The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

1560 / 2024-09-27 23:20:07

Spatial and Temporal Variability of CDOM Distribution in the northern Malacca Strait

Chromophoric Dissolved Organic Matter (CDOM),Dissolved Organic Matter (DOM),Malacca Strait,Remote sensing (RS),Coastal zone

Anthropogenic activities are influential in elevating dissolved organic matter (DOM) concentration in aquatic bodies. Chromophoric dissolved organic matter (CDOM) is a fraction of DOM that contains chromophores and absorbs surrounding lights. Increasing CDOM presence in water reduces photosynthesis available radiation (PAR) of sunlight that will affect primary productivity. Situated along the west coast of Peninsular Malaysia, the Malacca Strait is heavily industrialized, with nearby waters subjected to intense human activities. Our knowledge of biogeochemical properties such as CDOM and the application of remote sensing in scientific work in this region remains relatively sparse. Thus, our work is a preliminary study that focuses on understanding the biogeochemical variables that influence CDOM presence in this region while using remote sensing to further understand its spatial distribution and temporal variability. Water samples and hydrological parameters were collected in April 2023 along the northern Malacca Strait to analyse biogeochemical variables and establish their underlying relationship. The levels of CDOM recorded in this study range from 0.7947-3.0151 m^-1 with an average of 1.3483±0.0961 m^-1. The spatial distribution of CDOM throughout the northern strait was observed to be affected by adjacent terrestrial inputs and bathymetry characteristics of water bodies. Additionally, we conduct a comparative analysis between in-situ measurements and satellite data, yielding a robust outcome (R=0.52, p<0.01) and strong consistency with RMSE at 0.16 between the two datasets. The temporal variability of CDOM were further examined by analysing satellite data from 2013 to 2022. This analysis, supported by local meteorological data, revealed that the seasonal and interannual patterns are strongly influenced by the monsoon regime and regional climate. This study emphasised the importance of understanding the production and removal process of CDOM which is vital to comprehend its fate and influence on tropical water bodies. It is anticipated that this study further paves the way for remote sensing application and data development in this region.