137
CONCEPT OF CHROMATIC ADAPTATION AS IT APPLIES TO SPECTRAL SIGNATURES
IN NATURAL POPULATIONS OF PHYTOPLANKTON
Studies of accessory pigmentation of algae always seem to wind
up at the doorsteps of the hypothesis of chromatic adaptation. Arguments for and against this hypothesis have been reviewed by Ramus
(1981) and Dring (1982).
Both workers have concluded that with
regard to the vertical distribution of benthic algae in the sea, the
light/pigment relationship seems to be compatible with variations in
the levels of total irradiance which decreases with depth. Therefore,
the wavelength dependency of the accessory pigmentation does not seem
to be the important factor in the hypothesis.
Our fluorescence data on natural populations, i.e. the changes
in spectra, cannot be interpreted in terms of light quality or in
that fact, in terms of light intensity.
Using the above observations, we have tried to establish the hypothesis that the relationship of spectral change is closely associated with changes in the
abundance of algae, which, in the ocean, is regulated by the degrees
of eutrophication or oligotrophy of the water masses. Therefore, the
spectral fluorescent signatures are indicative of what one would call
the "nutrient status" in natural populations. One can rightly ask if
these are species assemblages or whether or not this chromatic change
is due to cellular-induced synthesis or decomposition.
With regard
to this type of chromatic adaptation, procaryotes and eucaryotes are
known to change their pigment composition with respect to light
quali ty and quantity - we cannot discount that some of this is
affecting the data that we have observed in these sections and
profiles.
However, direct microscopic counts indicated that these
spectral changes are associated wi th the dominance of certain groups
of organisms, such as diatoms and dinoflagellates and cryptomonads.
Therefore, we conclude that the spectral signatures are largely
affecting the assemblage of species and that these signatures, in a
crude sense, reflect diversity shifts in natural popUlations and are
associated with change in the nutrient level of the water masses.
POTENTIAL FOR REMOTE SENSING
In another paper (Yentsch and Phinney, 1984), we have attempted
to point out the drawbacks in applying and interpreting fluorescent
color group observations in terms of classical taxonomic classification; fluorescence signatures do not have enough information to
adequately distinguish, for example, dinoflagellates from diatoms
CONCEPT OF CHROMATIC ADAPTATION AS IT APPLIES TO SPECTRAL SIGNATURES
IN NATURAL POPULATIONS OF PHYTOPLANKTON
Studies of accessory pigmentation of algae always seem to wind
up at the doorsteps of the hypothesis of chromatic adaptation. Arguments for and against this hypothesis have been reviewed by Ramus
(1981) and Dring (1982).
Both workers have concluded that with
regard to the vertical distribution of benthic algae in the sea, the
light/pigment relationship seems to be compatible with variations in
the levels of total irradiance which decreases with depth. Therefore,
the wavelength dependency of the accessory pigmentation does not seem
to be the important factor in the hypothesis.
Our fluorescence data on natural populations, i.e. the changes
in spectra, cannot be interpreted in terms of light quality or in
that fact, in terms of light intensity.
Using the above observations, we have tried to establish the hypothesis that the relationship of spectral change is closely associated with changes in the
abundance of algae, which, in the ocean, is regulated by the degrees
of eutrophication or oligotrophy of the water masses. Therefore, the
spectral fluorescent signatures are indicative of what one would call
the "nutrient status" in natural populations. One can rightly ask if
these are species assemblages or whether or not this chromatic change
is due to cellular-induced synthesis or decomposition.
With regard
to this type of chromatic adaptation, procaryotes and eucaryotes are
known to change their pigment composition with respect to light
quali ty and quantity - we cannot discount that some of this is
affecting the data that we have observed in these sections and
profiles.
However, direct microscopic counts indicated that these
spectral changes are associated wi th the dominance of certain groups
of organisms, such as diatoms and dinoflagellates and cryptomonads.
Therefore, we conclude that the spectral signatures are largely
affecting the assemblage of species and that these signatures, in a
crude sense, reflect diversity shifts in natural popUlations and are
associated with change in the nutrient level of the water masses.
POTENTIAL FOR REMOTE SENSING
In another paper (Yentsch and Phinney, 1984), we have attempted
to point out the drawbacks in applying and interpreting fluorescent
color group observations in terms of classical taxonomic classification; fluorescence signatures do not have enough information to
adequately distinguish, for example, dinoflagellates from diatoms