A Study on the Attached Microflora and Microfauna along the Riverbank of the Downstream and Upstream Parts of the Pasig River System, Philippines

Abstract

The Pasig River system is a large river that runs across Metro Manila with two main tributaries. Marikina River and San Juan River. The aim of this study is to compare the attached microflora and microfauna on the non-living substrates along the riverbank of the downstream and upstream regions of the Pasig River system. This study also aims to identify potential bioindicator (s) that can be used in assessing the water quality of the Pasig River system. Two sampling sites were used in this study: a) Guadalupe River (downstream); and b) Marikina River (upstream). Cement substrates were collected from the two areas, and were brought to the laboratory for macroscopic and microscopic documentation. The surface of the substrates was scraped, prepared on a wet mount, and observed under the microscope. All the observed organisms were recorded using a video camera mounted on a microscope. A total of twenty-one (21) organisms were identified in this research. These include two (2) green algae, one (1) desmid, three (3) cyanobacteria, two (2) diatoms, four (4) protozoans, two (2) rotifers, one (1) arthropod, one (1) oligochaete, one (1) flatworm, one (1) nematode, and three (3) snail. Species of Oscillatoria, Scytonema. Spirogyra. Navicula, Nitzchia, Tokophyra, Vorticella, Rotaria. Chironomus larva, oligochaete, and nematode were all found in both sampling sites. Cladophora sp.. Brachionus sp.. flatworm, and snail from Family Thiaridac were only found in Guadalupe River. On the other hand, Closterium sp.. Hapalosiphon sp.. Bursaria sp., Euglena sp.. and snail from Family Lymnacidac and Family Physidae were only found in Marikina River. Potential bioindicators only found in Guadalupe River include Cladophora sp.. flatworm, and snail front Family Thiaridae (poor water quality). Those that were only found in Marikina River include Closterium sp. and snails from Family Lymnaeidae (indicator of clean and oligotrophic water); and Hapalosiphon sp.. Euglena sp. and snails from Family Physidae (indicator of water pollution).