Abstract

REY, Jorge R.  and  O'CONNELL, Sheila M.. Efectos de descargas de agua de manglares embalsados en las praderas submarinas y en la atenuación de la radiación solar en el estuario colindante. INCI [online]. 2003, vol.28, n.11, pp.639-645. ISSN 0378-1844.

We report the results of a study about the effects of point source discharges of poor quality water from impounded mangrove forests on the structure of seagrass meadows dominated by Syringodium filiforme Kützing, on seagrass carbohydrate stores, and on light penetration through the water column of the adjoining estuary. Very few significant effects of distance from the discharge point on seagrass cover, shoot density or canopy height of S filiforme were evident, and there were no consistent patterns in the values of these variables with distance from the discharge point. Depth of the sampling site did have a significant effect on the above variables, even though depth differences between shallow and deep sites were less than one meter. There was no evidence of significant effects attributable to sites or distance to the discharge source neither on stored soluble carbohydrates in the blades nor on the rhizomes of S. filiforme. The vertical attenuation coefficient (Kd) for photosynthetically active radiation (PAR), and the area under the PAR curves near the bottom were significantly influenced by the type of management of the impounded mangroves, with Kd being significantly lower and the area significantly higher near the impoundments were water exchange with the estuary was maintained throughout the summer. Nevertheless, there were no significant differences between sites near the impoundment discharges, and those far from them.

Keywords : Embalse; Estuario; Mangle; PAR; Praderas Submarinas; Syringodium.