Comparación de la variabilidad temporal de los índices de calidad de agua y eutrofización en la laguna Maylas del cantón Gualaceo

Abstract

Natural processes and human actions, especially eutrophication, cause the deterioration of water quality in lentic bodies. Unsustainable tourism and fish farming have affected the quality of the Maylas Lagoon in Gualaceo, which is an important source of natural water for the community. A study was conducted to evaluate water quality and the level of eutrophication in the lagoon using different indices. Physicochemical and microbiological parameters such as phosphorus, nitrates, chlorophyll-a, and dissolved oxygen, among others, were analyzed at six monitoring points during three winter months and three summer months. The results indicated that the water quality according to the NSF index was good in additive and multiplicative terms, but the Oregon index rated it as poor. In terms of trophic status, the TRIX and TFI (nitrogen) indices indicated an oligotrophic state, while the OECD and TFI (chlorophyll-a) agreed with the criterion that the lagoon was in a mesotrophic state. However, the most alarming scenario was the OECD index (phosphorus), which showed a hypereutrophic state. Significant differences were found between the winter and summer periods regarding the NSF, Oregon, OECD, and Carlson indices. Principal component analysis revealed that dissolved oxygen was the most relevant variable for water quality, while transparency was key for trophic status. Proper assessment of the trophic state will allow the implementation of effective management strategies to control and mitigate eutrophication problems in the Maylas Lagoon.