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FRR DATA Fluorescence Relative Fo Fm Fv PSII Flashlet Number
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Fluorescence Relative Flashlet Number
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Fluorescence Relative Flashlet Number Fluorescence Relative Time (s)
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Tropical Pacific Study
8 2001A 25o 25o Hawaii 2006 2005 6 15o 15o 2000 2003 5o 2001B 2002 2001D ‘GasEx’ Nitrate Concentrations (M) 5o 4 1994 ‘OliPac’ 5o 5o 2 2001C 15o 1995 IronExII 15o 25o 25o 120o E 140o E 160o E 180o 160o W 140o W 120o W 100o W 80o W >140,000 Variable fluorescence (FRRf) Incident PAR Chlorophyll & HPLC beam 660 nm Macronutrients spectral attenuation & absorption (AC9) Fe concentrations cDOM Photosynthesis-Irradiance (14C) particulate backscattering coefficients Phytoplankton absorption web.science.oregonstate.edu/ocean.productivity/ 26 short-term (18-30 h) enrichment experiments (control, +NO3, +NH4, +PO4, +Fe) Depth-resolved time-series stations
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2005 2006A PAR (uEin) Fo & Fm (relative) 2006B 2007 Sequence Number
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2005 2006A PAR (uEin) Fv/Fm (relative) 2006B 2007 Sequence Number
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2005 2006A Sigma PSII (relative) PAR (uEin) 2006B 2007 Sequence Number
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Fluorescence properties in the tropical Pacific:
20 25o Hawaii 15o PQ turnover time 5o 10 5o 15o 25o 120o E 140o E 160o E 180o 160o W 140o W 120o W 100o W 80o W 12:00 0:00 12:00 0:00 12:00 Time Low nitrate, low biomass zone High nitrate, high biomass zone 25 Slow PQ turnover 20 PQ pool electron turnover time 15 10 Rapid PQ turnover 5 N 160 140 120 90 80 60 40 20 00 20 40 80 S Latitude
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The nocturnal decrease: A PQ PQH2 Iron stress Nighttime Fv/Fm
12:00 0:00 0.1 0.2 0.3 Fv/Fm Nocturnal Decreases Photosynthesis OFF, Respiration ON Increasing PQ pool reduction and electron backtransfer Photosynthate supply running out PSI & PSII turnover at dawn Large nocturnal decreases require Fe stress, modest or better growth rates, but not high macronutrients Iron stress Ndh NADH Nighttime e FRRf Fdx O2 H20 1 2 Cyt b6 f PQ PQH2 Terminal oxidase PSII PQ PQH2 e e PSI e c553 e MAJOR electron backtransfer Slight electron backtransfer
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14-C data Blue = day, sunrise, sunset Pink = night
Time Series 2 8S, 125W Blue = day, sunrise, sunset Time Series 3 5S, 140W Time Series 4 - 0Eq, 140W Pink = night
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Dawn maxima: PQ Iron stress
High Dawn Maxima 0.5 Low dawn maxima require Fe stress, high macronutrients, but not rapid growth rates 0.4 Fv/Fm Low Dawn Maxima 0.3 0.2 0.1 N 160 140 120 100 80 60 40 20 00 20 40 80 S Latitude Iron stress FRRf fluorescence Fdx PQ PQH2 Cyt b6 f Isi PSII e PSI e e c553 H20 1 2 O2 + 2 H
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Nocturnal PSII cross-section decreases:
400 Large state transitions require Fe stress, significant prokaryotic biomass, but not high macronutrients 300 PSII (2 photon-1) 200 100 N 160 140 120 100 80 60 40 20 00 20 40 80 S Latitude ‘State transitions’
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PQ turnover: Long PQ turnover times require Fe stress-induced decreases in down-stream components
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Nocturnal decrease in Fv /Fm
Latitude 5o S 15o S 25o S 15o N 25o N 35o N 5o N 0.6 0.4 Dawn Fv /Fm maximum 0.2 165o E 175o W 155o W 135o W 115o W 95o W Latitude 5o S 15o S 25o S 15o N 25o N 35o N 5o N 60% 40% Nocturnal decrease in Fv /Fm 20% 0% 165o E 175o W 155o W 135o W 115o W 95o W Latitude 5o S 15o S 25o S 15o N 25o N 35o N 5o N I I II III I I 165o E 175o W 155o W 135o W 115o W 95o W Longitude
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POC / PON 2006A Blanks Sequential Station
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2005 2006A PON (ug L-1) 2006B Sequence Number
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2005 2006A POC (ug L-1) 2006B Sequence Number
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2005 2006A C:N ratio 2006B Sequence Number
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Turner fluorometer
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2005 2006A 2006B 2007 Sequence Number
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