Loulidi Ali, Buhl-Mortensen Lene, Rhinane Hassan, Houssa Rachida
Geoscience Laboratory, Faculty of Sciences Ain Chock, University Hassan II, Casablanca 20100, Morocco.
Institute of Marine Research (IMR), Bergen 5005, Norway.
Mar Environ Res. 2025 Feb;204:106898. doi: 10.1016/j.marenvres.2024.106898. Epub 2024 Dec 6.
The recent decline in the health status of deep-sea habitats around the world has pushed the need to document and map their distribution to preserve them in their marine ecosystems. This work describes deep-water coral habitats (133-729 m) and their associated communities, based on nine ROV video transects. These transects cover a 171 km sub-seafloor profile within a predefined 5560 km area along the North Atlantic coast of Morocco, surveyed in 2020 as part of a coral habitat mapping study under the FAO-NANSEN programme. The nine sites were initially explored using multibeam echosounder, to generate a detailed bathymetry map allowing for the positioning of video transects. Megafauna and sediment composition was recorded along transects, and in total 1854 individuals were annotated, and 59 taxa were identified. To identify coral communities and related species assemblages, we used a cluster analysis for classification and the ordination analysis Detrended Correspondence Analysis (DCA) to identify the environmental drivers behind the community patterns. Eight environmental variables were compared with the DCA ordination results, and the important variables were bedrock, mud and depth. The results revealed six megabenthic communities. Three groups were associated with soft sediments, mainly mud. Group I, at depths of 605-726 m, was characterized by Ceriantharia and Synaphobranchus kaupii. Group V, at 133 m depth, was dominated by Ceriantharia. Group VI, consisting of Centrostephanus sp. and a fish community (Scorpaenidae, Capros aper, and Macroramphosus sp.), was found at 201 m depth. In mixed bottoms, where mud is the dominant substrate, Group II was characterized by Crinoidea and sea pens (Funiculina quadrangularis and Virgularia mirabilis) at a depth range of 207-369 m, while Group III, found at depths of 465-602 m, was characterized by sea pens (Pennatula phosphorea and Funiculina quadrangularis), Crinoidea, and the key species Isidella elongata. Group IV, at 207 m depth, was represented by Sertularella sp. and Ellisella paraplexauroides as the dominant species. This first study about mapping deep sea coral habitats in the North Atlantic coast of Morocco reveals the identification of different habitats and new species. It contributes to Strengthen Science for Conservation and Sustainable Management of Deep-Water Corals in Morocco.
近年来，世界各地深海栖息地的健康状况不断下降，这使得记录和绘制其分布情况以在海洋生态系统中加以保护变得十分必要。这项工作基于九条遥控潜水器（ROV）视频样带，描述了深水珊瑚栖息地（深度为133 - 729米）及其相关群落。这些样带覆盖了摩洛哥北大西洋沿岸一个预先定义的5560平方千米区域内171千米的海底剖面，该区域于2020年进行了调查，是粮农组织 - 南森计划下珊瑚栖息地测绘研究的一部分。最初使用多波束回声测深仪对这九个地点进行探测，以生成详细的测深图，从而确定视频样带的位置。沿着样带记录了大型动物和沉积物成分，总共标注了1854个个体，并识别出59个分类单元。为了识别珊瑚群落和相关物种组合，我们使用聚类分析进行分类，并使用去趋势对应分析（DCA）排序分析来确定群落模式背后的环境驱动因素。将八个环境变量与DCA排序结果进行比较，重要变量为基岩、泥和深度。结果揭示了六个大型底栖生物群落。三个群落与软质沉积物有关，主要是泥。第一组位于605 - 726米深处，以海葵目和考氏长蛇鳗为特征。第五组位于133米深处，以海葵目为主。第六组由刺冠海星属物种和一个鱼类群落（鲉科、日本角鲨、长鳍鱼属）组成，位于201米深处。在以泥为主要基质的混合海底，第二组在207 - 369米深度范围内以海百合纲和海笔（四方柳珊瑚和奇异拟柳珊瑚）为特征，而第三组位于465 - 602米深处，以海笔（磷海鳃和四方柳珊瑚）、海百合纲以及关键物种长形艾氏柳珊瑚为特征。第四组位于207米深处，以小枝珊瑚属物种和副叉状埃氏珊瑚为优势物种。这项关于摩洛哥北大西洋沿岸深海珊瑚栖息地测绘的首次研究揭示了不同栖息地和新物种的识别情况。它有助于加强摩洛哥深水珊瑚保护与可持续管理的科学研究。
