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Assimilation of Oil-Derived Elements by Oysters Due to the Deepwater Horizon Oil Spill
journal contribution
posted on 2016-02-20, 04:52 authored by Ruth H. Carmichael, Amanda L. Jones, Heather K. Patterson, William C. Walton, Alberto Pérez-Huerta, Edward B. Overton, Meghan Dailey, Kristine L. WillettDuring and after the Deepwater Horizon Oil Spill (DWHOS),
oysters
(Crassostrea virginica) were exposed to oil and susceptible
to incidental consumption of surface and subsurface oil materials.
We determined the contribution of oil materials from the DWHOS to
diet of oysters by comparing carbon (C) and nitrogen (N) stable isotope
ratios in oyster shell to ratios in suspended particulate matter (SPM)
and in fresh and weathered oil. Average δ13C and
δ15N values in oyster shell (−21 ± 1‰
and 9–11‰, respectively) were consistent with consumption
of naturally available SPM as opposed to values in oil (−27
± 0.2‰, 1.6 ± 0.4‰). Stable isotope ratios
in oyster adductor muscle were similar to shell for δ15N but not δ13C, suggesting either a recent shift
in diet composition or differential assimilation of C between tissue
types. We found no evidence of assimilation of oil-derived C and N
and, therefore, no evidence of an oyster-based conduit to higher trophic
levels. Trace elements in shell were inconclusive to corroborate oil
exposure. These findings are not an indication that oysters were not
exposed to oil; rather they imply oysters either did not consume oil-derived
materials or consumed too little to be detectable compared to natural
diet.