GEOSCAN, résultats de la recherche


TitreProcess-driven characterization and mapping of seabed habitats within the Basque continental shelf (Bay of Biscay)
AuteurGalparsoro, I; Borja, A; Kostylev, V; Legorburu, I; Rodríguez, G; Muxika, I; Pedro, L; Pascual, M; Todd, B J
SourceEos, Transactions of the American Geophysical Union vol. 91, no. 26, 2010 p. 1
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20090337
Réunion2010 Ocean Sciences Meeting; Portland, Oregon; US; février 22-26, 2010
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetstechniques de cartographie; topographie du fond océanique; topographie du fond océanique; benthos; peuplements biologiques; biote; géologie marine
ProgrammeÉnergie renouvelable offshore, Géoscience en mer
Résumé(disponible en anglais seulement)
The process-driven benthic habitat mapping approach (Kostylev et al. 2005, Kostylev and Hannah 2007) is based on ecological theory that relates species life history traits to the properties of the environment, transforming maps of the physical environment into a map of benthic habitat types. The habitat template for benthic habitat mapping aggregates sets of environmental factors into two axis: (i) the 'Disturbance' axis, which reflects the intensity of habitat alteration or destruction, and is calculated as the sediment remobilisation; and (ii) the 'Scope for Growth' (SfG) axis, which describes the amount of energy available for growth and reproduction after adjusting the available food supply by environmental stressors that pose a cost for physiological functioning of organisms. This axis is calculated based on food availability (derived from the chlorophyll concentration on the seafloor), annual bottom temperature, temperature variability, and oxygen saturation. Each environmental parameter was interpolated and mapped at 5 m horizontal resolution. Disturbance and SfG layers were calculated from them in ArcGIS. We used 1,400 benthic samples in the analysis of relationship between distribution of fauna and habitat properties. Bray-Curtis similarity between samples was calculated and samples were grouped into 17 statistically significant classes. The rationale behind this approach is based on the supposition that if the species composition of two samples is similar it is likely that these samples come from similar habitats. BIOENV analysis showed that the most significant environmental variables affecting community composition were the annual temperature range and the sediment remobilisation, which are related to the SfG and Disturbance. Some of these groups were associated with low disturbance and high productivity zones such as harbour areas with high organic matter content sediments; high disturbance and low productivity classes were associated with shallow water areas affected by waves; and other groups were related to human modified habitats such as dumping sites and waste water discharge areas. In terms of the structural factors, the best response was obtained for diversity and richness of benthic communities with sediment remobilisation. The resulting habitat map for the Basque coast shows a continuum of environments where the gradients arise naturally from the data layers. In addition, the method reduces multiple environmental variables to the major selective forces responsible for defining the life history traits of species and as shown in this study - types of benthic communities. Moreover, mapping the combination of SfG and Disturbance allows estimation of the potential scale of impacts of different types of human activities on seabed habitats, and their recovery capacity.