Bark pH as a factor affecting the density of epiphytic terrestrial algae in Taman Wetland Putrajaya, Malaysia

Epiphytic terrestrial green algae are normally favoured by an environment with higher pH level. Air pollution in the atmosphere contributes to altering the bark pH and provides a better medium for algal growth. High absorption capacity of the microalgae makes it easy to accumulate atmospheric pollutants in their cells immediately. Habitats of epiphytic terrestrial algae are mostly characterized by aridity, and/or levels of temperature and light intensity. Bark pH of tree surfaces has been considered as one of the most important factors affecting the community structure of corticolousbiocells. The present work was designed to assess the effect of bark pH on the number of algal cells inhabiting 15 standing trees from the sampling station located in the Central Region of Peninsular Malaysia, Putrajaya. Several methods were used including field sampling, algal quantification, algal identification and measurement of bark pH. The study revealed that the density of epiphytic terrestrial algae was found to be significant with the bark pH (pvalue= 0.001). This positive correlation (r-value= 0.762) showed that bark pH does play an important role in the health of algal cells. The algae are believed to be able to tolerate higher bark pH. The alkaline bark pH altered the microalgal composition because it was found to be positively affecting the density of epiphytic microalgae. Therefore, higher bark pH significantly contributes to the enrichment of algal density.