QUANTIFYING THE SHORT-TERM TEMPERATURE EFFECT ON LIGHT-SATURATED PHOTOSYNTHESIS OF INTERTIDAL MICROPHYTOBENTHOS

A mathematical expression is proposed to describe the relationship bet ween the photosynthetic capacity (P-max) of natural assemblages of mot ile benthic diatoms and temperature. Experiments were performed in 2 d ifferent seasons to document the response of P-max to a rapid increase in temperature (3 degrees C h(-1)). In both cases, there was a progre ssive increase in P-max up to an optimum temperature (T-opt), beyond w hich P-max declined rapidly. T-opt did not change from September to De cember 1995, but the maximum photosynthetic capacity (P-MAX, i.e. P-ma x at T-opt) was twice as high in September as in December.