ABSTRACT: Sustainable expansion of global aquaculture depends on a thorough understanding of environmental impacts. Open-water culture operations produce waste food and faeces, the benthic impacts of which are a focus of regulation. Seabed interactions of wastes are complex, depending on current velocity, seabed substrate and waste material characteristics. The accuracy achieved in modelling intensity and spatial extent of impacts is contingent upon the representation of this interaction and its implications for resuspension. We used benthic flumes to study resuspension processes at 11 salmon aquaculture sites, covering a range of sediment types. Erosion rates and critical entrainment stress were computed at the cage edge and between 100 and 500 m away, characterising seabed erodibility in highly impacted and less impacted sediments. Heavily impacted cage-edge sediments had an erosion threshold (mean 0.02 N m^-2) that was an order of magnitude lower, and markedly less heterogeneous, than that of nearby less impacted sediments (mean across sites 0.19 N m^-2). This likely reflects a seabed which was smothered by waste material close to the depositional centre. Further out, the covering of waste material is less continuous, thinner, and more admixed with underlying sediments. Bed erosion rates were found to be a linear function of excess stress. The results provide important information on how benthic flumes can be deployed to collect spatial and temporal data for parameterisation of erosion and entrainment processes in numerical waste transport simulation models such as DEPOMOD, and the comparatively large field-based dataset should contribute to the goal of allowing a more realistic representation of particulate waste in these models.

中文翻译：

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水产养殖废物沉积模型中的参数化重悬

摘要：全球水产养殖的可持续发展取决于对环境影响的透彻了解。开放水域养殖活动产生废粮和粪便，其底盘影响是监管的重点。废物在海底的相互作用是复杂的，具体取决于当前的速度，海底基质和废物材料的特性。对影响的强度和空间范围进行建模的准确性取决于这种相互作用的表示形式及其对重新悬浮的影响。我们使用底栖水槽研究了11个鲑鱼养殖场的重悬过程，涵盖了各种沉积物类型。计算了笼缘和100至500 m之间的侵蚀速率和临界夹带应力，表征了受高度影响和影响较小的沉积物中的海床易蚀性。^-2）比附近受影响较小的沉积物低一个数量级，且异质性明显降低（平均跨站点0.19 N m ^-2））。这可能反映出海床被沉积中心附近的废物所淹没。再远一点，废料的覆盖面不连续，较薄，并且与下面的沉积物混合得更多。发现床层侵蚀率是过量应力的线性函数。研究结果提供了重要信息，说明如何利用底栖水槽收集时空数据，以在诸如DEPOMOD之类的数字废物运输模拟模型中对侵蚀和夹带过程进行参数化，并且相对较大的基于现场的数据集应有助于实现以下目标：在这些模型中更真实地表示了微粒废物。