PERSPECTIVES ON MECHANISMS DRIVING PARTCULATE ORGANIC CARBON (POC) FLUX: INSIGHTS FROM MEDFLUX
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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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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


Ocean carbon cycle l.jpg
Ocean Carbon Cycle (POC) FLUX: INSIGHTS FROM MEDFLUX

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)

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Why care about sinking particulate matter? (POC) FLUX: INSIGHTS FROM MEDFLUX

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)


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Sargasso Sea Fluxes (POC) FLUX: INSIGHTS FROM MEDFLUX

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)

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Sargasso Sea Elemental Fluxes (POC) FLUX: INSIGHTS FROM MEDFLUX

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)

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Martin Open Ocean Composite Curve (POC) FLUX: INSIGHTS FROM MEDFLUX

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)

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Biological Carbon Pump (POC) FLUX: INSIGHTS FROM MEDFLUX

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)


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POC flux and major biochemical abundances in the (POC) FLUX: INSIGHTS FROM MEDFLUX

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)

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Carbon fluxes and concentrations behave differently. (POC) FLUX: INSIGHTS FROM MEDFLUX

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)

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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)

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What should physically protect a fraction of their associated organic matter, and 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?

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U.S. Collaborators: physically protect a fraction of their associated organic matter, and 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.

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MONACO physically protect a fraction of their associated organic matter, and

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.

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Slide 4 physically protect a fraction of their associated organic matter, and

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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.)

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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

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MedFlux 2003 200-500 m/d.

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


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Elutriator 200-500 m/d.

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Most material falls at rates greater than 230 m/d. 200-500 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


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Organic Biomarkers as Diagenetic Indices 200-500 m/d.

(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)

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Principal components analysis of amino acids in elutriated NetTrap samples

Slower sinking particles

(NT 4 & 5)

Faster sinking particles

(NT 1-3)

MedFlux 2003

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MedFlux 2003 NetTrap samples

Opal

May-July

March-May

CaCO3

+ Litho

OM

(Xue et al. In prep)

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MedFlux 2003 NetTrap samples

Opal

CaCO3

+ Litho

OM

(Xue et al. in prep)

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Laboratory experiment comparing NetTrap samples

naked and calcified coccolithophorids

(Lee, Engel et al. In prep)

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MedFlux 2005 NetTrap samples

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  • “Unified Ballast-Aggregation Theory of Export” NetTrap samples

  • 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.

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