The iAtlantic BR10-Petrobras cruise was affected by the sad damage of the towed camera system. Still, we were able to perform one 2-hour long video profile with a good view of the sedimentary bottom of the Santos Basin slope area and some carbonate outcrops near the rim of the pockmarks. Lots of fish and shrimps were observed, indicating the area may be a productivity hotspot in the slope regions off Brazil.
We compensated for the camera system loss by increasing our seafloor mapping coverage with the unexpectedly very high resolution multibeam echosounder system (MBES) of RV Vital de Oliveira (~24 m). These efforts covered all of the shelf break/upper slope area and allowed us to see quite interesting unknown geological features that are worth exploring (see below). These included some very large (~2km) ridges which we speculated could be authigenic carbonate features. Also, there were much smaller linear ridges in between pockmarks which we sampled with the box corer and revealed they were covered with scleractinian coral rubble, suggesting they could be coral mounts. In one box corer we sampled a live black coral colony, which confirmed that there are corals sitting on top of these mounds.
The MBES also revealed many of what we believe are trawl fishing tracks. We plotted them against deep-sea trawl fishing records (for the period 2000 – 2008) and some of them matched perfectly, showing that they could be at least 17 years old. Quite amazing!
Thanks to the data acquisition capabilities of the RV Vital de Oliveira and the hard work of the crew we ended up with an extensive set of environmental data which will allow us to demonstrate how interesting and important this area of the Atlantic is. And of course, to provide strong justification for more cruises to this area in the future.
