Bluteau, C.

González-Pola, C. (César)

Ivey, G.

Jones, N.

Kelly, S.

Somavilla, R. (Raquel)

Sánchez, F. (Francisco)

English

Repositorio Institucional Digital del IEO

2. Sampling strategyHydrodynamic Environment and Ecosystem Diversity attwo Deep-Sea Marine Protected Areas in Southern BiscayCesar Gonzalez-Pola1 (cesar.pola@gi.ieo.es), Greg Ivey2, Nicole Jones2Francisco Sanchez1, Samuel Kelly3, Cynthia Bluteau2,Raquel Somavilla11. Le Danois Bank and Aviles Canyon System MPAsLe Danois1Spanish Instituteof Ocenography3. Main Results4. Discussion: Understanding thehydrodinamic constrainsPoster ME34B-08062The University ofWestern Australia3University ofMinnesota DuluthIn the early 2000`s Spain acknowledged the need ofcreating deep offshore marine protected areas (MPAs).In the Cantabrian Sea (southern Biscay) two hotspotareas, hosting valuable ecosystems, focused theattention. The first one is Le Danois Bank, anelongated seamount-like feature connected to thecontinental shelf by a saddle. The second one is theAviles Canyon System (ACS) that breaks the continuityof the northern Spanish continental shelf.Observational multidisciplinaryprograms carried out alloweda detailed identification ofhabitats and biologicalcommunities. As a long-termgoal these programs aimed tounderstand the ecosystemfunctioning as a whole withthe implicit focus in associatedcirculation and dynamics.The observational record includes deep seaphotogrametry as well as standard hydrographyand long-term mooring lines. A lander systemprovided high-frequency currents and thermalstructure tens of meters above bottom, togetherwith time lapse photographs, at selected sites.Le Danois Bank main feature isan anticyclonic recirculation areaassociated to the summit, a rockyoutcrop at the western side.Habitat is characterized bysponge aggregations andgorgonia. Intense short-termdynamics certainly play a role.Noteworthy structured coral reefsonly appeared in a relatively smallarea in one of the tributaries ofthe ACS (La Gaviera Canyon).Bottom seafloor there is markedlydifferent from somewhere else,characterized by sand ripples.The head of main Avilés Canyonis the main hake fishing ground ofthe Cantabrian Sea. Coralstructures exist at the steepestflanks, but sediment is smooth anddominant species are suspensionfeeders, like brisingella seastars.Bottom landers at thesesites showed distintivedynamics, the developmentand violent breaking of aninternal tidal bore was themain feature of La GavieraCanyon.Tidal phases arestrongly assymetric,being the upslope shortand violent. Upon thearrival of the upslopephase overturnsexceed the range ofthe thermistors chain,being estimated wellabove 100 meters, andstand several minutes.Local Kz withinoverturns reach10-1 m2 s-1 .A year-long near-bottom currentrecord captured the development ofthree benthic storms, events lastingseveral days in which currentsincreases up to 3-fold the tidal maxspeeds and direction swings rapidly,losing the uniformity of tidal regime.Analytic estimates confirmed that La Gaviera is the only canyon werelarge patches of the seafloor are critical or near-critical to the semidiurnalinternal tide. Nearby upper flanks show also large patches of criticalseafloor and large body forcing.A MITgcm model run of the internal tide, forced by M2alone, shows agreement with the dynamics recordedby the current-meters array.Comet-like sedimentsignatureStationary surfaceroughness seen on radar,probably caused by aninternal solitary wavebreakingField work was conducted under several projects, mainly ECOMARG (REN2002-00916/MAR, Spanish Science call)and INDEMARES (07/NAT/E/000732, UE LIFE+ call). Part of the analyis was carried out during a stay at the Universityof Western Australia (PRX12/00662, Spanish movility call). Support for results dissemnitaion was provided by thePrincipado de Asturias under GIDEP Research Group (GRUPIN14-144)Study regionCantabrian Sea (Southern Biscay)Terrain elevationmodel of Le DanoisBank seen from theNWAvilés CanyonSystemTerrain elevation modelof the Avilés CanyonSystem seen from theNW.Lander deployment Trawled sledAviles Canyon La Gaviera CanyonLander. c.a 800 mMooring. c.a. 1000 mMain Avilés CanyonLa Gaviera Canyon25 hours lander record on La GavieraCanyon, from top: along-canyon current(negative upslope), thermal structure,vertical velocity, Thorpe scales.La Gaviera Canyon90-min snapshot of thermal structure upon bore arrival13 month near-botttomcurrent speed at La GavieraCanyon mouthNear critical sites (0.7 < γ/c < 1.3). γ is seaoorsteepness and c angle of propagation of M2IT beamVertically integratedbarotropic bodyforce (Baines,1982) down to2000 m.γ/c zoom at La Gavieracanyon together with landerand mooring line sitesSurface internal-tidepressure at differentsnapshots.IT beams (M2amplitude) along asection crossing Avilésand Gaviera canyonsSee Gonzalez-Pola et.al.2012 (10.1016/j.dsr.2011.10.001) forLe Danois and Sanchez et.al. 2014 (10.1016/j.dsr2.2013.12.014)for La Gaviera Canyon. Further information in www.ecomarg.netLander deploymentBenthic storm

Hydrodynamic Environment and Ecosystem Diversity at two Deep-Sea Marine Protected Areas in Southern Biscay

González-Pola, César

Sánchez, Francisco

Somavilla, Raquel

Digital.CSIC

http://www.repositorio.ieo.es/e-ieo/bitstream/10508/10543/1/GonzalezPola_OSM2016_optim.pdf

Hydrodynamic Environment and Ecosystem Diversity at two Deep-Sea Marine Protected Areas in Southern Biscay

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