A Decade of Biogeochemical Monitoring in the Tropical Urban Saigon‐Dong Nai River‐Estuary Continuum, Vietnam

Abstract

Tropical Southeast Asian estuaries remain underrepresented in global water quality archives, limiting regional comparisons and the development of predictive biogeochemical models for monsoon‐driven coastal systems. To address this observational gap, this paper presents a quality‐controlled, 10‐year (2015–2025) biogeochemical data set for the Saigon‐Dong Nai River‐estuary continuum in southern Vietnam. The observing program couples a biweekly time series at four fixed stations with seven seasonal longitudinal transect campaigns across 27 sites along a 140 km gradient from freshwater to marine conditions, encompassing over 19,800 observations of physical parameters, nutrients, dissolved and particulate organic carbon, and chlorophyll‐ a . Technical validation confirms high internal consistency, including stoichiometric mass balance pass rates (>97%), stable certified reference material recovery (98%), and cross‐instrument analytical continuity. The temporal scope and tidal phase synchronization of these observations allow for the statistical partitioning of short‐term monsoonal variability from chronic, multiyear anthropogenic baseline shifts. This openly accessible data set provides an empirical foundation for investigating how extreme hydrological forcing and rapid urban wastewater loading may interact to shape estuarine hypoxia, organic matter transformation, and nutrient cycling in dynamic tropical estuaries.