Anodontites Spp. Shells Oxygen And Carbon Isotopes

Stable isotopic ratios (δ¹⁸O<em>_S</em> and δ¹³C<em>_S</em>) of carbonate powder samples from 4 bivalves shells: 2 <em>Anodontites elongatus</em> (Ae-1 &amp; Ae-2) from a peruvian site (near Iquitos, 3°44'32.2''S; 73°13'31.2''W) and 2 <em>Anotontites trapesialis</em> (At-1 &amp; At-2) from a brazilian site (Ilha Paciência, 3°19'21.0''S; 60°16'36.0''W). Samples were drilled in the hinge using a computer-monitored microdrilling equipment (New Wave^® Micromill). The hinge was sampled continuously from internal to external part of the shell taking care to maintain each sampling groove parallel to the growth lines. Distance between successive grooves was determined to have both enough carbonate powder for stable isotope analysis and an assumed infra-seasonal resolution considering that growth lines were annual due to the clear bimodal Amazonian environmental variability (dry/wet seasons). Successive grooves were spaced about 60 µm to sample 41± 26 µg of carbonate powder. On average, 9 and 6 sampling grooves were done per growth increment for <em>A. trapesialis</em> and <em>A. elongatus</em>, respectively. δ¹⁸O<em>_S</em> and δ¹³C<em>_S</em> data are given along the distance (d in mm) in the hinges from the oldest to the younger part of the shells (growth direction).