Medina-Gómez, I.; Villalobos-Zapata, G.J., and Herrera-Silveira, J.A., 2015. Spatial and temporal hydrological variations in the inner estuaries of a large coastal lagoon of the southern Gulf of Mexico.

Coastal lagoons receive significant inputs from river basins, leading to inner estuaries or fluvial lagoon subsystems subject to the bidirectional flow of energy, organic matter, nutrients, and sometimes toxic materials between river mouths and lagoons. Such exchanges are highly dynamic and enhance lagoon productivity. Terminos Lagoon (TL) is a large coastal lagoon in the southern Gulf of Mexico that has two deep permanent inlets connecting the lagoon to the Gulf and strong riverine input. We evaluated the influence of river discharge on seasonal and spatial patterns of water quality in six fluvial lagoon subsystems in TL. Six bimonthly samplings were carried out from February to December 2001. Temperature, salinity, dissolved oxygen, dissolved inorganic nutrients (nitrate, nitrite, ammonium, soluble reactive phosphorus, and soluble reactive silica), and chlorophyll a were measured. There were large differences between the western and eastern river mouths due to differences in river discharge and the nature of their watersheds (e.g., land use, size). Furthermore, the influence that the dominant depositional environment and local habitats (i.e. submerged aquatic vegetation) developing adjacent to these estuarine lagoon subsystems may exert over the nutrient concentrations of the water column is discussed. These differences were more evident during the rainy season when river discharge was highest. It is suggested that the input of N rather than P could have the greatest impact on TL in the future.