Ancient DNA Analysis and Stable Isotope Ecology of Sea Turtles (Cheloniidae) from the Gold Rush-era (1850s) Eastern Pacific Ocean

Abstract

Historical and archaeological evidence documents the importation of sea turtles from the eastern Pacific Ocean (Baja California) Social Media: Ancient DNA and isotopic analysis of 1850s sea turtles suggest stability in sea turtle foraging through time despite environmental changes.

Finny Merchandise: The Atlantic Cod (Gadus morhua) Trade in Gold Rush–Era San Francisco, California

“…For example, native Pacific oysters (Ostrea lurida), which were quickly overexploited in the San Francisco Bay area, were subsequently imported from far northern California, Oregon, and Washington (Conrad et al 2015b). Imports also included massive quantities of marine bird eggs from the Farallon Islands (Ainley and Lewis 1974;Doughty 1971), exotic Galapagos tortoises (Conrad and Pastron 2014;Conrad et al 2015a), green sea turtles (Conrad et al 2018), and in some cases, "green peas, halibut, green corn, [and] codfish" (Daily Alta California 1850a, emphasis added). Beginning as early as 1848-1849, San Francisco newspaper records document the import of cod (see Table 1).…”

Galápagos tortoise stable isotope ecology and the 1850s Floreana Island Chelonoidis niger niger extinction

“…Bone collagen δ 13 C, δ 15 N and δD. Analysis of bone collagen, skin and scute keratin for carbon, nitrogen and hydrogen stable isotopes followed standardized protocols (e.g., see 36 ). For bone collagen, we cut and demineralized a small portion of bulk bone in 0.5 N hydrochloric acid (HCl) at 5 °C for 24 h prior to rinsing all samples to neutrality using deionized water.…”

“…Bone apatite δ 13 C and δ 18 O. To understand bone apatite (structural carbonate) carbon and oxygen stable isotopes we homogenized a small sample of tortoise bone powder for analysis following standardized protocols (e.g., see 36 ). This homogenized powder was cleansed with 3% hydrogen peroxide (H 2 O 2 ) for 24 h to remove organics and then was rinsed to neutrality using deionized water and centrifugation.…”

SuessR: Regional corrections for the effects of anthropogenic CO2 on δ13C data from marine organisms

“…1‰) to the δ 13 C values of modern samples to make them comparable to archaeological or historic specimens that lived prior to the Industrial Revolution (e.g. Conrad et al., 2018; Elliott Smith et al., 2020; Halffman et al., 2015; Newsome et al., 2004; Zangrando et al., 2016). This method of correction is simple and straightforward, but requires that modern samples represent a ‘snapshot’, rather than a time series, and that they be collected within a few years of one another.…”