Biotic and abiotic retention, recycling and remineralization of metals in the ocean

• Published in: Nature Geoscience
• Main Authors: Boyd, Phillip, Ellwood, Michael, Tagliabue, Alessandro, Twining, B.S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group
• Subjects: Antarctic; Antarc*; Antarctic Climate and Ecosystems Cooperative Research Centre
• Online Access: http://hdl.handle.net/1885/233003; https://doi.org/10.1038/ngeo2876; https://openresearch-repository.anu.edu.au/bitstream/1885/233003/3/01_Boyd_Biotic_and_abiotic_retention%252C_2017.pdf.jpg

Trace metals shape both the biogeochemical functioning and biological structure of oceanic provinces. Trace metal biogeochemistry has primarily focused on modes of external supply of metals from aeolian, hydrothermal, sedimentary and other sources. However, metals also undergo internal transformations such as abiotic and biotic retention, recycling and remineralization. The role of these internal transformations in metal biogeochemical cycling is now coming into focus. First, the retention of metals by biota in the surface ocean for days, weeks or months depends on taxon-specific metal requirements of phytoplankton, and on their ultimate fate: that is, viral lysis, senescence, grazing and/or export to depth. Rapid recycling of metals in the surface ocean can extend seasonal productivity by maintaining higher levels of metal bioavailability compared to the influence of external metal input alone. As metal-containing organic particles are exported from the surface ocean, different metals exhibit distinct patterns of remineralization with depth. These patterns are mediated by a wide range of physicochemical and microbial processes such as the ability of particles to sorb metals, and are influenced by the mineral and organic characteristics of sinking particles. We conclude that internal metal transformations play an essential role in controlling metal bioavailability, phytoplankton distributions and the subsurface resupply of metals Support was provided by Australian Research Council Australian Laureate Fellowship project FL160100131 and Antarctic Climate and Ecosystems Cooperative Research Centre funding to P.W.B., an Australian Research Council Discovery Project DP130100679 to M.J.E. and P.W.B. B.S.T. was supported by US National Science Foundation grant OCE-1232814. Model simulations by A.T. are supported by N8 HPC Centre of Excellence, provided and funded by the N8 consortium and EPSRC (Grant No. EP/K000225/1).