Sms 598 application of remote and in situ ocean optical measurements to ocean biogeochemistry
Download
1 / 28

SMS 598: Application of Remote and In-situ Ocean Optical Measurements to Ocean Biogeochemistry - PowerPoint PPT Presentation


  • 131 Views
  • Uploaded on

SMS 598: Application of Remote and In-situ Ocean Optical Measurements to Ocean Biogeochemistry. Fluorescence. Mary Jane Perry 6 July 2007.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' SMS 598: Application of Remote and In-situ Ocean Optical Measurements to Ocean Biogeochemistry' - owen


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Sms 598 application of remote and in situ ocean optical measurements to ocean biogeochemistry

SMS 598: Application of Remote and In-situ Ocean Optical Measurements to OceanBiogeochemistry

Fluorescence

Mary Jane Perry6 July 2007


1. What is fluorescence? Measurements to Ocean2. What fluoresces in the ocean?3. Fluorescence as a proxy4. Types of fluorescence5. Instrumentation issues6. Examples7. Today’s labs


Fluorescence Measurements to Ocean: Re-emission of energy as a photon as an electron relaxes from a electronic excited stateFraction of energy absorbed atshorter wavelengths (higher frequency, higher energy) is re-emitted as a photon at longer wavelengths (lower frequency, lower energy). E = h = hc/Property of some molecules (not all)


Collin’s lecture Tuesday: Measurements to OceanAbsorption of a photon occurs if AND ONLY IFthe energy of the photon (E = h = hc/) is equal to the energy difference of an electron in the ground state (S0) and higher electronic states (Sn).Absorption is an “electronic transition”; (O(10-15 s))


Collin’s lecture Tuesday: Measurements to OceanAbsorption of a photon occurs if AND ONLY IFthe energy of the photon (E = h = hc/) is equal to the energy difference of an electron in the ground state (S0) and higher electronic states (Sn).Absorption is an “electronic transition”; (O(10-15 s))

Vibrational states w/in electronic states

Primary mechanism of energy loss to permit an electron to relax or return to S0 is by loss of heat (IR radiation); so-called radiationless decay; (O(10-12 s)).


http://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.htmlhttp://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.html

http://micro.magnet.fsu.edu/primer/java/jablonski/jabintro/index.html


Chlorophyll absorption (direct or via accessory pigs)http://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.html

Chlorophyll excited electron:

Photochemistry (charge separation)

Heat (many pathways)

Fluorescence at 686 nm (O(10-9 s))


Fluorescence emissionhttp://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.html1. always from lowest vibrational state of Sn2. red shifted – Stokes shift (higher , lower E)3. mirror image of absorption


F = E(http://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.html) . conc .fF = E() . a() .fwhereE() is excitation lamp energy conc is concentration a is () is absorption fis quantum yield of fluorescence = moles photons fluoresced moles photons absorbedif fwere constant, F ~ conc or a


Collin, Station 2 of today’s labhttp://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.html fluorescence excitation/emission* match of wavelengths E() and a() * energy transfer of chlorophyll ain vivo (living cell) vs. in vitro (out of cell, solvent)


What fluoresces in the ocean?http://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.htmlChlorophyll a– red(note, chlorophyll b only fluoresces in solvent –in vitro– so tightly coupled to chlorophyll a in membrane)PE– phycoerythrin (orange)CDOM – broad excitation, with some peaksGreen fluorescent protein (used in molecular staining) –from coral, jellyfish and some protozoans


CDOM F – proxy for ahttp://www.micro.magnet.fsu.edu/primer/java/fluorescence/exciteemit/index.htmlCDOMfor radiative transfer

aCDOM– proxy for DOM for carbon cycling

PE – specific taxa

Chl F – proxy for Chl – proxy for phytoplankton

and input to productivity and carbon models


Our ability to use proxies in any quantitative sense depends on this relationship:F = E() . conc .ff depends on temperature and environment(pH, ionic strength, interaction with other molecules for dissipation of energy, etc.)

chlorophyll a fluorescence in vitro (solvent, acetone)

f ~ 0.33

chlorophyll a fluorescence in vivo (living cell)

f ~ <0.05 – 0.03


Three types of fluorescence: on this relationship:1) active – artificial light source for E()– static: use for profiles of chl fluorescence; moorings; mobile platforms– time resolved (true tr is ~ femo/pico s for chemistry, like whole burning in CDOM; could consider pump & probe, variable F) 2) passive – sun is light source for E()


