Improper waste disposal may cause an increase in the levels of certain compounds in the water. Such compounds are phosphate and nitrates. The basis of this study was to correlate the levels of the two compounds to the growth of Canistrocarpus cervicornis (as identified by Dr. Lawrence Liao.), a brown algae known to grow in tropical waters, in Silut Bay, Liloan, Cebu. Six stations were selected for the study. Water samples were collected and was submitted to the water laboratory. The level of phosphate and nitrate in the water were tested. Compounds in the sediments and within the algae were not included.
Nitrate levels were obtained by the use of cadmium reduction through addition of Cu-Cd granules with water into a reduction column and then treated with the sample with the hydrogen ion concentrated (pH) adjusted. Turbidity was removed and absorbance level obtained using the UV-1800 Shimadzu UV Spectrophotometer. Phosphate levels were obtained using the ascorbic acid to which a sample was pipetted into a flask with a phenolphthalein indicator. Absorbance obtained by the use of the same spectrophotometer as with the nitrates which is the UV-1800 Shimadzu UV Spectrophotometer. Glass electrode buffered with KCl was connected to the Thermo Scientific Orion 3-star was used to read the pH. Other physico-chemical tests were obtained by the use of a laboratory thermometer for the water temperature and a Secchi disc for turbidity.
Increase growth of Canistrocarpus cervicornis was observed in stations with slightly low nitrate levels and showed no relationship with phosphate due to its affinity to the sediments in the bay. Certain stations with high level of nitrates with lower algal growth could be caused by the functioning fish pond right beside the specific station. Photosynthesis and the capacity of macroalgae to retain internal nitrate were some of the factors that affect the algal growth within the area. Macroalgae tend to grow in areas with lower nitrate levels but had no significant effect with the phosphate level. A yearlong sampling is advised to future researchers to further investigate the cause and effect of the different levels of phosphate ant nitrate and other probable factors that may affect the growth of macroalgae.