rather steep drop-offs above a thermal limit. Eppley (1972) plotted a scatter diagram
from a similar data compilation of rates from batch cultures, but without
distinguishing the species. He then fitted an upper envelope to the data, using an
exponential equation. Actual μmax values for individual species do not look much like
the envelope. The higher points, especially below 10°C are mostly for diatoms, which
have higher growth potential than other phytoplankton, when only internal
physiological interactions (rates set by temperature) are limiting. Flagellates are
mostly slower. Bissinger et al. (2008) analyzed a larger data-set, completed a
thorough statistical analysis and proposed this modification of Eppley’s equation:
(^) which suggests that growth at lower temperatures may be up to 30% faster than
estimated from the original Eppley equation (Fig. 3.18).
Fig. 3.17 Temperature effect on phytoplankton growth rate for several species:
diatoms left, flagellates right. Dashed line on the right is the “Eppley curve”, μ
(doublings/day) = 0.85 exp(0.063T).
(^) (After Smayda 1976.)
Fig. 3.18 Daily doubling rates of a wide variety of phytoplankton cultured at a range