Marine debris is a threat to our ocean that can be more effectively addressed through monitoring and assessment of items stranded on shorelines. This study engaged citizen scientists to conduct shoreline marine debris surveys according to a published NOAA protocol within the Greater Farallones and Olympic Coast National Marine Sanctuaries on the west coast of the United States. Here, we use the results of these multi-year monitoring data to estimate marine debris abundance and temporal trends, and identify drivers of debris loads. Changes in debris counts and composition are shown to reflect seasonal patterns of coastal upwelling and downwelling, but longer temporal trends in overall debris loads depend on the sampling window. Identifying drivers of stranded debris is challenging given the observational nature of the data. A linear increase in total expected debris counts was observed when up to five participants are conducting a survey, suggesting a need to standardize the number of participants and their search pattern for debris in shoreline monitoring efforts. Lastly, we discuss the application of shoreline marine debris data to evaluate the impact of management decisions and identify new targets for mitigation.

中文翻译：

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使用公民科学数据在两个美国国家海洋保护区内的海滩上搁浅海洋碎片的时间趋势和潜在驱动因素

海洋垃圾对我们的海洋构成威胁，可以通过监测和评估搁浅在海岸线上的物品来更有效地解决。这项研究邀请公民科学家根据已发布的 NOAA 协议在美国西海岸的大法拉隆群岛和奥林匹克海岸国家海洋保护区内进行海岸线海洋垃圾调查。在这里，我们使用这些多年监测数据的结果来估计海洋垃圾的丰度和时间趋势，并确定垃圾负载的驱动因素。碎片数量和成分的变化反映了沿海上升流和下降流的季节性模式，但整体碎片负载的较长时间趋势取决于采样窗口。鉴于数据的观察性质，确定搁浅碎片的驱动因素具有挑战性。当最多五名参与者进行调查时，观察到预期碎片总数呈线性增加，这表明需要标准化参与者数量及其在海岸线监测工作中寻找碎片的模式。最后，我们讨论了应用海岸线海洋垃圾数据来评估管理决策的影响并确定新的缓解目标。