The physical oceanographic conditions along the Mid-Atlantic Ridge north of the Azores in June–July 2004

Abstract

Atlantic has been a challenge to quantify due to strong and variable wind-forcing, and strong and variable deep currents that lead to large uncertainties in the use of the standard dynamical method. Since 1999 we have been operating an acoustical Doppler current profiler on a container vessel that operates between Denmark and Greenland to repeatedly sample upper ocean currents across the northeast Atlantic. Individual transects exhibit a highly energetic mesoscale variability, but ensemble-averaging of the sections reveals a striking organization of the mean field along the Reykjanes Ridge: a distinct southward flow along its eastern slope and two clearly defined peaks with seasonal modulation flowing to the north along its western slope. Higher values of eddy kinetic energy (about 150-600 cm 2 s À2) are observed along the transect, O(1.5) greater than surface drifter estimates.

Demosponges from the Northern Mid-Atlantic Ridge shed more light on the diversity and biogeography of North Atlantic deep-sea sponges

“…In the North Atlantic, the Gulf Stream gives the eastward North Atlantic Current (NAC) which crosses the MAR around the CGFZ (Søiland et al, 2008). The northern edge of the NAC (temperate waters) runs alongside the subpolar front (colder waters) which shifts between 488N and 538N (Søiland et al, 2008).…”

“…Additional records were also added for (i) Geodia atlantica from the Kerry Head Reefs cruise CV13012 (August 2013, chief scientist: Louise Allcock, material sorted by C. Morrow, identifications by PC) and for (ii) Geodia macandrewii from the Porcupine Bank (CE13008 campaign, June 2013, RV 'Celtic Explorer' using the ROV 'Holland I', chief scientist: Louise Allcock, material sorted by C. Morrow, identifications by PC). Maps of boreo-arctic Thenea species and Poecillastra compressa have also been updated from Steenstrup & Tendal (1982) (Søiland et al, 2008). (Ingolf, BIOICE 1991, Stelletta tuberosa (Ingolf), Stelletta rhaphidiophora (Ingolf, Lynch 1972-1973, BIOICE, Paamiut 1994 and Stylocordyla borealis (BIOICE, BIOFAR 1987-1993, Michael Sars 1902.…”

“…The trawl was a Campelen 1800 shrimp trawl with a 22 mm mesh size cod-end liner and a 12-17 m by 4.5 m opening at 50 m doorspread. Environmental data associated with the trawls were nearbottom measurements obtained with a CTD sensor (Søiland et al, 2008). For a detailed station list with coordinates, depths and environmental data, and for a full account of the approach and methods for sampling of the benthic fauna during this expedition, see Bergstad & Gebruk (2008).…”

Year-round distribution and habitat preferences of the Bugio petrel

“…This region (see area a in Fig. 1) is located in the vicinity of the Sub-Polar Front, where cool and productive sub-Artic waters mix with warmer and less productive regimes of the central North Atlantic (Søiland et al 2008). Research has just recently revealed the importance of this area as a hotspot of seabird biodiversity, with several seabird taxa foraging there during different phases of their annual cycle: Some species use this area as their main wintering ground (Sooty shearwaters Puffinus griseus: Hedd et al 2012; black-legged kittiwakes Rissa tridactyla: González-Solís et al 2011, Frederiksen et Roscales et al 2011.…”

The Azores Confluence Zone

“…The oceanographic conditions in the Mid-Atlantic Ridge (MAR) region adjacent to the Azores Archipelago has been the subject of many scientific studies (e.g., Gould, 1985;Mailly et al, 1997;Alves and Verdière, 1999;Pingree et al, 1999;Alves et al, 2002;Juliano and Alves, 2007;Søliland et al, 2008;Barbosa et al, 2011;Lázaro et al, 2013). Fewer studies however, center on the oceanographic processes affecting the Azores Islands per se.…”