Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea

H. Van Haren, I. Taupier-Letage, J. A. Aguilar, A. Albert, M. Anghinolfi, G. Anton, S. Anvar, M. Ardid, A. C. Assis Jesus, T. Astraatmadja, J. J. Aubert, R. Auer, B. Baret, S. Basa, M. Bazzotti, V. Bertin, S. Biagi, C. Bigongiari, M. Bou-Cabo, M. C. BouwhuisA. Brown, J. Brunner, J. Busto, F. Camarena, A. Capone, G. Carminati, J. Carr, D. Castel, E. Castorina, V. Cavasinni, S. Cecchini, P. Charvis, T. Chiarusi, M. Circella, R. Coniglione, H. Costantini, N. Cottini, P. Coyle, C. Curtil, G. De Bonis, M. P. Decowski, I. Dekeyser, A. Deschamps, C. Distefano, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, U. Emanuele, J. P. Ernenwein, S. Escoffier, F. Fehr, V. Flaminio, K. Fratini, U. Fritsch, J. L. Fuda, G. Giacomelli, J. P. Gómez-González, K. Graf, G. Guillard, G. Halladjian, G. Hallewell, A. J. Heijboer, Y. Hello, J. J. Hernández-Rey, J. Hößl, M. de Jong, N. Kalantar-Nayestanaki, O. Kalekin, A. Kappes, U. Katz, P. Kooijman, C. Kopper, A. Kouchner, W. Kretschmer, R. Lahmann, P. Lamare, G. Lambard, G. Larosa, H. Laschinsky, D. Lefèvre, G. Lelaizant, G. Lim, D. Lo Presti, H. Loehner, S. Loucatos, F. Lucarelli, K. Lyons, S. Mangano, M. Marcelin, A. Margiotta, J. A. Martinez-Mora, G. Maurin, A. Mazure, M. Melissas, T. Montaruli, M. Morganti, L. Moscoso, H. Motz, C. Naumann, M. Neff, R. Ostasch, G. Palioselitis, G. E. Pâvâlaş, P. Payre, J. Petrovic, P. Piattelli, N. Picot-Clemente, C. Picq, R. Pillet, V. Popa, T. Pradier, E. Presani, C. Racca, A. Radu, C. Reed, G. Riccobene, C. Richardt, M. Rujoiu, G. V. Russo, F. Salesa, F. Schoeck, J. P. Schuller, R. Shanidze, F. Simeone, M. Spurio, J. J.M. Steijger, T. Stolarczyk, C. Tamburini, L. Tasca, S. Toscano, B. Vallage, V. Van Elewyck, M. Vecchi, P. Vernin, G. Wijnker, E. de Wolf, H. Yepes, D. Zaborov, J. D. Zornoza, J. Zúñiga

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15 Citations (Scopus)

Abstract

An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170m above the sea bed at 2475m. The ADCP measured downward vertical currents of magnitudes up to 0.03ms-1 in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35ms-1. These observations coincided with high light levels detected by the telescope, interpreted as increased bioluminescence. During winter 2006 deep dense-water formation occurred in the Ligurian subbasin, thus providing a possible explanation for these observations. However, the 10-20 days quasi-periodic episodes of high levels of acoustic reflection, light and large vertical currents continuing into the summer are not direct evidence of this process. It is hypothesized that the main process allowing for suspended material to be moved vertically later in the year is local advection, linked with topographic boundary current instabilities along the rim of the 'Northern Current'.

Original languageEnglish
Pages (from-to)875-884
Number of pages10
JournalDeep-Sea Research Part I: Oceanographic Research Papers
Volume58
Issue number8
DOIs
Publication statusPublished - 2011 Aug

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Keywords

  • ANTARES neutrino telescope
  • Acoustic ADCP observations
  • Bioluminescence
  • Deep Mediteranean
  • Dense water formation
  • Episodic downward current
  • Northern boundary current
  • Optical photo-multiplier observations

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science

Cite this

Van Haren, H., Taupier-Letage, I., Aguilar, J. A., Albert, A., Anghinolfi, M., Anton, G., Anvar, S., Ardid, M., Assis Jesus, A. C., Astraatmadja, T., Aubert, J. J., Auer, R., Baret, B., Basa, S., Bazzotti, M., Bertin, V., Biagi, S., Bigongiari, C., Bou-Cabo, M., ... Zúñiga, J. (2011). Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea. Deep-Sea Research Part I: Oceanographic Research Papers, 58(8), 875-884. https://doi.org/10.1016/j.dsr.2011.06.006