26 Citations
Benthic sampling was conducted during the DIVA 1-3 expeditions on board RV Meteor between 2000 and 2009: DIVA 1 (Me 48/1), 06.07.2000-02.08.2000, Walvis Bay – Walvis Bay; DIVA 2 Me 63/2, 25.02.2005 – 30.03.2005, Cape Town (South Africa) – Mindelo (Cape Verdes); DIVA 3 Me 79/1, 10.07.2009 – 23.08.2009, Montevideo (Uruguay – Ponta Delgada (Azores). Study area The study area encompasses five abyssal basins of the equatorial and South Atlantic, including the Argentine and Brazil basins located in the SW Atlantic, the Guinea basin in the equatorial Atlantic, as well as the Angola and Cape basins in the SE Atlantic. The hydrography of South Atlantic surface waters is dominated by the South Atlantic subtropical gyre, which is clockwise bounded by the Benguela current system in the East, the Antarctic circumpolar current in the South, the Brazil current in the West and the South Equatorial Current in the North (Rhein et al., 1996; Palma & Matano 2017). Deep water masses consist of North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW). The southernmost basins, i.e. the Argentine and Cape basins, are mainly bathed in cold and dense AABW. In the eastern basins, the Walvis ridge separates the Cape from the Angola basin. While the abyssal seabed of the Cape basin is dominated by AABW, the Walvis ridge obstructs the AABW flow into the Angola basin, the latter being dominated by NADW and the inflow of Antarctic Intermediate Water (AAIW) that can cross the ridge (Taley, 1996). The investigated abyssal areas differ greatly in terms of food availability, which is supposed to be significantly lower in the Cape and southern Angola basins and increases towards the north in the northern Angola and eastern Guinea basins (Kröncke & Türkay 2003; Kröncke et al. 2013). In contrast, almost the opposite pattern is seen in the south-western basins, i.e. high oceanic productivity over the Argentine basin, a decline in entry the subtropical gyre and then again an increase towards the equator (Mollenhauer et al. 2004). Sampling Macrofauna was obtained by means of an EBS equipped with an epinet (below) and a supranet (above). The mesh size of the nets is 500 µm. The cod ends are equipped with net-buckets containing a 300 µm mesh window (Brenke, 2005). In addition, a box was developed for sampling in warm, tropical waters, which covers the code ends and keeps the samples cool on their way through the water column. The EBS was towed on the seabed for 10 minutes each t...