# Light and Photosynthesis - PowerPoint PPT Presentation

Light and Photosynthesis

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Light and Photosynthesis

## Light and Photosynthesis

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1. Light and Photosynthesis • Light in the Ocean • Intensity • Color • Inherent Optical Properties • Apparent Optical Properties • Remote Sensing • Photosynthesis • Light Absorption • Light Reactions • Dark Reactions I need a work study student (library work, will pay) Oscar Schofield (oscar@ahab.rutgers.edu)

2. For satellite remote sensing the wavelength is the key to what you want to measure. c = l/u e = hu = hc/l

3. Figure 6

4. 2500 mmol photons m-2 s-1 5.0 mmol photons m-2 s-1 I) Light Irradiance Intensity z1 Ed1 Z (meters) Dz • Because of • Lambert Beers Law • the ocean is dim z2 Ed2 • Plant life is • dependent on light Lambert Beers Law Ed2 = Ed1e-Dz*Kd 3) The 1% light level for the majority of the is 100 m or less?

5. Early Optics Alexander the Great

6. The color of the sea shows a great deal of variability from the deep violet-blue of the open ocean to degrees of green and brown in coastal regions. Before the advent of sensitive optical instruments, color was determined by visual comparison against standard reference standards such as the Forel Ule Color scale.

7. Today Robot-mounted Hyperspectral Absorption meter January 2003

8. Your future will include robots patrolling the waters for you as optical instruments are now small

9. What kind of measurements are there? Inherent Optical Properties: Those optical properties that are fundamental to the piece of water, not dependent on the geometric structure of the light field. (absorption, scattering, attenuation) Apparent Optical Properties: Those optical properties that are fundamental to the piece of water and are dependent on the geometric structure of the light field. (light intensity, reflectance)

10. Why IOP Measurements? • Absorption, a color • Scattering, b clarity • Beam attenuation, c (transmission) a + b = c The IOPs tell us something about the particulate and dissolved substances in the aquatic medium; how we measure them determines what we can resolve

11. Photo S. Etheridge Photo S. Etheridge Why IOP Measurements? • Absorption, a color

12. Why IOP Measurements? • Absorption, a • Scattering, b clarity

13. Review of IOP Theory Fo Ft Incident Radiant Flux Transmitted Radiant Flux No attenuation

14. Review of IOP Theory Fo Ft Incident Radiant Flux Transmitted Radiant Flux Attenuation

15. Fa Absorbed Radiant Flux Loss due to absorption Fo Ft Incident Radiant Flux Transmitted Radiant Flux

16. Fb Scattered Radiant Flux Loss due to scattering Fo Ft Incident Radiant Flux Transmitted Radiant Flux

17. Loss due to beam attenuation(absorption + scattering) Fb Scattered Radiant Flux Fa Absorbed Radiant Flux Fo Ft Incident Radiant Flux Transmitted Radiant Flux

18. Conservation of radiant flux Fb Scattered Radiant Flux Fa Absorbed Radiant Flux Fo Ft Incident Radiant Flux Transmitted Radiant Flux Fo = Ft +Fa+Fb

19. 0c dx = -0dF/F x x Beam Attenuation Measurement Theory c = fractional attenuance per unit distance, attenuation coefficient • c = DC/Dx Fb • c Dx = - DF/F Fa Fo Ft • c(x-0) = -[ ln(Fx)-ln(F0)] • c x = -[ ln(Ft)-ln(Fo)] • c x = -ln(Ft/Fo) • c (m-1) = (-1/x)ln(Ft/Fo) Dx

20. Linking VIDEO and Vertical profile with Optical Products and SwimmerVisibility Air Force Targets Real Time Video 13:40 15:40 11:40 Node A 18:20 1m 19:25 Swimmer Visibility Model REAL TIME – Camera at NODE A Optical Mooring c532 TIME Plans to return July 00 with NAVO.

