Interest in extracting mineral resources from the seafloor through deep-sea mining has accelerated in the past decade, driven by consumer demand for zinc, cobalt, and rare earth elements. Ongoing studies evaluating environmental impacts of deep-sea mining have shown significant effects on the composition and activity of benthic fauna. Yet, deep-sea mining impacts on the microscopic spectrum of seafloor life are rarely considered. In April 2018, scientists met to define the microbial ecosystem services that should be considered when assessing potential impacts of deep-sea mining. We described potential major losses of microbial ecosystem services at active hydrothermal vents, and major ecosystem service degradation at inactive massive sulfide deposits without extensive mitigation efforts. Assessment of impacts to microbial ecosystem services at seamounts with ferromanganese crusts is too poorly understood to be definitive. We also hypothesized important impacts to primary production capacity and other microbial functions within manganese nodule fields. Indeed, a subsequent study on the effects of a deep-sea mining experiment on seafloor microbial communities at the Peru Basin nodule field, showed a dramatic loss in microbial cell abundances and activities. Growth estimates suggested that microbially mediated biogeochemical functions require over half a century to return to undisturbed levels. Baseline assessments of microbial diversity, biomass, and, biogeochemical function need to be considered in environmental impact assessments of deep-sea mining.

Primary Presenter: Maria Pachiadaki, Woods Hole Oceanographic Institution (mpachiadaki@whoi.edu)

Authors:

Beth Orcutt,   ()

James Bradley,   ()

William Brazelton,   ()

Emily Estes,   ()

Jacqueline Goordial,   ()

Julie Huber,   ()

Rose Jones,   ()

Nagissa Mahmoudi,   ()

Jeffrey Marlow,   ()

Sheryl Murdock,   ()

Maria Pachiadaki,   ()