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SEASONAL EFFECT ON THE RELATIONSHIP BETWEEN THE PHOTOSYNTHETIC CAPACITY OF INTERTIDAL MICROPHYTOBENTHOS AND TEMPERATURE 1
Author(s) -
Blanchard Gérard F.,
Guarini JeanMarc,
Gros Philippe,
Richard Pierre
Publication year - 1997
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1997.00723.x
Subject(s) - biology , photosynthesis , acclimatization , abiotic component , intertidal zone , zoology , irradiance , photosynthetic capacity , bloom , range (aeronautics) , photoperiodism , botany , ecology , atmospheric sciences , physics , materials science , quantum mechanics , composite material
The response of the photosynthetic capacity (P max ) of microphytobenthos to short‐term variations of temperature (in the range 5–35° C) was assessed on a seasonal basis. The relationship is described mathematically, and relevant physiological parameters are identified: P MAX , the maximum value of P max achieved at T opl , the optimum temperature. Estimated values of T opt do not change significantly throughout the year and remain close to 25° C. It is thus concluded that T opt is not influenced by seasonal variations in the daily range of mud surface temperature. Identical conclusions hold for T max (ca. 38° C), the thermal threshold beyond which no photosynthesis occurs. Conversely, P MA estimates exhibit substantial variability: P MAX (mean ± root mean square error) is highest in April (11.18 ± 0.42 [μg C · [μg Chl a] −1 · h −1 ) during the beginning of the annual increase in temperature, photoperiod, and maximum irradiance and is lowest in December (3.04 ± 0.16 μg C · [μg Chl a] −1 · h −l ). From an ecological point of view, the short‐term and seasonal variations of P MAX suggest that the microphytobenthic community takes advantage of the abiotic spring environmental conditions, allowing the onset of the bloom. Nevertheless, no “acclimation strategy” (i.e. shifts in T opt and T max that prevent temperature inhibition in summer or improve photosynthetic rates in winter) is apparent from our results.