Methods in Molecular Biology (2020) 1980: 41–45
DOI 10.1007/7651_2017_100
© Springer Science+Business Media New York 2017
Published online: 02 December 2017
Measurement of Fluorescence for Monitoring Algal Growth
and Health
Kristian Spilling and Jukka Sepp € al € a
Abstract
Measuring fluorescence is a noninvasive, inexpensive, and quick way of determining biomass concentration
and health of the algae. Fluorescence is generally positively correlated with chlorophyll a and can as such be
used as a proxy for biomass. In addition, the proportion variable fluorescence of maximal fluorescence is a
measure of photochemical efficiency, which is affected by stress in a very early stage and can as such be used
as a proxy for algal health.
Keywords DCMU, Microalgae, OJIP curves, Variable fluorescence
1 Introduction
Light provides the energy needed for running photosynthesis and is
an absolute requirement for autotrophic (photosynthetically driven)
growth [1]. The main light-harvesting pigment in algae, chlorophyll
a (Chl a), is fluorescent. When light energy is absorbed by Chl a, part
of this energy re-emitted as a light photon, i.e., fluorescence, after an
exited electron returns to the ground state. The Chl a fluorescence
light is emitted with a peak at approximately 680 nm, and measuring
the fluorescence can be used as a proxy for Chl a, photochemical
efficiency, and electron transport rate. The measurement of Chl
a fluorescence can be done either in vivo, within living cells, or
in vitro, after extraction of the Chl a pigment with a solvent such
as acetone or ethanol. In this chapter we will only deal with measurements of in vivo fluorescence.
The fate of absorbed light energy has three potential pathways:
(1) it drives the photochemical reaction, which provides the chemical
energy and reduces power needed to fix carbon from CO 2 into biomass; (2) it may be converted to heat; or (3) it may be re-emitted as
fluorescence [1]. The energy content in light photons varies depending
on the wavelength (color of the light), i.e., a blue light photon carries
more energy than red light photon. However, for the photochemical
reaction and fluorescence emission, it is only the energy difference
between the ground state and singlet state 1 (S1) that is used, meaning
41
DOI 10.1007/7651_2017_100
© Springer Science+Business Media New York 2017
Published online: 02 December 2017
Measurement of Fluorescence for Monitoring Algal Growth
and Health
Kristian Spilling and Jukka Sepp € al € a
Abstract
Measuring fluorescence is a noninvasive, inexpensive, and quick way of determining biomass concentration
and health of the algae. Fluorescence is generally positively correlated with chlorophyll a and can as such be
used as a proxy for biomass. In addition, the proportion variable fluorescence of maximal fluorescence is a
measure of photochemical efficiency, which is affected by stress in a very early stage and can as such be used
as a proxy for algal health.
Keywords DCMU, Microalgae, OJIP curves, Variable fluorescence
1 Introduction
Light provides the energy needed for running photosynthesis and is
an absolute requirement for autotrophic (photosynthetically driven)
growth [1]. The main light-harvesting pigment in algae, chlorophyll
a (Chl a), is fluorescent. When light energy is absorbed by Chl a, part
of this energy re-emitted as a light photon, i.e., fluorescence, after an
exited electron returns to the ground state. The Chl a fluorescence
light is emitted with a peak at approximately 680 nm, and measuring
the fluorescence can be used as a proxy for Chl a, photochemical
efficiency, and electron transport rate. The measurement of Chl
a fluorescence can be done either in vivo, within living cells, or
in vitro, after extraction of the Chl a pigment with a solvent such
as acetone or ethanol. In this chapter we will only deal with measurements of in vivo fluorescence.
The fate of absorbed light energy has three potential pathways:
(1) it drives the photochemical reaction, which provides the chemical
energy and reduces power needed to fix carbon from CO 2 into biomass; (2) it may be converted to heat; or (3) it may be re-emitted as
fluorescence [1]. The energy content in light photons varies depending
on the wavelength (color of the light), i.e., a blue light photon carries
more energy than red light photon. However, for the photochemical
reaction and fluorescence emission, it is only the energy difference
between the ground state and singlet state 1 (S1) that is used, meaning
41