Scientia Marina, Vol 80, No S1 (2016)

Fine-scale water mass variability inside a narrow submarine canyon (the Besòs Canyon) in the NW Mediterranean Sea


https://doi.org/10.3989/scimar.04322.05A

Jordi Solé
Institut de Ciències del Mar, CSIC , Spain

Mikhail Emelianov
P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences Nakhimovsky , Russian Federation

Alexander Ostrovskii
P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences Nakhimovsky , Russian Federation

Pere Puig
Institut de Ciències del Mar, CSIC , Spain

Emilio García-Ladona
Institut de Ciències del Mar, CSIC , Spain

Abstract


In this work we report short-term measurements of the thermohaline structure and velocity field inside a narrow submarine canyon by means of a yo-yo–like profiler. An Aqualog profiler was deployed inside the Besòs Canyon in the northwestern Mediterranean continental margin, providing a unique data set on the vertical evolution of water column characteristics with unprecedented fine-scale spatial and temporal resolution. The observations reported here show a very dynamic transient short-term response with a complex vertical structure not observed previously in any submarine canyon of this region. The vertical distribution of water masses was characteristic of the western Mediterranean basin with Atlantic waters (AW) at the surface, Western Intermediate waters (WIW) in the middle and Levantine Intermediate (LIW) waters below. Turner angle and empirical orthogonal functions show that double-diffusive and isopycnal mixing are the main dominant processes at small scales. The interfaces of the three layers exhibit highly vertical excursions in relatively short times. At the surface, deepening of AW was observed, associated with flow intensification events. Deeper in the water column, within the submarine canyon confinement, the WIW-LIW interface uplifts about 100-150 m. These motions are associated with relatively up- and down-canyon–enhanced current events (up to 15-20 cm s-1 at 500 and 800 m depths) along the canyon axis. The time scales of the vertical variability were concentrated in a broad band around the semi-diurnal and local inertial frequencies within the WIW and LIW layers.

Keywords


fine-scale variability; submarine canyon; yo-yo like profiler; thermohaline structure; AW; WIW; LIW

Full Text:


HTML PDF XML

References


Allen S.E., Durrieu de Madron X. 2009. A review of the role of submarine canyons in deep-ocean exchange with the shelf. Ocean Sci. 5: 607-620. http://dx.doi.org/10.5194/os-5-607-2009

Arnau, P.A. 2000. Aspectos de la variabilidad de mesoescala de la circulación marina en la plataforma continental catalana. Ph. D. Thesis, Universitat Politècnica de Catalunya.

Canals M., Company J.B., Martín D., et al. 2013. Integrated Study of Mediterranean Deep Canyons: Novel Results and Future Challenges. Progr. Oceanogr. 118: 1-27. http://dx.doi.org/10.1016/j.pocean.2013.09.004

Carlson D.F., Ostrovskii A.G., Kebkal K., et al. 2013. Moored automatic mobile profilers and their applications. In: Oen Gal (ed.), Advanced in Marine Robotics. LAP LAMBERT Academic Publishing. pp. 169-206. https://www.researchgate.net/publication/241279384_ Moored_automatic_mobile_profilers_and_their_applications

Crépon M., Wald L., Monget J.M. 1982. Low-frequency waves in the Ligurian Sea during December 1977. J. Geophys. Res. 87: 595-600. http://dx.doi.org/10.1029/JC087iC01p00595

Durrieu de Madron X. 1994. Hydrography and nepheloid structures in the Grand-Rhône Canyon. Cont. Shelf Res. 14: 457-477. http://dx.doi.org/10.1016/0278-4343(94)90098-1

Durrieu de Madron X., Radakovitch O., Heussner S., et al. 1999. Role of the climatological and current variability on shelf-slope exchanges of particulate matter: Evidence from the Rhone continental margin (NW Mediterranean). Deep-Sea Res. Part I 46: 1513-1538. http://dx.doi.org/10.1016/S0967-0637(99)00015-1

Flexas M.M., Boyer D.L., Espino M., et al. 2008. Circulation over a submarine canyon in the NW Mediterranean. J. Geophys. Res. 113: C12002. http://dx.doi.org/10.1029/2006JC003998

Font J. 1987. The path of the Levantine Intermediate Water to the Alboran Sea. Deep-Sea Res. 34: 1745-1755. http://dx.doi.org/10.1016/0198-0149(87)90022-7

Font J., Salat J., Tintoré J. 1988. Permanent features of the general circulation in the Catalan Sea. Oceanol. Acta, vol. sp. 9: 51-57.

