Biomarkers reveal sea turtles remained in oiled areas following the Deepwater Horizon oil spill.

Assessments of large-scale disasters, such as the Deepwater Horizon oil spill, are problematic because while measurements of post-disturbance conditions are common, measurements of pre-disturbance baselines are only rarely available. Without adequate observations of pre-disaster organismal and environmental conditions, it is impossible to assess the impact of such catastrophes on animal populations and ecological communities. Here, we use long-term biological tissue records to provide pre-disaster data for a vulnerable marine organism.

Stable isotopic comparison between loggerhead sea turtle tissues.

Rationale: Stable isotope analysis has been used extensively to provide ecological information about diet and foraging location of many species. The difference in isotopic composition between animal tissue and its diet, or the diet-tissue discrimination factor, varies with tissue type. Therefore, direct comparisons between isotopic values of tissues are inaccurate without an appropriate conversion factor.

Determination and maternal transfer of heavy metals (Cd, Cu, Zn, Pb and Hg) in the Hawksbill sea turtle (Eretmochelys imbricata) from a nesting colony of Qeshm Island, Iran.

This study was conducted to determine trace metal concentrations (Cd, Cu, Zn, Pb and Hg) in blood and three egg fractions from Eretmochelys imbricata nesting on Qeshm Island in Iran. The results showed detectable levels of all analytes in all fractions. Pb and Hg were detectable in the blood and eggs, reflecting a maternal transfer.

Effect of repeated tissue sampling on growth rates of juvenile loggerhead turtles Caretta caretta.

We evaluated the effect of repeated tissue sampling on growth rates of juvenile loggerhead sea turtles Caretta caretta. Samples of blood, skin, and scute (keratinized epidermal layer covering the bony shell) were collected at 3 intervals over a 120 d period from 37 loggerheads; 8 control turtles were not sampled. No infections or scarring occurred at the sampling sites, and growth in mass of experimental and control turtles was not significantly different.

Individual specialists in a generalist population: results from a long-term stable isotope series.

Individual variation in resource use has often been ignored in ecological studies, but closer examination of individual patterns through time may reveal significant intrapopulation differences. Adult loggerhead sea turtles (Caretta caretta) are generalist carnivores with a wide geographical range, resulting in a broad isotopic niche. We microsampled scute, a persistent and continuously growing tissue, to examine long-term variation in resource use (up to 12 years) in 15 nesting loggerhead turtles.

Effects of preservation method on stable carbon and nitrogen isotope values.

Some methods of tissue preservation have significant effects on values of stable isotopes of carbon (delta(13)C) and nitrogen (delta(15)N), but studies on this topic are scattered in the literature. The goals of this study were to (1) summarize the results from studies of preservation effects in the literature and (2) test the effects of four common preservatives on delta(13)C and delta(15)N in epidermis tissue of three turtle species. Turtle tissue samples were subjected to up to five time intervals in five methods of preservation: drying at 60 degrees C for 24 h (the control), immersion in a 70% ethanol solution, immersion in a saturated NaCl aqueous solution, freezing at -10 degrees C in a frost-free freezer, and immersion in a dimethyl sulfoxide (DMSO)-ethylenediaminetetraacetic acid buffer.

Effects of growth and tissue type on the kinetics of 13C and 15N incorporation in a rapidly growing ectotherm.

The use of stable isotopes to investigate animal diets, habitat use, and trophic level requires understanding the rate at which animals incorporate the 13C and 15N from their diets and the factors that determine the magnitude of the difference in isotopic composition between the animal's diet and that of its tissues. We determined the contribution of growth and catabolic turnover to the rate of 13C and 15N incorporation into several tissues that can be sampled non-invasively (skin, scute, whole blood, red blood cells, and plasma solutes) in two age classes of a rapidly growing ectotherm (loggerhead turtles, Caretta caretta). We found significant differences in C and N incorporation rates and isotopic discrimination factors (Delta 13C = delta 13Ctissues - delta 13Cdiet and Delta 15N = delta 15Ntissues - delta 15Ndiet) among tissues and between age classes.

The 'lost years' of green turtles: using stable isotopes to study cryptic lifestages.

Ignorance of the location or inaccessible locations of lifestages can impede the study and management of species. We used stable isotopes of carbon and nitrogen to identify the habitats and diets and to estimate the duration of a 'missing' lifestage: the early juvenile stage of the green turtle, Chelonia mydas. Stable isotopes in scute from young herbivorous green turtles in shallow-water habitats revealed that they spend 3-5 years as carnivores in oceanic habitats before making a rapid ontogenetic shift in diet and habitat.