López-Portillo, J.; Lara-Domínguez, A.L.; Vázquez, G., and Aké-Castillo, J.A., 2017. Water quality and mangrove-derived tannins in four coastal lagoons from the Gulf of Mexico with variable hydrological dynamics In: Martinez, M.L.; Taramelli, A., and Silva, R. (eds.), Coastal Resilience: Exploring the Many Challenges from Different Viewpoints. Journal of Coastal Research, Special Issue No. 77, pp. 28–38. Coconut Creek (Florida), ISSN 0749-0208.This study explored the spatial variability of physico-chemical water variables (i.e., salinity, nitrogen, phosphorus and tannins) in contrasting seasons in four coastal lagoons (Chica y Grande, La Mancha, Sontecomapan and El Ostión) along Veracruz state, Mexico. We also calculated the mangrove and central basin water areas and associated them to physico-chemical data to analyze them by means of Principal Component Analysis (PCA) due to high correlation among variables. Finally, we elaborated coded maps of each lagoon to represent the gradients of the variables with statistically significant loadings in either of the first two components accounting for 50 to 70% of total data variability. In La Mancha, NH4, NO3 and RP but not salinity were associated with river outflows. In Grande and Chica, NH4, NO3 and RP were higher near the lagoon inlet, but the major river outflows was also in that area, confounding their actual source. Finally, NO3 were strongly associated with river outflows in Sontecomapan and El Ostión. However, the concentrations of tannins were directly associated with mangrove cover in the four lagoons. Our results indicate that the connection with the sea, the position of the inflowing rivers, and the morphology of the lagoon provides the “estuarine signature” of each lagoon.