ESR 33:281-289 (2017)  -  DOI: https://doi.org/10.3354/esr00819

δ13C and δ15N in the endangered Kemp’s ridley sea turtle Lepidochelys kempii after the Deepwater Horizon oil spill

Kimberly J. Reich1,2, Melania C. López-Castro1, Donna J. Shaver3, Claire Iseton1, Kristen M. Hart4, Michael J. Hooper5, Christopher J. Schmitt5,*

1Trophic Ecology and Sea Turtle Research Laboratory, Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553, USA
2Trophic Ecology and Sea Turtle Research Laboratory, Department of Biology, Palm Beach Atlantic University, West Palm Beach, FL 33401, USA
3National Park Service, Padre Island National Seashore, Corpus Christi, TX 78480-1300, USA
4US Geological Survey, Southeast Ecological Science Center, Davie, FL 33314, USA
5US Geological Survey, Columbia Environmental Research Center, Columbia, MO 65201, USA
*Corresponding author:

ABSTRACT: The Deepwater Horizon explosion in April 2010 and subsequent oil spill released 3.19 × 106 barrels (5.07 × 108 l) of MC252 crude oil into important foraging areas of the endangered Kemp’s ridley sea turtle Lepidochelys kempii (Lk) in the northern Gulf of Mexico (GoM). We measured δ13C and δ15N in scute biopsy samples from 33 Lk nesting in Texas during the period 2010 to 2012. Of these, 27 were equipped with satellite transmitters and were tracked to traditional foraging areas in the northern GoM after the spill. Differences in δ13C between the oldest and newest scute layers from 2010 nesters were not significant, but δ13C in the newest layers from 2011 and 2012 nesters was significantly lower compared to 2010. δ15N differences were not statistically significant. Collectively, the stable isotope and tracking data indicate that the lower δ13C values reflect the incorporation of oil rather than changes in diet or foraging area. Discriminant analysis indicated that 51.5% of the turtles sampled had isotope signatures indicating oil exposure. Growth of the Lk population slowed in the years following the spill. The involvement of oil exposure in recent population trends is unknown, but long-term effects may not be evident for many years. Our results indicate that C isotope signatures in scutes may be useful biomarkers of sea turtle exposure to oil.


KEY WORDS: Sea turtles · Oil spill · Gulf of Mexico · Biomarkers · Stable isotopes · Satellite telemetry · Tracking


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Cite this article as: Reich KJ, López-Castro MC, Shaver DJ, Iseton C, Hart KM, Hooper MJ, Schmitt CJ (2017) δ13C and δ15N in the endangered Kemp’s ridley sea turtle Lepidochelys kempii after the Deepwater Horizon oil spill. Endang Species Res 33:281-289. https://doi.org/10.3354/esr00819

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