The “beneficial uses” of dredged sediment are increasingly being explored for habitat restoration and beach nourishment, but beneficial uses must be tempered by evaluating impacts to organisms. We studied a subtidal nearshore deposition site intended to aid beach nourishment where a “thin-layer” sediment deployment method was employed to minimize mounding and disperse sediment within a proscribed area. Baited benthic video landers (BVLs) in a Before-After Control-Impact (BACI) experimental design were used to test the acute effects (within one hour of deposition) of sediment deposition on dominant epifaunal Dungeness crab (Cancer magister) and dog whelk (Nucella spp). The effects of sediment deposition depths and the lateral surge (the turbidity front transiting the seafloor) were both considered. Observations revealed sedimentation levels were limited to <4 cm and burial likely posed no direct threat to epifauna. However, video and instrument measurements showed the lateral surge to impact the BVLs as a 1 to 3 m/s sediment-laden front. Crabs were significantly impacted, while gastropods were more resistant to dislodgment. However, the high velocity impact was relatively brief (2 to 7 min). Further, crabs returned to forage at BVLs after a mean lag of about 20 min post-impact. These results indicate an acute but ephemeral impact effect on crab, and support use of the thin-layer deposition method to minimize burial. Our novel use of BVLs in a BACI experimental design were an effective means of evaluating sediment impacts to targeted mobile epifaunal species, and video observations were informative for understanding lateral surge dynamics and the behavioral interactions of organisms.

越来越多地探索疏dr沉积物的“有益用途”以恢复生境和养育海滩，但必须通过评估对生物的影响来调节有益用途。我们研究了旨在帮助海滩营养的潮下带近岸沉积物，其中采用了“薄层”沉积物布放方法，以最大程度地减少堆积并在受禁区域内分散沉积物。在前后对照（BACI）实验设计中，诱饵底栖视频着陆器（BVL）用于测试沉积物沉积对优势表观雌雄大蟹（巨蟹座巨蟹座）和狗胡须的急性影响（沉积一小时内）（Nucellaspp）。都考虑了沉积物沉积深度和侧向涌浪（浊度锋经过海底）的影响。观察发现，沉积物水平限制在<4 cm，埋葬可能不会对动物群落构成直接威胁。但是，视频和仪器测量结果显示，横向波动以1到3 m / s的速度充满了沉积物。蟹受到显着影响，而腹足动物更耐移出。但是，高速冲击是相对短暂的（2至7分钟）。此外，在撞击后平均滞后约20分钟后，螃蟹在BVL处恢复觅食。这些结果表明对螃蟹有急性但短暂的影响，并支持使用薄层沉​​积方法以最大程度地减少埋葬。