Diatom Assemblages in Surface Sediments Along Nutrient and Salinity Gradients of Thi Vai Estuary and Can Gio Mangrove Forest, Southern Vietnam

In order to assess the current ecological status of the tidal Thi Vai Estuary and the Can Gio Mangrove Forest in Southern Vietnam, we evaluated the spatial diatom composition and abundance in surface sediments and their relation to physical and chemical parameters of the water. Major changes in the distribution of diatom assemblages were determined by multivariate statistical analyses. Principal component analysis (PCA) was used to ordinate environmental variables of the water, showing a clear gradient along the estuary, with higher nutrient levels (total phosphorus and total nitrogen) and lower dissolved oxygen (DO) concentrations at upstream sites. Canonical correspondence analysis (CCA) was used to determine the species-environmental relationship. Total phosphorus (TP) and DO (p