Dead pigs used to investigate ‘dead zones’

Dead pigs used to investigate ‘dead zones’

By Victoria Gill
Mar 4, 2010, Science reporter, BBC News

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Crabs and other scavengers put nutrients back into the marine ecosystem

 

By ending up in ocean experiments (rather than on the dinner table), the pigs have provided scientists with some intriguing new data.

"The dead pigs were not my idea," says Dr Verena Tunnicliffe, professor of marine biology at the University of Victoria in Canada.

She explained that she and her colleagues were "piggybacking" on forensics research in order to study low-oxygen zones, sometimes known as "dead zones", in the ocean.

Your browser may not support display of this image. Your browser may not support display of this image. A lot of people
[when they die] end up in the ocean – either accidentally or through foul play Your browser may not support display of this image.  

Professor Vernea Tunnicliffe, University of Victoria

 

The pigs are used by forensics researchers because – strange as it might seem – we humans are remarkably pig-like in our anatomy. We share their relatively hairless skin, are similar in size, and our flesh has a similar make-up.

And these things are important when you are trying to find out what happens to a human body if it ends up in the ocean.

Because another unpleasant reality is that many bodies – particularly in a coastal area like British Columbia – are discovered there.

"The ocean is a big place and there are a lot of people who work at sea and a lot of people who live on the coast. As a result, a lot of people [when they die] end up in the ocean," says Professor Tunnicliffe. "Either accidentally or through foul play.

"If you need to know how long it’s been since death, if you’re looking at the remains and there are marks on them, you need to find out – how did those marks come about?"

Looking at what happens to the pigs enables forensics researchers to better understand those processes.

Deep sea pigs

This grisly research gave Professor Tunnicliffe the opportunity to study seafloor scavengers.

"This big hunk of meat on the seafloor represented a good food source for these marine creatures," she says.

"Scavengers are very important in the world. They’re what allow things to restore."

So she and her team used the pigs to investigate the increasing problem of oxygen depletion in coastal areas.

Low-oxygen (hypoxic) zones are caused by the nutrient-rich run-off from agricultural land. This feeds algae in the ocean. When this algae dies, sinks and decomposes, it consumes most of the vital oxygen supply in the water.

At its worst, this can lead to a dead zone – an area of seafloor that is so low in oxygen that all of the marine animals either die or, if they can survive the move, are forced into habitats in shallower water.

Your browser may not support display of this image. Your browser may not support display of this image. The scavengers know something’s there and they arrive almost immediately and set up residence Your browser may not support display of this image.  

Professor Verena Tunnicliffe

 

One dramatic example is the dead zone in the Gulf of Mexico. Here, nutrient-laden water runs out into the Gulf from the Mississippi River causing one of the world’s largest dead zones.

The zone, which is continually contracting and expanding, has been estimated to average approximately 16,000 sq km. Almost nothing, apart from bacteria, can live there.

So Professor Tunnicliffe and her team set out to find out "how low marine scavengers would go", in terms of oxygen, for a free lunch.

They placed three pigs into very oxygen-poor zones in the Saanich Inlet, which is off the coast British Columbia. Each pig was lowered with a camera and oxygen-measuring equipment.

Scientists could operate the cameras from shore thanks to an experimental undersea observatory called Venus (The Victoria Experimental Network Under the Sea).

 

2017-01-17T09:22:14+00:00March 8th, 2010|News|Comments Off on Dead pigs used to investigate ‘dead zones’

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