Padstow Bay and Surrounds BSH
Feature class depicting broadscale habitat features at The Padstow Bay and Surrounds MCZ. The map is a result of an integrated analysis of existing MBES full coverage of bathymetry and partial coverage of backscatter data from the Civil Hydrography Programme (CHP) and dedicated ground-truthing survey data, collected in 2013. Habitat classes observed at each ground-truthing station were used to inform a semi-automated process of map production using object-based image analysis (OBIA). The map shows the seabed at the site to be characterised largely by outcropping bedrock (ÔÇÿA3.2 Moderate energy infralittoral rockÔÇÖ and ÔÇÿA4.2 Moderate energy circalittoral rockÔÇÖ), with deposits of ÔÇÿA5.1 Subtidal coarse sedimentÔÇÖ in valleys and crevasses in the rock and flat areas of ÔÇÿA5.2 Subtidal sand ÔÇÿ, mainly closer to shore.
Simple
- Alternate title
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GB001333
- Date (Publication)
- 2018-04-26
- Date (Creation)
- 2014-02-13
- Citation identifier
- EMODnetSeabedHabitats / GB001333
- Point of contact
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Organisation name Individual name Electronic mail address Role DEFRA
open@defra.gsi open@defra.gsi.gov.uk
Owner Natural England
enquiries@naturalengland.org enquiries@naturalengland.org.uk
Custodian
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GEMET - INSPIRE themes, version 1.0
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Habitats and biotopes
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- Use limitation
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┬® DAERA. Data may be re-used under the terms of the Open Government Licence.
- Use limitation
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geossAttribution
- Access constraints
- Other restrictions
- Other constraints
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no limitation
- Spatial representation type
- Vector
- Denominator
- 4000
- Language
- English
- Topic category
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- Biota
- Oceans
- Begin date
- 2013-01-23
- End date
- 2013-04-03
- Reference system identifier
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EPSG
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WGS 84 (EPSG:4326)
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7.9
- Topology level
- Geometry only
- Distribution format
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Name Version ESRI Shapefile
1.0
- OnLine resource
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Protocol Linkage Name WWW:LINK-1.0-http--link
http://randd.defra.gov.uk/Document.aspx?Document=12850_PadstowBayandSurroundsMCZ_SummarySiteReport_V3.pdf Padstow Bay and Surrounds MCZ Post-survey Site Report
WWW:LINK-1.0-http--link
https://www.emodnet-seabedhabitats.eu/access-data/launch-map-viewer/?zoom=18¢er=-0.00005,0.00045&layerIds=501&baseLayerId=1&activeFilters=NobwRANghgngpgJwJIBMwC4CsAGAjAGjADMBLCAF0VQwBYB2Q0ixAGQHs2BrAVwAdUAzhmABdRmUoIAKnAAe5DGADiAIWx4AzFrABfEUA EMODnet Seabed Habitats Map Viewer
OGC:WMS
https://ows.emodnet-seabedhabitats.eu/geoserver/emodnet_view_maplibrary/wms? gb001333
OGC:WFS
https://ows.emodnet-seabedhabitats.eu/geoserver/emodnet_open_maplibrary/wfs? gb001333
WWW:LINK-1.0-http--link
https://files.emodnet-seabedhabitats.eu/data/EMODnetSBHsurvey_GB001333.zip EMODnet Seabed Habitats download
- Hierarchy level
- Dataset
Conformance result
- Date (Publication)
- 2009-12-15
- Explanation
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See the referenced specification
- Pass
- Yes
Conformance result
- Date (Publication)
- 2010-12-08
- Explanation
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See the referenced specification
- Pass
- Yes
- Statement
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The Padstow Bay and Surrounds MCZ overlaps with an area of existing Multibeam Echosounder (MBES) bathymetry and backscatter data acquired by the Maritime and Coastguard Agency (MCA) under the Civil Hydrography Programme (CHP). Consequently, no dedicated acoustic survey was carried out at the site. The MBES bathymetry covers most of the site. Backscatter is available from two survey blocks (Figure 2).
Ground-truth sampling for the site was planned using an existing bottom texture dataset created by the MCA based on their survey data. The bottom texture categories are not directly translatable to BSH, but the dataset enabled the placement of sampling stations equally on different bottom types The full array of stations, with the MCA interpretation of bottom texture, is illustrated below, in Figure 3.
