4th International Submarine Canyon Symposium (INCISE2018)

5-7 November 2018, Shenzhen, CHINA

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This is the detail of The unknown role of submarine canyons – Linking habitat and faunal patterns to organic matter cycling in Whittard Canyon.

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Author
Sofia Ledin
Co-Author(s)
Gerard Duineveld, Marc Lavaleye, Gert-Jan Reichart, Furu Mienis
Abstarct Title
The unknown role of submarine canyons – Linking habitat and faunal patterns to organic matter cycling in Whittard Canyon.
Abstarct Body
Submarine canyons are regarded as major conduits for particle and organic matter (OM) transport from the continental shelf to the food deprived deep sea. The heterogeneous topography in canyon systems interacts with the hydrography, generating distinctive currents and numerous varieties of habitats. The Whittard Canyon system (Celtic Margin, NE Atlantic) was visited during cruises in 2017 and 2018 with R/V Pelagia. In this canyon complex hydrodynamics and related particle transport are mainly steered by internal tides. Habitat and macrofaunal distributions were mapped to study their link with the abiotic environment and OM availability. For this purpose, tethered video and image transects were made in the most eastern branch of Whittard Canyon. Intervals (10m per 50m) were analysed by applying distance and depth as factors, where all visible fauna, substrate variations and particle densities were noted. Habitat variation was furthermore linked to abiotic factors like temperature, salinity and oxygen, which were logged simultaneously, and sedimentary organic carbon content as derived from bottom samples. Preliminary results indicate a varied faunal assemblage along the canyon transects. Substrate changed rapidly in canyon transects both with distance and depth. Shallower depths of 250-500m with coarse substrate are characterised by crustaceans, while in soft sediment at depths near 1000m Pennatulacean, Porifera and Echinodermata are primarily observed. Octocorals were very abundant on hard substrate at depths below 1000m. The eastern and western canyon walls each displayed a different faunal assemblage. Lower abundance and species variation are observed on the western canyon wall in contrast to the eastern wall at comparable depths. Through linking habitat variation with faunal patterns, we can explore their potential use as proxies for OM availability and mineralization in canyon systems. In the near future we aim to utilize interdisciplinary methods to obtain a more comprehensive understanding of Whittard Canyons faunal and habitat variations, by integrating microbial data, eDNA and abiotic factors.
INCISE Theme
Session 3: Patterns and heterogeneity in submarine canyons
Presentation Type
Oral Presentation
Keywords
Submarine canyons, Habitat heterogeneity, Faunal patterns, Organic Matter cycling, Whittard Canyon

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