From 1 - 10 / 19
  • An important task undertaken this year was to define sub-regional areas of the ICES greater North Sea eco-region. The sub-regional areas correspond to meaningful eco-logical units whose boundaries are defined by strong gradients in their physical oceanography, such as changes in depth, sediment transport, salinity, oxygen and currents. The four sub-regions of the ICES greater North Sea eco-region are; i. North-ern North Sea, ii. Southern North Sea, iii. Skagerrak and Kattegat, and iv. English Channel

  • Cartography of benthic communities to promoting adequate strategies for the use, management and conservation of littoral areas depending on the ecological value of the different benthic communities established and on the local geographical distribution.

  • Mapis based on the interpretation of various types of data from a number of surveys carried out between 2011-2012 both in the intertidal and subtidal zones. Additionally the seabed « Carte G » from the French hydrographic survey (SHOM) was used in the interpretation process. In the tidal zone the identification was made by interpreting coastal ortho-photographs from BD Ortho (2005 et 2009) and digitising them on scale 1 : 2000ème with further qualification of the polygons based on ground truth data. For the subtidal zone, several data sources from 2011 were available: bathymetric lidar (with sounding density about 1pt*3m-2), side scan sonar (resolution of about 0.2m), underwater video, sediment and fauna samples collected with grabs and trawls. Addtionnally a single beam sounder was running at all times during the transects, which contributing to improve the depth DTM. In the outer rocky circalittoral zone, side scan sonar corridors were surveyed with a coverage of 30-50% depending on places. In the offshore deep circalittoral zone (known as La Grande vasière) where soft sediment is predominant, side scan sonar coverage was reduced to about 5-10%. In these latter two circalittoral zones, interpolation between sonar corridors was supported by SHOM « Carte G » (approx. scale 1:100000) along with a 100m resolution depth DTM. On rocky seabed, exposure at the seabed was described using kinetic energy from a combination of wave and current hydrodynamic models according to the methods described in: http://doi.org/10.13155/49975. Rocky substrate in intertidal and infralittoral zones was derived from the combined interpretation of both the topographic and bathymetric Lidar DTMs and aerial photographs, where permitted by water transparency. Various representations of the DTMs (slope, hillshade) helped delineate rocky outcrops with good reliability. Biological qualification of the substrate polygons was made through taxonomic analysis of benthos samples collected by MNHN in the framework of the project"Ecological assessment of Natura 2000 site - Roches de Penmarc’h".The final habitat classification was a synthesis of the main habitat classifications, namely: Generic habitats from the Habitat Directive (EUR 27), Elementary habitats from the French Cahiers d’habitats, The Rebent classificationand EUNIS level 4 as much as possible.

  • JNCC requested that BGS carry out geostatistical analysis of sediment sample data from the CEND 8/12 survey of Swallow Sand MCZ and CEND 6/13 survey of South-west Deeps (West) MCZ in order to produce maps of sediment distribution in the sites. For each of the MCZ a geostatistical analysis of the data is reported leading to the selection of a robust linear model of corregionalization for the composition of the sediment, based on the additive log-ratio transformation of data on mud, sand and gravel content. This model is then used for spatial prediction on a 250-m grid. At each grid node a prediction distribution is obtained, conditional on neighbouring data and the selected model. By sampling from this distribution, and back-transforming onto the original compositional simplex of the data, we obtain a conditional expectation for the proportions of sand, gravel and mud at each location, a 95% confidence interval for the value at each node, and the probability that each of the four sediment texture classes that underly the EUNIS habitat classification is found at the node.

  • Predicted distribution of Annex 1 Reef habitat using data from SEA 6 survey data from S/V Kommander Jack Irish Sea survey 2004, Legs 2 qnd 3. Geophysical acoustic data and groundtruthing by photos and video was used for analysis.

  • Details the merged substrate maps produced within the proposed Skerries and Causeway Proposed Marine SAC.

  • JNCC requested that BGS carry out geostatistical analysis of sediment sample data from the CEND 8/12 survey of Swallow Sand MCZ and CEND 6/13 survey of South-west Deeps (West) MCZ in order to produce maps of sediment distribution in the sites. For each of the MCZ a geostatistical analysis of the data is reported leading to the selection of a robust linear model of corregionalization for the composition of the sediment, based on the additive log-ratio transformation of data on mud, sand and gravel content. This model is then used for spatial prediction on a 250-m grid. At each grid node a prediction distribution is obtained, conditional on neighbouring data and the selected model. By sampling from this distribution, and back-transforming onto the original compositional simplex of the data, we obtain a conditional expectation for the proportions of sand, gravel and mud at each location, a 95% confidence interval for the value at each node, and the probability that each of the four sediment texture classes that underly the EUNIS habitat classification is found at the node.

  • A geostatistical analysis of the data is reported leading to the selection of a linear model of corregionalization for the composition of the sediment, based on the additive log-ratio transformation of data on mud, sand and gravel content. This model is then used for spatial prediction on a 250-m grid. At each grid node a prediction distribution is obtained, conditional on neighbouring data and the selected model. By sampling from this distribution, and backtransforming onto the original compositional simplex of the data, we obtain a conditional expectation for the proportions of sand, gravel and mud at each location, a 95% confidence interval for the value at each node, and the probability that each of the four sediment texture classes that underlie the EUNIS habitat classification is found at the node.

  • This map covers both the intertidal zone and subtidal zones of the study sites. It is made from high resolution remote sensing data - both acoustic and optical - from various surveys carried out over the period 2008 to 2013 of various types: (i) multibeam echosounder (MBES), side scan sonar (SSS), RoxAnn acoustic ground discrimination system (AGDS), (ii) ortho-photography (the “Ortholittorale survey” from 2000), (iii) topographic and bathymetric lidar . It was complemented by (i) underwater video,(ii) sediment and biological grab samples, (iii) ground truth data from surveys in the tidal and infralittoral zone using GPS, annotations and photography.The habitat classification was a synthesis of the main habitat classifications, namely:Generic habitats from the Habitat Directive (EUR 27), Elementary habitats from the French Cahiers d’habitats, The Rebent classificationand EUNIS level 4 as much as possible. Map scale is in the range of 1:20000, with local improvements to 1:10000.

  • Marine Scotland Science surveyed 260 km2 of coastline west of the Isle of Lewis using swath bathymetry and drop frame TV camera and video. The bathymetry, backscatter data and ground truthing were used to interpret habitat maps of the seabed.