and antipatharians (e.g. Leiopathes glaberrima) in Annex 2 of the Barcelona Convention, and they have been incorporated into the Spanish List of Wildlife Species in
Special Protection Regime.
9.7.2 Bathyal Soft Bottoms
Soft bottoms are the most widespread habitats in the bathyal stage of the Alboran Sea
and elsewhere, the sediments originating either from deposition of planktonic
organisms or from sediment mobilization from the shelf to the slope or along the
slope due to the contouritic transport (Emig 1997; Muñoz et al. 2008; Cartes et al.
2004; Templado et al. 2012). These sediments can be of different textures (from
bioclastic gravel to clay), and they generally display a higher mud content in deep
areas with low hydrodynamism (Muñoz et al. 2008; Ciércoles et al. 2018). Although
these bathyal soft-bottom communities occur from the shelf break to the base of the
slope, most available information comes from the upper and middle slope (between
200 and 600 m depth) compared to the lower slope (Sibuet 1974; Salas 1996; García
Raso 1996; Abad et al. 2007; Hebbeln et al. 2009; Gofas et al. 2011, 2014b; Pardo
et al. 2011; de la Torriente et al. 2014, 2018; Ciércoles et al. 2018).
A prominent feature of the upper bathyal slope, often continued from the shelf
edge, is the local occurrence of coarse bioclastic sands and gravels in areas with
moderate to strong bottom currents that winnow the fine sediments (e.g. cold-water
coral rubble) (de la Torriente et al. 2014). The benthic fauna of these bottoms
includes some small solitary corals (Caryophyllia spp.) and actiniarians (Actinauge
richardi); small gorgonians (Bebryce mollis, Swiftia dubia); both sedentary (Serpula
vermicularis on bioclasts) and mobile (Hyalinoecia tubicola) polychaetes; the molluscs Limopsis aurita, Xenophora crispa, Fusiturris similis, Antalis panorma,
Bathyarca philippiana, B. pectunculoides, Astarte sulcata and Neomenia carinata;
the decapods Ebalia nux, Cymonomus granulatus; the crinoid Leptometra
phalangium; and the echinoid Cidaris cidaris, both of them also dominating sometimes hard bottoms (Salas 1996; García Raso 1996; Abad et al. 2007; Hebbeln et al.
2009; Gofas et al. 2011, 2014b; de la Torriente et al. 2014, 2018; Ciércoles et al.
2018; Moya-Urbano and Rueda pers. comm.). In some areas with dense aggregations of Leptometra phalangium (e.g. Djibouti Bank, Fig. 9.22), a high diversity of
molluscs has been registered with more than 150 species, including new records for
the Mediterranean Sea (e.g. Turbonilla vaillanti) and new species for science
(e.g. Melanella scarifata, Graphis pruinosa, Alexandromenia avempacensis)
(Gofas et al. 2014b; Pedrouzo et al. 2014). Suspension feeders seem to be dominant
in this type of community as a result of the moderate bottom currents that occur in
graves and coarse sand bottoms (Gofas et al. 2014b). Because of its exceptional
richness, both in numbers and in the quality of the species, this type of bathyal
community with Leptometra and Limopsis must be considered a high priority for
habitat conservation in the Mediterranean deep sea (Grinyó et al. 2020).
9 Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A. . .
339
Special Protection Regime.
9.7.2 Bathyal Soft Bottoms
Soft bottoms are the most widespread habitats in the bathyal stage of the Alboran Sea
and elsewhere, the sediments originating either from deposition of planktonic
organisms or from sediment mobilization from the shelf to the slope or along the
slope due to the contouritic transport (Emig 1997; Muñoz et al. 2008; Cartes et al.
2004; Templado et al. 2012). These sediments can be of different textures (from
bioclastic gravel to clay), and they generally display a higher mud content in deep
areas with low hydrodynamism (Muñoz et al. 2008; Ciércoles et al. 2018). Although
these bathyal soft-bottom communities occur from the shelf break to the base of the
slope, most available information comes from the upper and middle slope (between
200 and 600 m depth) compared to the lower slope (Sibuet 1974; Salas 1996; García
Raso 1996; Abad et al. 2007; Hebbeln et al. 2009; Gofas et al. 2011, 2014b; Pardo
et al. 2011; de la Torriente et al. 2014, 2018; Ciércoles et al. 2018).
A prominent feature of the upper bathyal slope, often continued from the shelf
edge, is the local occurrence of coarse bioclastic sands and gravels in areas with
moderate to strong bottom currents that winnow the fine sediments (e.g. cold-water
coral rubble) (de la Torriente et al. 2014). The benthic fauna of these bottoms
includes some small solitary corals (Caryophyllia spp.) and actiniarians (Actinauge
richardi); small gorgonians (Bebryce mollis, Swiftia dubia); both sedentary (Serpula
vermicularis on bioclasts) and mobile (Hyalinoecia tubicola) polychaetes; the molluscs Limopsis aurita, Xenophora crispa, Fusiturris similis, Antalis panorma,
Bathyarca philippiana, B. pectunculoides, Astarte sulcata and Neomenia carinata;
the decapods Ebalia nux, Cymonomus granulatus; the crinoid Leptometra
phalangium; and the echinoid Cidaris cidaris, both of them also dominating sometimes hard bottoms (Salas 1996; García Raso 1996; Abad et al. 2007; Hebbeln et al.
2009; Gofas et al. 2011, 2014b; de la Torriente et al. 2014, 2018; Ciércoles et al.
2018; Moya-Urbano and Rueda pers. comm.). In some areas with dense aggregations of Leptometra phalangium (e.g. Djibouti Bank, Fig. 9.22), a high diversity of
molluscs has been registered with more than 150 species, including new records for
the Mediterranean Sea (e.g. Turbonilla vaillanti) and new species for science
(e.g. Melanella scarifata, Graphis pruinosa, Alexandromenia avempacensis)
(Gofas et al. 2014b; Pedrouzo et al. 2014). Suspension feeders seem to be dominant
in this type of community as a result of the moderate bottom currents that occur in
graves and coarse sand bottoms (Gofas et al. 2014b). Because of its exceptional
richness, both in numbers and in the quality of the species, this type of bathyal
community with Leptometra and Limopsis must be considered a high priority for
habitat conservation in the Mediterranean deep sea (Grinyó et al. 2020).
9 Benthic Fauna of Littoral and Deep-Sea Habitats of the Alboran Sea: A. . .
339