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Mercury exposure may suppress baseline corticosterone levels in juvenile birds

Environmental Science & Technology

By:
ORCID iD , ORCID iD , and
https://doi.org/10.1021/es300668c

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Abstract

Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury concentrations in down feathers of recently hatched (<3 days) and blood of older (15-37 days) Forster's tern (Sterna forsteri) chicks in San Francisco Bay, California. Baseline fecal corticosterone metabolite concentrations were negatively correlated with mercury concentrations in blood of older chicks (decreasing by 81% across the range of observed mercury concentrations) while accounting for positive correlations between corticosterone concentrations and number of fledgling chicks within the colony and chick age. In recently hatched chicks, baseline fecal corticosterone metabolite concentrations were weakly negatively correlated with mercury concentrations in down feathers (decreasing by 45% across the range of observed mercury concentrations) while accounting for stronger positive correlations between corticosterone concentrations and colony nest abundance and date. These results indicate that chronic mercury exposure may suppress baseline corticosterone concentrations in tern chicks and suggests that a juvenile bird's ability to respond to stress may be reduced via the downregulation of the HPA axis.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Mercury exposure may suppress baseline corticosterone levels in juvenile birds
Series title:
Environmental Science & Technology
DOI:
10.1021/es300668c
Volume:
46
Issue:
11
Year Published:
2012
Language:
English
Publisher:
ACS Publications
Publisher location:
Washington, DC
Contributing office(s):
Western Ecological Research Center, San Francisco Bay-Delta
Description:
8 p.
First page:
6339
Last page:
6346