Laboratory of Marine Geology and Physical Oceanography, Department of Geology, University of Patras, 26500, Rion, Greece.
Laboratoire Environnement Ressources Provence-Azur-Corse, Station de Corse, IFREMER, Immeuble Agostini, Z.I, Furiani, 20600, Bastia, France.
J Environ Manage. 2022 Apr 15;308:114647. doi: 10.1016/j.jenvman.2022.114647. Epub 2022 Feb 3.
Monitoring of marine litter at the sea surface, the beaches and the seafloor is essential to understanding their sources, pathways and sinks and design effective clean-up programs or increase public awareness for reducing litter waste. Up until today, seafloor litter is the least exploited component of marine litter. Although the protocols for recording and assessing seafloor litter in the deep-sea environments are currently being actively defined and practiced, shallow seafloor litter survey protocols are still notably under-developed. Moreover, trawling for fishing, which is the main means for collecting seafloor litter data, needs to be phased out in the coming years due to its high environmental footprint and be replaced by less destructive ways based on underwater imagery. In this paper we propose an integrated approach for assessing in detail the spatiotemporal distribution and composition of seafloor litter in shallow coastal environments, using common towed underwater cameras. Effort has been put to correctly estimating spatial litter densities regarding the true coverage of the visualized area, which was efficiently extracted through photogrammetric reconstruction of the seafloor. Interpretation of the spatial distribution of litter was aided by auxiliary bathymetric and swath sonar backscatter datasets, to determine the seabed geomorphological features that control their dispersion and composition. Local geo-morphology, along with any reported coastal anthropogenic activity, are correlated to seafloor litter densities to investigate the temporal and spatial dynamics that control their distribution and temporal trends in Syros Island, Cyclades, Greece. There, in the context of LIFE DEBAG project, monitoring of an urbanized shallow bay for 3 consecutive years has been performed to assess the impact of an intensive local awareness raising campaign to the local environment. A significant reduction of litter densities under the impact of this campaign has been documented, while links between the seafloor litter transport dynamics and the seabed micro- and macro-topography were made evident. Monitoring litter densities on the seafloor of urbanized shallow bays proved to be a prospective way of tracking marine litter pressures on the local marine environment.
对海面、海滩和海底的海洋垃圾进行监测，对于了解其来源、途径和归宿以及设计有效的清理计划或提高公众减少垃圾浪费的意识至关重要。直到今天，海底垃圾仍然是海洋垃圾中最少被开发的部分。尽管目前正在积极定义和实践用于记录和评估深海环境中海底垃圾的协议，但浅层海底垃圾调查协议仍然明显不够发达。此外，由于其对环境的高影响，用于收集海底垃圾数据的拖网捕捞在未来几年需要逐步淘汰，并代之以基于水下图像的破坏性更小的方法。在本文中，我们提出了一种综合方法，使用常见的拖曳式水下摄像机来详细评估浅海沿海环境中海底垃圾的时空分布和组成。我们努力正确估计空间垃圾密度，以反映可视化区域的真实覆盖范围，这是通过对海底进行摄影测量重建来有效地提取的。通过辅助水深和条带声纳反向散射数据集来解释垃圾的空间分布，以确定控制其分散和组成的海底地貌特征。当地的地貌形态，以及任何已报告的沿海人为活动，都与海底垃圾密度相关联，以调查控制其分布和时空趋势的时空动态。在希腊基克拉迪群岛的锡罗斯岛，在 LIFE DEBAG 项目的背景下，对一个连续三年进行了城市化浅海湾的监测，以评估当地环境的密集地方宣传活动对垃圾的影响。记录到在这场运动的影响下，垃圾密度显著降低，同时还发现了海底垃圾输运动态与海底微地形和宏地形之间的联系。对城市化浅海湾海底垃圾密度的监测被证明是跟踪海洋垃圾对当地海洋环境压力的一种有前景的方法。
