Phytoplankton responds to environmental variables in Bali Straits, Indonesia

Abstract

The ecological significance of phytoplankton within the small pelagic ecosystem cannot be overstated, as it serves as a vital food source for various marine biota, including larvae, juveniles, and small pelagic fish. This study marks the first investigation in the Bali Straits concerning the relationship between phytoplankton abundance and in situ environmental variables, employing an innovative additive model to develop a predictive system. The primary objective of this research is to elucidate the impact of environmental variables on phytoplankton abundance in the Bali Straits. During the year 2013, time series plankton samples and corresponding environmental variables, such as pH, nitrate (NO3), phosphate (PO4), chlorophyll-a (Chl), and silica (SiO3), were collected. Utilizing stepwise generalized additive models (GAMs), we assessed the response of two major phytoplankton groups, namely diatoms and dinoflagellates, to the prevailing environmental variability. Our findings unveil distinct response patterns for each group, with diatoms displaying a deviance explained (DE) of 38.40%, and dinoflagellates with 35.5%. Notably, both groups exhibited significant responses to NO3 and SiO3, while pH solely exerted a significant impact on dinoflagellates. In contrast, PO4 and Chl displayed comparatively lower influence on the abundance of both phytoplankton groups. This study contributes to a deeper understanding of the ecological dynamics in the Bali Straits and enhances our predictive capabilities in this critical marine ecosystem.