Lu Xun, Shen Chengcheng, Yang Chenghao, Xu Weikun, Yang Juan, Wang Chunsheng, Sun Dong
Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources Hangzhou P. R. China.
School of Marine Science China University of Geosciences Beijing P. R. China.
Ecol Evol. 2024 Oct 17;14(10):e70427. doi: 10.1002/ece3.70427. eCollection 2024 Oct.
The oligotrophic tropical western Pacific region is characterized by a high density of seamounts, with the Kyushu-Palau Ridge (KPR) being the longest seamount chain here. Effective spatial management plans for seamount ecosystems necessitate an understanding of distribution patterns and key environmental factors influencing benthic communities. However, knowledge regarding deep-sea biodiversity patterns over intricate topography remains limited. In this study, we investigated a seamount with a water depth of 522 m at the summit located in the southern section of KPR. Survey transects were conducted from 522 m to 4059 m. By analyzing video-recorded data obtained by a human-occupied vehicle (HOV) during dives and environmental variables derived from bathymetry, distinct assemblages were identified through noise clustering. α- and β-diversity patterns within the seamount megabenthic community were analyzed across the depth gradient, along with investigation of their environmental drivers. A total of 10,596 megafauna individuals were documented, categorized into 88 morphospecies and statistically separated into six distinct community clusters using noise clustering analysis. Species abundance and richness were highest within the 700-800 m water depth range, declining notably beyond 2100 m, indicating a critical threshold for habitat classification in this region. The β-diversity of megabenthic communities was high (0.836). Although β-diversity patterns along the depth gradient were mostly dominated by differences in species richness, the contribution of species replacement increased with depth, becoming dominant at depths greater than 3000 m. Depth emerged as the primary driver of spatial variation in community structure, while near-bottom current velocity, topographic parameters (bathymetric position index, slope), and substrate type also influenced the formation of microhabitats. The study highlights the depth gradients, thresholds, and other intricate environmental factors shaping the spatial heterogeneity of these communities. It provides valuable insights for the future development of effective survey and conservation strategies for benthic biodiversity on the KPR.
贫营养的热带西太平洋地区以海山密度高为特征，其中九州-帕劳海岭（KPR）是这里最长的海山链。有效的海山生态系统空间管理计划需要了解影响底栖生物群落的分布模式和关键环境因素。然而，关于复杂地形上深海生物多样性模式的知识仍然有限。在本研究中，我们调查了位于KPR南段、山顶水深522米的一座海山。调查断面从522米至4059米进行。通过分析载人潜水器（HOV）潜水期间获得的视频记录数据以及从测深数据得出的环境变量，通过噪声聚类识别出不同的群落组合。分析了海山大型底栖生物群落内的α多样性和β多样性模式随深度梯度的变化情况，并对其环境驱动因素进行了调查。共记录了10596个大型动物个体，分为88个形态物种，并使用噪声聚类分析将其统计分为六个不同的群落簇。物种丰度和丰富度在水深700 - 800米范围内最高，在2100米以上显著下降，表明该区域栖息地分类的一个关键阈值。大型底栖生物群落的β多样性较高（0.836）。尽管沿深度梯度的β多样性模式大多由物种丰富度差异主导，但物种更替的贡献随深度增加，在深度大于3000米时占主导地位。深度成为群落结构空间变化的主要驱动因素，而近底流速、地形参数（测深位置指数、坡度）和基质类型也影响微生境的形成。该研究突出了深度梯度、阈值和其他复杂环境因素对这些群落空间异质性的塑造作用。它为未来制定KPR底栖生物多样性的有效调查和保护策略提供了有价值的见解。
