A local scale analysis of manganese nodules influence on the Clarion-Clipperton Fracture Zone macrobenthos.

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Publisher: Elsevier B.V.
Document Type: Article
Length: 410 words

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Highlights * GSR B4S03 nodule-rich and nodule-free stations are characterized by similar sedimentary parameters. * The nodule-rich stations showed comparable macrofauna densities but higher-taxon diversity to that of the nodule-free station. * The sampling effort was insufficient to characterize the dominant taxa's diversity at morphospecies level. * When the family level is considered 90% of the diversity was sampled during this study. * The high number of singletons, the patchiness and low densities may lead to an underestimation of species diversity. * The high number of singletons, the patchiness and low densities may lead to an overestimation of endemism. Abstract The present investigation focuses on the Global Sea Mineral Resources contract area B4S03 site in the Clarion-Clipperton Fracture Zone nodule fields. We investigated the sedimentary characteristics and the higher-taxon (order/class) and lower-taxon (family, morphospecies) diversity of the soft sediment macrobenthos with special focus on the dominant taxa (Isopoda, Polychaeta, Tanaidacea) in relation to nodule abundance. Across all analyses no consistent and/or significant differences between the two nodule-rich and the nodule free stations were found in terms of abiotic or biotic factors, suggesting that both habitat-types have similar sedimentary conditions and that macrofauna is represented by comparable densities and higher-taxon diversity across stations. Rarefaction/accumulation curves and sample coverage analysis shows that the current sampling effort was insufficient to characterize the B4S03 site diversity at morphospecies level but covered 90% of the diversity at the family level for the three dominant taxa. The high number of singletons encountered, the patchiness and low densities of the investigated taxa coupled to the logistically limited potential for replication per habitat/station, may point to under-sampling bias of the current study with the risk to underestimate species diversity and overestimate endemism. We recommend a more extensive sampling with the combination of molecular tools coupled with taxonomical expertise. Author Affiliation: (a) Marine Biology Laboratory, Ghent University, Ghent, Belgium (b) Flanders Marine Institute, Oostende, Belgium (c) Department of Invertebrate Zoology and Hydrobiology, University of Lodz, Lódz, Poland (d) Ifremer, Centre Bretagne, REM EEP, Laboratoire Environnement Profond, ZI de la Pointe du 5 Diable, CS 10070, F-29280, Plouzan, France (e) Biocenter Grindel & Zoological Museum, University of Hamburg, Hamburg, Germany * Corresponding author. Article History: Received 30 March 2020; Revised 9 November 2020; Accepted 15 November 2020 Byline: Pasotti Francesca [francesca.pasotti@ugent.be] (a,*), Lisa Mevenkamp (a), Ellen Pape (a), Magdalena Blazewicz (c), Paulo Bonifácio (d), Torben Riehl (e), Bart De Smet (b), Nene Lefaible (a), Lidia Lins (a), Ann Vanreusel (a)

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Gale Document Number: GALE|A649421100