Institut de Ciències del Mar, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
Institut de Ciències del Mar, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
Sci Total Environ. 2024 Feb 20;912:168752. doi: 10.1016/j.scitotenv.2023.168752. Epub 2023 Nov 21.
Maërl habitats are composed of coralline red algae species that can live freely rolling on the seabed and forming nodules, the so-called rhodoliths, or incrusted forming coralligenous habitats. Maërl habitats are generally distributed in the Mediterranean at a depth of between 30 m and 70 m and are considered one of the most emblematic Mediterranean seabeds. In the present study, the complex structure of maërl habitats was investigated to i) characterise the relief features and classify the different sediments, ii) to estimate the abundance of the coralline red algae (both rhodoliths and encrusting ones) and iii) to analyse the biodiversity of the species inhabiting the habitat. Data were obtained from an approximately 11 km-long transect, using non-intrusive sampling methods, integrating information from video images collected using the Remotely Operated Vehicle LIROPUS (IEO_CSIC), and multibeam bathymetry and backscatter data. Video images were used to reconstruct (using GIS) the habitat structure and characteristics. Throughout the transect, a strong relationship between habitat characteristics and the effect of trawling activity and the geomorphology of the studied area was observed. The closed area to fishing activity showed a high abundance of rhodoliths in well-structured megaripples reliefs. Contrarily, the areas affected by fishing showed an important destructuring of the relief with a low density of rhodoliths. Last, the muddy bottoms showed areas with no characteristic features and no rhodoliths. All this information has allowed to reconstruct the maërl habitat in the Blanes continental shelf (NW Mediterranean) and analyse the fragmentation of the assemblages seen in the video to assess its good environmental status (GES), and finally to identify the level of ecological integrity of this vulnerable habitat.
柳珊瑚生境由能够在海底自由滚动并形成结核的珊瑚藻物种组成，这些结核被称为石珊瑚，或附着形成珊瑚礁生境。柳珊瑚生境一般分布在地中海，水深 30-70 米之间，被认为是最具代表性的地中海海底之一。在本研究中，对柳珊瑚生境的复杂结构进行了调查，以 i）描述地貌特征并对不同沉积物进行分类，ii）估计珊瑚藻（石珊瑚和附着珊瑚）的丰度，iii）分析栖息在生境中的物种的生物多样性。数据来自一条约 11 公里长的横切，使用非侵入性采样方法，结合使用 IEO_CSIC 的遥控潜水器 LIROPUS 采集的视频图像信息，以及多波束水深和反向散射数据。视频图像用于使用 GIS 重建生境结构和特征。在整个横切中，观察到生境特征与拖网活动的影响以及研究区域的地貌之间存在很强的关系。禁止捕捞活动的封闭区域显示出结构良好的巨纹层状地貌中石珊瑚的高丰度。相反，受捕捞影响的区域 Relief 严重破坏，石珊瑚密度低。最后，泥泞的底部显示出没有特征和石珊瑚的区域。所有这些信息都使我们能够重建布兰卡斯大陆架（西北地中海）的柳珊瑚生境，并分析视频中看到的集合体的破碎化，以评估其良好的环境状况（GES），并最终确定这种脆弱生境的生态完整性水平。
