Wind turbines kill bats

[Firethorn]

Freshwater's ability to contain dissolved oxygen decreases as water temperature increases.  Fish "breathe" dissolved oxygen through their gills.
Cold water lowers fish metabolism (fish are cold blooded) and they don't need as much oxygen.  Warm water raises fish metabolism, requiring more oxygen..

Which is why I specified 'warmer but not too hot'.  In most cases it actually gives the fish a wider gradient of temperature to select from.  Warmer water encourages marine plants to grow faster, helping to keep the O2 levels up and provide food for the bottom of the chain.

It also has the fish being more active - therefore eating more, more likely to take a bait.

"the bends": caused by breathing nitrogen or other gases under pressure, which are not metabolized by the body.

From my reading, it's not cause by taking in the gasses under pressure, it's what happens when they start exiting solution when the pressure decreases - thus why the bends becomes a problem for surfacing divers.  And nitrogen DOES dissolve into the blood at 1 atm, it's just that at that point there's not enough of it to cause an issue as a pressure low enough to offgas the nitrogen is also going to be too low pressure to provide enough O2.

As for the bats, maybe the same sort of thing will be need as for birds - I believe they altered the design of the blades somewhat to avoid bird kills as well.

[BridgeRunner]

You miss the point. Nuclear plants do not kill ANYTHING. Seabrook is surrounded by wetland marshes, silent and pristine.

Exactly.  Tell me again why we hate nuclear power? 

Seriously, when did nuclear power become evil?  It's farking awesome. 

Yeah, my home town is getting another coal-fired power plant.  Yay.

Only solution is that "someday" we'll have windfarms in the thumb, and until then we should use less power.  You'd think that considering how much economic trouble this town is in and has been in, they'd be  glad to have increasing power needs.  Nope.  Lansing is better off as a ghost town, I guess.

[richyoung]

folks got the bends long before scuba

..by excavating at depth under pressure conditions: see: "sand hogs".... no "p word" (pressure), no "bends"...

[Iain]

No idea who is right here, but wiki talks about people flying in unpressurised aircraft or hot air balloons at significant altitude getting decompression sickness, or the bends

http://en.wikipedia.org/wiki/Decompression_sickness#Ascent_to_altitude_in_the_atmosphere

[richyoung]

"the bends": caused by breathing nitrogen or other gases under pressure, which are not metabolized by the body.

From my reading, it's not cause by taking in the gasses under pressure, it's what happens when they start exiting solution when the pressure decreases - thus why the bends becomes a problem for surfacing divers.  And nitrogen DOES dissolve into the blood at 1 atm, it's just that at that point there's not enough of it to cause an issue as a pressure low enough to offgas the nitrogen is also going to be too low pressure to provide enough O2.

You have to be uner pressure, and signifigant pressure at that, for long enough to absorb the nitrogen in the FIRST PLACE!  That is how bottom time is calculated for deep dives - the amount of air you have, minus a reserve, minus the time for decompression stops, is how long you can stay on the bottom.   If you don't take the gasses in under pressure, as you pointed out, pressures low enough to cause bends also cause other things more important to worry about.

Interstingly, what the bats are experiencing is indeed like one danger that divers face, its actually a form of barotrauma:  divers can get this if they take a deep breath at depth, and then do not exhale during a free ascent - the lungs expand until blood vessels rupture, then you drown in your own juices.

As for the bats, maybe the same sort of thing will be need as for birds - I believe they altered the design of the blades somewhat to avoid bird kills as well.

Not that I'm aware of - although they are trying not to put them in bird and bat travel corridors.

