Submarine canyons support high biomass communities as they act as conduits where sediments, nutrients, and organic matter from continental shelves, or those that are carried along by slope currents, are transported into the abyssal zone. The Porcupine Bank Canyon (PBC), located on the Irish continental margin and isolated from terrigenous inputs, reveals a complex terrain and substrate variation that affect the distribution of benthic fauna. Here, ROV-based benthic video, conductivity-temperature-depth (CTD), current velocity profiles, suspended particulate organic matter (POM) and bathymetric data were assessed to determine the controls on the distribution of benthic megafauna throughout the canyon. Multivariate analysis of the benthic community reveals significant differences in community structure among habitats and site locations throughout the canyon. Furthermore, these results show that non-reef habitats exhibit more variation in the composition of benthic taxa than coral reef and rubble habitats, with the following species contributing most to the structural differentiation between habitats: Leiopathes glaberrima (12.46%), Hexadella dedritifera (10.37%), Cidaris cidaris (9.31%), Aphrocallistes beatrix (9.33%), Araeosoma fenestratum (9.11%), Stichopathes cf. abyssicola (7.39%), Anthomastus grandiflorus (4.66%), and Benthogone rosea (3.84%). In addition, greater diversity, taxa evenness and high abundance of motile fauna were observed in non-reef habitat and the canyon flank. Seabed terrain features (depth, slope) are the most important environmental drivers that affect benthic taxa distribution while site locations and habitat type are the categorical variables that influence taxa distribution in the PBC. The highest mean current speed was observed on the canyon flank where the highest Shannon’s diversity was recorded while mean current speed ranged from 18.2–31.3 cm s–1. As the PBC is cut off from direct terrigenous input, this research contributes to understanding cold-water coral habitat responses to natural Northeast Atlantic environmental conditions. The findings of the current study will inform key stakeholders on how to responsibly interact with the canyon benthic habitats and can help inform policy makers on the effective conservation and management of the cold-water coral habitat in the PBC and other canyons.

中文翻译：

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非珊瑚礁栖息地对于海底峡谷中的珊瑚礁和碎石栖息地对底栖生物多样性和组成是否重要？大西洋东北部豪猪银行峡谷底栖巨型动物分布的控制分析

海底峡谷支持高生物量群落，因为它们充当了来自大陆架的沉积物、营养物和有机物或由斜坡流携带的那些被输送到深海区的管道。位于爱尔兰大陆边缘并与陆源输入隔离的豪猪银行峡谷 (PBC) 揭示了影响底栖动物分布的复杂地形和基质变化。在这里，评估了基于 ROV 的底栖视频、电导率-温度-深度 (CTD)、电流速度剖面、悬浮颗粒有机物 (POM) 和测深数据，以确定对整个峡谷底栖巨型动物分布的控制。底栖群落的多变量分析揭示了整个峡谷栖息地和站点位置之间群落结构的显着差异。此外，这些结果表明，与珊瑚礁和碎石栖息地相比，非珊瑚礁栖息地在底栖类群的组成上表现出更多的变化，以下物种对栖息地之间的结构差异贡献最大：Leiopathes glaberrima (12.46%)、Hexadella derritifera (10.37) %)、Cidaris cidaris (9.31%)、Aphrocallistes beatrix (9.33%)、Araeosoma fenestratum (9.11%)、Stichopathes cf. abyssicola (7.39%)、Anthomastus grandiflorus (4.66%) 和 Benthogon rosea (3.84%)。此外，在非珊瑚礁栖息地和峡谷侧翼观察到更大的多样性、分类群均匀性和高丰度的活动动物群。海底地形特征（深度、坡度）是影响底栖类群分布的最重要的环境驱动因素，而站点位置和栖息地类型是影响 PBC 中类群分布的分类变量。在记录了最高香农多样性的峡谷侧翼观察到最高平均水流速度，而平均水流速度范围为 18.2–31.3 cm s–1。由于 PBC 与直接陆源输入隔绝，这项研究有助于了解冷水珊瑚栖息地对东北大西洋自然环境条件的反应。当前研究的结果将告知主要利益相关者如何负责任地与峡谷底栖栖息地互动，并可以帮助决策者了解 PBC 和其他峡谷冷水珊瑚栖息地的有效保护和管理。