Seabed mining could come at a high price for a unique fauna

Abstract

The deep seafloor is teeming with life, most of which remains poorly known to science. It also constitutes an important reserve of natural resources, particularly minerals, that mining companies will start harvesting in the next few years (Nat Rev Earth Environ, 1, 2020, 158). In this context, broad biodiversity assessments of deep‐sea ecosystems are urgently needed to establish a baseline prior to mining. However, significant gaps in our taxonomic knowledge and the high cost of sampling in the deep sea limit the effectiveness of conventional morphology‐based surveys. In this issue of Molecular Ecology, Laroche et al. (Mol Ecol, 2020) capitalize on high throughput molecular methods to conduct one of the most detailed and rigorous surveys of the composition and biogeography of deep‐seafloor metazoan communities to date. The authors show that deep seamounts in the Clarion Clipperton Zone are inhabited by rich metazoan communities that are distinct from those of the surrounding abyssal plains. These results have important conservation implications: if communities on deep seamounts were to persist after large‐scale industrial mining operations on the surrounding plains, the seamounts would not serve as appropriate reservoirs to repopulate impacted areas.

Framing Cutting-Edge Integrative Deep-Sea Biodiversity Monitoring via Environmental DNA and Optoacoustic Augmented Infrastructures

“…Addressing conservation priorities in the deep sea, and monitoring the level of effectiveness of conservation measures are critical steps. The use of eDNA analyses has been recently extended to biodiversity assessment in the context of deepseabed mining of polymetallic nodules to guide management of this deep-sea resource exploitation that is foreseen to have one of the highest environmental impacts in the near future (Wedding et al, 2015;Laroche et al, 2020a;Leray and Machida, 2020), being also suggested as a cost-effective method (Le et al, 2021). The performance of this high throughput approach has also been tested in impact assessment of offshore oil and gas drilling and extraction (Laroche et al, 2018), and in fish stock assessment to inform fishery management (Salter et al, 2019).…”