This dataset includes the findings from the seabed survey of the Braemar Pockmarks and Scanner Pockmark Sites of Community Importance (SCI), as defined in the European Commission Habitats Directive 92/43/EEC. The pockmark features present within both of the SCIs are a series of crater-like depressions on the seafloor, and can include the Directives Annex I habitat Submarine structures made by leaking gases. These structures consist of large blocks, pavements, slabs and smaller fragments of carbonate rock, including methane-derived authigenic carbonate (MDAC).
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Vector data is used to represent geographic data
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Denominator
50000
Language
English
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Reference System Information
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http://www.opengis.net/def/crs/EPSG/0/3857
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Statement
Full-coverage acoustic multibeam bathymetry and backscatter data were acquired during the survey. Areas of distinct acoustic signatures from multibeam data were delineated using the semi-automated eCognition software. Standard univariate and multivariate analyses on the taxa abundance data were performed to identify distinct faunal assemblages. Presence of the Annex I habitat Submarine structures made by leaking gases within the Braemar Pockmark SCI was suggested through observations of seabed structures on the video and still image data, and confirmed following laboratory analysis of carbonate samples (MDAC) collected in a number of grab samples. Sidescan sonar records also provided evidence of gas bubbles in the water column, which appeared to be venting from one of the pockmarks. The survey data was analysed and reported by Cefas, and the polygon dataset was then formatted by JNCC to meet the Data Exchange Format v4.1 required for EMODnet uploads in August 2023.