Global warming has driven a loss of dissolved oxygen in the ocean. This paper demonstrates that zooplankton consumption of microplastic reduces grazing on primary producers, potentially causing an additional anthropogenic driver of deoxygenation. In regions where primary production isn't macronutrient-limited, reduced grazing pressure increases export production and organic particle remineralisation, decreasing oxygen inventory. Using an Earth system model, the authors estimate this could decrease oxygen inventory by as much as 10% in the North Pacific and accelerate global oxygen loss by 0.2-0.5% relative to 1960 values by 2020. While significant uncertainty exists, this highlights a novel feedback between plastic pollution and ocean deoxygenation.

K. Kvale, A. E. F. Prowe, C.-T. Chien, A. Landolfi, A. Oschlies