Interest in understanding the extent of plastic and specifically microplastic pollution has increased on a global scale. However, we still know relatively little about how much plastic pollution has found its way into the deeper areas of the world’s oceans. The extent of microplastic pollution in deep-sea sediments remains poorly quantified, but this knowledge is imperative for predicting the distribution and potential impacts of global plastic pollution. To address this knowledge gap, we quantified microplastics in deep-sea sediments from the Great Australian Bight using an adapted density separation and dye fluorescence technique. We analyzed sediment cores from six locations (1–6 cores each, n = 16 total samples) ranging in depth from 1,655 to 3,062 m and offshore distances ranging from 288 to 356 km from the Australian coastline. Microplastic counts ranged from 0 to 13.6 fragments per g dry sediment (mean 1.26 ± 0.68; n = 51). We found substantially higher microplastic counts than recorded in other analyses of deep-sea sediments. Overall, the number of microplastic fragments in the sediment increased as surface plastic counts increased, and as the seafloor slope angle increased. However, microplastic counts were highly variable, with heterogeneity between sediment cores from the same location greater than the variation across sampling sites. Based on our empirical data, we conservatively estimate 14 million tonnes of microplastic reside on the ocean floor.

中文翻译：

---

澳大利亚大湾深海沉积物中的微塑料污染

在全球范围内，人们对了解塑料，特别是微塑料污染程度的兴趣有所增加。然而，我们对有多少塑料污染进入了世界海洋的更深处知之甚少。深海沉积物中微塑料污染的程度仍然很难量化，但这些知识对于预测全球塑料污染的分布和潜在影响是必不可少的。为了解决这一知识差距，我们使用适应性密度分离和染料荧光技术量化了大澳大利亚湾深海沉积物中的微塑料。我们分析了六个位置（每个 1-6 个岩心，n = 16 个总样本）的沉积物岩心，深度范围为 1,655 至 3,062 m，离澳大利亚海岸线的离岸距离为 288 至 356 公里。微塑料计数范围为每克干沉积物 0 到 13.6 个碎片（平均 1.26 ± 0.68；n = 51）。我们发现微塑料的数量比其他深海沉积物分析中记录的要高得多。总体而言，沉积物中微塑料碎片的数量随着表面塑料数量的增加和海底坡角的增加而增加。然而，微塑料数量变化很大，来自同一位置的沉积物核心之间的异质性大于采样点之间的差异。根据我们的经验数据，我们保守估计海底有 1400 万吨微塑料。沉积物中微塑料碎片的数量随着表面塑料数量的增加和海底倾斜角的增加而增加。然而，微塑料数量变化很大，来自同一位置的沉积物核心之间的异质性大于采样点之间的差异。根据我们的经验数据，我们保守估计海底有 1400 万吨微塑料。沉积物中微塑料碎片的数量随着表面塑料数量的增加和海底倾斜角的增加而增加。然而，微塑料数量变化很大，来自同一位置的沉积物核心之间的异质性大于采样点之间的差异。根据我们的经验数据，我们保守估计有 1400 万吨微塑料存在于海底。