From "The Open Sea", Part 1: "The World of the Plankton", by Sir
Alistair Hardy, 1956.
(thanks to Barney Balch for this quotation)
"A well-known herring skipper, Mr. Ronald Bells, who is also a keen
naturalist, has recently written, under the pen-name of "Peko", an excellent
article on this white water in World Fishing (July 1954). He
describes how this water gives 'the queer impression of whiteness coming
upwards: as if the light was below the sea instead of above it.' He then
refers to recent views that the coccoliths are shields reflecting light from
their owners which normally live in tropical seas where the illumination is
too strong; 'and here', he writes, 'was the perfect explanation of the fairy
glow or white reflection that I had experienced long ago, and wrote about
before I knew even that this organism existed ...' "
Nowadays we suspect that the coccoliths do not act as light shields or light
screens to protect their owners from the too-intense illumination. This is
because (1) coccolith-bearing cells, (2) "naked" cells, and (3) Ehux
cells with coccoliths removed by acid, all share the same response to very
high light intensities. The light intensity at which the maximum
photosynthetic rate is achieved is not affected by the possession of
coccoliths (Paasche & Klaveness, 1970), and neither is the light intensity
at which photoinhibition starts to decrease photosynthetic rate (Nanninga &
Tyrrell, 1996). If the coccoliths were acting as light screens then we
would expect different photosynthetic performance at high light intensities
(e.g. no photoinhibition) when the cells are covered with coccoliths.
Instead we see no significant difference.
It is now confirmed that the coccoliths themselves are causing the
too-intense ambient illumination (see
rather than reducing it for the cells they cover.
Toby Tyrrell : T.Tyrrell@noc.soton.ac.uk