MEPS 543:173-186 (2016)  -  DOI: https://doi.org/10.3354/meps11549

Environmental effects on elemental signatures in eastern oyster Crassostrea virginica shells: using geochemical tagging to assess population connectivity

Ian R. Kroll1,2,*, Abigail K. Poray1, Brandon J. Puckett3,4, David B. Eggleston3, F. Joel Fodrie1,2

1Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3437 Arendell Street, Morehead City, NC 28557, USA
2Department of Marine Sciences, University of North Carolina at Chapel Hill, 3202 Venable Hall, Chapel Hill, NC 27599, USA
3Center for Marine Science and Technology, North Carolina State University, 303 College Circle, Morehead City, NC 28557, USA
4Present address: North Carolina National Estuarine Research Reserve, 101 Pivers Island Road, Beaufort, NC 28516, USA
*Corresponding author:

ABSTRACT: We evaluated the utility of geochemical tagging methods to discern larval connectivity among an invertebrate metapopulation within a large (~5000 km2) temperate estuary. Specifically, we examined how estuarine-scale gradients in temperatures (21° to 26.5°C), salinities (12.5 to 20 ppt), and trace metal concentrations (ambient, +16 ppb Mn and 0.16 ppb Pb, or +32 ppb Mn and 0.32 ppb Pb) affect Crassostrea virginica larval-shell signatures of Mn, Sr, Ba, and Pb in controlled mesocosms. We also utilized field-collected, newly settled oysters across Pamlico Sound, NC, USA, to explore signature variability among natural temperature and salinity gradients and examine the spatial resolution at which geochemical signatures can be used to discriminate between collection regions. Mesocosm experiments revealed environmentally and statistically significant interactive effects between temperature and salinity on elemental ratios in larval oyster shells, favoring higher Sr concentrations in cooler, fresher water, but no effects of these factors on Ba signatures. Mesocosm trials also showed increased Mn signatures in larval shell following from spiking mesocosms with Mn solutions; however, this relationship did not hold for Pb following analogous elemental spikes. Our field collections of recent settlers showed similar patterns of high Sr at relatively low salinities and temperatures, without clear environmental gradients for Ba. Overall, we found that across regional (35 km) spatial scales, environmental variables, such as salinity and temperature, can generate distinct multi-elemental signatures between putative natal sites. However, if sites are close together or located in similar environments, discrimination among sites appears greatly reduced. We suggest that geochemical tagging provides a promising approach for characterizing larval connectivity among subpopulations within whole-estuarine systems.


KEY WORDS: Bivalve larvae · Connectivity · Crassostrea virginica · Geochemical tagging · Larval dispersal · Laser ablation ICP-MS · Oysters · Salinity · Temperature


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Cite this article as: Kroll IR, Poray AK, Puckett BJ, Eggleston DB, Fodrie FJ (2016) Environmental effects on elemental signatures in eastern oyster Crassostrea virginica shells: using geochemical tagging to assess population connectivity. Mar Ecol Prog Ser 543:173-186. https://doi.org/10.3354/meps11549

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