Grantee Research Project Results
Evaluating the Stress Response of Wild Birds as a Bioindicator of Sub-Lethal Acute and Chronic Effects of Crude Oil ExposureEPA Grant Number: FP917350
Title: Evaluating the Stress Response of Wild Birds as a Bioindicator of Sub-Lethal Acute and Chronic Effects of Crude Oil Exposure
Investigators: Lattin, Christine R
Institution: Tufts University
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 2011 through July 31, 2014
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2011) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Emerging Environmental Approaches and Challenges: Innovative Investigations for Oil Spill Impacts
One of the most important yet least understood of oil’s biological impacts is on the stress response. Studies show petroleum can interact in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why-does petroleum change stress hormone receptor concentrations in the brain or peripheral tissues, does it disrupt feedback mechanisms or stress hormone production, or both? This study uses both laboratory and field components to systematically quantify the effects of Gulf of Mexico crude oil on the stress response and stress hormone receptors of wild birds. This will allow an evaluation of whether these physiological measures can be used as bioindicators of sub-lethal acute and chronic effects of crude oil exposure.
This study proposes to clarify petroleum-induced changes to the hypothalamus-pituitary-adrenal (HPA) axis responsible for the release of glucocorticoid stress hormones. The study has three goals to: (1) determine what the HPA functioning of an oil-compromised bird looks like, including tissue concentrations of stress hormone receptors; (2) examine HPA functioning in birds both immediately after crude oil ingestion and several months later to look for long-term effects of oil exposure; and (3) compare the effects on the HPA of several different crude oils. The first stage of this project will take place in the laboratory, using wild-caught House Sparrows as a model species. The second stage of the project includes fieldwork in the Gulf of Mexico to determine if wild shorebirds fit expected profiles of oil-exposed animals, both in terms of HPA functioning and receptor concentrations.
By the project’s end, there will be a much deeper understanding of how ingested petroleum impacts the stress response of wild birds, not just at the level of secreted hormone, but also upstream and downstream of the adrenal glands. The study will provide a better idea of how long to expect oil-induced disruptions to the HPA axis to last: will these effects persist 3 months, 6 months or a year later? Furthermore, based on differences in response to different crude oils, the study will be able to start to identify which components of petroleum do the most damage to the HPA axis. The strength of this project’s approach is that it goes above and beyond just measuring stress hormone concentrations in the blood, and examines negative feedback mechanisms, maximal possible response and stress hormone receptors.
Potential to Further Environmental / Human Health Protection
A clearer understanding of petroleum’s effects on wild birds is essential to help people better respond to oil spills and their aftermath ( for example, better prioritization of sites to manage), and to fully understand the conservation impacts of these spills. This project could potentially also allow people not only to identify exposure in wild shorebirds from contaminated areas, but also in other species, including humans.