Figure 1

Study area and sampling sites. (A) Map showing the Abrolhos shelf physiography and the distribution of reefs in the near-shore and mid-shelf arcs (light blue) and drilling sites (Red dots). (B) Side Scan Sonar imagery of mid and outer shelf areas, showing complex submerged reef morphologies. (C) Aerial drone image of the “chapeirões” at the Parcel dos Abrolhos (research boat is 20 m long, for scale reference); (D) Satelite image (Ikonos 2, 4 m resolution) of Abrolhos Archipelago and its adjacent “chapeirão” reef system (indicated by yellow pixels); (E) Schematic view of the 11 cores sampled from the tops and walls of the three reef pinnacles at 4, 15 and 25 m water depth (not on scale). Aerial photo by Fernando Moraes/Rede Abrolhos.