Effects of toxic elements on blood analytes of loggerhead sea turtles (Caretta caretta) nesting on Casey Key, Florida

Abstract

Loggerhead sea turtles (Caretta caretta) are an internationally threatened species and are protected under the U.S Endangered Species Act. Numerous factors contribute to the threatened status of loggerheads such as habitat loss, nest predation, boat strikes, as well as marine pollution including anthropogenic contaminants (e.g., toxic elements). Toxic elements such as arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) can exert their effects on marine organismal health at low concentrations. Reptiles, including marine turtles, are susceptible to accumulation of toxic elements due to their long life span, low metabolic rate, and highly efficient conversion of prey into biomass. These elements can elicit negative effects on marine turtle development, reproduction, and immune function. Here, we hypothesized that As, Cd, Pb, and Hg may affect nesting loggerhead turtle health and immune function. We found that As, Cd, and Hg were negatively correlated with plasma globulins and total white blood cell concentrations, indicating immunosupression. Our results suggest that toxic elements are potentially impacting the overall health of loggerhead turtles, which has important conservation implications for shaping environmental health and safety policies.