Yager MANTRA talk081804

MANTRA/PIRANA CO2 Data Status(as of August 15, 2004): 

MANTRA/PIRANA CO2 Data Status (as of August 15, 2004)

Slide2: 

Sarah Cooley The Role of the Amazon Plume in the Western Tropical Atlantic Ocean Inorganic Carbon Budget

Is the Amazon Plume a CO2 sink?: 

Is the Amazon Plume a CO2 sink? Ternon et al., Mar. Chem., 1999 Ternon cruises (fall, spring 95-96) found depressed salinity in conjunction w/ lowered fCO2

Slide4: 

Körtzinger, GRL, 2003 Conclusions: fCO2 = K*salinity Plume = CO2 sink Kortzinger saw same effects far offshore. Both studies common conclusions are that fco2 is roughly proportional to salinity, and the plume can act as a co2 sink b/c it’s undersaturated WRT the atmosphere.

Atlantic Cruise Tracks: 

M/P 8, April - May 2003 Atlantic Cruise Tracks M/P 1, January-February 2001 M/P3, June-August 2001

Slide6: 

MP8 underway pCO2 (in situ temp; Lanczos filter (3h))

Slide7: 

MP1 and MP3 pCO2 (calculated from discrete DIC andamp; ALK surface samples)

Mechanisms?: 

Mechanisms? H0: Physical mixing of Amazon plume and Atlantic is the sole cause for lowered summer DIC, TA H1: If physical mixing doesn’t fully account for observations, biological activity is also responsible.

DIC, TA data, all cruises: 

DIC, TA data, all cruises

Possible Biological Effects: 

Z DIC Production Summer Winter Winter SML Expected Z Respiration Winter SML DIC Enhanced production? Or enhanced respiration? Summer Expected Winter Possible Biological Effects S.R. Cooley

Biological/Physical Effects : 

Biological/Physical Effects Mixing model calculates proportional contributions of plume, seawater (Assumes conservative TA, salinity) Calculate predicted DIC Compare predicted, observed DIC plume seawater observed

Slide12: 

Mass balance: Mixing Model To determine relative contributions of River (R), Precip (P), Evap (E), and Ocean (O) R + P - E + O = 1 SrR + SpP - SeE + SoO = Sobs ArR + ApP -AeE + AoO = Aobs P/E (or P-E) = n Where: End member salinities: End member Alkalinities: n varies monthly Sr = 0.0 Ar = 325 µmol/kg Sp = 0.0 Ap = 0.0 µmol/kg Se = 0.0 Ae = 0.0 So = 36.05 Ao = 2365 µmol/kg

Summer plume influence: 

Summer plume influence

Slide14: 

Mass balance Use the calculated relative contributions of River (R), Precip (P), Evap (E), and Ocean (O) to determine Oceanic Carbon (Co) from the Observed Carbon (Cobs) CrR + CpP - CeE + CoO = Cobs Co = Cobs - CrR - CpP + CeE O Where: Fractions R, P, E, and O End member DIC concentrations: are calculated from Cr = 325 µmol/kg Salinity and Alk mass Cp = 14 µmol/kg balance Ce = 0.0 µmol/kg

Slide15: 

Slide16: 

39 27 49 43 (1 m) 43 (5 m) 43 (10 m) 23 (4; 1 m) 23 (27; 10 m) 23 (27; 1 m) 23 (21; 1 m) Oceanic DIC is calculated by a mixing model that removes the effects of the river, precip, and evap. Changes from the winter background (~2020) are presumed to be due to biological activity.

Slide17: 

Alternatively, you can project what DIC you would expect from the mixing model and compare to observations. MP3 Monte Carlo Error Analysis (n=1000)

Slide18: 

MP8 (Note scale shift from MP3)

Slide19: 

27 39 43 (5 m) 17 44 46 52 53 (17) 53 (2) 33

Slide20: 

33 35 49 53 39 52 41 44 48 29 No POC data yet available for Sta 23 No DOC data yet available for Sta 43

Slide21: 

39 49 46 35 33 30 21 39 41 No DOC data yet available for Sta 23, 27,43 22

July plume conditions: 

July plume conditions Inshore Offshore Mixing 5.9 x 1010 1.9 x 109 1.5 x 109 2.8 x 109 1.2 x 109 1.3 x 1013 4.2 x 1013 ?? Units in g C d-1 S. Cooley

II. OC Export Estimates: 

II. OC Export Estimates Coupled mass-balance of DIC, DI13C in SML Use M/P DIC and TA values Analyze additional samples for DI13 C Average air-sea ∆pCO2 from in-line pCO2 data Quantify OC export rates from photic zone in spring season CT CT CT

Slide24: 

Zhang andamp; Quay 1997

Slide25: 

Slide26: 

MP2 (April 2001) MP5 (Jun-Jul 2002) MP6 (Sep-Oct 2002) Surface Ocean fCO2 (µatm)

Slide27: 

MP6 pCO2 (assumes constant SST = 25)

Slide28: 

Qualitative correlation between DIC in SML and N* at 200m

Slide29: 

Slide30: 

SigmaT DIC (µmol/kg) ALK (µmol/kg) MP9 Station 17