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Milman reports: "Escalating carbon dioxide emissions will cause fish to lose their fear of predators, potentially damaging the entire marine food chain, joint Australian and US research has found."

A lemon damselfish finding shelter in coral. Exposure to CO2 will make it more adventurous and endanger its life. (photo: Bates Littlehales/Corbis)
A lemon damselfish finding shelter in coral. Exposure to CO2 will make it more adventurous and endanger its life. (photo: Bates Littlehales/Corbis)

Entire Marine Food Chain at Risk From Rising CO2 Levels in Water

By Oliver Milman, Guardian UK

14 April 14


Fish will make themselves vulnerable by being attracted to predator odour and exhibiting bolder behaviour

scalating carbon dioxide emissions will cause fish to lose their fear of predators, potentially damaging the entire marine food chain, joint Australian and US research has found.

A study by the Australian Institute of Marine Science, James Cook University and the Georgia Institute of Technology found the behavior of fish would be “seriously affected” by greater exposure to CO2.

Researchers studied the behavior of coral reef fish at naturally occurring CO2 vents in Milne Bay, in eastern Papua New Guinea.

They found that fish living near the vents, where bubbles of CO2 seeped into the water, “were attracted to predator odour, did not distinguish between odours of different habitats, and exhibited bolder behaviour than fish from control reefs”.

The gung-ho nature of CO2-affected fish means that more of them are picked off by predators than is normally the case, raising potentially worrying possibilities in a scenario of rising carbon emissions.

More than 90% of the excess CO2 in the atmosphere is soaked up by the oceans. When CO2 is dissolved in water, it causes ocean acidification, which slightly lowers the pH of the water and changes its chemistry. Crustaceans can find it hard to form shells in highly acidic water, while corals risk episodes of bleaching.

The AIMS study found the diversity of fish at the CO2 vents was not influenced by the extra carbon, but that fish’s nerve stimulation mechanisms were altered, meaning the smell of predators became alluring.

“What we have now also found in our study of fish behaviour in this environment is that the fish become bolder and they venture further away from safe shelter, making them more vulnerable to predators,” said Alistair Cheal, co-author of the research.

While fish at the vents faced fewer predators than usual, the consequences for fish in the wider ocean could be significant as more CO2 was dissolved in the water.

“Continuous exposure does not reduce the effect of high CO2 on behaviour in natural reef habitat, and this could be a serious problem for fish communities in the future when ocean acidification becomes widespread as a result of continued uptake of anthropogenic CO2 emissions,” the study said.

A report released last year, which had input from the University of Western Australia’s Oceans Institute, found global warming could cause oceans to become 170% more acidic by the end of the century, the fastest rate of acidification in the past 300 million years.

Hugh Sweatman, research scientist at AIMS, said: “The acidification of the ocean is much discussed because it’s potentially a gigantic thing. It’s the difference between normal water and soda water, if you like.

“Ocean acidification seems to reverse sensations in fish so that things that smell repulsive become attractive. The small change in pH has a big impact on the fish.

“Little fish are generally very nervous and stay close to shelter. This reverses this, meaning they are more vulnerable and become eaten more quickly.” your social media marketing partner


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-13 # Malcolm 2014-04-15 00:39
I don't understand. They say, "Crustaceans can find it hard to form shells in highly acidic water, while corals risk episodes of bleaching."

Where is this "highly acid water"? The ocean's pH has dropped somewhere from around 8.3 to around 8.2. "Highly acidic", to me at least, means way down around 2.0. I think the fish are probably not too worried about so-called acidification" in fact, any fish who has access to a chemistry book knows that pH over SEVEN is not acid at all-it's a BASE!

The fishes would also know that there are only SEVEN strong acids, and carbonic acid is NOT one of them. Carbonic acid is a WEAK acid!

