The Benthic Megafaunal Assemblages of the CCZ (Eastern Pacific) and an Approach to their Management in the Face of Threatened Anthropogenic Impacts

Abstract

We present here the results of a UNESCO/IOC baseline study of the megafaunal assemblages of the polymetallic nodule ecosystem of 5 areas within the Clarion Clipperton Zone (CCZ) of the eastern Pacific Ocean. The work was undertaken with a view to investigating the structure of the epifaunal populations associated with the benthic biotopes being targeted for nodule mining and developing an appropriate set of management tools and options. The general characteristics of nodule ecosystem and assemblages and their sensitivity to deep-sea mining are discussed in relation to water masses, surface to seabed water circulation, the nepheloid layer and processes taking place at the sediment interface. Management tools considered include species diversity and vulnerability indexes, GIS systems, zoning, and 3D rapid environmental assessment (REA). These strategies are proposed for trial during pilot mining operations within the CCZ.

Successful Blue Economy Examples With an Emphasis on International Perspectives

“…In addition to obvious destruction of sea life living at the mine site, there are other adverse effects on biodiversity and ecological processes such as those associated with sediment-plume generation, toxic chemical release, noise, etc. (Levin et al, 2016;Vanreusel et al, 2016;Gollner et al, 2017;Jones et al, 2017;Tilot et al, 2018). The cumulative effects of these, along with other ocean pressures such as climate change (Guidetti and Danovaro, 2017) and pollution, need to be considered during this pre-mining phase in order to properly assess impacts.…”

Unexpected high abyssal ophiuroid diversity in polymetallic nodule fields of the Northeast Pacific Ocean, and implications for conservation

“…24). Furthermore, the large-sized brittle-stars collected with the remotely operated vehicle were matched with their in-situ photos allowing a more accurate estimation of morphospecies which in turn could facilitate the more accurate annotation of photos and video transects used in various biodiversity assessment studies (Tilot et al, 2018) Mean COI genetic intraspecific distances (K2P) of brittle stars (0.00-0.057) were concordant with previous ophiuroid studies (0.00-0.042: Khodami et al, 2014 and 0.00-0.064: Boissin et al, 2017), while the mean COI interspecific genetic distances (0.052-0.512) were found to be noticeably higher. This could be attributed both to the great phylodiversity of ophiuroids collected from the polymetallic fields, spanning over 11 families and 5 orders, and to the discovery of previously undescribed diversity up to the family level (Christodoulou et al, 2019).…”

Unexpected high abyssal ophiuroid diversity in polymetallic nodule fields of the northeast Pacific Ocean and implications for conservation

“…In addition to these protection measures, the ISA has stipulated that prior to exploitation, a benthic biological baseline study must be undertaken for each exploration contract area, and the possible environmental impacts arising from exploration should be assessed. Nodule mining carries significant environmental concerns, including negative direct and indirect impacts on the biodiversity (Ramirez-Llodra et al, 2011;Vanreusel et al, 2016;Van Dover et al, 2017;. The removal of the nodules and associated organisms could result in habitat loss, fragmentation or modification while the generation of sediment plumes may bury the organisms or clog their feeding apparatuses and thus disrupt the food webs (Ramirez-Llodra et al, 2011;Vanreusel et al, 2016;Van Dover et al, 2017;Stratmann et al, 2018).…”

“…Nodule mining carries significant environmental concerns, including negative direct and indirect impacts on the biodiversity (Ramirez-Llodra et al, 2011;Vanreusel et al, 2016;Van Dover et al, 2017;. The removal of the nodules and associated organisms could result in habitat loss, fragmentation or modification while the generation of sediment plumes may bury the organisms or clog their feeding apparatuses and thus disrupt the food webs (Ramirez-Llodra et al, 2011;Vanreusel et al, 2016;Van Dover et al, 2017;Stratmann et al, 2018). Unfortunately, accurate documentation of species diversity, which comprises the first step in understanding patterns and structures in different levels of biodiversity and biogeographical and ecological processes and is essential for marine ecosystems' management, remains poor across the CCZ (Amon et al, 2016).…”