Johann Pope M. Molina, Abigail L. Grecia, Jan Parvin B. Zoluaga (March 2011)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Little information is known on the effects of the Jaro Floodway on the nearby coastal waters of Brgy. Bitoon, Jaro. Trophic state index is an important parameter in determining the state of the water, namely, the nutrient level. The chlorophyll-a content of this portion of the Iloilo strait can be used to calculate its trophic state index. Water samples were gathered from three randomly selected sites near the opening of the floodway. The sites were each 1 m deep, and within the range of 10 44’53.73″ N-10 44’57.36″ N and 122 35’35.43″ E-122 35’58.37″E. The samples were brought to the Philippine Science High School- Western Visayas Campus for Filtration. An improvised filtration apparatus was used, along with 0.45 um Millipore membrane filters. The filters were frozen overnight and macerated in a 90% aqueous acetone solution within a test tube using a homogenizer. The result was steeped overnight. The process of spectrophotometry was used to obtain their optical densities at certain wavelengths. These optical densities were used to calculate the mean chlorophyll-a content, for calculation of the Carlson’s trophic state index. The trophic state index value of the region was 63.42651 for the 2nd week of November 2010, 68.95827 for the 4th week of November 2010, and 68.54504 for the 2ndweek of December 2010. These values, within the range of 50-70, classified the Bitoon coastal region’s waters as eutrophic, having a high nutrient content. Bodies of water that have nutrient levels that are above average tend to have a high risk of oxygen depletion, which may drive away the aquatic life that fisherman catch for a living.