Photo of clownfish hiding in reef
Image: Flickr/gwylow71
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Monterey, Calif.—Mental problems at sea? Fish and mollusks could begin to have them—thanks to rising CO2 levels. Some of the resulting behaviors are odd, some compromising, and they reveal just how fundamentally carbon emissions are affecting our increasingly fragile Earth.
As humans emit more carbon dioxide into the atmosphere, more of the gas is absorbed by the oceans, gradually making the water more acidic. Numerous studies in recent years have documented how lower pH (higher acidity) can make it harder for shellfish and tiny organisms to form shells or internal skeletons and to reproduce. The acidity often forces the organisms to expend extra energy to counteract ill effects on their metabolisms as well. But now scientists are finding that lower pH can also mess with ocean animals' minds.
Small clown fish (yes, Nemo), for example, normally stay extremely close to the coral in which they spend their entire lives. But as the water becomes increasingly acidic—as in various recent experiments—they tend to wander farther and farther from home. This uncharacteristic "boldness" is not necessarily a good trait because the farther they swim, the more likely they are to get eaten by predators. Greater acidity also "impairs their ability to discriminate between the smell of kin and not, and of predators and not," according Philip Munday, a professor and research fellow at the Coral Reef Studies center at James Cook University in Australia, who conducted the experiments and presented results at a symposium here this week called The Ocean in a High-CO2 World.
Other species exhibit equally unusual behaviors. A snail known as Chilean abalone, which adheres to rocks along wave-swept shores, quickly rights and reattaches itself when it is dislodged, an important skill for avoiding predators. But when CO2 levels were raised by about 50 percent, some snails were slow to right themselves and others did not do so at all. "Their decision-making is delayed," said Patricio Manriquez, a researcher at the Southern University of Chile. Some snails took wrong turns in trying to avoid crab predators, and some even turned into the crab's claws instead of away from them.
In experiments done at the Monterey Bay Aquarium Research Institute here, hermit crabs living in highly acidic conditions did not show the increased boldness of Munday's clown fish, but they took far longer to withdraw into their shells than normal when they came under attack from a potential predator (in this case, a toy octopus).
Researchers are not sure what is causing the peculiar behaviors but Munday suspects that elevated CO2 levels interfere with a neurotransmitter called GABA, which plays a key role in modulating activity in the brain and nervous system of virtually all animals, including humans. In one experiment, Munday exposed reef fish to high CO2, which interfered with their sense of smell. He then administered a compound that helps to facilitate activity by receptors that sit on nerve cells and direct the cells' responses to GABA, and the abnormality was reversed. Because GABA is so ubiquitous, Munday fears that ocean acidification could cause sensory and behavioral problems for many sea creatures if global CO2 levels continue to rise.
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11 Comments
Add CommentYet another in a long line of unscientific articles by a publication that used to publish science and now publishes pure propaganda.
Reply | Report Abuse | Link to thisQuestion-when the PH level in the local area of the ocean naturally varies more in a month than the amount it would increase in years due to it becoming less basic, are the fish dumber each month?
The spam comment above trying to advertise a pointless job is more atually correct than unScientific American as of late
Since you don't understand the meaning of "propaganda," you probably don't understand the meaning of "quibbling" either.
Reply | Report Abuse | Link to thisFirst, these are experiments to see what might happen, so let's not go to descriptors like "dumber." But to the point, even if a fish functions well within a pH range that varies by year, season or even day, that range is still affected by the overall ocean trend. So let's say a fish functions well in pH between 8.2 and 7.8, and the global ocean pH is 8.0. If the global pH drops, the range drops with it. So if global pH drops to 7.9, the range may drop to 8.1 to 7.7--outside what the fish functions well in. Numerous speakers made this point, and showed curves for actual organisms, at the conference.
Reply | Report Abuse | Link to thisAs we see this reaction is a MIXTURE of Hydrocarbon Chemicals☺☻
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Breath
http://wiki.answers.com/Q/How_much_CO2_is_emitted_per_breath
We as humans do not breath out Hydrocarbon Chemicals.
Not to demeanor the petroleum companies in any way, yet
the need for alternative energy☺☻
Pure gasoline is a combination of hydrocarbon chemicals, which are compounds made up entirely of the elements carbon and hydrogen. When pure gasoline is burned under ideal conditions, the carbon and hydrogen combine with oxygen from the air. This reaction releases heat and converts the hydrocarbons into carbon dioxide gas and ordinary water.
Read more: What is Car Exhaust? | eHow.com http://www.ehow.com/facts_5212260_car-exhaust_.html#ixzz27wQA5ZTN
@mfischetti
Reply | Report Abuse | Link to thisI hate it when they speak of "the oceans are becoming more acidic", that sounds so like battery acid pool acid, acid mine drainage, vinegar and lemon juice. Obviously an image you try to generate. But what you are really saying is, that it is becoming slightly less acidic. And still far away from becoming acidic. The little shelled animals and corals won't dissolve in a steaming cloud of acid all of a sudden. And if you take your toddler down to the beach its teeth won't dissolve. Keep it real and don't exaggerate so shamelessly.
Sorry I meant the oceans are becoming slightly less alkaline.
Reply | Report Abuse | Link to thisMost people don't like seafood anyway.
Reply | Report Abuse | Link to thisFanandala, it's YOU that does the exaggeration! The sad reality is that in the past 27 years,the Great Barrier Reef in Australia has halved.
Reply | Report Abuse | Link to thisIt is no good trying to shoot the messenger, in this case: Scientific American.
sunnystrobe raises the alarm:
Reply | Report Abuse | Link to this"The sad reality is that in the past 27 years,the Great Barrier Reef in Australia has halved."
Is GW the only reason you can conceive of, as to the cause of the damage to the GBR? Even if so, with Man's contribution of 3% of natural CO2 emissions... how do you attribute GBR damage to climate, let alone AGW. Certainly bleaching has other attribution phenomenon (ie pollution, fertilizer run-off, predatory species invasions, etc). GK
"The sad reality is that in the past 27 years,the Great Barrier Reef in Australia has halved."
Reply | Report Abuse | Link to thisFirstly the Great Barrier Reef has NOT haled in the past 27 years at all, as a Queenslander I can tell you it has not got any smaller than it was when I was kid 50 years ago, it has how ever halved over the last 2,000 years.
I t has had problems over the years with Crown of Thorns, which grew to plague proportions years ago, but it was found to be a "Natural" event every fifty to one years. It has also had bleaching, at one stage, again a "Natural" event.
The greatest threat the GBR is tourism, and boating people not respecting the reef and using anchors on the reef. They are doing more damage than anything "warming" will ever do. But nothing is been done to prevent them, why because they bring in billions of dollars each year.
Second Para should read "It has had problems over the years with Crown of Thorns, which grew to plague proportions years ago, but it was found to be a "Natural" event every fifty to one *hundred* years. It has also had bleaching, at one stage, again a "Natural" event.
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