Sampling equipment comprised a 0.1 m2 mini Hamon grab. On recovery, the grab was emptied into a large plastic bin and a representative sub-sample of sediment (approx. 0.5 litres) taken for Particle Size Analysis (PSA). The remaining sample was photographed and sieved over a 1 mm mesh sieve to collect the benthic fauna. Fauna were preserved in buffered 4% formaldehyde for later processing ashore. See the survey report for details of the sediment sampling methodology (Godsell 2013). Video footage and still images of the seabed were collected with an underwater camera system and sediment type determined by the use of grab samples. The camera images helped to characterise surficial sediments and associated epifaunal communities. The camera was mounted on a drop down frame with two high intensity LED strip lights and collected both video and still images. A reference scale was used in the video and still images. Set-up and operation followed the MESH ÔÇÿRecommended Operating Guidelines (ROG) for underwater video and photographic imaging techniquesÔÇÖ (Coggan et al., 2007). Video was recorded simultaneously to a Sony GV-HD700 DV tape and a computer hard drive. A video overlay was used to provide station metadata, time and GPS position (central reference point of the vessel) in the recorded video footage.
Camera tows lasted a minimum of 10 minutes, with the sledge towed at ca. 0.5 knots (ca. 0.25 m s ÔÇô1 ) across a 100 m diameter ÔÇÿbullringÔÇÖ centred on the sampling station. Still images were captured at regular 10ÔÇô15 m intervals and also opportunistically if specific features of interest were encountered. Video and still images were analysed Padstow Bay and Surrounds MCZ Post-survey Site Report 9 following an established protocol used by Cefas and the JNCC (Coggan and Howell 2005; JNCC, in prep.; see Annex 5). In all, 64 ground-truth stations were visited (Figure 3). Hamon grabs were successful at 27 stations and successful drop camera deployments were completed at all 64 stations. Station metadata are presented in Appendix 1. For further detail on ground-truth sample collection see the Padstow Bay and Surrounds rMCZ Survey Reports (Godsell, 2013; Ware, 2013).
All new maps and their derivatives have been based on a WGS84 datum. A new habitat map for the site was produced by analysing and interpreting the available acoustic data (as detailed above) and the ground-truth data collected during the dedicated survey of this site. To make use of the best available data, the habitat map was produced as a combination of three separate analyses of the existing acoustic data and the newly acquired ground-truthing data. A habitat map covering the whole area with MBES bathymetry coverage (Figure 2) was produced using only the bathymetry and its derivatives (Map 1). The CHP backscatter data was acquired during two surveys using different MBES systems on board different vessels and has therefore been treated as two separate datasets. Consequently, separate maps were produced for backscatter block 1 (Map 2) and block two (Map 3) including bathymetry, bathymetry derivatives and backscatter layers in the analysis. The three maps were combined to form the final habitat map by giving preference to the most accurate map where they overlapped.
To produce the updated habitat map, the segmentation objects in Maps 1, 2 and 3 were classified into ÔÇÿA3.2 Moderate energy infralittoral rockÔÇÖ, ÔÇÿA4.2 Moderate energy circalittoral rockÔÇÖ, ÔÇÿA5.1 Subtidal coarse sedimentÔÇÖ and ÔÇÿA5.2 Subtidal sandÔÇÖ according to the cut-off values identified in the three CI analysis for the appropriate variables. In Maps 2 and 3, patches of noise were clearly identifiable by their narrow rectangular shape, even spacing and much lower backscatter values from the surrounding objects. All objects identified as noise, were merged into their surrounding objects. The resulting final classified objects were exported into GIS, dissolved into continuous polygons and the map was simplified by reclassifying polygons smaller than 200 m2 into the surrounding habitat type. The three maps were merged into one map, with Maps 2 and 3 taking preference over Map 1 in areas of overlap.
Metadata
- File identifier
- d61365c0-ba62-4f81-a7d6-38c06d94115b XML
- Metadata language
- English
- Character set
- MD_CharacterSetCode_utf8
- Hierarchy level
- Dataset
- Date stamp
- 2020-01-15T12:07:48
- Metadata standard name
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ISO19115
- Metadata standard version
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2003/Cor.1:2006
- Metadata author
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Organisation name Individual name Electronic mail address Role JNCC
HabitatMapping@jncc.gov HabitatMapping@jncc.gov.uk
Point of contact