Consideration of midwater ecosystems is required to fully evaluate the environmental risks of deep-sea mining

Jeffrey Drazen1, Craig R Smith1, Kristina Gjerde2, Steven H D Haddock3, Glenn S Carter4, Malcolm R Clark5, Anela Choy6, Pierre Dutrieux7, Erica Goetze1, Chris Hauton8, Mariko Hatta9, J. Anthony Koslow10, Astrid Brigitta Leitner11, Aude Pacini12, Thomas Peacock13, Jessica Nicole Perelman1, Tracey Sutton14, Les Watling15 and Hiroyuki Yamamoto16, (1)University of Hawai'i at Mānoa, Department of Oceanography, Honolulu, United States, (2)International Union for Conservation of Nature, Cambridge, United States, (3)Monterey Bay Aquarium Research Institute, Moss Landing, CA, United States, (4)University of Hawaii, Manoa, Honolulu, HI, United States, (5)National Institute of Water & Atmospheric Research, Wellington, New Zealand, (6)Scripps Institution of Oceanography, UCSD, Integrative Oceanography Division, La Jolla, CA, United States, (7)Lamont-Doherty Earth Observatory, Palisades, NY, United States, (8)National Oceanography Centre Southampton, United Kingdom, (9)University of Hawaii at Manoa, Oceanography, Honolulu, United States, (10)University of California, SD, Scripps Institution of Oceanography, La Jolla, CA, United States, (11)University of Hawaii, Manoa, Oceanography, Honolulu, HI, United States, (12)University of Hawaii at Manoa, Hawaii Institute of Marine Biology, United States, (13)Dept of Mech Eng - RM 1-310, Cambridge, United States, (14)Nova Southeastern University, Marine and Environmental Sciences, Dania Beach, FL, United States, (15)University of Hawaii at Manoa, Honolulu, HI, United States, (16)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan
Despite rapidly growing interest in deep seabed mineral exploitation, environmental research and management have focused on potential impacts to benthic environments and have paid little attention to pelagic ecosystems. Yet pelagic ecosystems have established ecological and societal importance. Seafloor mining activities will generate sediment plumes and noise in the benthic boundary layer and higher in the water column that may have extensive ecological effects in deep midwaters, depths from ~200m to the seafloor. These ecosystems represent more than 90% of the livable volume on our planet, contain a fish biomass 100 times greater than the global annual fish catch, connect shallow-living ecosystems to deeper ones including the benthos, and play key roles in carbon export, nutrient regeneration, and in the provisioning of harvestable fish stocks. These deep midwater ecosystem services as well as biodiversity could be negatively affected by mining. We will examine the potential effects of deep seabed mining on midwater ecosystems and provide specific recommendations on how ecosystem risks could be more comprehensively and effectively evaluated.