SONNE SO242/1

The first leg of cruise SO242 will re-map (visually and acoustically) and sample seafloor and water column within the DISCOL Experimental Area (DEA) in the Peru basin for biological, geochemical and oceanographical studies . This area has been studied repeatedly between 1989 and 1997 during several cruises with RV SONNE (I) to investigate the impact of a mechanical disturbance of the seafloor – similar to Mn-nodule mining – on deep sea ecosystems over longer time in qualitative and quantitative terms.
In comparison to the last cruise (SO106; 1996) strongly advanced technology will be used. AUV ABYSS will map the seafloor with side scan sonar and multibeam echosounder and a newly developed camera system. At the same time video-guided multicorer, gravity corer, box corer or epibenthic sleds will be deployed by underwater navigation at the seafloor. Two landers and one mooring will acquire physical and time-laps camera data from the water column and the seafloor.
Aim of SO242-1 is to completely map the original DEA area in such high resolution and full coverage that detailed comparisons with older data are possible. Biological sampling will show to which extend the ecosystem recovered/changed after the last inventory in 1996. Geochemical studies of samples taken inside and outside the disturbance tracks and in reference areas will show how different geochemical conditions with the sediment column are and if they changed over time.
The scientific work will continued during SO242-2.
Both cruises are part of the JPIOceans project "Ecological aspects of deep-sea mining"