Instrumentation issues (a few): on this relationship:Sensors – trend toward smaller, lighter, low power, robust, more sensitive, smaller sensing volume; biofouling issuesE() varies among instruments aps() will vary among cells, based on accessory pigments; does E() match aps()? Manufacturer change in LEDs to 470 nm. Different (), different accessory pigmentsCalibrationsensor side: dark reading, temperature response of electronics and optics, stability and driftfluorophore side: (CDOM, Chl): temperature response (-1–2%/ºC), behavior of fAttenuation of signal – turbidity (nonlinear response)


Example of on this relationship:passive or solar-stimulated fluorescence from Babin and Huot (recall Curt’s lecture, Hydrolight output)


Other issues: on this relationship:1) satellite images only available on clear days; bias of high light/quenching; what is f? 2) how to interpret, E(), a (), depth resolution

from Babin and Huot;they caution its use in

turbid waters (not F)


F = E( on this relationship:) . conc .f

Note: important temperature effect on f

(watch out if room temp changes)

~ - 1–2% F / ºC

F

Not just chl a, also degradation

pigments (pheophytin a).

Fo reading = chl a + pheo; add H+;

Fa reading = new pheo + old pheo

(2 readings, 2 equations, 2 unknowns)

BUT: also chlorophyll b and its

degradation products. Filter set.

concentration

Example of active /static benchtop application (Ststion 1):fluorescence of solvent-extracted chlorophyll a


Chlorophyll on this relationship:mg/m3

PAR

GoMOOS Buoy E (Roesler)

From Falkowski and Raven 1997

Chlorophyll fluorescence and extracted concentration of chlorophyll early AM vs. noon.

Example of active /static in situ application for living cells (Station 3) two types: flush-face and flow-through.Used on ship-based profiling systems, moorings, floats and gliders.

Glider fluorescence, Wash. Coast


Example of mid day fluorescence quenching

Mid-day fluorescence quenching on this relationship:

Example of mid-day fluorescence quenching

0

  • Quenching observed to 11m

  • Fluoresence quenched up to 80% at surface

Depth (m)

40

112.48

Year Day

118.2

-- Mixed Layer Depth (MLD)

So maybe for biomass, should we concentrate on night-time measurements in vivo fluorescence measurements?

Sackmann et al, MS.


Mid day fluorescence quenching
Mid-day fluorescence quenching on this relationship:

  • MORNING

  • MID-DAY

  • AFTERNOON

Sackmann et al., unpub.


Mid day fluorescence quenching1
Mid-day fluorescence quenching on this relationship:

  • MORNING

  • MID-DAY

  • AFTERNOON

Sackmann et al., unpub.


Mid day fluorescence quenching2
Mid-day fluorescence quenching on this relationship:

  • MORNING

  • MID-DAY

  • AFTERNOON

Sackmann et al., unpub.


PAR on this relationship:

Fluorescence

Time

Figure 2: Damariscotta River in situ chlorophyll a fluorescence and PAR (μmol photons/s/m2)vs. time.


PAR on this relationship:

Fv/Fm

Time

Figure 4:Normalized variable fluorescence (Fv/Fm) and PAR (μmol photons/s/m2) vs. time.


Fluorescence induction curve on this relationship:(issues of timing and of initial state)

Fv = Fm - Fo

Fluorescence induction curve: rapid rise and slow decline


Fluorescence induction curves for dark adapted cells
Fluorescence induction curves, for dark-adapted cells on this relationship:

Fast rise (< second); #1 – low light;

#2 – high light adapted; #3 DCMU

Slow rise (< minute)

photoreduction of QA to QA- and

connectivity among Reaction Centers

photochemical, thermal

and other quenching


Saturday experiment on this relationship:* automoatic: continuous measurement of PAR, F, and bb* student teams; hourly sampling of chlorophyll a (extract) and Fv/Fm with FIRe (Station 4)Questions:How does incident light affect in situ F of phytoplankton in the DRE (tides, mixing, variable PAR)?What is the relationship between quenching or photoinhibition of in situ F and Fv/Fm? And could Fv/Fm help to interpret F?Lightening ––––– don’t sample!


ad