The large-scale environmental impact experiment DISCOL—reflection and foresight

It is now accepted that environmental impact studies should accompany societyʹs growing interest in exploiting deep-sea resources. A large-scale experiment, DISCOL (Disturbance and recolonisation experiment in a manganese nodule area of the deep South Pacific) was conducted to evaluate potential impacts from mining on the deep-sea bed. DISCOL was the first of a series of projects aimed at better understanding impacts of industrial-scale mining of polymetallic nodules upon the seafloor and its biological community. A schedule of biological work, including a disturbance scheme and sampling patterns, for another 12-year period is described that builds on the DISCOL results, but is strictly valid only for this area. However, future experiments may use estimates from the DISCOL data as a first approximation in their planning phase, but will need to conduct site-specific sampling to establish a baseline.