[richyoung]

No idea who is right here, but wiki talks about people flying in unpressurised aircraft or hot air balloons at significant altitude getting decompression sickness, or the bends

http://en.wikipedia.org/wiki/Decompression_sickness#Ascent_to_altitude_in_the_atmosphere

From the article:

There is no specific altitude threshold that can be considered safe for everyone below which it can be assured that no one will develop altitude DCS, but there is very little evidence of altitude DCS occurring among healthy individuals at pressure altitudes below 18,000 feet (5,500 m) who have not been scuba diving. Individual exposures to pressure altitudes between 18,000 feet (5,500 m) and 25,000 feet (7,600 m) have shown a low occurrence of altitude DCS. Most cases of altitude DCS occur among individuals exposed to pressure altitudes of 25,000 feet (7,600 m) or higher. A US Air Force study of altitude DCS cases reported that only 13 percent occurred below 25,000 feet (7,600 m) The higher the altitude of exposure, the greater the risk of developing altitude DCS. It is important to clarify that although exposures to incremental altitudes above 18,000 feet (5,500 m) show an incremental risk of altitude DCS they do not show a direct relationship with the severity of the various types of DCS ...

You need oxygen to stay conscious above 10,000 feet.   To get DCS withou exposure to pressure conditions, you need very rareified circumstances - like trying to set a balloon altitude record, (or flying a U2), AND having a pressure suit failure.  Or bailing out of a jet fighter at altittude. Its not going to be a problem in most people's, (or bat's) lives.

[cassandra and sara's daddy]

what kinda pressure differential is generated when a blade like that moves at 160 mph? from the low side tothe high side

[Iain]

National Geographic have changed their article to include the term barotrauma.

NOTE: About 90 percent of the bats studied suffered from barotrauma. The name of the ailment was restored to this article for clarification purposes after initial publication

[Tallpine]

National Geographic have changed their article to include the term barotrauma.

NOTE: About 90 percent of the bats studied suffered from barotrauma. The name of the ailment was restored to this article for clarification purposes after initial publication

I'm guessing that the bats suffer from DQS

(Don Quixote Syndrome)

 

[Firethorn]

Or bailing out of a jet fighter at altittude.

Wouldn't the fact that the pilot's going to be descending tend to take care of the matter?

On the diving thing - isn't there a number of fancy things you can do to reduce/eliminate the need for decompression waits?  Stuff like breathing pure O2 at the deeper levels, or using helium instead?

[brimic]

Wind turbines can kill bats without touching them by causing a bends-like condition due to rapidly dropping air pressure, new research suggests.

Tennis rackets kill bats too, though by a completely different mechanism. 

[richyoung]

what kinda pressure differential is generated when a blade like that moves at 160 mph? from the low side tothe high side

The absolute maximum, if it could pull a perfect vacuum, would be one atmosphere - about 14.7 pounds per square inch.  I would be shocked if its even close to half of that.

[richyoung]

Or bailing out of a jet fighter at altittude.

Wouldn't the fact that the pilot's going to be descending tend to take care of the matter?

Once he gets low enough, but again, if he's bailing out high enough that bends is an issue, and his suit doesn;t work, he's already having issues.  Normally you want to stay with the plane until it gets below 18,000 feet.

On the diving thing - isn't there a number of fancy things you can do to reduce/eliminate the need for decompression waits?  Stuff like breathing pure O2 at the deeper levels, or using helium instead?

They use something called 'trimix" that reduces the danger of nitrogen narcosis and bends, but does not eliminate the need to decompress, as at those pressures, other gasses dissolve into the blood as well.

[richyoung]

National Geographic have changed their article to include the term barotrauma.

NOTE: About 90 percent of the bats studied suffered from barotrauma. The name of the ailment was restored to this article for clarification purposes after initial publication

Gee - where have I heard that term before?

"Interstingly, what the bats are experiencing is indeed like one danger that divers face, its actually a form of barotrauma:  divers can get this if they take a deep breath at depth, and then do not exhale during a free ascent - the lungs expand until blood vessels rupture, then you drown in your own juices."

[Physics]

Another hijack: 

You miss the point. Nuclear plants do not kill ANYTHING. Seabrook is surrounded by wetland marshes, silent and pristine.

