Relatório de Cruzeiro CORALFISH: Condor, Voador e Banco Açores 2010 a bordo do NRP Almirante Gago Coutinho. (datas 5 a 13 Agosto 2010) Autores: Fernando Tempera, Filipe Porteiro, Marina Carreiro-Silva, Andreia Braga-Henriques, Eva Giacomello, Ana Branco, Pedro Ferreira, Pedro Ribeiro, Telmo Morato, Ricardo Santos, Projectos: CoralFISH (IMAR, FP7), CONDOR (UAc, EEA), CORAZON (IMAR, FCT), Hermione (UAc, FP7) Objectivos: mapear as comunidades bentónicas dos monte submarinos Condor e Voador, identificar novas zonas de corais de águas frias, comparar a comunidade de peixes associada a zonas com e sem corais, recolher amostras biológicas e de água do mar, levantamento multifeixe (batimetria e backscatter) dos dois montes submarinos e outras áreas importantes, colocação de módulos de colonização no banco Condor. Navio: NRP Almirante Gago Coutinho Chefe de cruzeiro: Leg1- Ricardo Serrão Santos (monte submarino Condor); Leg2- Fernando Tempera (monte submarino Voador) Equipa científica: Leg 1- Ricardo Santos, Fernando Tempera, Filipe Porteiro, Marina C. Silva, Andreia Henriques, Eva Giacomello, Ana Branco (LNEG) e Pedro Ferreira (LNEG) Leg 2- Fernando Tempera, Telmo Morato, Marina C. Silva, Andreia Henriques, Pedro Ribeiro, Ana Branco (LNEG) e Pedro Ferreira (LNEG)

Cold-water corals (CWCs) thrive in areas with complex and rough topography favoring the development of highly diverse benthic communities. Several biotic and abiotic factors including organic matter supply, temperature, bottom roughness and currents are important drivers of ecosystem structure and functioning in deep-sea environments at different spatial and temporal scales. Little is known, however, how basin-scale changes in the ocean climate affect these drivers at local scales. Here, we use high-resolution implementations of the hydrodynamic model ROMS-AGRIF for estimating characteristic spatial and temporal scales of local hydrodynamics in response to variations of basin-scale currents imposed by distinct changes of the Atlantic Meridional Overturning Circulation (AMOC) in the past century. We focus on two CWC communities on the SE Rockall Bank slope and at Condor Seamount. We considered two contrasting AMOC states that were identified from the 1958–2009 hindcast of the 1/20° resolution VIKING20 North Atlantic basin-scale ocean circulation model and used as boundary conditions for the high-resolution local area models. At SE Rockall Bank, variability of near-bottom currents in both regions was largely dominated by tidal dynamics, but strongly modified by AMOC induced basin-scale variations of water mass properties and bottom currents. During strong AMOC years, waters in the main CWC depth corridor (600–1200 m) were cooler and less saline but were dominated by stronger bottom currents when compared with conditions during weak AMOC years. At Condor Seamount, bottom currents were largely unaffected by AMOC related changes close to the summit at water depths < 400 m. Kinetic energy dissipation rates derived from the 3D near-bottom velocity field appeared to positively relate with the in-situ CWC distribution. Kinetic energy dissipation is therefore proposed as a mechanistic descriptor of CWC presence as it provides a more mechanistic view of hydrodynamics driving organic matter supply to filter and suspension-feeding communities.