Estado trófico y variación estacional de nutrientes en los ríos y canales del humedal mixohalino de Bahía Samborombón (Argentina)

N. SCHENONE; A. V. VOLPEDO; A. FERNÁNDEZ CIRELLI.

Limnética

Asociación Ibérica de Limnología

Lugar: Madrid, España; Año: 2008 vol. 27 p. 65 - 72

0213-8409

Trophic state and nutrient seasonal variation in the rivers and channels of the Samboromb´on Bay mixohaline wetland (Argentina) Samboromb´on Bay is the most extensive mixohaline wetland of Argentina (244000 ha.). It has an extension of 150 km. along the occidental coast of the exterior zone of the Rýo de la Plata, from Punta Piedras (35◦27 S; 56◦45 O) to Punta Rasa (36◦22 S; 56◦35 O). The trophic state of the rivers and channels that cross this wetland was evaluated by the determination of total nitrogen (N) and total phosphorus (P) concentrations in ten stations situated from north to south of the bay. Samples were grouped according to seasonal variability, separating two periods, low water period and high water period. A hypertrophic state was observed in most of the analyzed stations, phosphorus being the limiting nutrient in almost every case in both periods. In addition to the seasonal variation in the nutrient concentrations, a spatial variation was observed in a north to south direction. Physico-chemical parameters were taken into account and, along with the nutrient concentration values, were analyzed by PCA (Principal Component Analysis), which suggested the existence of two groups with different characteristics. The increase in nutrients input in this ecosystem could cause alterations on the productivity of the area and on the activities of the region such as coastal fisheries.