Philippine Journal of Science
150 (5): 1231-1243, October 2021
ISSN 0031 – 7683
Date Received: 14 Dec 2020
Limnology of Lake Wood: an Ancestral Lake
of the Subanen Tribe
Marjohn Y. Baludo1*, Rey Donne S. Papa3, and Francis S. Magbanua2
1Institute of Environmental Science and Meteorology; 2Institute of Biology
University of the Philippines Diliman, Quezon City 1101 Philippines
3Department of Biological Sciences, College of Science; and
Research Center for the Natural and Applied Sciences and the Graduate School
University of Santo Tomas, Manila 1015 Philippines
*Corresponding author: mybaludo@up.edu.ph
ABSTRACT
Relatively limited information exists on Lake Wood’s limnology and ecology, an ancestral lake of the Subanens. Here, we provide a limnological characterization of the lake – exploring its physical, chemical, and biological features. The data on lake morphometry were gathered using an echosounder; lower depth water samples were collected using a Niskin water sampler for physicochemical analyses while surface water samples were collected at five sampling sites for phosphate (PO4) analysis; and zooplankton samples were collected at several depths through vertical towing in March–April 2019. Lake Wood, located at 320 m above sea level, has an extensive surface area covering 7.38 km2 with a maximum depth of 85 m. Lake water comes from rainfall, small rivers, and groundwater and empties into the Dumanquilas Bay via its only outlet – the Biswangan River. Land use of the lake is predominantly cultivated land. Moreover, based on the trophic state index (TSI), the lake’s current trophic status is eutrophic. During the study periods, thermocline and oxycline formed at 15 m below the surface of the lake. We recorded three cladocerans (Ceriodaphnia cornuta, Diaphanosoma cf.sarsi, and Moina micrura) and one copepod species (Thermocyclops crassus) in the lake, all of which are common limnetic species found in the Philippines. Based on our findings, we recommend more efforts to manage and rehabilitate the lake to control and manage eutrophication’s negative impacts. Finally, our study contributes to understanding lakes in Mindanao that are less represented in Philippine freshwater research.