Estimating excess noise from deep sea mining: a simulated test case

There at least two major potential consequences of deep sea mining: sediment plumes and energy input into the ocean. One of the major forms of energy input is ocean noise generated by the mining process. Project TRIDENT was set up under the Horizon Europe framework of the European Union, with the aim of contributing to a sustainable exploitation of seabed mineral resources, by developing a reliable, transparent and cost-effective system for prediction and continuous environmental impact monitoring of exploration and exploitation activities in the deep sea. Among the parameters monitored under TRIDENT there is ocean sound by means of in-situ, middle field and far-field fixed water column acoustic recorders and moving acoustic gliders. The area chosen for TRIDENT activity and system demonstration is the Tropic seamount, located to the south of Canary Islands. This paper sets up the modelling tools to determine to which extent the noise generated by a continuous mining activity on top of the Tropic seamount couples into the sound channel and propagates to the surrounding area. The difference between the measured (or modelled) ocean sound with and without mining activity is usually called excess noise level and is instrumental for developing indicators of environmental impact to sensitive species within acoustic range of the mining site.