From the “CO2 is the most deadly omnipotent force in the Universe department”, comes this tragic story of poor Nemo the clownfish, so disoriented by CO2 that he can’t choose the right path to swim. Rebuttal(s) follow in subsequent posts, but first here is the story on the research from James Cook University. Original press release here, ABC news story below. Look for a Disney/Pixar sequel soon, sure to frighten the children. – Anthony
Rising CO2 may lead Nemo to danger
By Katherine Nightingale for ABC Science Online
Global warming could have an unexpected effect on the clownfish star of Finding Nemo and his kind, by making them indulge in risky behaviour, say researchers.
Previous research indicates that as carbon dioxide (CO2) levels in the atmosphere climb the surface water of the oceans could become acidic.
Scientists have already shown that this acidification interferes with fish larvae’s sense of smell and ability to find a suitable home.
Now research led by marine researcher Professor Philip Munday of James Cook University (JCU) has found it could also make fish less aware of – and even attracted to – predators.
They publish their research this week in the Proceedings of the National Academy of Sciences journal.
As part of the study, the researchers put clownfish and damselfish larvae into seawater equivalent to that which would be found if the atmosphere contained 700 ppm and 850 ppm of CO2 – levels that could be reached by the end of the century.
They found that after four days, half of the larvae in the 700 ppm group were less able to detect the smell of a predator, while all the larvae in 850 ppm group were actually attracted to the predator scent.
Damselfish larvae that were then released onto a reef were more active and behaved more boldly than normal, spending less time near shelter and more time near predators. They were also five to nine times more likely to die than normal fish born in 390 ppm conditions.
Profound implications
The results suggest this could have a huge impact on ocean biodiversity.
“Being attracted to the smell of a predator isn’t likely to be a very good thing,” Mr Munday said.
Professor David Booth, a marine ecologist at the University of Technology Sydney who was not involved in the study, says the behavioural choices made by young fish are thought to strongly affect populations.
“This finding of negative effects on such choices could have profound implications for the dynamics of fish populations,” he said.
The researchers are now trying to pin down why acidification causes the fish to behave more boldly, as well as looking at the wider effects on population balance in reef ecosystems.
Mr Munday says, for example, different species could have different tolerances, and acidification could make predators more or less inclined to eat.
Professor Geoffrey Jones, also of JCU and the ARC Centre of Excellence for Coral Reef Studies, said the research took the level of concern about the effects of climate change on coral reef fish “to a whole new level”.
“Without drastic action to cut emissions, all we can do is hope that fish will be able to adapt,” Mr Jones said.
“However, given that the rate of CO2 increase is unprecedented, there are no grounds for optimism.”
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Gosh, look at this, CO2 (confirmed by sampling and analysis) bubbling right out of the sea floor next to healthy reef corals. More on this later.
Pat Moffit,
Maybe I’m cynical, but in making the choice of the particular fish species, maybe it was thought to be particularly iconic for kids? Perhaps there was something premeditated in the results that was intended to scare the kids?
Bob_FJ
July 10, 2010 at 3:07 pm
Clownfish and damsels were most likely selected because the are exceptionally hardy and are very easy to maintain in an aquarium. They are also about the only marine aquarium subjects that can be breed in captivity.
DesertYote, Reur July 11, 2010 at 5:19 pm
So obviously my suspicions were groundless…. Just a coincidence.
I notice that in your earlier comment of July 9, 2010 at 8:32 am , you wrote in part this:
Do you think that applies to the official release by the university?
http://www-public.jcu.edu.au/news/JCUPRD1_058449
You also wrote:
I’m sure that you would find it interesting since you seem to have some special interest in marine aquaria. However, providing the university release is not lying about its own paper, (and presumably the authors have sighted the release), then it is unnecessary to read the paper in order to find that the methodology and conclusions are just plain daft. For instance, the baby clownfish were subjected to what the authors estimated might be the water conditions with long-term atmospheric CO2 hypothesised to reach 700 & 850 ppm, (including higher temperatures?), which is impossible to determine in the oceans. For there to be any effect on the fish in the aquaria, some arbitrary exposure time would need to be chosen, but how much effect is sought, and would it be the same without long-term physical/genetic adaptation through significant generations of the fish. Then, in the aquaria, (where they were bred free of predators?), after these poor little fishies nosies have been adjusted (or not adjusted) to a sudden change of conditions, they are then plunged into the unfamiliar colder more alkaline conditions at the reef! Maybe they were suffering withdrawal symptoms or shock? Who knows?
