the north-western coast. August showed almost two-fold as much plastic as the other months, and the number of items decreased significantly with distance from the coastline. A positive correlation was found with the fractal dimension of the coastline indicating higher coastal plastic debris retention in areas with a higher fractal dimension and backtracking simulations indicated that marine litter was mainly locally sourced. Overall results indicate a significant small scale variability of nearshore coastal marine plastic in the Balearic Islands.

中文翻译：

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巴利阿里群岛的塑料碎片近岸时空海面拖网。

每月在西地中海巴利阿里群岛马略卡岛沿海岸线的七个地点进行近海海面蝠ta拖网。所有拖网（n = 63）中均存在塑料海洋垃圾，总平均丰度为858,029±4,082,964项/ km2（均值±标准差），重量为4,520±22,806 g（DW）/ km2，微塑料含量为（ 74％）占据了尺寸类。聚乙烯（LDPE和HDPE）是最常见的聚合物（70％），具有较高的空间异质性，尤其是在西北海岸。8月的可塑性几乎是其他月份的两倍，并且物品的数量随着与海岸线距离的增加而显着下降。发现与海岸线的分形维数呈正相关，这表明分形维数较高的地区沿海塑料碎片的滞留量较高，而回溯模拟表明，海洋垃圾主要来自当地。总体结果表明，巴利阿里群岛的近岸沿海海洋塑料存在小规模的变化。