1. A Recipe for Ocean Productivity, with Variations John Marra Lamont-Doherty Earth Observatory Palisades, NY USA

2. What I’m going to talk about An alternate (sort of) algorithm for remotely-sensed primary productivity An alternate (sort of) algorithm for remotely-sensed primary productivity Absorption and Pigments in phytoplankton, and in the algorithm Absorption and Pigments in phytoplankton, and in the algorithm Variations caused by mesoscale phenomena Variations caused by mesoscale phenomena

3. An alternate (non-B&F) model of remotely-sensed primary productivity P(z) =  (E,N)  a* ph  [Chla(z)]  E(z) Agreement found between pigment and irradiance and 14 C uptake in several studies Agreement found between pigment and irradiance and 14 C uptake in several studies Coupled: based on absorption properties of the ocean, and has some stability Coupled: based on absorption properties of the ocean, and has some stability Allows for physiological adaptation Allows for physiological adaptation Challenge is to understand how quantum yield and absorption vary with environmental properties Challenge is to understand how quantum yield and absorption vary with environmental properties

4. Agreement found between calculations based on pigment and irradiance, with 14 C uptake in different areas C assim. (calculated) C assim. (observed) Units: mmols C m -3 d -1 Boreal NA Gulf of Maine Sargasso Sea

5. Productivity Algorithm: What we need to know, minimum Variability in Quantum Yield? Variability in Quantum Yield? Chlorophyll-a as a function of depth? Chlorophyll-a as a function of depth? Chlorophyll-specific absorption as a function of depth? Chlorophyll-specific absorption as a function of depth? Spatial variability of Chlorophyll-specific absorption? Spatial variability of Chlorophyll-specific absorption? Function of irradiance; constant maximum Gaussian (sub-surface max) up to a threshold Assumed constant with depth; averaged over Assumed constant with depth; averaged over Varies with SST? Current version of the model

6. How the algorithm is (somewhat) stabilized and coupled. Productivity (Euphotic Depth) Irradiance Absorption Chlorophyll increase decrease increase decrease (all else being equal) increase …but basing an algorithm on absorption means also knowing absorption from water and other components

7. Phytoplankton Absorption and Environmental Variables Community composition Environmental variables Absorption spectra

8. Absorption in Phytoplankton Objective is to create rules for the geographic and temporal variability in a* ph (sensu Hoepffner and Sathyendranath, 1992) Objective is to create rules for the geographic and temporal variability in a* ph (sensu Hoepffner and Sathyendranath, 1992) Avoid using relationships based on the [Chl-a] (e.g., Bricaud et al., 1995; Cleveland, 1995) Avoid using relationships based on the [Chl-a] (e.g., Bricaud et al., 1995; Cleveland, 1995)  Up to now it seems that a * ph ( ) is only considered in terms of the biological effects: pigment packaging and species composition, cell size.  Chlorophyll-a: as biomass, as an adaptable property, as a trophic indicator? Assume that a* ph does not vary within the first two optical depths (literature supports, but not unanimous) Assume that a* ph does not vary within the first two optical depths (literature supports, but not unanimous)

9. How we might expect absorption properties to vary with SST Absorption Sea-Surface Temperature a*p? a*ph? a*ps? (Not a physiological relationship!)

10. Chlorophyll-specific absorption and SST Sea Surface Temperature (ºC) a*ph (m 2 mg chl -1 ) (Marra and Trees, submitted)

11. P B opt and Temperature? Temperature (ºC) P B opt [(mgC)(mgChl) -1 h -1 )] (thanks to J. Cullen’s presentation at the Bangor Productivity Conference, March 2002) (Based on physiology)

12. A Sample View of Algorithm Output: January, 1998 gC m -2 d -1

13. The Oceanic Mesoscale and Phytoplankton Variability Two studies, two anti-cyclonic eddies, both hemispheres Two studies, two anti-cyclonic eddies, both hemispheres Eddy Haulani off the island of Hawaii Eddy Haulani off the island of Hawaii An eddy spawned by the Leeuwin Current (off W. Australia) An eddy spawned by the Leeuwin Current (off W. Australia)

14. Vaillancourt, Marra, Bidigare, and Seki., submitted The birth of the eddy, Haulani, near Hawaii I in Fall, 2000

15. Eddy Haulani as Ocean Color Vaillancourt et al., submitted 19 November, 2000 (Dotted line indicates SST feature for same date) SeaWiFS image, courtesy NASA GFSC and Orbital Sciences Corp.

16. Community composition in and out of the Hawaii eddy Larger forms are found in greater numbers inside the eddy. (Picoplankton do not change much.)

17. Eddies in the Leeuwin Current …Thomas Moore, LDEO and CSIRO, Hobart

18. The anti-cyclonic (“convergent”) eddy with the ocean color signal

19. From Moore et al., 2001 Anti-cyclonic eddy We then compared the pigment composition of coastal water and that in the eddy….

20. Pigment analysis of coastal (Sta 52) and eddy (Sta 62) samples Total quantity of pigment is the same Total quantity of pigment is the same Pigment composition nearly the same (loss of alloxanthin, fucoxanthin, Chl c1+c2) Pigment composition nearly the same (loss of alloxanthin, fucoxanthin, Chl c1+c2) Coastal Offshore eddy, 3 months later From Moore et al., 2001

21. So, in conclusion… The Productivity Algorithm: promising, but needs work The Productivity Algorithm: promising, but needs work  How does phytoplankton absorption vary with environmental properties?  What about other absorbing components?  Quantum yield parameterization?  Non-absorption based observations (e.g., FRRF)  Environmental determinants to  max Instead of PvsE parameters (like P B opt ), focus on a ph and pigments Instead of PvsE parameters (like P B opt ), focus on a ph and pigments Go from satellite reflectances -> productivity? Go from satellite reflectances -> productivity? We need to understand the differences caused by vertical as opposed to horizontal processes in eddies We need to understand the differences caused by vertical as opposed to horizontal processes in eddies

22. Variations in Quantum Yield Vaillancourt et al., in press, DSR II