Font J., García-Ladona E., García-Gorriz E. 1995. The seasonality of mesoscale motion in the northern current of the western Mediterranean Sea: several years of evidence, Oceanol. Acta 18(2), vol sp. PRIMO 0, pp. 207-219, ISSN: 0399-1784.

García E., Tintoré J., Pinot J.M., et al. 1994. Surface circulation and dynamics of the Balearic Sea, In: La Violette P. (ed.), The Seasonal and Interannual Variability of the Western Mediterranean. Coastal and Estuarine Studies, AGU. 46: 73-91, ISBN: 0-87590-260-X. http://dx.doi.org/10.1029/ce046p0073

Gili J.-M., Bouillon J., Pages F. 1998. Origin and biogeography of the deep-water Mediterranean Hydromedusae including the description of two new species collected in submarine canyons of Northwestern Mediterranean. Sci. Mar. 62: 113-134.

Hickey B.M. 1997. The Response of a Steep-Sided, Narrow Canyon to Time-Variable Wind Forcing. J. Phys. Oceanogr. 27: 697-726. http://dx.doi.org/10.1175/1520-0485(1997)027<0697:TROASS>2.0.CO;2

Hopkins T.S. 1978. Physical processes in the Mediterranean basins. In: Kjerfve B. (ed.), Estuarine transport processes. Univ. South Carolina Press, pp. 269-310.

Huthnance J.M. 1995. Circulation, exchange and water masses at the ocean margin: the role of physical processes at the shelf edge. Progr. Oceanogr. 35: 353-431. http://dx.doi.org/10.1016/0079-6611(95)80003-C

IOC, SCOR and IAPSO. 2010. The international thermodynamic equation of seawater – 2010: Calculation and use of thermodynamic properties . Intergovernmental Oceanographic Commission, Manuals and Guides No. 56, UNESCO (English), 196 pp.

Jordi A., Orfila A., Basterretxea G., et al. 2005. Shelf-slope exchanges by frontal variability in a steep submarine canyon. Progr. Oceanogr. 66: 120-141. http://dx.doi.org/10.1016/j.pocean.2004.07.009

Klinck J. M. 1996. Circulation near submarine canyons: A modeling study. J. Geophys. Res. 101: 1211-1223. http://dx.doi.org/10.1029/95JC02901

La Violette P.E., Tintoré J., Font J. 1990. The surface circulation of the Balearic Sea. J. Geophys. Res. 95(C2): 1559-1568. http://dx.doi.org/10.1029/JC095iC02p01559

Lacombe H., Tchernia P. 1972. Caracteres hydrologiques et circulation des eaux en Mediterranée. In: Stanley D.J. (ed.), The Mediterranean Sea. Dowden Hutchinson Ross Inc., Stroudsburg, pp. 26-36.

Lopez-Fernandez P., Calafat A., Sanchez-Vidal A., et al. 2013. Multiple drivers of particle fluxes in the Blanes submarine canyon and southern open slope: Results of a year round experiment. Progr. Oceanogr. 118: 95-107. http://dx.doi.org/10.1016/j.pocean.2013.07.029

López-García M.J., Millot C., Font J., et al. 1994. Surface circulation variability in the Balearic basin. J. Geophys. Res. 99: 3285-3296. http://dx.doi.org/10.1029/93JC02114

Mason E., Pascual A. 2013. Multiscale variability in the Balearic Sea: an altimetric perspective. J. Geophys. Res. 118: 3007-3025. http://dx.doi.org/10.1002/jgrc.20234

Masó M., Tintoré J. 1991. Variability of the shelf water off the northeast Spanish coast. J. Mar. Syst. 1: 441-450. http://dx.doi.org/10.1016/0924-7963(91)90008-I

Masó M., La Violette P.E., Tintoré J. 1990. Coastal flow modification by submarine canyons along the NE Spanish coast. Sci. Mar. 54: 343-348.

