Tidal flats form behind mangrove forests and are critical coastal ecosystems influenced by ocean and land-based processes. To assess microplastics (MPs, <5 mm) distribution within tidal flats we studied four sites in southwest Puerto Rico with varying mangrove densities and anthropogenic influences. We characterized MPs from surface sediments along a transect at each tidal flat. On average 148.64 ± 138.87 MPs kg−1 were collected with the majority (55.5 %) 0.3–1 mm in size. MPs abundance within transects was positively correlated to distance from mangroves at three sites. The most common polymers were polyethylene (48.4 %) and polypropylene (16.1 %). As expected, the roadside site had the highest abundance of MPs, but surprisingly, a remote island site had the second highest amount. Two other sites likely benefited from thicker mangrove cover and less human interference. While mangroves minimized MPs accumulation, improved waste management is also needed to reduce MPs delivered to these ecosystems.

中文翻译：

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微塑料在波多黎各 La Parguera 潮滩的分布


滩涂形成于红树林后面，是受海洋和陆地过程影响的重要沿海生态系统。为了评估潮滩内微塑料（MP，<5 mm）的分布，我们研究了波多黎各西南部具有不同红树林密度和人为影响的四个地点。我们表征了每个潮滩沿样带的表层沉积物的 MP。平均收集了 148.64 ± 138.87 MPs kg-1，其中大多数 （55.5%） 的大小为 0.3-1 mm。在三个地点，样带内的 MPS 丰度与距红树林的距离呈正相关。最常见的聚合物是聚乙烯 （48.4%） 和聚丙烯 （16.1%）。正如预期的那样，路边站点的 MP 数量最高，但令人惊讶的是，偏远岛屿站点的数量第二高。另外两个地点可能受益于更厚的红树林覆盖和更少的人为干扰。虽然红树林最大限度地减少了 MP 的积累，但也需要改进废物管理以减少输送到这些生态系统的 MP。