OCRT 5/5/2009JRM & MBFluorescence Beyond Fluorescence Line Height – Making sense of chlorophyll fluorescence Ru Morrison Mike Behrenfeld

OCRT 5/5/2009JRM & MBFluorescence You can’t see a whale from space but you can see … Seeing inside phytoplankton from space

OCRT 5/5/2009JRM & MBFluorescence Outline What is phytoplankton fluorescence?What is phytoplankton fluorescence? The current fluorescence paradoxThe current fluorescence paradox Fluorescence variabilityFluorescence variability –Games of chance –Changing the odds – 2003, 2008, 2009 What fluorescence can doWhat fluorescence can do What fluorescence can’t doWhat fluorescence can’t do What we need to do!What we need to do!

OCRT 5/5/2009JRM & MBFluorescence What is phytoplankton fluorescence? Fluorescence Line Height Fluorescence Efficiency or quantum yield, φ f ratio of photons out to in

OCRT 5/5/2009JRM & MBFluorescence The Fluorescence Paradox Two potential and mutually incompatible usesTwo potential and mutually incompatible uses –Abundance - need constant fluorescence efficiency –Physiology - need variable fluorescence efficiency.

OCRT 5/5/2009JRM & MBFluorescence Fluorescence variability – games of chance Fluorescence comes from PSII (mainly)Fluorescence comes from PSII (mainly) Φ f = chance getting an absorbed photon to PSII and then back out againΦ f = chance getting an absorbed photon to PSII and then back out again Variability comes from quenchingVariability comes from quenching –Photochemical quenching (qP) –Non-photochemical quenching Antennae quenching (qE)Antennae quenching (qE) PSII RC downregulation / damage (qI)PSII RC downregulation / damage (qI) –Changes in proportion of PSII to total absorption

OCRT 5/5/2009JRM & MBFluorescence NPQ Dominates in Satellite Derived measurements Energy Dependent Quenching – decreases φ f with increasing irradiance PSII downregulation (photoinhibition) – suppresses φ f at all irradiances Changing the odds from Morrison L&O, 2003 PQNPQ Scalar Irradiance Quantum Yield of Fluorescence

OCRT 5/5/2009JRM & MBFluorescence Changing the odds – 2008 Behrenfeld et al., BGD, 2009

OCRT 5/5/2009JRM & MBFluorescence Nutrient stress Behrenfeld et al., BGD, 2009 But Schallenberg et al. (2008) suggested macronutrient stress increased φ f with unbalanced growth conditions

OCRT 5/5/2009JRM & MBFluorescence Detection of iron stress effects. Behrenfeld et al., BGD, 2009

OCRT 5/5/2009JRM & MBFluorescence Changing the odds

OCRT 5/5/2009JRM & MBFluorescence Gulf of Maine case Study Climatologies ( )

OCRT 5/5/2009JRM & MBFluorescence Gulf of Maine case Study Climatologies ( ) Dec Jan

OCRT 5/5/2009JRM & MBFluorescence Gulf of Maine case Study Climatologies ( ) Dec Jan

OCRT 5/5/2009JRM & MBFluorescence

OCRT 5/5/2009JRM & MBFluorescence Seasonal Climatology

OCRT 5/5/2009JRM & MBFluorescence Basin Scale Patterns Goodwin et al., 2009

OCRT 5/5/2009JRM & MBFluorescence Timing of stratification onset and spring bloom

OCRT 5/5/2009JRM & MBFluorescence What can Fluorescence do Give insights into phytoplankton physiologyGive insights into phytoplankton physiology –Iron stress –Photocompensation / acclimation with growth irradiance that incorporates hydrodynamics

OCRT 5/5/2009JRM & MBFluorescence What Fluorescence can’t do Abundance apart from geographically and spatially limited studies.Abundance apart from geographically and spatially limited studies.

OCRT 5/5/2009JRM & MBFluorescence What do we need to do? Minimize calibration uncertainties in the FLH productMinimize calibration uncertainties in the FLH product Develop operational φ f productDevelop operational φ f product Investigate the heck out of it in-light of these recent insights.Investigate the heck out of it in-light of these recent insights. –With current missions How do you separate nutrient and photoacclimation effects?How do you separate nutrient and photoacclimation effects? –For upcoming missions (GEOCAPE interesting)