Philippine Journal of Science
154 No. 1: 169-178, February 2025
ISSN 0031 – 7683
Date Received: 08 Aug 2024

Janell Carmina A Sihay, Cristy S. Acabad, and Cesar L. Villanoy

Satellite-derived observations of chlorophyll-a (Chl-a) concentration reveal patterns of enhancement, particularly at the west side of Camiguin Island in Bohol Sea, the Philippines. Previous studies have linked basin-scale chlorophyll variability with interannual rainfall anomalies due to the El Niño–Southern Oscillation. However, the role of other mesoscale processes such as upwelling, eddies, and island effects remains unexplored. Here, we analyzed ocean data to determine the related processes to the observed enhancement. We determined the spatiotemporal variability and distribution of Chl-a in the Bohol Sea. We found that Chl-a
varies most on the seasonal scale following monsoon forcing. The west Camiguin enhancement is prominent during the northeast monsoon (NEM). We found that strong NEM winds drive mixing, upwelling, and particle entrainment (i.e. Chl-a as a proxy for phytoplankton). The monsoonal physical processes create favorable conditions for finer-scale enhancement through island wakes generated from the interaction of winds and currents with Camiguin Island.