This cruise is part of the Seabed Mining And Resilience To EXperimental impact (SMARTEX) project funded by the UK Natural Environment Research Council (Grant Reference NE/T003537/1). This is the second UK cruise to the Clarion Clipperton Zone (CCZ) in the northern equatorial Pacific, an area likely to be targeted for deep-sea mining for polymetallic nodules. The first (JC120) was carried out in 2015. Scientific aims: 1. Understand the remaining impact of a realistic mining test on the benthic environment and its fauna after 44 years; 2. Assess natural temporal change in macrofaunal communities between 1989 and 2023 (at PRA site); 3. Provide the first characterisation of megafaunal species and communities present at APEI-13 (linked outreach and policy interaction aim); 4. Characterise the environment and ecology of the UK-1 area in advance of a planned nodule collector test. BGS collected deep sea sediments and nodules during JC241. Porewaters were extracted for trace metals, nutrients and alkalinity. Sediments were analysed for trace element geochemistry, loss on drying, particle size analysis and bulk and clay mineralogy by XRD. Micro XRF and SEM imaging was used to image the geochemistry of entire nodule cross sections and laser ablation ICP-MS line transects were performed across selected entire nodules for high resolution geochemical profiles. Finally, physical property analysis of sediment collected during JC241 was utilised to model the physical and temporal response of deep-sea sediment to the compression caused by a deep-sea mining vessel. More information and the cruise report are available at www.bodc.ac.uk/resources/inventories/cruise_inventory/report/18136/.
