USING STABLE ISOTOPES TO ESTIMATE FOOD RESOURCES OF MANGROVES WITH DIFFERENT GRANULOMETRIC FRACTIONS

WENDEBORN, M M; COSTA, T. M.; COLPO KARINE D.

Boutcatu, SP

Workshop; I Workshop Internacional de Isótopos Estáveis em Ciências da Vida; 2017

Stable isotopes analysis is an important tool to evaluate the trophic ecology, and lead us to identify the organisms present in the soil of estuarine environments. To estimate the choice of different sediment size by fiddler crab Leptuca uruguayensis, we standardized the organic matter quantity in each sediment. We also verified whether the organic compound of each soil fraction (0,500mm; 0,250mm; 0,125mm) used in our work has the same food resources using stable isotopes analysis (Carbon ? δ 13 C and Nitrogen - δ 15 N). Organic compounds sampling was made using sieves with different mesh opening (1mm; 0,500mm; 0,250mm; 0,125mm), in lower spring tide, from February to December 2016 in Itapanhaú River (23º49?46.8?S 46º09?49.3?W), Bertioga, coast of São Paulo State. Our data showed no significant difference of food resource available among organic compounds in different soil fractions (0,500mm; 0,250mm; 0,125mm) used in our work (Table 1). Besides that, according to isotopic signatures, we found that organic compound consist mostly of microphytobenthos, phytoplankton and mangrove tree leaves.