Martín J., Palanques A., Puig P. 2007. Near-bottom horizontal transfer of particulate matter in the Palamós Submarine Canyon (NW Mediterranean). J. Mar. Res. 65: 193-218.

Martín J., Durrieu de Madron X., Puig P., et al. 2013. Sediment transport along the Cap de Creus Canyon flank during a mild, wet winter. Biogeosciences 10: 3221-3239. http://dx.doi.org/10.5194/bg-10-3221-2013

Millot C. 1999. Circulation in the Western Mediterranean Sea. J. Mar. Syst. 20: 423-442. http://dx.doi.org/10.1016/S0924-7963(98)00078-5

Navarra A., Simoncini V. 2010. A Guide to Empirical Orthogonal Functions for Climate Data Analysis. Springer. http://dx.doi.org/10.1007/978-90-481-3702-2

Ostrovskii A.G., Zatsepin A.G., Soloviev V.A., et al. 2013. Autonomous System for Vertical Profiling of the Marine Environment at a Moored Station. Oceanology 53: 233-242. http://dx.doi.org/10.1134/S0001437013020124

Ovchinnikov I.M., Plakhin E.A., Moskalenko L.V., et al. 1976. Hydrology of the Mediterranean Sea. Hydrometeoizdat, Leningrad, 376 pp. (in Russian).

Palanques A., García-Ladona E., Gomis D., et al. 2005. General patterns of circulation, sediment fluxes and ecology of the Palamós (La Fonera) submarine canyon, northwestern Mediterranean. Progr. Oceanogr. 66: 89-119. http://dx.doi.org/10.1016/j.pocean.2004.07.016

Pascual A., Nardelli B.B., Larnicol G., et al. 2002. A case of an intense anticyclonic eddy in the Balearic Sea (western Mediterranean). J. Geophys. Res. 107: 3189. http://dx.doi.org/10.1029/2001JC000913

Pascual A., Gomis D., Haney R.L., et al. 2004. A quasigeostrophic analysis of a meander in the Palamós Canyon: Vertical velocity, geopotential tendency, and a relocation technique. J. Phys. Oceanogr. 34: 2274-2287. http://dx.doi.org/10.1175/1520-0485(2004)034<2274:AQAOAM>2.0.CO;2

Pingree R.D. 1972. Mixing in deep stratified ocean. Deep-Sea Res. 19: 549-562. http://dx.doi.org/10.1016/0011-7471(72)90039-3

Pinot J.M., Ganachaud A. 1999. The role of Winter Intermediate Waters in the spring–summer circulation of the Balearic Sea. Part I: hydrography and inverse box modelling. J. Geophys. Res. 104: 29843-29864. http://dx.doi.org/10.1029/1999JC900202

Pinot J.M., Tintoré J., Lopez-Jurado J.L., et al. 1995. Three-dimensional circulation of a mesoscale eddy/front system and its biological implications. Oceanol. Acta 18: 389-400.

