Cystoseira baccata meadows along the French Basque coast (Bay of Biscay) as a reference for the implementation of the Water Framework and Marine Strategy EU directives

Abstract

Cystoseira baccata, a biological quality element for the implementation of the Water Framework and Marine Strategy EU Directives, is a dominant species in the subtidal rocky bottoms of the Basque coast. As part of this issue and given the need to better understand the functional character of benthic rocky ecosystems and use them as a reference to anthropogenic changes, two samplings campaigns were conducted in 2014 and 2017. Several population parameters (i.e. frond density, frond length frondlength/total frond-length ratio and taxonomic richness of epibionts) of C. baccata were studied from three sites monitored within the Water Directive Framework in relation to bathymetry during the two campaigns. The results showed a significant influence of bathymetry on frond density, frond length and the epibiotic load, and also an effect of sampling time for the seaweed and epibionts (epiflora and epifauna). The characterization of these functional population parameters for C. baccata under natural conditions are extremely valuable for its application to monitoring programs evaluating the ecological status of coastal waters in this region. Highlights ► Contribution of new knowledge on C. baccata habitat and population. ► Confirmation of interest of this engineering species in implementation MSFD. ► Swell effect influencing density and individual height. ► Ratio of length is pertinent metric to discriminate epibiosis considering levels.

The Red Seaweed Giant Gelidium (Gelidium corneum) for New Bio-Based Materials in a Circular Economy Framework

“…In Europe, G. corneum forms widespread beds, usually subtidal zones up to about 25 meters in depth. As to the substrate, the species prefers growing on slightly sloping regular bedrock, with little to moderate sand sedimentation [77,92]. In these temperate waters, Gelidium species reach high abundances and frequencies.…”

“…G. corneum is harvested in Portugal, Spain, France, and Morocco, G. amansii and G. latifolium in Japan, Taiwan, Korea, and Indonesia, and G. robustum in Mexico. Smaller quantities of G. lingulatum, G. chilense, and G. rex are harvested in Chile, whereas G. pristoides, G. abbottiorum G. pteridifolium, G. capense are harvested in China, Namibia, and South Africa [46,92,108,109]. The biomass may be gathered from beach-cast seaweeds, using nets or rakes, a method common in countries such as South Africa, Australia, and New Zealand [110].…”

Epiphytic algal flora associated with habitat-forming brown seaweed in a central Mediterranean coastal area (Conero Riviera, Adriatic Sea): diversity and relationship with environmental variables

“…Rocky coastal habitats are typically colonized by numerous sessile organisms, including large canopy-forming seaweeds. These organisms are often constructors of biocenoses and enhance biodiversity thanks to their tridimensionality (Sales & Ballesteros, 2009;Casamajor et al, 2019).…”

“…Assessments of the epibiota associated with Cystoseira s.l. have mainly focused on the macroepiphytic communities (Ballesteros, 1988;Lluch & Garreta, 1989;Morales-Ayala & Viera-Rodríguez, 1989;Arrontes, 1990;Ballesteros, 1990aBallesteros, , 1990bOtero-Schmitt & Sanjuan, 1992;Otero-Schmitt & Pérez-Cirera, 1996;Belegratis et al, 1999;Simakova, 2009;Sales et al, 2012;Mačic & Svirčev, 2014;Piazzi et al, 2018;Casamajor et al, 2019;Kozak et al, 2020;Prazukin et al, 2020;Afanasyev & Akatov, 2021). Additional investigations of the epiflora associated with Cystoseira assemblages, including a detailed assessment of the epiphytic microphytobenthos, would be of great relevance in environmental monitoring programs since fast shifts in the epiphytic composition can be caused by a deterioration of the physiological state of the host due to external stressors (Karez et al, 2004;Casamajor et al, 2019).…”