Bizarre - and worrying

[dieseltaylor]

Whilst I am now getting to the point where I accept everything in our world can affect anything else, and a lot of the time not beneficially, this one seems a long way from being an obvious effect.

Mercury 'turns birds homosexual'

By Victoria Gill

Science and nature reporter, BBC News

Mercury affects the behaviour of white ibises by "turning them homosexual", with higher doses resulting in males being more likely to pair with males.

Scientists in Florida and Sri Lanka studied the effect of mercury in the birds' diet. Their aim was to find out why it reduced the ibises' breeding.

Mercury pollution can come from burning coal and waste, and run-off from mines.The report, in Proceedings of the Royal Society B, shows that wetland birds are particularly badly affected by it.

We're seeing very large reproductive effects at very low concentrations

Peter Frederick, biologist

Although the researchers already knew that eating mercury-contaminated food could affect an animal's development, they were surprised by the "strange" results of this experiment.

"We knew mercury could depress their testosterone (male sex hormone) levels," explained Dr Peter Frederick from the University of Florida, who led the study. "But we didn't expect this."

The team fed white ibises on food pellets that contained concentrations of mercury equivalent to those measured in the shrimp and crayfish that make up the birds' wetland diet.

The higher the dose of mercury in their food pellets, the more likely a male bird was to pair with another male. Dr Frederick and his colleagues say the study shows that mercury could dramatically reduce the breeding rates of birds and possibly of other wildlife.

The exact mechanism that causes this change in behaviour is not yet fully understood.But mercury is known to disrupt hormonal signalling, so it could have a direct impact on the sexual behaviour that is mediated by those hormones.Importantly, the males with the higher mercury doses performed far fewer courtship displays, so they were more likely to be "ignored" by females.

Wetland habitats, like the Florida Everglades that are home to these birds, are particularly vulnerable to mercury contamination. Bacteria that live in the thick, oxygen-free sludge chemically alter the mercury, turning it into its most toxic form - methylated mercury.And this chemical can act as a sort of biological impostor, mimicking hormones that act as the body's natural chemical signals.

Some of these signals are involved in reproductive behaviour - they may stimulate an animal to carry out a courtship display or motivate it to mate.

"We're seeing very large reproductive effects at very low concentrations [of mercury]," said Dr Frederick. "So we really need to be paying more attention to this."

When a wetland is warm all year round, like the Everglades, it is an ideal environment for this methylation process.Scientists refer to these conditions as a "Goldilocks mixture".

Dr Frederick says that measures could be taken to clean up any sources of mercury where they are close to wetland habitats - for example by filtering or "scrubbing" the smoke from nearby coal-burning power plants.

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Gary Heinz, a wildlife researcher from the US Geological Survey in Maryland, who was not involved in the study, told the BBC that mercury was "a serious problem in many aquatic environments"."It cannot be broken down, only be moved about and transformed from one chemical form to another," he said."And any effect that might reduce the productivity of a species would likely be harmful in nature."

Dr Heinz said the next step would be to study the reproductive behaviour of mercury-contaminated animals in the wild.

Story from BBC NEWS:

http://news.bbc.co.uk/go/pr/fr/-/earth/hi/earth_news/newsid_9243000/9243902.stm

[Michael Emrys]

Why do you find that hard to at least conceive of? This sentence: "And this chemical can act as a sort of biological impostor, mimicking hormones that act as the body's natural chemical signals" provides at least a plausible explanation for the mechanism. It seems to be as yet unproven, but it might be a fruitful (no pun intended) avenue to explore.

Michael

[Stalins Organ]

I foresee legion angst filled moments as mercury poisoning gets blamed for homosexuality by one side of fundamentalists, and labelled as irrelvant by the other.

I further predict there will be no meeting of minds on the issue!

[JonS]

The expression is "mad as a hatter", not "gay as a hatter"

[Stalins Organ]

Give it time......

[Affentitten]

My grandad used to refer to homosexuals as "brown hatters". Perhaps there is a link there?

[Michael Emrys]

The expression is "mad as a hatter", not "gay as a hatter"

But were they speaking of ibises? Do ibises even wear hats? I imagine them in something more like an old fashioned aviator's cap than a sombrero or a homburg.

Michael