The Photophysiology of Benthic Diatoms in the Intertidal Flats of Pulau Pinang (Malaysia)

The in-situ photosynthetic activity in tropical intertidal benthic diatom response to environmental variation was assessed this study by measuring chlorophyll fluorescence. investigation carried out during the lowest tide January (non-rainy day) and February 2013 (post-rainy at two sampling sites (A B) from each selected location (Pantai Jerejak, Teluk Bahang Tanjung Bungah, Pulau Pinang, Malaysia). Samples of surface sediment (top 0.5 cm) were collected, a extracted as biomass estimation. Assessments diatoms made using pulse-amplitude modulated (PAM) fluorometer. Fifty-three species identified, representing 27 genera three studied locations. Both locations showed similarities diversity abundance. Two-way ANOVA no significant differences (p = 0.430) richness (Margalef Index) among locations, with an average value 6.33±0.247. flats dominated Cocconeis, Navicula, Actinoptychus, Diploneis. community has low maximum quantum yields, Fv/Fm (ranging 0.170 0.340) is often light-limited (Photoacclimation Index, Ek, ranging 67.96 236.71 mol photons m-2 s-1). relative electron transport rate (rETRmax) low, values 3.45 35.51 across Fluctuation salinity caused decrease activity. This suggests that indicated poorly adapted microalgal constantly light-limited. However, time-series data needed determine ability these communities adapt changing environment.