Variation in the mobilization of mercury into Black-winged Stilt Himantopus himantopus chicks in coastal saltpans, as revealed by stable isotopes

Tavares, P.C., Kelly, A., Maia, R., Lopes, R.J., Serrão Santos, R., Pereira, M.E., Duarte, A.C. and Furness, R.W. (2008) Variation in the mobilization of mercury into Black-winged Stilt Himantopus himantopus chicks in coastal saltpans, as revealed by stable isotopes. Estuarine, Coastal and Shelf Science, 77(1), pp. 65-76. (doi:10.1016/j.ecss.2007.09.015)

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Publisher's URL: http://dx.doi.org/10.1016/j.ecss.2007.09.015

Abstract

Causes of variation in mobilization of mercury into Black-winged Stilt Himantopus himantopus chicks were studied through analysis of stable isotope ratios of carbon and nitrogen. Blood and breast feathers were collected from chicks in coastal saltpans during successive breeding seasons. Detritus samples and potential prey (macroinvertebrates) were also collected. Total mercury concentrations and stable isotope signatures were measured using atomic absorption spectroscopy and isotope ratio mass spectrometry respectively. Mercury levels in Chironomidae, Corixidae and Hydrophilidae correlated with mercury levels in chick feathers. Differences of delta N-15 signatures between macroinvertebrate groups indicated that they belong to different trophic levels. delta N-15 signatures of invertebrates correlated with mercury levels in invertebrates and chicks, but not with delta N-15 signatures in chicks. Between-group and between-site differences of delta N-15 signatures and mercury levels in invertebrates suggested that they contribute differently to mercury mobilization into chicks, and their relative contribution depends on prey availability in each site. Inter-site differences in the biomagnification factor reinforced that idea. delta C-13 signatures in invertebrates marked a larger range of carbon sources than just detritus. Variation of water inflow regime and prey availability may cause between-group and between-site differences of delta C-13 signatures in prey. Discrepancies between feather and blood for delta C-13 signatures in Praias-Sado and Vaia suggested that temporal variation of prey availability may be the main factor affecting mercury mobilization into chicks in both those cases, since their water inflow regimes are the same. The lowest levels of delta C-13 signatures in Vau suggested that water inflow regime may be the main factor in this case, since no discrepancy existed in delta C-13 signatures between blood and feather.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Furness, Professor Robert
Authors: Tavares, P.C., Kelly, A., Maia, R., Lopes, R.J., Serrão Santos, R., Pereira, M.E., Duarte, A.C., and Furness, R.W.
Subjects:Q Science > QL Zoology
G Geography. Anthropology. Recreation > GE Environmental Sciences
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Estuarine, Coastal and Shelf Science
ISSN:0272-7714

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