Chl-a Fluorescence Measurements
Pierre Jaccard
10.06.2013 - MyOcean
Tutorial, NERSC, Bergen
1
Differences from Physical Sensors
•
•
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•
•
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Living species
Measurement principle differs
Chl-a Fluoresence is not Chl-a
Proxy
Neither really bad or good
Rather better or worse
Correct values from HPLC
Pierre Jaccard
10.06.2013 - MyOcean
Tutorial, NERSC, Bergen
2
Fluctuations in CHLAFL / CHLACONC
• Problem for using Chla_fl as phytoplankton
biomass estimation
• Search for “solutions” in Ferrybox data series and
other dataset/time-series from other
investigations using data on:
– Sun light
– Day length
– Temperature
– Species composition
– ...
K. Sørensen, M. Norli and A.
Folkestad
3
Measurements In Practice
Pierre Jaccard
10.06.2013 - MyOcean
Tutorial, NERSC, Bergen
4
Ferrybox Chl_a time-series 2002-2008
Fluorescence high at
small concentrations
Fluorescence low at
high concentrations
No yearly calibration of the fluorescence
Better match at
high concentrations
With yearly calibration of the fluorescence
K. Sørensen, M. Norli and A. Folkestad
5
FerryBox seasonal and night and day
variation
Yearly calibration of the Chl-a
fluorescense using all the Chla_hplc water samples
K. Sørensen, M. Norli and A. Folkestad
• Most months show the
same trend:
• High ratio at night
• Lower ratio at daytime
6
Variation of Chl-a_Fl/Chl-a for algal culture
Determined during
dark adapted algal
from a exponetial
growing algal culture
0.9
0.8
0.7
Chl-a_Fl/Chl-a
0.6
0.5
0.4
Factor
6 all
species
tested
0.3
0.2
0.1
Factor
2.5- 3 for
Norw.
waters
0
1
2
3
4
5
6
7
8
Algal culture
K. Sørensen, M. Norli and A. Folkestad
9
Nr.
1
2
3
4
5
6
7
8
9
Algekulturer
Chrysochromulina polylepis
Dunaliella tertiolecta
Emiliania huxleyi
Oscilatoria agardii
Prorocentrum minimum
Prymnesium parvum
Phaeodactylum tricornutum
Selenastrum capricornutum
Skeletonema costatum
7
Validation of the chlorophyll-a
fluorescence with monitoring data
K. Sørensen, M. Norli and A. Folkestad
8