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ASLO 2005 Summer Meeting

PERSPECTIVES ON MECHANISMS DRIVING PARTCULATE ORGANIC CARBON (POC) FLUX: INSIGHTS FROM MEDFLUX Cindy Lee, Rob Armstrong, Anja Engel, Jianhong Xue, Aaron Beck, Zhanfei Liu, Kirk Cochran, Michael Peterson, Stuart Wakeham, and Juan-Carlos Miquel. ASLO 2005 Summer Meeting. Ocean Carbon Cycle.

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ASLO 2005 Summer Meeting

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  1. PERSPECTIVES ON MECHANISMS DRIVING PARTCULATE ORGANIC CARBON (POC) FLUX: INSIGHTS FROM MEDFLUXCindy Lee, Rob Armstrong, Anja Engel, Jianhong Xue, Aaron Beck, Zhanfei Liu, Kirk Cochran, Michael Peterson, Stuart Wakeham, and Juan-Carlos Miquel ASLO 2005 Summer Meeting

  2. Ocean Carbon Cycle Pool units: 1015 gC Flux units: 1015 gC/y Intermediate and deep ocean 38,100 (from Doney, S.C. and D. Schimel 2002. Global change - The future and the greenhouse effect. Encyc. Life Sci., Macmillan Publ. Ltd., www.els.net) 2/26

  3. Why care about sinking particulate matter? It is one of the few processes that removes C from the ocean for long enough to ameliorate the increasing CO2 concentration over time. Bermuda Atlantic Time-Series Station 3/26 (from USJGOFS Image Gallery)

  4. Sargasso Sea Fluxes Phytoplankton Biomass (monthly average) Organic Carbon Flux (bimonthly average) Carbonate Flux Organic C Flux CZCS pigments (mg C/m2d) (mg C/m2d) (mg/m3) Inorganic Carbon Flux (bimonthly average) (Deuser, W.G., F. E. Müller-Karger, R. H. Evans, O. B. Brown, W.E. Esaias and G. C. Feldman. 1990. Surface-ocean color and deep-ocean carbon flux: How close a connection? Deep-Sea Res. II 37: 1331-1343) 4/26

  5. Sargasso Sea Elemental Fluxes Ca Al Mg Sr Mn Ti Ba Vx10 I (Deuser, W. G., E. H. Ross and R. F. Anderson. 1981. Seasonality in the supply of sediment to the deep Sargasso Sea and implications for the rapid transfer of matter to the deep ocean. Deep-Sea Res. 28: 495–505) 5/26

  6. Martin Open Ocean Composite Curve F=1.53(z/100)-0.858 (Martin, J.H., G.A. Knauer, D.M. Karl, W.W. Broenkow. 1987. VERTEX: carbon cycling in the northeast Pacific. Deep-Sea Res. 34: 267-285) 6/26

  7. Biological Carbon Pump CO2 N2 fixation of C, N by phytoplankton respiration grazing excretion physical mixing of DOC egestion aggregate formation Lateral advection break up Base of euphotic zone active vertical migration passive sinking of POC, PIC consumption, repackaging decomposition respiration (zooplankton) (bacteria) excretion Seabed 7/26 (from OCTET Report, 2000)

  8. POC flux and major biochemical abundances in the Equatorial Pacific 2 Percent of Organic Carbon POC Flux, mg/m d 0.01 100 20 40 60 80 0 1.0 100 Plankton Amino Acid 105 m Trap 1000 m Trap Uncharacterized Lipid >3500 m Trap Sediment Carbohydrate Pigment (Wakeham, S. G. and C. Lee. 1993. Production, transport, and alteration of particulate organic matter in the marine water column. In: M.H. Engel and S. A. Macko (eds) Organic Geochemistry, pp. 145-169. Plenum Press) 9/26

  9. Carbon fluxes and concentrations behave differently. Organic carbon fluxes decrease with depth to varying degrees at different locations. The percent of total mass made up by organic carbon reaches a constant value at depth, ~5%. (Armstrong R. A., C. Lee, J.I. Hedges, S. Honjo and S.G.Wakeham. 2002. A new, mechanistic model for organic carbon fluxes in the ocean based on the quantitative association of POC with ballast minerals. Deep-Sea Res. II, 49: 219-236) 8/26

  10. We hypothesized that ballast minerals on sinking particles physically protect a fraction of their associated organic matter, and that the ratio of organic carbon to ballast is key to predicting variability in export fluxes and sinking velocities of organic carbon. Labile Total Flux Ballast associated (Armstrong et al. 2002) 10/26

