The Global Ocean Carbon Cycle Rik Wanninkhof, NOAA/AOML Annual OCO review, June 2007: Celebrating Our Past, Observing our Present, Predicting our Future: Ocean Observations as a Key to Global Understanding.

“Jean Baptiste Fourier is credited with the discovery in his essay in 1827 that gases in the atmosphere might increase the surface temperature of the Earth” Wikipedia The NOAA Carbon groups highlight: 180 years of greenhouse gas research NOAA highlights 200 years of science, service, and stewardship.

The Overriding questions: 8 Pg C/yr released to the atmosphere ≈ 4 ppm increase 4 Pg C/yr remains ≈ 2 ppm Where does the remaining C go to? How does this change with time? What causes the changes? What are the ecosystem impacts?

CO 2 Research Breakthroughs and New Questions Arising from OCO Sponsored Observations Three major programs: 1.Global Ocean CO 2 inventories 2.Air-Sea CO 2 fluxes from ships and moorings 3.Data Management, Analysis and Synthesis 4.(Coastal Carbon Research)

1. Global Ocean CO 2 Inventories CLIVAR/CO2 Repeat Hydrography Sponsors:NOAA/OCO, NSF/OCO Participants: (NOAA funded) PMEL/AOML & CI’s Measurements: CO 2, hydro, nutrients, O 2, CFC, SF 6 I8S/I9N January/April, 2007

Determine the Decadal Uptake of Anthropogenic CO 2 Uncertainty: < 4 Pg/C/decade (out of an estimated 20 Pg C) Approach: Differencing with previous inventory estimates Findings: Atlantic Pacific 25 ˚W 152 ˚W (mol m -2 yr -1 ) Northern Hemisphere Southern Hemisphere [Global estimate : 0.5 mol/m 2 /yr ] But: ∆ = C anthro + ∆C Natural + ∆C Climate ≠ 0≠ 0 Ocean biogeochemistry not in steady state on decadal timescales Research question: How to determine anthropogenic CO 2 ? Eastern Pacific 153 ˚W Sabine et al. BAMS, 2007

I8S-I9N Re-occupation Courtesy J. Bullister, PMEL

Research/observational needs- Inventories -Need better estimates of changes in productivity and respiration - Need better estimates of ventilation and mixing - Use of transient tracers, such as SF 6 Bullister and Sonnerup, 2007

Objective: Constrain regional air-sea CO 2 fluxes to 0.2 Pg C year Findings: Global climatology estimate 30 % less than previous (Attributed to increased data and improved procedures, not global change) Interannual variability ≈ 10 % 2. Surface water CO 2 (Moorings and ship of opportunity)

Updated Air-Sea CO 2 Flux Climatology Uptake = 1.2 Pg C year Takahashi et al. 2007

2. Models suggest a positive feedback in SO- Increasing winds- increasing upwelling-increasing pCO 2w Research question: Are there (positive) feedbacks? Le Quere et al. Science May, North Atlantic observations suggest decreasing uptake

Collaborations in the North Atlantic and North Pacific Started 2002, operational 2005 onwards Courtesy D. Bakker CarboOcean

3. Data Management, Analysis and Synthesis  Production of flux maps [ F = k s ∆pCO 2 ]  North Atlantic and North Pacific synthesis  LAS server for pCO 2 data - Takahashi climatology - Takahashi database - Original data

4. Coastal CO 2 : What are the magnitudes and what causes the variations in CO 2 fluxes in coastal region? State Of the Carbon Cycle Report (SOCCR): Northern Regions: Sink ≈ 0.2 Pg C Southern regions Source ≈ 0.2 Pg C

Coastal Survey Cruises First Synoptic Measurements of CO 2 along the coasts

Jiang et al., In Preparation Determination of Seasonal Cycles of pCO 2 in Coastal Regions Excursions in pCO 2 in coastal ocean >> open ocean

Coastal (upwelling) regions sensitive to ocean acidification When pCO 2 levels in seawater approach 1000 µatm dissolution of calcium carbonate (aragonite) will occur. Coastal upwelling regions such as the Peru upwelling system, the Arabian Sea, West Coast of US, and near bathymetric features in the US experience such levels in the surface water and could serve as test beds for ocean acidification research.

Thank you

And now to deflect the first question: The New Yorker May 28, 2007