Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study sheds light on how marine animals survive stress

26.05.2010
Findings indicate how wildlife responds to environmental and ecological disasters

For marine iguanas living in the Galapagos Islands, an El Niño 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 Niño 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 Niño-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 Niño. 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.

Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.

Alexander Reid | EurekAlert!
Further information:
http://www.tufts.edu

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>