21. Optically-Deep Optically-Shallow Whitecaps Micro-bubbles Shallow Ocean Floor Suspended Sediments Phytoplankton Benthic Plants 1/Kd CDOM-Rich Water • Collect a signal, about 95% of the signal • is determined by the atmosphere. • 2) Relate the reflectance to the physics, chemistry, • and/or biology in the water. R = Bb/(a+Bb)

22. 0.7 0.6 0.5 0.4 Absorption (1/m) 0.3 0.2 0.1 0 400 450 500 550 600 650 700 -0.1 wavelength (nm) Changing the relative proportions of materials in the water column also impacts color of the water Dissolved organics Phytoplankton

23. Absorption (m-1) 0 1 a490 a550 0 Backscatter (m-1) 0.03 0 0 0 0 6 6 6 6 Depth (m) Depth (m) Depth (m) Depth (m) 12 12 12 12 Bb488 Bb589 0 2 4 6 8 10 0 2 4 6 8 10 0 2 4 6 8 10 0 2 4 6 8 10 Distance (km) Distance (km) Distance (km) Distance (km)

24. 2 1.5 Ratio 1 Bb488/Bb589 a490/a550 0.5 0 5 10 Distance (km)

25. That Pristine Blue NJ Water

26. Courtesy of Hans Graber, Rich Garvine, Bob Chant, Andreas Munchow, Scott Glenn and Mike Crowley

27. Influence of Optical Properties on Laser Performance Target 3 m Based on Surface Values

28. Changes in the color of the reflectance as the load of material changes in the water column. Water Leaving Radiance Reflectance

29. Color variability at multiple scales around Tasmania from CZCS image Causes? Strong winds, strong currents, bottom togography, etc. Tasmania GSFC, NASA

30. 0.3 0.2 phytoplankton absorption (m-1) 0.1 0 400 500 600 700 wavelength (nm)

31. 0.08 chl a chl b 0.06 chl c PSC PPC 0.04 absorption coefficient (m2 mg-1) 0.02 0.0 400 450 500 550 600 650 700 wavelength (nm)

32. chl c chl b phycobilins chl b chl a chl a carotenoids chl a-chl c-carotenoids 20 1.25 chl a-chl b-carotenoids chl a-phycobilins Spectral Irradiance ( mW cm-2 nm-1) 1.0 15 0.75 Relative Absorption 10 0.50 5 0.25 0 0 400 450 500 550 600 650 700 Wavelength (nm)

33. Chlorophyll a : all phytoplankton (used as a measure of concentrations) Chlorophyll b : green algae Chlorophyll c : chromophytes (dinoflagellates, diatoms, coccolithophorrids) Carotenoids : fucoxanthin (dinoflagellates, diatoms, coccolithophorrids) 19’-hexanoyfucoxanthin (coccolithophorrids) alloxanthin (cryptophytes) peridinin (dinoflagellates)

34. Photosynthesis Heat Fluorescence Energy gained Different Excitation Orbitals In a molecule Energy hv Ground State

35. CO2 QA Fd CH2O Fluorescence QB 2H+ e - PQH2 RC II RC I P680+ 2H+ z Light-Harvesting Pigments O2+ 4H+ 2H2O PAR

36. NUCLEUS LHC gene Repressor proteins Days to Weeks P Qa LHC LHC PH Minutes to Hours CYTOSOL CHLOROPLAST H+ + 1/2CO2 1/2CH2O + 3/2ADP + 3/2Pi 6H+ NADPH H+ + NADP+ 3/2ATP + 3/2Pi 3/2ADP + 3/2Pi Fd 2H+ 2H+ STROMA Qb Fa/Fb CF1 PQ 2 x e- PQ Qb PQ Qb Fx PQ PQ D1 e- THYLAKOID MEMBRANE D2 ATP synthase complex A0 Cytochrome b6-f-Fenn Pheo Photosystem II Photosystem I e- CF0 P700 P680 PC/ cyt c6 E E e- 4Mn Yz fluorescence 2H+ 2H+ 1/2 O2 + 2H+ H2O THYLAKOID LUMEN

37. 3.5 0.08 Pmax 0.06 2.5 quantum yield of oxygen evolution 0.04 1.5 oxygen evolution 0.02 0.5 0 0 0 50 100 150 200 250 300 light intensity

38. Biomass Nutrients Photosynthesis Irradiance Intensity Ik Z (meters)