Beyond Fluorescence Line Height

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Beyond Fluorescence Line Height Making sense of
chlorophyll fluorescence

• Ru Morrison
• (Ru.Morrison_at_unh.edu)
• Mike Behrenfeld
• (behrenfm_at_science.oregonstate.edu)

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You cant see a whale from space but you can see
Seeing inside phytoplankton from space
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Outline

• What is phytoplankton fluorescence?
• The current fluorescence paradox
• Fluorescence variability
• Games of chance
• Changing the odds 2003, 2008, 2009
• What fluorescence can do
• What fluorescence cant do
• What we need to do!

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What is phytoplankton fluorescence?
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The Fluorescence Paradox

• Two potential and mutually incompatible uses
• Abundance - need constant fluorescence efficiency
• Physiology - need variable fluorescence
  efficiency.

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Fluorescence variability games of chance

• Fluorescence comes from PSII (mainly)
• Ff chance getting an absorbed photon to PSII
  and then back out again
• Variability comes from quenching
• Photochemical quenching (qP)
• Non-photochemical quenching
• Antennae quenching (qE)
• PSII RC downregulation / damage (qI)
• Changes in proportion of PSII to total absorption

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Changing the odds - 2003
PQ
NPQ
NPQ Dominates in Satellite Derived
measurements Energy Dependent Quenching
decreases ff with increasing irradiance PSII
downregulation (photoinhibition) suppresses ff
at all irradiances
Quantum Yield of Fluorescence
Scalar Irradiance
from Morrison LO, 2003
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Changing the odds 2008
Behrenfeld et al., BGD, 2009
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Nutrient stress
Behrenfeld et al., BGD, 2009
But Schallenberg et al. (2008) suggested
macronutrient stress increased ff with unbalanced
growth conditions
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Detection of iron stress effects.
Behrenfeld et al., BGD, 2009
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Changing the odds - 2009
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Gulf of Maine case Study Climatologies (2004-2007)
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Gulf of Maine case Study Climatologies (2004-2007)
Dec
Jan
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Gulf of Maine case Study Climatologies (2004-2007)
Jan
Dec
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(No Transcript)
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Seasonal Climatology
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Basin Scale Patterns
Goodwin et al., 2009
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Timing of stratification onset and spring bloom
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What can Fluorescence do

• Give insights into phytoplankton physiology
• Iron stress
• Photocompensation / acclimation with growth
  irradiance that incorporates hydrodynamics

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What Fluorescence cant do

• Abundance apart from geographically and spatially
  limited studies.

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What do we need to do?

• Minimize calibration uncertainties in the FLH
  product
• Develop operational ff product
• Investigate the heck out of it in-light of these
  recent insights.
• With current missions
• How do you separate nutrient and photoacclimation
  effects?
• For upcoming missions (GEOCAPE interesting)