Incidentally, isn’t there also a thing about clown fish gender adaptation?
Bob_FJ
July 11, 2010 at 7:33 pm
Clownfish are “Sequential Protandrus hermaphrodites”. The largest is a female. The next largest is a breeding male. The remaining are immature males. If the female is removed, the breeding male will grow larger and become the female. One of the non-breeding males will mature and become the breeding male.
Actually, I am not all that interested in Marine Ecology. My main focus is extreme freshwater habitats such as desert streams. I have also worked with estuary systems which I found fascinating (talk about fast changing and extreme water chemistry! BTW, there are a number of brackish and even fresh water damsels). Marine bores me, but I have still have to be knowledgeable.
The university press release was terrible, obviously written by a marxist indoctrinated journalist major with no knowledge of the sciences. There is almost nothing here that indicates what is actually in the paper. It is probably all a lie. I am not even surprised anymore when lead authors misrepresent there own studies for the press. After all it really does not matter, its not like its peer reviewed or anything, and if it serves the greater good, then lying is ok.
DesertYote, Reur July 12, 2010 at 4:23 pm
Thanks your very interesting comment. I think you were a bit strong concerning the accuracy of the university release though; after all it cannot possibly cover everything in the paper itself, even if it were totally accurate. What is rather disturbing for me is that apparently:
They publish their research this week [per July 7] in the ‘Proceedings of the National Academy of Sciences journal‘.
And…. In addition to the findings of the SIX author’s, apparently Professor David Booth, and Professor Geoffrey Jones add their gloomy prognostications and seal of approval to the paper. There are also extensive quotes. In small part, the lead author Munday is quoted thus:
“When we released them [the fry] on the reef, we found that they swam further away from shelter and their mortality rates were five to eight times higher than those of normal baby fish,” Professor Munday says…
I’d be surprised if this is a fabricated statement, but anyway, regardless of its considerable ambiguity, you did put your finger on an elementary methodology problem of theirs when you wrote earlier:
This shows right away that normal aquaria conditions do NOT emulate the reef, and thus that each of these two exposures are likely to affect the fish in any number of different ways that are open to speculation.
Some 45 years ago and before, I was a keen freshwater tropical fish keeper and breeder, and was accidentally successful in breeding an “unbreedable” loach. One day I discovered that their small community tank was apparently lifeless because of extremely low temperature due to power loss in a cold room. (English winter). However, the community mostly recovered, with ONLY the loaches, eye bogglingly spawning frantically in normal temperature water. The other species showed no response other than some dying, and were easy to net out to protect the fry. Inherently then, one has to be very careful in nature in predicting processes or drawing conclusions after any unnatural stress, especially if it is severe, however that may be defined or assumed. (modest temperature changes etc, are of course common practice in stimulating fish breeding in aquaria)
Oh, and some species are said to return to their birthplace through some sophisticated biological mechanisms which I guess still remain speculative. (?) OK, lets take some Atlantic Salmon, artificially breed them in freshwater tanks, and then release them in the Pacific at the right size. What will they do about returning home?
I guess though that these JCU coral reef experts et al will get adequate funding to continue their research, given the extreme gravity of their published findings!
Here is an interesting article from ‘Australia News Watch’, addressing problems with the media reporting of the “Nemo paper”, and the methodology of the researchers.
http://abcnewswatch.blogspot.com/2010/07/rising-co2-may-lead-nemo-to-change-not.html