65
In the sixties, the pioneer of pigment analysis for chemotaxonomic purposes in marine
phytoplankton studies had been S.W. Jeffrey (1961, 1968). She convinced most biological
oceanographers of the promises of this approach by publishing her finding of high
chlorophyll b concentrations in the open ocean, which, as she argued (Jeffrey, 1976), revealed
the abundance of a group of phytoplanktonic algae that was until that time not known to occur
there at any numbers of importance: green algae. This was the only taxonomic entity of
microalgae characteristically containing ChI b according to the literature of the time (Weber
and Wettern, 1980; Van den Hoek, 1978). Jeffrey's report drew much attention, but it can
now be regarded as an example of the danger of neglecting, more conventional methods for
detection of natural phytoplankton components, notably microscopy. Green algae may be
present in the open ocean (Takahashi and Hori, 1984), but we now know that except in
estuarine regions (Lubian and Establier, 1980) or coastal upwellings (Gieskes and Kraay,
1986b; Gieskes et al., 1988), where green algae can be prominent, most chlorophyll b in the
ocean is associated with picoplanktonic Prochlorophytes, not green algae (Chisholm et al. ,
1988; Gieskes et al., 1988; Olson et al., 1990; Veldhuis and Kraay, 1990) - afortiori, most
so-called ChI b is in fact not even normal ChI b but a derivative, possibly containing a
divinyl bond (Goericke, pers. comm.), that gives it a red-shifted absorption spectrum (Gieskes
et al., 1979, their Fig. 2; see also Neveux et al., 1989; and see Fig. 3). Prochlorophytes do
not contain violaxanthin (Burger-Wiersma et al., 1986) while green algae do (Van den Hoek,
1978), so ChI b presence without a trace of violaxanthin indicates that Prochlorophytes
contribute to a phytoplankton population - a straightforward way to detect and quantify this
group's abundance (Gieskes et al., 1988). Such subtle pigment analysis is best performed after
separation by high-performance liquid or thin-layer chromatography (HPLC, HPTLC).
Nevertheless, Jeffrey's early TLC work has given the interest in pigment analysis its
momentum, and it continues to do so even now that modern HPLC has replaced paper
chromatography (Jeffrey, 1961; Jensen and Sakshaug, 1973), thin-layer chromatography
(Jeffrey, 1968, 1981), HP-thin-layer chromatography (Wright and Jeffrey, 1987), and the
conventional ways of HPLC (Abaychi and Riley, 1979).
As I have argued, pigment analysis should not be applied indiscriminately in studies of
taxonomy and succession of natural phytoplankton populations, but it is still valuable as a tool
for population structure analysis because manipulation, fixation and preservation of samples
needed for alternative methods (ranging from conventional microscopy and Confocal Laser
Scanning microscopy to flow-cytometry) tend to destroy an unknown proportion of the cells.
Also, the presence of cells associated with aggregates of particulate matter, with marine snow,
or with other organisms in symbioses (e.g. Cox et al., 1985; Knight and Mantoura, 1985),
including alga-alga symbioses (e.g. in dinoflagellates: Schnepf and Elbrachter, 1988; cf.
In the sixties, the pioneer of pigment analysis for chemotaxonomic purposes in marine
phytoplankton studies had been S.W. Jeffrey (1961, 1968). She convinced most biological
oceanographers of the promises of this approach by publishing her finding of high
chlorophyll b concentrations in the open ocean, which, as she argued (Jeffrey, 1976), revealed
the abundance of a group of phytoplanktonic algae that was until that time not known to occur
there at any numbers of importance: green algae. This was the only taxonomic entity of
microalgae characteristically containing ChI b according to the literature of the time (Weber
and Wettern, 1980; Van den Hoek, 1978). Jeffrey's report drew much attention, but it can
now be regarded as an example of the danger of neglecting, more conventional methods for
detection of natural phytoplankton components, notably microscopy. Green algae may be
present in the open ocean (Takahashi and Hori, 1984), but we now know that except in
estuarine regions (Lubian and Establier, 1980) or coastal upwellings (Gieskes and Kraay,
1986b; Gieskes et al., 1988), where green algae can be prominent, most chlorophyll b in the
ocean is associated with picoplanktonic Prochlorophytes, not green algae (Chisholm et al. ,
1988; Gieskes et al., 1988; Olson et al., 1990; Veldhuis and Kraay, 1990) - afortiori, most
so-called ChI b is in fact not even normal ChI b but a derivative, possibly containing a
divinyl bond (Goericke, pers. comm.), that gives it a red-shifted absorption spectrum (Gieskes
et al., 1979, their Fig. 2; see also Neveux et al., 1989; and see Fig. 3). Prochlorophytes do
not contain violaxanthin (Burger-Wiersma et al., 1986) while green algae do (Van den Hoek,
1978), so ChI b presence without a trace of violaxanthin indicates that Prochlorophytes
contribute to a phytoplankton population - a straightforward way to detect and quantify this
group's abundance (Gieskes et al., 1988). Such subtle pigment analysis is best performed after
separation by high-performance liquid or thin-layer chromatography (HPLC, HPTLC).
Nevertheless, Jeffrey's early TLC work has given the interest in pigment analysis its
momentum, and it continues to do so even now that modern HPLC has replaced paper
chromatography (Jeffrey, 1961; Jensen and Sakshaug, 1973), thin-layer chromatography
(Jeffrey, 1968, 1981), HP-thin-layer chromatography (Wright and Jeffrey, 1987), and the
conventional ways of HPLC (Abaychi and Riley, 1979).
As I have argued, pigment analysis should not be applied indiscriminately in studies of
taxonomy and succession of natural phytoplankton populations, but it is still valuable as a tool
for population structure analysis because manipulation, fixation and preservation of samples
needed for alternative methods (ranging from conventional microscopy and Confocal Laser
Scanning microscopy to flow-cytometry) tend to destroy an unknown proportion of the cells.
Also, the presence of cells associated with aggregates of particulate matter, with marine snow,
or with other organisms in symbioses (e.g. Cox et al., 1985; Knight and Mantoura, 1985),
including alga-alga symbioses (e.g. in dinoflagellates: Schnepf and Elbrachter, 1988; cf.