Spatial and Temporal Variability of Physico-chemical Parameters in Songsong Island, Kedah, Malaysia.

Abstract

Marine ecosystems are distinctive environments and habitats that are increasingly under threat from multiple pressures, including global warming, coastal development, pollution, and other human-induced impacts. Therefore, this study examines the seasonal variations in key physico-chemical parameters of seawater around Songsong Island, Kedah, Malaysia to better understand the environmental conditions influencing the local marine ecosystem. Data were collected from 12 stations during both the Southwest (SWM) and Northeast Monsoon (NEM) periods to address a knowledge gap in seasonal variability across the island. Seawater physico-chemical parameters measured included pH, salinity, temperature, conductivity, dissolved oxygen (DO), Total Ammoniacal-Nitrogen (TAN), and orthophosphate (PO₄³⁻). Findings revealed moderate spatial and seasonal variability. Seawater pH was decrease during the NEM (average pH 7.91 ± 0.033) compared to the SWM (7.96 ± 0.022). Besides, salinity increased slightly in the NEM (30.63–31.54 ppt) compared to the SWM(29.50–30.82 ppt). Thus, conductivity also increased during NEM (51.75 ± 3.84 mS/cm) compared to SWM (52.01 ± 0.44 mS/cm). Moreover, seawater temperature was higher during the SWM (30.57–31.01°C), while DO levels remained healthy across both seasons. Notably, TAN concentrations were much higher in the NEM (1.02 ± 0.317 mg/L) than in the SWM (0.04 ± 0.017 mg/L), possibly due to reduced dilution and anthropogenic inputs. Conversely, PO₄³⁻ levels were greater during the SWM with an (0.190 ± 0.0881 mg/L) compared to the NEM (0.050 mg/L ± 0.003 mg/L), with a much greater variability. Two-way ANOVA analyses confirmed that there is no significant different between sampling stations while there have significant different between monsoon seasons (p < 0.05) except for conductivity, highlighting spatial heterogeneity and seasonal influences. These results underline the impact of monsoonal dynamics, river discharge, rainfall and human activities on seawater characteristics. The study provides a valuable baseline for environmental monitoring and supports conservation and management strategies for coastal ecosystems around Songsong Island.