Light and Photosynthesis 1)Light in the Ocean I)Intensity II)Color III)Inherent Optical Properties IV)Apparent Optical Properties V)Remote Sensing 2)Photosynthesis I)Light Absorption II)Light Reactions III)Dark Reactions Oscar Schofield I need a work study student (library work, will pay)

For satellite remote sensing the wavelength is the key to what you want to measure. c =   = h  hc 

Figure 6

I) Light Z (meters) Irradiance Intensity Lambert Beers Law Ed 2 = Ed 1 e -  z*Kd Ed 2 Ed 1 z1z1 z2z2 zz 1)Because of Lambert Beers Law the ocean is dim 2)Plant life is dependent on light 3) The 1% light level for the majority of the is 100 m or less? 2500  mol photons m -2 s  mol photons m -2 s -1

Alexander the Great Early Optics

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.

Today Robot-mounted Hyperspectral Absorption meter January 2003

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

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)

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

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

Why IOP Measurements? Absorption, a Scattering, b clarity

Review of IOP Theory oo Incident Radiant Flux No attenuation Transmitted Radiant Flux tt

Review of IOP Theory Attenuation tt oo Incident Radiant Flux Transmitted Radiant Flux

Loss due to absorption  a Absorbed Radiant Flux oo Incident Radiant Flux tt Transmitted Radiant Flux

Loss due to scattering  b Scattered Radiant Flux oo Incident Radiant Flux tt Transmitted Radiant Flux

Loss due to beam attenuation (absorption + scattering)  a Absorbed Radiant Flux  b Scattered Radiant Flux tt oo Incident Radiant Flux Transmitted Radiant Flux

Conservation of radiant flux  a Absorbed Radiant Flux  b Scattered Radiant Flux  o =  t +  a +  b tt oo Incident Radiant Flux Transmitted Radiant Flux

Beam Attenuation Measurement Theory tt aa bb c = fractional attenuance per unit distance, attenuation coefficient  c =  C/  x  c  x = -  /   c x = -  ln(  t /  o )  c (m -1 ) = (-1/x)  ln(  t /  o ) oo xx  0 c dx = -  0 d  /  xx  c(x-0) = -[ ln(  x )-ln(  0 )]  c x = -[ ln(  t )-ln(  o )]

1m Air Force Targets 11:40 Swimmer Visibility Model Swimmer Visibility Model REAL TIME – Camera at NODE A TIME Optical Mooring c532 Linking VIDEO and Vertical profile with Optical Products with Optical Products and SwimmerVisibility and SwimmerVisibility Plans to return July 00 with NAVO. 13:4015:4018:20 19:25

Phytoplankton CDOM-Rich Water Suspended Sediments Benthic Plants 1/Kd Optically-ShallowOptically-Deep Micro-bubbles Whitecaps Shallow Ocean Floor 1)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 = B b /(a+B b )

Phytoplankton Dissolved organics Changing the relative proportions of materials in the water column also impacts color of the water

Distance (km) 01 Absorption (m -1 ) 00.03Backscatter (m -1 ) Depth (m) Depth (m) Distance (km) Distance (km) Distance (km) Depth (m) Depth (m) B b 488 B b 589 a490a550

a490/a B b 488/B b 589 Distance (km) Ratio

That Pristine Blue NJ Water

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

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

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

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

wavelength (nm) phytoplankton absorption (m -1 )

chl a chl b chl c PSC PPC wavelength (nm) absorption coefficient (m 2 mg -1 )

Wavelength (nm) Spectral Irradiance (  W cm -2 nm -1 ) chl a chl b chl c chl b carotenoids phycobilins Relative Absorption chl a-chl c-carotenoids chl a-chl b-carotenoids chl a-phycobilins

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)

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

PAR Light-Harvesting Pigments RC IIRC I e - QAQA QBQB 2H + PQH 2 2H + Fd CO 2 CH 2 O P680 + z 2H 2 O O 2 + 4H + Fluorescence

THYLAKOIDMEMBRANE STROMA CYTOSOL LHCLHC 1/2 O 2 + 2H + H2OH2O 4Mn Yz e-e- 2H + PQ QbQb QbQb Cytochrome b 6 -f-Fe nn 2H + PC/ cyt c 6 Photosystem I CHLOROPLAST P700 A0A0 FxFx Fa/ FbFa/ Fb FdFd ATP synthase complex CF 0 CF 1 3/2ADP + 3/2Pi 3/2ATP + 3/2Pi NADPH H + + NADP + 6H + 1/2CH 2 O + 3/2ADP + 3/2Pi H + + 1/2CO 2 THYLAKOID LUMEN E P680 Pheo e-e- e-e- Photosystem II D2 D1 E QaQa QbQb 2 x e - PH Minutes to Hours NUCLEUS P LHC gene Repressor proteins Days to Weeks fluorescence

light intensity oxygen evolution quantum yield of oxygen evolution Pmax

Irradiance Intensity Z (meters) IkIk Photosynthesis Biomass Nutrients