And hold your breath, because the next time you exhale, you'll actually be exhaling carbonic acid. (I just realized that this may be why we don't exhale FISH. It's all coming together. Thanks, Ollie!
+9 # Jerome 2014-04-15 02:53
Unfortunately the author used the phrase "highly acidic water." The problem is the water is becoming more acidic. A basic explanation of the the Carbonate/Bicar bonate Buffer System is availableat:htt p:// 03/07/the-carbo natebicarbonate -buffer-system/ . As more CO2 is dissolved into the oceans' waters, the pH shifts lower. Lower pH reduces the ability of organisms that make calcium carbonate shells. pH between 8.0 and 8.3 is the critical range for life in the oceans.
The seemingly small change in pH, from about 8.25 to 8.14 is actually an increase of hydrogen ions of about 29% because the pH scale is logarithmic. Most alarming is the prediction that the pH is going to continue falling by 0.3 to 0.5, to well below what oceanic life can tolerate. A major crash in ocean ecosystems with losses of whole food chains is possible.
+4 # Jerome 2014-04-15 02:56
Please go to Wikipedia:
for a far better explanation than I've given.
+4 # Activista 2014-04-15 01:14
I found this article bit strange also - but the acidification of oceans is real - all food chain is affected - we are transforming this super rich environment into the desert:‎
Coral reefs house some of the most diverse and productive ecosystems on the planet, and provide a vital ... But as the carbon dioxide dissolves, it forms an acid.... "75% of the world's coral reefs are under threat, both from local activities and global processes related to climate change."
-3 # BKnowswhitt 2014-04-15 13:18
This i'd like to see more about scientifically as coral is a living thing. However the blasphemous unscientific hystrionics about Climate Change .. won't let reasonable debate. We have been gamed by it all. Al Gore's made Millions .. give us some more elaboration on the reefs and CO2 then ... if you can ... it would be informative .. if you are objectively trying to get to that conclusion .. thanks ....
0 # Activista 2014-04-16 01:15
Search "reefs and CO2" and you get"
Scholarly articles for reefs and CO2
Coral reefs: sources or sinks of atmospheric CO2? - ‎Ware - Cited by 142
… of CaCO3 and its effect on atmospheric CO2 - ‎Opdyke - Cited by 181
… reefs may start dissolving when atmospheric CO2 … - ‎Silverman - Cited by 173
Climate, Carbon and Coral Reefs - WMO‎
World Meteorological Organization
Tropical coral reefs cover an area of over 284 000 km2, providing habitat for thousands ... High CO2 emissions lead to “double trouble” for coral reefs. First, the ...
CO2, Global Warming and Coral Reefs: Prospects for the ...‎
Science and Public Policy Institute
Jan 12, 2009 - Summary for Policy Makers One of the long-recognized potential consequences of the ongoing rise in the air's CO2 content is CO2-induced ...
-5 # Valleyboy 2014-04-15 01:58
I think this kind of apocalyptic headline is what puts the "apathetic masses" off climate change.
+1 # Kootenay Coyote 2014-04-15 08:50
-5 # BKnowswhitt 2014-04-15 13:15
Now 90% of CO2 is going into the Oceans? Out of the atmosphere .. then that must mean there's not much going into the atmosphere correct? So no global warming effect as claimed to raise and trap heat there. We are warned two if by land, two if by sea .. oh forlorn and two different hypothesis's ... CO2 does nothing to the atmosphere period .. so now it's concentrated in the water supply by 90% - more lies i suspect?
-2 # BKnowswhitt 2014-04-15 13:19
Sorry one if by land two if by see ... three and it's a lie to you and me ...
-4 # BKnowswhitt 2014-04-15 16:31
How about all of the toxic gases that are released by the volcanic earths core into the ocean. CO2 is one? How about methane and even more toxic life threatening gases on a regular basis into the oceans floor? Maybe the fish are 'drunk' from all of that. How about some objective evidence via real scientific study isolating all those factors in a controlled environs on live fish .. instead of popycock inflammatisatio n of a mostly false argument .. That's it's CO2 killing off hte fucking planet .. when there is no real evidence to that. Now the gases released on a daily basis in our cities is killing us and our lungs .. how about just sticking with those truths ....
0 # Activista 2014-04-16 01:27
Bob - from Oregon - go to Corvallis-OSU and learn ..
"Human-caused climate change is caused by addition of anthropogenic greenhouse gases to the atmosphere. The addition of these extra greenhouse gases act to exacerbate the natural greenhouse effect. These contributions are predominately from the burning of fossil fuels, but a small amount are also from land use changes. Carbon dioxide emissions from the burning of fossil fuels are the most significant source of anthropogenic greenhouse gases. Global atmospheric concentrations of carbon dioxide have risen almost 100 ppm since their pre-industrial (1750) value of 280 ppm.
Go and learn ...
0 # Billy Bob 2014-04-15 21:07
Why is it that whenever the subject of global warming comes up, HALF OF THE COMMENTS ARE BY 2 RIGHT WING TROLLS?

Too bad RSN doesn't have the balls to stand up to 2 trolls.
0 # Malcolm 2014-04-16 10:39
Newsweek has put together a calm, accurate assessment of where we are at in the climate change deterioration. Here's very brief synopsis:

"Even if the world went carbon-neutral tomorrow, we’d be in for more: because of the CO2 that has already been emitted, we’re on track for another 5 degrees of warming. Batten down the hatches."

An even briefer synopsis. We are TOTALLY FUCKED. Time to head for the hills. Then run in circles, scream and shout!

Alas, they don't bother to mention whether that 5° is measured in °F or °C. Surprising, since it makes a fairly big difference. 1.0°C=1.8°F! In other words, if we are ging to have average global temps rise by 5° CENTIGRADE, that's NINE DEGREES FAHRENHEIT. Under that scenario, we aren't totally fucked, we are totally TOAST!
-1 # Activista 2014-04-16 11:39
"Time to head for the hills..." or to the water (not dry Northern California) - plant trees that provide shade and moisture -
Water will be resource we will be fighting for .. get out of the cities ..

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