Pinot J.-M, López-Jurado J.L., Riera M. 2002. The CANALES experiment (1996-1998). Interannual, seasonal, and mesoscale variability of the circulation in the Balearic Channels. Progr. Oceanogr. 55: 335-370. http://dx.doi.org/10.1016/S0079-6611(02)00139-8

Puig P., Palanques A., Guillén J., et al. 2000. Deep slope currents and suspended particle fluxes in and around the Foix submarine canyon (NW Mediterranean). Deep-Sea Res. Part I 47: 343-366. http://dx.doi.org/10.1016/S0967-0637(99)00062-X

Puig P., Palanques A., Orange D.L., et al. 2008. Dense shelf water cascades and sedimentary furrow formation in the Cap de Creus Canyon, northwestern Mediterranean Sea. Cont. Shelf Res. 28: 2017-2030. http://dx.doi.org/10.1016/j.csr.2008.05.002

Puig P., Palanques A., Martín J. 2014. Contemporary Sediment- Transport Processes in Submarine Canyons. Annu. Rev. Mar. Sci. 6, 53-77. http://dx.doi.org/10.1146/annurev-marine-010213-135037 PMid:23937169

Radko T. 2013. Double-diffusive convection. Cambridge Univ. Press, Cambridge, ISBN 978-0-521-88074_9. http://dx.doi.org/10.1017/CBO9781139034173

Ruddick B. 1983. A practical indicator of the stability of the water column to double-diffusive activity. Deep-Sea Res. 30: 1105-1107. http://dx.doi.org/10.1016/0198-0149(83)90063-8

Rubio A., Arnau P.A., Espino M., et al. 2005. A field study of the behaviour of an anticyclonic eddy on the Catalan continental shelf (NW Mediterranean). Progr. Oceanogr. 66: 142-156. http://dx.doi.org/10.1016/j.pocean.2004.07.012

Rubio A., Barnier B., Jordà G., et al. 2009. Origin and dynamics of mesoscale eddies in the Catalan Sea (NW Mediterranean): Insight from a numerical model study. J. Geophys. Res. 114: C06009. http://dx.doi.org/10.1029/2007JC004245

Salat J., Cruzado A. 1981. Masses d'eau dans la Mediterranee Occidentale: Mer Catalane et eaux adjacentes. Rapp. Comm. Int. Exploit. Sci. Mer Mediterranee 27: 201-209.

Salat J., Font J. 1987. Water mass structure near and offshore the Catalan coast during winters 1982 and 1983. Ann. Geophys. 5B: 49-54.

Salat J., García M.A., Cruzado A., et al. 2002. Seasonal changes of water mass structure and shelf slope exchanges at the Ebro Shelf (NW Mediterranean). Cont. Shelf Res. 22: 327-348. http://dx.doi.org/10.1016/S0278-4343(01)00031-0

Sammari C., Millot C., Prieuri L. 1995. Aspects of the seasonal and mesoscale variabilities of the Northern Current in the western Mediterranean Sea inferred from the PROLIG-2 and PROS-6 experiments. Deep-Sea Res. Part I 42: 893-917. http://dx.doi.org/10.1016/0967-0637(95)00031-Z

Spurgin J.M., Allen S.E. 2014. Flow dynamics around downwelling submarine canyons. Ocean Sci. 10: 799-819. http://dx.doi.org/10.5194/os-10-799-2014

Tintoré J., Wang D.P., La Violette P.E. 1990. Eddies and thermohaline intrusions of the shelf/slope front off the northeast Spanish coast. J. Geophys. Res. 95: 1627-1633. http://dx.doi.org/10.1029/JC095iC02p01627

Xu J.P. 2011. Measuring currents in submarine canyons: Technological and scientific progress in the past 30 years. Geosphere 7: 868-876. http://dx.doi.org/10.1130/GES00640.1

Zhurbas V.M., Laanemets Y.Y., Lips U.K., et al. 1987. On the possibility of classification of thermohaline fine structure ocean, based on calculation of statistical characteristics. In: Structure of hydro-physical fields of the Norwegian and Greenland Seas, IOAN, Moscow, pp. 43-48.

Zúñiga D., Flexas M.M., Sanchez-Vidal A., et al. 2009. Particle fluxes dynamics in Blanes submarine canyon (Northwestern Mediterranean). Progr. Oceanogr. 82: 239-251. http://dx.doi.org/10.1016/j.pocean.2009.07.002




Copyright (c) 2016 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Contact us scimar@icm.csic.es

Technical support soporte.tecnico.revistas@csic.es