168
Application of these techniques for quantitative analysis of light
absorption together with measurements of photosynthesis has allowed
assessment of the dependence of photosynthetic quantum efficiency on the
irradiance level of growth (Mitchell and Kiefer, 1983).
We found that
photoadaptation can lead to a three fold increase in quantum efficiency
for exponentially growing, nutrient saturated field cultures incubated at
different light levels. This is consistent with our model of photosynthesis (Kiefer and Mitchell,1983). We are currently analyzing in situ
quantum efficiency using these techniques and preliminary results indicate
that deep euphotic zone samples have higher efficiencies. Obviously,
absorption by non-photosynthetic pigments in the natural samples will
cause interpretive problems; nevertheless, knowledge of total ecological
efficiency of photosynthesis can be determined and could be very useful
for satellite image analysis.
These quantitative corrections for absorption and fluorescence spectra offer a new tool with which to investigate phytoplankton photosynthetic processes in both the laboratory and field. The absorption coefficient technique can be accomplished using a spectrophotometer interfaced with a microcomputer, equipment commonly available even in routine
field experiments. With efficient computer programming, spectral absorption coefficients can be determined more easily than a fluorometric
analysis of extracted chlorophyll.
V. REFERENCES
Barer R (1955) Spectrophotometry of clarified cell suspensions.
Sci. 121:709-715.
Bricaud A, A Morel and L Prieur (1983) Optical efficiency factors of
some phytoplankters. Limnol.Oceanogr. 28:816-832.
Butler W (1962) Absorption of light by turbid materials.
J.Opt.Soc. Am.
52:292-299.
Dubinsky Z and T Berman (1976) Light utilization efficiencies of phytoplankton in Lake Kinneret(Sea of Galilee). Lirnnol.Oceanogr. 21:
226-230.
Duntley SQ (1942) Optical properties of diffusing materials. J.Opt.Soc.
Am. 32:61-69.
Faust MA and CH Norris (1982) Rapid in vivo analysis of chlorophyll pigments in intact phytoplankton cultures. Br.Phycol.J. 17:351-361.
Eppley, RW, EH Ringer, EL Venrick and MM Mullin (1973) A study of plankton
dynamics and nutrient cycling in the central gyre of the North
Central Pacific Ocean. Limnol.Oceanogr. 18:534-551.
Jassby AD and T Platt (1976) Mathematical formulation of the relationship
between photosynthesis and light for phytoplankton. Limnol.Oceanogr.
21:540-547.
Application of these techniques for quantitative analysis of light
absorption together with measurements of photosynthesis has allowed
assessment of the dependence of photosynthetic quantum efficiency on the
irradiance level of growth (Mitchell and Kiefer, 1983).
We found that
photoadaptation can lead to a three fold increase in quantum efficiency
for exponentially growing, nutrient saturated field cultures incubated at
different light levels. This is consistent with our model of photosynthesis (Kiefer and Mitchell,1983). We are currently analyzing in situ
quantum efficiency using these techniques and preliminary results indicate
that deep euphotic zone samples have higher efficiencies. Obviously,
absorption by non-photosynthetic pigments in the natural samples will
cause interpretive problems; nevertheless, knowledge of total ecological
efficiency of photosynthesis can be determined and could be very useful
for satellite image analysis.
These quantitative corrections for absorption and fluorescence spectra offer a new tool with which to investigate phytoplankton photosynthetic processes in both the laboratory and field. The absorption coefficient technique can be accomplished using a spectrophotometer interfaced with a microcomputer, equipment commonly available even in routine
field experiments. With efficient computer programming, spectral absorption coefficients can be determined more easily than a fluorometric
analysis of extracted chlorophyll.
V. REFERENCES
Barer R (1955) Spectrophotometry of clarified cell suspensions.
Sci. 121:709-715.
Bricaud A, A Morel and L Prieur (1983) Optical efficiency factors of
some phytoplankters. Limnol.Oceanogr. 28:816-832.
Butler W (1962) Absorption of light by turbid materials.
J.Opt.Soc. Am.
52:292-299.
Dubinsky Z and T Berman (1976) Light utilization efficiencies of phytoplankton in Lake Kinneret(Sea of Galilee). Lirnnol.Oceanogr. 21:
226-230.
Duntley SQ (1942) Optical properties of diffusing materials. J.Opt.Soc.
Am. 32:61-69.
Faust MA and CH Norris (1982) Rapid in vivo analysis of chlorophyll pigments in intact phytoplankton cultures. Br.Phycol.J. 17:351-361.
Eppley, RW, EH Ringer, EL Venrick and MM Mullin (1973) A study of plankton
dynamics and nutrient cycling in the central gyre of the North
Central Pacific Ocean. Limnol.Oceanogr. 18:534-551.
Jassby AD and T Platt (1976) Mathematical formulation of the relationship
between photosynthesis and light for phytoplankton. Limnol.Oceanogr.
21:540-547.