Balance hidrológico y de nutrientes en un humedal costero del Pacífico Sur de México

Abstract

Coastal lagoons can export or import different amount of materials according to the geographical localization and fluvial and marine regimes associated to them. Talking this in account, water, salinity and nutrient balances (NO₂, NO₃, NH₄ y PO₄) were measured in coastal wetland. The volume of fresh water that penetrated into the wetland was different in the two years (1991 and 1992), with a 0.87m³/s average. It was high in September (1.62m³/s) and low in April (0.37m³/s) with 31.4x10⁶ m³/yr. Marinne water was more constant with an average per year of 1.72m³/s, and 28.5x10⁶/yr. This situation favored to oligihaline condition. Nitrates were the most abundant with a high input of 7.5µM in June (16.8 µM) and low input of 1.6 mM in December. The exportation was twice the importation with an average of 14.5 µM. The ammonium and nitrites were second in place in exportation. The fluvial input of orthophosphates to wetland was less than to the sea exportation. The lower amount caused by a diminishing river flow. The export of nutrients from the wetland  was greater than the import, with 86.5 ton/yr vs 48.2 ton/yr, respectively. The former meaning, a great marine nutrient enrichment by consequence of the mangrovve area.