Impact of ferromanganese ore pollution on phytoplankton CO2 fixation in the surface ocean

• Published in: Marine Pollution Bulletin
• Main Authors: Dabrowska, Alicja, Kamennaya, Nina A., Murton, Bramley J., Zubkov, Mikhail V.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: South Atlantic Ocean
• Online Access: http://nora.nerc.ac.uk/id/eprint/524876/; https://nora.nerc.ac.uk/id/eprint/524876/1/1-s2.0-S0025326X19306022-main-2.pdf; https://doi.org/10.1016/j.marpolbul.2019.07.062

Because ferromanganese polymetallic crusts can become a global resource of valuable elements the ecological impact of seafloor crust mining requires evaluation. Whilst the detrimental impact on deep-ocean benthos is established, experimental evidence about the mining hazard to surface-ocean is sparse. When retrieved, mined crusts can leach elements potentially harmfull to the core oceanic CO2-fixers – phytoplankton. To directly assess the magnitude of this potential hazard at ocean-basin scale, we examine the impact of ore slurry on phytoplankton CO2 fixation along a meridional transect through the South Atlantic Ocean. Within 12 h crust slurry additions caused a 25% decrease of CO2 fixation in the subtropical region and 15% in the temperate-polar region. Such moderate susceptibility of phytoplankton indicates limited release of harmful elements from tested polymetallic powder. Although this implies that environmentally sustainable seafloor mining could be feasible, longer-term complex studies of the mining impact on the surface ocean are required.