Effect of Intensity and Mode of Artificial Upwelling on Particle Flux and Carbon Export

• DOI: 10.3389/fmars.2021.742142
• Publication Date: 2021-10-27T04:41:07Z
• Authors: Moritz Baumann; Jan Taucher; Allanah J. Paul; Malte Heinemann; Mari Vanharanta; Lennart T. Bach; Kristian Spilling; Joaquin Ortiz; Javier Arístegui; Nauzet Hernández-...; Isabel Baños; Ulf Riebesell
• Keywords: Biological pump; Redfield ratio; Carbon fibers; Total inorganic carbon; Mesocosm

Reduction of anthropogenic CO 2 emissions alone will not sufficiently restrict global warming and enable the 1.5°C goal Paris agreement to be met. To effectively counteract climate change, measures actively remove carbon dioxide from atmosphere are required. Artificial upwelling has been proposed as one such removal technique. By fueling primary productivity in surface ocean with nutrient-rich deep water, it could potentially enhance downward fluxes particulate organic (POC) sequestration. In this study we investigated effect different intensities artificial combined two modes (recurring additions vs. singular addition) on POC export, sinking matter stoichiometry remineralization depth. We carried out a 39 day-long mesocosm experiment subtropical North Atlantic, where fertilized oligotrophic waters amounts water. The total nutrient inputs ranged 1.6 11.0 μmol NO 3 – L –1 . found that hand export under more than doubled, molar C:N ratios increased values around Redfield (6.6) ∼8–13, which is beneficial for potential removal. On other hand, was remineralized at faster rates showed lower velocities, led shallower depths. Particle properties were favorable recurring mode, while mode increase pronounced. both roughly half produced retained water column until end experiment. This suggests plankton communities still process adjustment, possibly due response times producers consumers. There thus need studies longer experimental durations quantify responses fully adjusted communities. Finally, our results revealed affects variety particle properties, intensity applied control strength effects.