Navigation Links
Study sheds light on how marine animals survive stress
Date:5/25/2010

MEDFORD/SOMERVILLE, Mass. -- For marine iguanas living in the Galapagos Islands, an El Nio can be deadly. Some die from starvation while others survive. Scientists have long believed that the difference between life and death for the iguana depended on the animals' ability to secrete the stress hormone corticosterone.

Under stressful conditions, corticosterone functions like a spigot by controlling how the body expends energy during an emergency. It is associated with the "fight or flight" response to stress and is similar to cortisol in humans. But corticosterone can also be lethal if the spigot is not turned off, according to a study of marine iguanas published in the May 26 online issue of the Proceedings of the Royal Society.

The findings could provide insight into how wildlife in the Gulf of Mexico will respond to the current oil spill. Animals will secrete corticosterone to help them cope with the disaster. However, prolonged hormone production could factor into how well animals are able to survive the crisis.

From 2002 through 2008, a research team led by Tufts University Professor of Biology L. Michael Romero studied corticosterone levels in iguanas on Santa Fe Island before and after the El Nio that struck in late 2002.

The team, funded by the National Science Foundation, included co-author Martin Wikelski from the Max Planck Institute for Ornithology and Konstanz University.

The Galapagos Islands' marine iguanas are a suitable model for study because they live in predictable natural conditions. The animals feed exclusively on marine algae. Their greatest and almost only threat or stress occurs during recurrent El Nio-induced food shortages, when a decrease of algae can lead to starvation.

The scientists captured 98 healthy male iguanas on the island in December 2002, just weeks before the El Nio. They injected a group of the animals with a hormone to stimulate a biological process called negative feedback which lowers the natural corticosterone levels in the animals' blood. The animals responded in one of two ways. Some reacted by shutting shut down the release of corticosterone. In other iguanas, the secretion of corticosterone continued, producing excessive concentrations of the hormone in the blood.

Romero and Wikelski returned to Santa Fe Island in July 2003. Twenty-three of the animals had starved to death, but seventy-five had survived.

According to Romero, the dead iguanas were imperiled by their inability to turn off their stress response. This produced elevated corticosterone levels. In this condition, the animals had depleted the protein reserves that could be processed into energy during a stressful event. In their weakened condition, these iguanas were more susceptible to starvation than their counterparts.

Romero points to several major implications of the findings. First, negative feedback is a vital component of a successful stress response. "The results from the iguanas indicate that the better an individual is at coping with stress -- by turning off the response as soon as possible -- the better the chance they have to survive," he says.

The ultimate goal of the research, says Romero, is "to understand what causes stress in wild animals; what physiological mechanisms are turned on in response to stress and how those mechanisms help the animals survive in their natural habitats."

This work has immediate implications for the current oil spill in the Gulf of Mexico. "As animals encounter the spill, they will have a robust release of corticosterone to help them cope with the consequences of the oil," says Romero. "However, those animals that can best turn off their corticosterone response once the initial danger from the oil has passed will probably be the most likely to survive," he says.


'/>"/>

Contact: Alexander Reid
alexander.reid@tufts.edu
617-627-4173
Tufts University
Source:Eurekalert

Related biology news :

1. Childhood obesity indicates greater risk of school absenteeism, Penn study reveals
2. A study by the MUHC and McGill University opens a new door to understanding cancer
3. Study begins to reveal clues to the cause and progression of sepsis
4. Clones on task serve greater good, evolutionary study shows
5. New study warns limited carbon market puts 20 percent of tropical forest at risk
6. New study examines how rearing environment can alter navigation
7. Study links cat disease to flame retardants in furniture and to pet food
8. New continent and species discovered in Atlantic study
9. Study shows link between alcohol consumption and hiv disease progression
10. Feeling hot, hot, hot: New study suggests ways to control fever-induced seizures
11. Study finds environmental tests help predict hospital-acquired Legionnaires disease risk
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/28/2017)... , March 28, 2017 The ... Hardware (Camera, Monitors, Servers, Storage Devices), Software (Video Analytics, ... Region - Global Forecast to 2022", published by MarketsandMarkets, ... 2016 and is projected to reach USD 75.64 Billion ... and 2022. The base year considered for the study ...
(Date:3/24/2017)... 24, 2017 The Controller General of Immigration from ... Abdulla Algeen have received the prestigious international IAIR Award for the ... Continue Reading ... ... Controller Abdulla Algeen (small picture on the right) have received the IAIR ...
(Date:3/23/2017)... The report "Gesture Recognition and Touchless Sensing Market by Technology (Touch-based ... to 2022", published by MarketsandMarkets, the market is expected to be worth USD ... 2022. Continue Reading ... ... ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... and LAGUNA HILLS, Calif. , Oct. ... Cancer Research, London (ICR) and University ... SKY92, SkylineDx,s prognostic tool to risk-stratify patients with multiple myeloma ... MUK nine . The University of Leeds ... partly funded by Myeloma UK, and ICR will perform the ...
(Date:10/10/2017)... ... 2017 , ... San Diego-based team building and cooking events company, Lajollacooks4u, has ... The bold new look is part of a transformation to increase awareness, appeal to ... period. , It will also expand its service offering from its signature gourmet cooking ...
(Date:10/10/2017)... 10, 2017 International research firm Parks Associates announced ... at the TMA 2017 Annual Meeting , October 11 in ... residential home security market and how smart safety and security products impact ... Parks Associates: Smart Home ... "The residential security market has ...
(Date:10/9/2017)... DIEGO , Oct. 9, 2017  BioTech ... biological mechanism by which its ProCell stem cell ... critical limb ischemia.  The Company, demonstrated that treatment ... amount of limbs saved as compared to standard ... the molecule HGF resulted in reduction of therapeutic ...
Breaking Biology Technology: