| Autor: |
Fregoso-López MG; Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Av. Ciudad Universitaria 3000, 04510, Coyoacán, Ciudad de México, Mexico., Armienta-Hernández MA; Instituto de Geofísica, Universidad Nacional Autónoma de México, Av. Universidad 3000, 04510, Coyoacán, Ciudad de México, Mexico.; El Colegio de Sinaloa, Centro, Culiacán, Sinaloa, Mexico., Alarcón-Silvas SG; Posgrado en Ciencias en Recursos Acuáticos, Facultad de Ciencias del Mar, Universidad Autónoma de Sinaloa, Av. de los Deportes s/n Ciudad Universitaria, 82017, Mazatlán, Sinaloa, Mexico., Ramírez-Rochín J; Centro de Investigaciones Biológicas del Noroeste, Av. Instituto Politécnico Nacional 195, 23096, La Paz, Baja California Sur, Mexico., Fierro-Sañudo JF; Posgrado en Ciencias Agropecuarias, Colegio de Ciencias Agropecuarias, Universidad Autónoma de Sinaloa, Boulevard San Ángel s/n Fraccionamiento San Benito, Predio Las Coloradas, 8000, Culiacán, Sinaloa, Mexico., Páez-Osuna F; El Colegio de Sinaloa, Centro, Culiacán, Sinaloa, Mexico. paezos@ola.icmyl.unam.mx.; Instituto de Ciencias del Mar y Limnología, Unidad Académica Mazatlán, Universidad Nacional Autónoma de México, Joel Montes Camarena s/n, 82040, Mazatlán, Sinaloa, Mexico. paezos@ola.icmyl.unam.mx. |
| Abstrakt: |
This study assessed the spatial and temporal nutrient variability in the El Fuerte River basin in northwestern Mexico, considering its effects on the water trophic status as well as the nutrient loading to the Gulf of California. Physicochemical parameters, inorganic species of nitrogen, phosphate, total nitrogen, total phosphorus, and chlorophyll-a (chl-a) were quantified at 16 selected sites along the river in April (dry season) and October (rainy season) 2017. Mean concentrations of nutrients during dry and rainy seasons were 36.3 ± 24.1 and 55.1 ± 74.6 μg L -1 of total ammonia nitrogen, 3.4 ± 3.6 and 4.5 ± 3.5 μg L -1 of NO 2 - -N, 190.8 ± 256.0 and 163.6 ± 261.0 μg L -1 of NO 3 - -N, 42.4 ± 44.2 and 104.9 ± 76.2 μg L -1 of PO 4 3- -P, 1.0 ± 1.3 and 691 ± 2242 mg L -1 of TN, 0.06 ± 0.06 and 0.08 ± 0.09 mg L -1 of TP, and 0.9 ± 0.6 and 2.0 ± 0.9 μg L -1 of chl-a with significant differences (p < 0.05) between sites and seasons. When waters are transported downstream, nutrient levels are enriched by 4 to 35 times compared to those upstream due to increased population and agriculture downstream, confirming the hypothesis of the study. The calculated TN and TP fluxes were 1.23 × 10 4 and 3.57 × 10 1 ton year -1 , respectively. Factor analysis indicated that inorganic nitrogen species and phosphorus are the main factors affecting the river water quality. Despite N excess during the rainy season, the river reached mesotrophic waters due to phosphorus limitation. This suggests the need to establish a water quality monitoring program to understand the vulnerability of the river course to changes in its trophic state. |
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