Hydrogen isotope assimilation and discrimination in green turtles [RESEARCH ARTICLE]

Laura Pages Barcelo, Jeffrey A. Seminoff, Hannah B. Vander Zanden, T. Todd Jones, Karen A. Bjorndal, Alan B. Bolten, Walter Mustin, Geraldine Busquets-Vass, and Seth D. Newsome Although hydrogen isotopes (2H) are commonly used as tracers of animal movement, minimal research has investigated the use of 2H as a proxy to quantify resource and habitat use. While carbon and nitrogen are ultimately derived from a single source (food), the proportion of hydrogen in consumer tissues originates from two distinct sources: body water and food. Before hydrogen isotopes can be effectively used as a resource and habitat tracer, we need estimates of (net) discrimination factors (2HNet) that account for the physiologically mediated differences in the 2H values of animal tissues relative to that of the food and water sources they use to synthesize tissues. Here we estimated 2HNet in captive green turtles (Chelonia mydas) by measuring 2H values of tissues (epidermis and blood components) and dietary macromolecules collected in two controlled feeding experiments. Tissue 2H and 2HNet values varied systematically among tissues, with epidermis having higher 2H and 2HNet values than blood components, which mirrors patterns between keratinaceous tissues (feathers, hair) and blood in birds and mammals. Serum/plasma of adult female green turtles had significantly lower 2H values compared to that of juveniles, likely due increased lipid mobilization associated with reproduction. This is the first study...
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: RESEARCH ARTICLE Source Type: research