Of the equations that have been proposed
to describe the utilization of light by
phytoplankton, a few are based on grossly
oversimplified models of photosynthesis;
the rest are completely empirical. This being
the case, the only valid criterion for
judging the relative merits of the different
formulations is their ability to describe
data with the minimum number of well
chosen parameters. As discussed at some
length in Platt et al. (1975), by “well
’ Present address : Lawrence Berkeley Laboratory,
Energy and Environment Division, University
of California, Berkeley 94720.
chosen” we mean parameters which are, as
far as possible, mututally independent, and
which have an informative physical interpretation,
that is a significance transcending
their role as operators in a particular
mathematical expression.
Here we compare the merits of eight different
representations of the photosynthesis-
light relation judged according to this
criterion of ability to describe experimental
data. We treat only that part of the curve
up to and including light saturation. We
shall not consider the range of light levels
above the threshold of photoinhibition,
where the introduction of at least one additional,
independent parameter would be required
for a complete description (Platt et
al. 1975).