EGU22-10868
https://doi.org/10.5194/egusphere-egu22-10868
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

A weak role for Southern Ocean nutrient drawdown in low latitude marine export production

Keith Rodgers1,2, Olivier Aumont3, Katsuya Toyama4, Laure Resplandy5,6, Masao Ishii4, Keith Lindsay7, Ryohei Yamaguchi1,2, Daisuke Sasano8, and Tohiya Nakano8
Keith Rodgers et al.
  • 1IBS Center for Climate Physics (ICCP), Pusan National University, Busan, Korea, Republic of (krodgers@pusan.ac.kr)
  • 2Pusan National University, Busan, Republic of Korea
  • 3Sorbonne Universités, UPMC, Univ. Paris 06-CNRS-IRD-NHNH, LOCAN/IPSL, Paris, France
  • 4Oceanography and Geochemistry Research Department, Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan
  • 5Princeton University, Department of Geosciences, Princeton, NJ, USA
  • 6Princeton Environmental Institute, Princeton, NJ, USA
  • 7National Center for Atmospheric Research, Boulder, CO, USA
  • 8Global Environmental and Marine Department, Japan Meteorological Agency, Tokyo, Japan

The low-latitude ocean regions spanning 30°S-30°N are thought to account for more than 50% of the global export production. However, previous analyses of paleo-proxy records and modeling studies strongly suggest contradictory evidence as to whether low latitude nutrient cycling and export production is locally or non-locally controlled. Here we address this question through the new application of observational (PACIFICA) and modeling (NEMO-PISCES) tools and show that low latitude recycling of nutrients within the thermocline overturning structures is largely responsible for sustaining low latitude export production (60%) for the mean state, with only second-order controls from the injection of new (preformed) nutrients from the Southern (16%) and northern (9%) oceans.  The implications for understanding controls on long-term changes under sustained anthropogenic climate perturbations is investigated using CMIP6 Earth system models under idealized 4xCO2 forcing, where significant reductions in low-latitude export production and net primary production over 30°S-30°N are investigated.

How to cite: Rodgers, K., Aumont, O., Toyama, K., Resplandy, L., Ishii, M., Lindsay, K., Yamaguchi, R., Sasano, D., and Nakano, T.: A weak role for Southern Ocean nutrient drawdown in low latitude marine export production, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10868, https://doi.org/10.5194/egusphere-egu22-10868, 2022.