Goldfish Make Alcohol To Survive In Icy Waters, Study Finds

Posted: Aug 12 2017, 10:34am CDT | by , in News | Latest Science News

 

Goldfish Make Alcohol to Survive in Icy Waters, Study Finds
Credit: caringpets.org
 

Scientists have figured out how goldfish produce alcohol to live without oxygen

Oxygen is crucial for life on Earth. Humans and most other animals can not survive long without oxygen. Yet goldfish and their close relatives stay alive for days, even months, in oxygen-free environments beneath frozen lakes. Their bodies have a remarkable ability for producing alcohol. It won’t let them die in extreme winter conditions.

Researchers now explain how the mechanism works. When oxygen levels drop in winter, goldfish evolve a set of proteins that converts anaerobically produced lactic acid into ethanol. The ethanol then diffuses across their gills and allows them to avoid a dangerous build-up of lactic acid in the body.

In the absence of oxygen, the consumption of carbohydrates leads to the production of lactic acid. If goldfish cannot get rid of this lactic acid, they would die within few minutes. But unlike many other animals, goldfish have not just one but two sets of proteins. The second set activates in the absence of oxygen and turn carbohydrates into alcohol that would otherwise breakdown within a cell's mitochondria and provides energy.

While one set of the proteins appears in other species, the existence of second set in goldfish is unusual. It’s something that sets them apart from other species. Researches suggest that common ancestor of goldfish and crucian carp adapted to extremely cold conditions some 8 million years ago.

“The adaptation is very rare among animals.” Michael Berenbrink an evolutionary physiologist at the University of Liverpool told New Scientist.

By making alcohol, crucian carp and goldfish can survive months under icy water. So, the lack of oxygen in winter season is not a concern for these animals. 

“During their time in oxygen-free water in ice-covered ponds, which can last for several months in their northern European habitat, blood alcohol concentrations in crucian carp can reach more than 50 mg per 100 milliliters, which is above the drink drive limit in these (Scotland and northern European) countries,” said Dr Berenbrink.

"However, this is still a much better situation than filling up with lactic acid, which is the metabolic end product for other vertebrates, including humans, when devoid of oxygen."

This metabolic adaptation gave goldfish an advantage over other fish in the water that would normally kill without oxygen. 

"The ethanol production allows the crucian carp to be the only fish species surviving and exploiting these harsh environments, thereby avoiding competition and escaping predation by other fish species with which they normally interact in better oxygenated waters,” said lead author Dr Cathrine Elisabeth Fagernes, from the University of Oslo.

"It's no wonder then that the crucian carp's cousin the goldfish is arguably one of the most resilient pets under human care."

 

 

 

 

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Hira Bashir covers daily affairs around the world.

 

 

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