Correct when they are working properly.  I think the folks that used to live in Prypiat, Ukraine might disagree with your statement however. 

[MicroBalrog]

Why woud anybody care if wind turbines kill bats?

[cassandra and sara's daddy]

bats are protected in some areas and fill a very useful niche in the ecosystem

[MicroBalrog]

bats are protected in some areas and fill a very useful niche in the ecosystem

Let me put it this way:

A small amount of birds are killed every year by passing aircrft. Some are even rare birds. We don't stop flying.

A small amount of animals are killed by combined harvesters. Do we stop growing grain?

Is the damage to bats great enough to stop us using wind turbines?

[MicroBalrog]

Another hijack: 

You miss the point. Nuclear plants do not kill ANYTHING. Seabrook is surrounded by wetland marshes, silent and pristine.

Correct when they are working properly.  I think the folks that used to live in Prypiat, Ukraine might disagree with your statement however. 

Single, isolated incident related to faulty construction and design.

[cassandra and sara's daddy]

there is a faction of the moonbats opposed to wind power. at that point throw out logic

[MicroBalrog]

there is a faction of the moonbats opposed to wind power. at that point throw out logic

There's a faction of the moonbats opposed to practically anything, I suppose.

[Physics]

Single, isolated incident related to faulty construction and design.

What faulty construction/design?  I always thought it was due to human error, and for the most part wiki seems to support this.  I do agree though, that nuclear power is a good thing overall.  We just need to figure out how to store the waste, because as many know, Hanford is not a very fun place to be downstream to. 

Anyways, sorry, /hijack.

[Gewehr98]

Quote from: Firethorn on August 26, 2008, 12:59:52 PM
Quote from: richyoung on August 26, 2008, 12:21:31 PM
Or bailing out of a jet fighter at altittude.

Wouldn't the fact that the pilot's going to be descending tend to take care of the matter?


Once he gets low enough, but again, if he's bailing out high enough that bends is an issue, and his suit doesn;t work, he's already having issues.  Normally you want to stay with the plane until it gets below 18,000 feet.

Not that big a deal, really.  My ejection seat and parachute pack had an 1800psi little green oxygen bottle attached to my O2 mask - keeping me "pressurized" until I descended to thicker, non-hypoxic air.  Most military ejection seats have such amenities.

As for the three-eyed fish downstream of Three Mile Island/Hanford/Chernobyl/Tokai Mura...



BTW, I love wind turbines.  We've had one generating 36 volts DC for many years on my dad's farm.  There have been no dead bats or birds in the "kill zone" since the old WinCo Wincharger started spinning there, but I'm sure somebody can come up with something along the lines of it causing sterility, early onset menopause, or anything else related to the current fashionable trend of bashing renewable energy.  Go figure - if it ain't coming from fossil fuel, it must be bad! 

[280plus]

early onset menopause

So that was YOUR turbine, wait till I tell the missus! 

 

[Regolith]

Single, isolated incident related to faulty construction and design.

What faulty construction/design?  I always thought it was due to human error, and for the most part wiki seems to support this.  I do agree though, that nuclear power is a good thing overall.  We just need to figure out how to store the waste, because as many know, Hanford is not a very fun place to be downstream to. 

Anyways, sorry, /hijack.

Human error may have been what sparked the incident, but it was the poor design of the nuclear reactor that allowed the disaster to be as bad as it was.

IIRC, the reactor only had a single "shell" of concrete containing the core, which provided for only partial containment.  In the event of a melt down, it's the shell that prevents the radiation from entering the atmosphere, and Chernobyl's inadequate one cracked under the pressure buildup.  Most modern reactors can have two or more massively thick shells that prevent a meltdown from getting that far.  Then there are new technologies like pebble-bed reactors, which are highly unlikely to cause meltdown due to their design.

According to Wikipedia, they did eventually decide that the design was what contributed most to the disaster: http://en.wikipedia.org/wiki/Chernobyl_disaster#Possible_causes_of_the_disaster