<b>The role of sediment on the energy availability for fishes in the upper Paraná river floodplain</b> - doi: 10.4025/actascibiolsci.v34i4.9335

Resumo

This study aimed to identify potential sources of organic matter in sediment, using stable isotopes of carbon (delta¹³C) and nitrogen (delta¹⁵N). Sediment samples were gathered from the margin and in center of three subsystems: Ivinheima, Paraná and Baia, in August/2001. The samples were fractionated granulometrically and separated by size (< 200 µm; 70-200 µm; > 70 µm), prepared and sent to CENA / USP, for identifying the isotopes proportions. Significant differences were detected in the isotopic ratios of the sediment only between sampling stations. The Baía channel presented the lowest delta¹³C values, while the highest ones were recorded in Paraná river. At this last, delta¹⁵N values were negative (-14.41‰). We did not verify significant difference in isotopic composition between the particle sizes of sediment, and between the sampling points. The main sources of carbon for the sediment were C₃ macrophytes, periphyton and particulate organic carbon (POC).