NASA A regional eddy-resolving carbon cycle model surrounding the

1. Eddy-driven changes in phytoplankton community composition and biogeochemical cycling in the Sargasso Sea VIMS NASA A regional eddy-resolving carbon cycle model surrounding the Bermuda Atlantic Time-Series Study (BATS) site: analysis of remotely sensed and in situ observations http://science.whoi.edu/users/mcgillic/tpd/anim.html NSF EDdy Dynamics, MIxing, Export, and Species composition http://science.whoi.edu/users/mcgillic/eddies/Eddies_Project.html

2. New Production in the Open Ocean

3. Hypotheses H1: Eddy-induced upwelling, in combination with diapycnal mixing in the upper ocean, introduces new nutrients into the euphotic zone. H2: The increase in inorganic nutrients stimulates a physiological response within the phytoplankton community. H3: Differing physiological responses of the various species bring about a shift in community structure. H4: Changes in community structure lead to increases in export from, and changes in biogeochemical cycling within, the upper ocean.

4. Three types of eddies in the Sargasso Sea Depth Conceptual model: Cyclones and Mode-Water Eddies will cause plankton blooms as they form and intensify.

5. Objectively Mapped Sea Level Anomaly Real time data feed: Bob Leben, CCAR http://www-ccar.colorado.edu/realtime/nwatlanticreal-time_ssh).

6. Cyclone C1 Temp. Sal. Fluor. O2 Sat SLA and shipboard ADCP Hydro Section: 0-250m

7. C1 Phytoplankton Species Composition CHORS HPLC + Letelier et al. (1993)

8. Cyclone C1 oxygen profiles Inside Survey 1 Outside Survey 1 Inside Survey 2 BATS Envelope Implied remineralization: 1-3 X ANP

9. Target Feature A4 Cross Section Sea Level Anomaly

10. A4 Chl Peak vs. BATS 1988-2003 Shipboard cell counts: Chaetoceros spp. 8000 colonies l-1 15 cells per colony = ~105 cells l-1 Typical diatom conc: 1-10 cells l-1 A4 enhancement: 4-5 orders of magnitude above background CHORS HPLC: diatoms>60% total Chl a A4 Peak = 1.4 # Observations μg Chl a l-1 BATS: mean=.28; std=0.14; max=1.15

11. MODIS Image of A4August 6, 2005 Chlorophyll SST

12. A4 Productivity vs. BATS 1988-2003 Primary Production (mg C m-3 d-1)

13. A4 Deep Oxygen Anomaly BATS envelope Implied remineralization = 1.6 X ANP

14. A Regional Hindcast Model Around BATS Valery Kosnyrev http://science.whoi.edu/users/mcgillic/tpd/tpd.html

15. BATS Retrospective Analysis 1993-1995 Sweeney et al. (2003) % total Chl BATS HPLC + Letelier et al. (1993) Blue: Cyclones Red: Anticyclones Pink: Mode-water Eddies

16. Why are Mode-water eddies so productive? • Enhanced mixing: trapping and amplification of • near-inertial motions (Kunze, 1985) • Upwelling due to eddy-wind interactions • (Martin and Richards, 2001)

17. Martin and Richards

18. Upwelling calculations for A4 Vertical velocity wave=0.27 m d-1 QSCAT Ship

19. Revisions to the conceptual model Picoplankton Diatoms

20. Conclusions EDDIES data document extreme variability Chl a, 14C Productivity, O2 Cyclones and MWEs produce phytoplankton blooms MWEs: extraordinary (relative to BATS) sustained diatom biomass MWEs favor enhanced nutrient supply enhanced mixing upwelling (wind + heating) Export flux can be inferred from O2 anomalies in the aphotic zone C1 signal: 1-3 x ANP: “The Smoking Gun”

21. A High Resolution Model of the North Atlantic WHOI LANL Dennis McGillicuddy Mat Maltrud Larry Anderson Rick Smith Scott Doney Cyclones + MWEs; τ (ua,uo); diatoms + picoplankton

22. End

23. ADCP Shear: C5, A4, C3 (OC415)

24. Cyclone C1 oxygen profiles Inside, Survey 1 Outside, Survey 1 Inside, Survey 2 Implied remineralization: 1-3 X ANP

25. A4 Productivity vs. BATS 1988-2003 BATS: blue dots 14C Productivity Inside A4 Core Depth (m) PP (mg C m-3 d-1)

26. BATS Retrospective Analysis 1993-1995 Sweeney et al. (2003) BATS HPLC + Letelier et al. (1993) % total Chl Blue: Cyclones Red: Anticyclones Pink: Mode-water Eddies