High mesopelagic carbon remineralization traced by particulate biogenic barium in the North Atlantic Ocean

The high resolution section of particulate “excess Ba” (Baxs) measured by Lemaitre and co-authors (2018, see reference below) along the GEOVIDE GA1 section (R/V Pourquoi Pas? spring 2014) confirmed the ability of this parameter as proxy of the particulate organic carbon (POC) remineralization. Despite their importance for the biological pump quantification, POC remineralization data are still very scarce in the world ocean (see figure B below). Lemaitre’s work is a major contribution: besides validating the relationship between Baxs and oxygen consumption, it revealed significant remineralization rates at the time and location of the cruise, allowing establishing a biological pump scheme along the section (see figure C below). The link between the estimated POC export fluxes and the surface ecosystems is also discussed.

18 Lemaitre lFigure: (A) Relationship of the mesopelagic Baxs concentration versus the O2 consumption rate using the Southern Ocean transfer function (Dehairs et al., 1997) and the transfer function obtained in this study for the North Atlantic. (B) Summary of published POC remineralisation fluxes in the world ocean. (C) General schematic of the biological carbon pump in different provinces of the North Atlantic during GEOVIDE. Click here to view the figure larger.

Reference:

Lemaitre, N., Planquette, H., Planchon, F., Sarthou, G., Jacquet, S., García-Ibáñez, M. I., Gourain, A., Cheize, M., Monin, L., André, L., Laha, P., Terryn, H., Dehairs, F. (2018). Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic. Biogeosciences, 15(8), 2289–2307. http://doi.org/10.5194/bg-15-2289-2018

Latest highlights

Science Highlights

Dissolved iron and manganese fates reveal processes along the hydrothermal TAG plume

González-Santana and co-workers performed high-spatial resolution analyses of dissolved iron and manganese samples collected at the Mid Atlantic Ridge

20.10.2020

Science Highlights

The power of combining geochemical tracer data with direct current measurements

Learn about new discoveries done combining seawater Rare Earth Elements concentrations and direct physical oceanographic observations

14.10.2020

Science Highlights

Loss of old Arctic sea ice increases methylmercury concentrations

Researchers from the SCRIPPS, the Stockholm Natural Museum and the Mediterranean Institute of Oceanography show the importance of sea ice composition on methylmercury budgets

02.09.2020

Science Highlights

Estimating Atmospheric Trace Element Deposition Over the Global Ocean

A recently developed method based on the natural radionuclide beryllium-7 has provided a means to estimate the bulk atmospheric trace element deposition velocity

Rechercher