Gazul is the shallowest mud volcano (MV) within the Shallow Field of Fluid Expulsion (SFFE) of the northeastern Gulf of Cádiz (NE Atlantic; 300–1200 m depth). The SFFE represents an important geo- and biodiversity area that was designated as a Site of Community Importance under the European Habitats Directive in 2014. In this study, geological features, habitats and associated biodiversity, as well as anthropogenic impacts, were characterized at Gazul MV from underwater imagery and multibeam bathymetry. Multivariate methods using the Bray-Curtis similarity index identified six main habitats, each of which harbored a characteristic faunal assemblage that included: (1) sandy ripple bottoms typified by the actiniarian Actinauge richardi; (2) sandy, muddy, coarse sand and bioclastic bottoms dominated by the solitary coral Flabellum chunii; (3) coarse sand and bioclastic bottoms, together with soft sediments covered by scattered methane-derived authigenic carbonates (MDACs) (mixed bottoms), characterized by the echinoid Cidaris cidaris; (4) hard bottoms comprising MDACs dominated by a wide variety of sponges and gorgonians; (5) coral-rubble bottoms typified by the presence of colonial scleractinian communities dominated by Madrepora oculata; and (6) mixed bottoms characterized by the presence of a styelid ascidian. Slope and water depth were the main factors explaining assemblages’ distribution, which was also supported by the presence of MDACs such as slabs, crusts and chimneys on the seafloor, as well as by the geomorphologic diversity of Gazul MV. The results highlight Gazul MV as an eco-biologically important area harboring different vulnerable marine ecosystem (VME) elements with indicator taxa such as scleractinians, sponges, gorgonians and black corals. ROV images revealed abandoned or lost fishing gears and marine debris on the seafloor, indicating anthropogenic impacts in Gazul MV and adjacent areas. Indeed trawling fisheries activities have also been detected in Vessel Monitoring System datasets. A fishery restricted area is recommended in Gazul MV due to the occurrence of diverse VMEs and species included in different conservation directives and conventions.

Gazul是加的斯东北海湾（NE大西洋；深度300-1200 m）的浅层流体驱替浅层（SFFE）内最浅的泥火山。SFFE代表着重要的地理和生物多样性地区，根据欧洲人居指令于2014年被指定为社区重要场所。在这项研究中，Gazul MV表征了地质特征，栖息地和相关生物多样性以及人为影响来自水下图像和多波束测深法。使用Bray-Curtis相似性指数的多变量方法确定了六个主要生境，每个生境都具有特征性的动物群落，其中包括：（1）以猕猴桃Actinauge richardi为代表的沙质波纹底部; （2）砂质，泥质，粗砂和生物碎屑性底部，以孤立的珊瑚Flabellum chunii为主；（3）粗砂和生物碎屑底，以及由甲烷衍生的自生碳酸盐（MDACs）（混合底）覆盖的软沉积物，其特征为棘突类C虫；（4）由MDAC组成的硬底，其中MDAC的种类繁多，由各种海绵和高粱组成；（5）珊瑚瓦砾塔底为代表的由主导殖民社区礁石的存在Madrepora藻; （6）混合的残渣，其特征在于存在一个苯甲类海藻。坡度和水深是解释组合物分布的主要因素，海底平板，地壳和烟囱等MDAC的存在以及Gazul MV的地貌多样性也支持了组合物的分布。结果突出表明，Gazul MV是一个生态生物学重要地区，拥有不同的脆弱海洋生态系统（VME）要素，并带有指示分类群，例如巩膜菌，海绵，石和黑珊瑚。ROV图像显示海底遗弃或丢失的渔具和海洋垃圾，表明人为影响了Gazul MV及其附近地区。实际上，在船只监测系统数据集中也发现了拖网捕捞活动。