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| Titel |
Quantification of a rock platform bioerosion by the sea urchin Paracentrotus lividus (Lamarck, 1816): the Basque Coast case (Bay of Biscay). |
| VerfasserIn |
Vincent Regard, Marie-Noëlle de Casamjor, Grégoire M. Maillet, Melody Prémaillon, Nathalie Caill-Milly |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143914
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| Publikation (Nr.) |
 EGU/EGU2017-7682.pdf |
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| Zusammenfassung |
| The French Basque Coast is an actively eroding rocky coast. In the study area it is made of
flysch with a circa 40 degrees-dip; it is exposed to an average significant wave height of 1.8 m
and peak period of 9.6 s. It is mesotidal (spring tide of ∼4m). The current rocky shore
platform is carved into the flysch layering. We focus on sea urchin Paracentrotus lividus
contribution to rock shore erosion. Indeed, this sea urchin has a burrowing behaviour.
An ecological study has been conducted for stock assessment, from shore to 10
m-deep. It indicates that sea urchins are burying their own shelter and are not reusing
former ones. Below the depth of 10 m, sea urchins densities are very low and burial
behavior is considered insignificant. Estimates of sea urchin density, and biomass are
provided, making possible to evaluate the average erosion rate along this coast due
to burying. It is of the order of 0.17 mm/y between 0 and 3 m below sea level,
∼0.05 mm/y between 3 and 5 m-deep, ∼0.02 mm/y between 5 and 8 m below
sea level, and finally drops to negligible under 8 meters below sea-level. Close
to the 0 level, it is thus between 30 and 5% of the expected value (evaluated to
be 0.5-3 mm/y after 5-10 cm/y cliff retreat rate and a 1-2 degrees platform dip).
The overall sea urchin contribution to shore platform erosion is not negligible. |
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