Flocculation and deep-sea mining plumes

Deep-sea mining Industry and academia are presently investigating the potential of deep-seamining for valuable resources such as poly-metallic nodules. Nevertheless, the process of manoeuvring, excavating, and processing these resources poses a threat to the deep-sea environment through the generation of plumes of suspended fine-grained solids, which have the potential to damage benthic fauna by smothering or burying them. Assessing the impact of plumes requires an understanding of how far they disperse through bottomcurrents and how their suspended loads change over time. The affected area may be overestimated by current numerical simulations as they neglect the crucial process of flocculation, whereby fine particles aggregate into larger and faster-sinking clumps. The effect of flocculation on plume dispersion is still not well comprehended, engendering ambiguity in monitoring techniques dependent on optronic and acoustic sensors that are sensitive to particle size but do not take into account flocculation. To tackle these concerns, it is essential to undertake research that centres on studying flocculation characteristics in marine sediments. This includes carrying out controlled laboratory experiments to gain a better understanding of the critical conditions for flocculation. Additionally, it involves scaling up these experiments to replicate real-world plume dispersion and devising precise measuring methods for flocculated particle suspensions. This thesis focuses only on benthic sediment plumes...