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Algal turf molluscan communities in the Strait of Gibraltar: effects of substrate instability

2016; Frontiers Media; Volume: 3; Linguagem: Inglês

10.3389/conf.fmars.2016.05.00151

2296-7745

Sánchez Candela, Gallardo Carmen, Salas Carmen, Serge Gofas,

Marine Bivalve and Aquaculture Studies

Event Abstract Back to Event Algal turf molluscan communities in the Strait of Gibraltar: effects of substrate instability Candela Sánchez1, Carmen Gallardo1*, Carmen Salas1 and Serge Gofas1 1 Universidad de Malaga, Biologia Animal, Spain Rock slabs in the intertidal zone are characterized by a clear differentiation between organisms living on the upper surface, exposed to sunlight, and those found on the lower surface in a sciaphilous enclave. In order to characterize each of those compartments we studied the molluscan taxocenosis as a representative element of the mobile fauna, and identified the species forming the algal turf on the upper side and the species of sponges mostly found on the lower, sciaphilous side. This study was carried out in the rocky intertidal zone of Isla de Tarifa (36º00.10’N - 05º36.47’), within the “Parque Natural del Estrecho” marine protected area. Square plots of 1600 cm2 (3 replicas) of algal turf growing on bedrock were sampled, and four rock slabs with an upper surface comprised between 440 and 3500 cm2 were sampled for upper surface, lower surface and the underlying sediment. The algae on the bedrock and the upper part of slabs are mostly turf-forming species among which the species Ellisolandia elongata, Jania rubens y Asparagopsis armata are prevalent. On the lower side of slabs, there are no algae and the substrate is covered by sessile invertebrates, mainly sponges but also colonial tunicates and cnidarians. Molluscs were represented by 4686 specimens belonging to 99 species. The highest species richness and highest abundance of specimens was found in the photophilous stratum, the dominant species being Nodulus spiralis, Rissoella opalina, Tricolia nordsiecki, Gibbula tingitana, Eatonina fulgida, Skeneopsis planorbis and Setia bruggeni among others. In the sciaphilous stratum, Bittium simplex, Gibberula philipii and Cardita calyculata were dominant species. There were significant differences between the community of the algal turf and that of the underpart of slabs, but the latter appears very heterogeneous, possibly due to the diversity of sessile species and to perturbations which affect the slabs. Regarding possible effect of perturbations, this study provides evidence that the size of slabs is critical for the structuration of the habitat. This structuration was extremely clear on the largest slab, which cannot be turned over by wave action, whereas on the smaller slabs, the communities were found increasingly homogenised and de-structured as slab size decreases. When turned upside down, slabs are liable to loose both the algal turf, smothered under the rock without the needed sunlight, and the sciaphilous species which cannot withstand exposure to sunlight during the diurnal low tide. A large part of the molluscan species are endemic to the Strait of Gibraltar (7 species, 418 specimens) or to a broader Ibero-Moroccan area (14 species, 913 specimens), which denotes the uniqueness on the intertidal benthic community of this area. Acknowledgements Ths work is part of M.Sc. degree project "Diversidad Biológica y Medio Ambiente", Universidad de Málaga, of the first author. Sampling in MPA "Parque Natural del Estrecho" with permission from Consejería de Medio Ambiente, Junta de Andalucía. Keywords: molluscs, Algal turf, Strait of Gibraltar, habitat differentiation, endemism Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016. Presentation Type: Poster Presentation Topic: 1. ECOLOGY, BIODIVERSITY AND VULNERABLE ECOSYSTEMS Citation: Sánchez C, Gallardo C, Salas C and Gofas S (2016). Algal turf molluscan communities in the Strait of Gibraltar: effects of substrate instability. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00151 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2016; Published Online: 03 Sep 2016. * Correspondence: Ms. Carmen Gallardo, Universidad de Malaga, Biologia Animal, Malaga, Malaga, 29071, Spain, gallardomartin.carmen@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Candela Sánchez Carmen Gallardo Carmen Salas Serge Gofas Google Candela Sánchez Carmen Gallardo Carmen Salas Serge Gofas Google Scholar Candela Sánchez Carmen Gallardo Carmen Salas Serge Gofas PubMed Candela Sánchez Carmen Gallardo Carmen Salas Serge Gofas Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.