  11. What should we know about sinking particles? Are ballast minerals a key to predicting carbon export? What role does aggregation play in sinking? Are ballast and aggregation equally important throughout the water column? Do minerals physically protect a fraction of their associated total organic matter? 11/26

  12. U.S. Collaborators:Lynn Abramson, SUNYRobert Armstrong, SUNYAaron Beck, SUNYKirk Cochran, SUNYAnja Engel, SUNY->AWICindy Lee, SUNY Zhanfei Liu, SUNYMichael Peterson, Seattle Gillian Stewart, SUNYJennifer Szlosek, SUNYStuart Wakeham, Savannah Jianhong Xue, SUNY European Collaborators: Scott Fowler, Monaco Joan Fabres, UB->SUNY Beat Gasser, Monaco Madeleine Goutx, Marseille Catherine Guigue, Marseille Pere Masqué, UAB Juan Carlos Miquel, Monaco Brivaela Moriseau, Brest Olivier Rageneau, Brest Alessia Rodriguez y Baena, Monaco Richard Sempéré, Marseille Christian Tamburini, Marseille Elisabet Verdeny, Barcelona See http://www.msrc.sunysb.edu/MedFlux/ for more information. 12/26

  13. MONACO MedFlux Sampling site Slide 15 To test ballast ideas we collected sinking particles using sediment traps, in-situ pumps and nets at the French JGOFS DYFAMED site in the western Mediterranean. 13/26

  14. Slide 4 14/26

  15. In 2003, mass flux peaked after the spring bloom and rapidly decreased with time at both 200 and 800 m. We measured the percent organic carbon in the trap samples. The percent organic carbon is higher when mass fluxes are lower. MedFlux Time-series Mooring: March-May 2003 (Peterson, M.L., S.G. Wakeham, C. Lee, J.C. Miquel and M.A. Askea. 2005. Novel techniques for collection of sinking particles in the ocean and determining their settling rates. Limnol. Oceanogr. Methods, submitted.) 15/26

  16. At 200 m, highest particle flux occurs at rates between 200-500 m/d. Percent organic carbon is higher at lower settling velocities. MedFlux Settling Velocity Trap: March-May 2003 (Peterson et al. submitted) MedFlux 2003 16/26

  17. MedFlux 2003 Positive correlation Negative correlation Parameters are: %ASP, GLU, HIS, SER, ARG, GLY, BALA, ALA, TYR, GABA, MET, VAL, PHE, LEU, LYS, SER+GLY+THR, TAA, LIPIDS, Neuts/TFA, %MASS, Po, Th234, OC/MASS, IC/MASS, TN/MASS 17/26

  18. Elutriator 18/26

  19. Most material falls at rates greater than 230 m/d. Th activity was higher at lower settling velocities. Total Mass in Elutriator Fractions (g)  Mass 234Th Activity 234Th Activity (dpm/g) MedFlux 2003 19/26

  20. Organic Biomarkers as Diagenetic Indices (Sheridan C.C., C. Lee, S.G. Wakeham, and J.K.B. Bishop. 2002. Suspended particle organic composition and cycling in surface and midwaters of the equatorial Pacific Ocean. Deep-Sea Res. I 49: 1983-2008) 20/26

  21. Principal components analysis of amino acids in elutriated NetTrap samples Slower sinking particles (NT 4 & 5) Faster sinking particles (NT 1-3) MedFlux 2003 21/26

  22. MedFlux 2003 Opal May-July March-May CaCO3 + Litho OM (Xue et al. In prep) 22/26

  23. MedFlux 2003 Opal CaCO3 + Litho OM (Xue et al. in prep) 23/26

  24. Laboratory experiment comparing naked and calcified coccolithophorids (Lee, Engel et al. In prep) 24/26

  25. MedFlux 2005 25/26

  26. “Unified Ballast-Aggregation Theory of Export” • If mineralized plankton aggregate faster, then mineralized plankton would be preferentially exported from the euphotic zone, and aggregation could be considered as the first step in the association between carbon and minerals in sinking particles. Ballast may become more important at depth. • This narrows the possible theories for preservation at depth. • This makes the current acidification of the ocean even more worrisome as increasing acidification dissolves forams and coccolithophorids so that there might be less flux, less organic C export, and thus less CO2 permanently removed from the surface ocean. 26/27

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