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Assessment of carbon export and mineralization during KEOPS

Assessment of carbon export and mineralization during KEOPS (contribution of VUB & MRAC, Brussels). N. Savoye (VUB) D. Cardinal (MRAC) S. Jacquet (VUB) M. Elskens (VUB) F. Dehairs (VUB). KEOPS meeting, Endoume, 2&3 March 2004. CO 2. Primary production. nutrients. Export production.

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Assessment of carbon export and mineralization during KEOPS

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  1. Assessment of carbon export and mineralization during KEOPS (contribution of VUB & MRAC, Brussels) N. Savoye (VUB) D. Cardinal (MRAC) S. Jacquet (VUB) M. Elskens (VUB) F. Dehairs (VUB) KEOPS meeting, Endoume, 2&3 March 2004

  2. CO2 Primary production nutrients Export production DOC, DON Context Ocean surface Euphotic zone Mixed layer  KEOPS meeting, Endoume, 2&3 March 2004

  3. Primary and new production (13C, 15N, f-ratio) Export production (234Th) Primary production nutrients Mineralization (part. mesopel. Baex) Export production DOC, DON Context Ocean surface Euphotic zone Mixed layer  KEOPS meeting, Endoume, 2&3 March 2004

  4. 234Th, 238U (dpm l-1) 234Th 238U POC:234Th ratio of sinking particles POC flux (g m-2 d-1) Export production estimated from 234Th-deficit: principle 238U 234Th (t1/2=24d) secular equilibrium Thorium: strong adsorption on particles 234Th flux (dpm m-2 d-1) KEOPS meeting, Endoume, 2&3 March 2004

  5. BaXS (pmol l-1) 0 (Dehairs et al., 1997) 200 Meso-Baxs = 17200 x JO2 +185 400 Redfield O2/C ratio (175/127) 600 800 Mineralized carbon 1000 Mesopelagic BaXS informs on carbon mineralization KEOPS meeting, Endoume, 2&3 March 2004

  6. Particulate Ba: CLIVAR-SR3 (140°E); Spring 2001 Cardinal et al., submitted to DSR I KEOPS meeting, Endoume, 2&3 March 2004

  7. CLIVAR-SR3 (2001) 140°E Early spring ANTARES 4 (1999) Summer (Crozet-Kerguelen Basin SAZ ’98 (1998) 140°E Summer KEOPS meeting Endoume 2&3 March 2004

  8. 140°E CLIVAR-SR3 SAZ’98 Summer (SAZ ’98) Spring CLIVAR-SR3 KEOPS meeting Endoume 2&3 March 2004

  9. STF SAZ +31 d SAF PFZ PF-N ice edge IPFZ PF-S AZ-S +17 d SACCF Southern +11 d SIZ SBACC Clivar SR3 cruise: October 30 – December 14, 2001 Tasmania 45°S 50°S 55°S 60°S 65°S Antarctica 135 140 145 150°E KEOPS meeting, Endoume, 2&3 March 2004

  10. SAZ SIZ SAF PFZ IPFZ AZ-S PF-S PF-N SACCF 1.0 40 0.8 30 0.6 C production (mmol C/m2/d) 20 New production f-ratio 0.4 10 0.2 Latitude (°S) f-ratio 0.0 0 13C-uptake 48 50 52 54 56 58 60 62 64 66 Primary and new production From Savoye et al., GRL, 2004 KEOPS meeting, Endoume, 2&3 March 2004

  11. 40 2000 35 30 1500 25 C flux (mmol m-2 d-1) 20 234Th flux (dpm m-2 d-1) 1000 15 10 SAZ SIZ SAF PF-S PFZ IPFZ AZ-S PF-N SACCF 500 5 0 0 46 51 56 61 66 Latitude (°S) 234Th flux C flux 234Th fluxes and export production Collaboration with K. Buesseler (WHOI) T. Trull (ACE-CRC) M. Rutgers van der Loeff (AWI) KEOPS meeting, Endoume, 2&3 March 2004

  12. 600 4.0 3.5 500 3.0 400 2.5 meso-BaXS (pmol/l) 300 2.0 C mineralization (mmol m-2 d-1) 1.5 SAZ 200 SIZ SAF PF-S PFZ IPFZ AZ-S PF-N SACCF 1.0 100 0.5 0 0.0 Latitude (°S) 46 51 56 61 66 meso-Baxs C mineralization mesopelagic BaXS and carbon mineralization From Cardinal et al., submitted to DSR I KEOPS meeting, Endoume, 2&3 March 2004

  13. 40 35 30 25 C flux (mmol C/m2/d) 20 15 SAZ SIZ SAF PF-S PFZ IPFZ AZ-S PF-N SACCF 10 5 0 46 51 56 61 66 Latitude (°S) New production 13C uptake C export C mineralization Carbon cycle from surface to mezopelagic layers KEOPS meeting Endoume 2&3 March 2004

  14. 100 80 100 New production 60 80 export production 40 60 % of primary production mesopelagic C mineralization 20 40 0 20 SAZ SIZ SAF PF-S PF-N SACCF PFZ IPFZ AZ-S 0 46 51 56 61 66 % of new production % of export production mesopelagic C mineralization % of primary production Carbon cycle from surface to mesopelagic layers KEOPS meeting, Endoume, 2&3 March 2004

  15. 25 20 15 Mesopelagic C-mineralization (% of primary production) 10 5 0 0 10 20 30 40 Diatom C (% of phytoplankton C) Mesopelagic C mineralization and diatoms y = 0.4938x + 4.1764 R2 = 0.72 y = 2.05 x0.66 R2 = 0.90 KEOPS meeting, Endoume, 2&3 March 2004

  16. Future developments • Comparison with deep ocean sediment trap flux data • Focus on time series (EIFEX, KEOPS, VERTIGO, ..) to track the dependency of export and mineralization on production, processes that are not necessarily in phase • Focus on O2 consumption measurements during time series to better constrain mesopelagic mineralization and BaXS accumulation KEOPS meeting, Endoume, 2&3 March 2004

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