We’ve already had a “climate craziness of the week” so I’ll just file this bit of blather under another category. First, this article in The Independent, which aims to scare the children.
Now here’s the press release from the University of Bristol. Note the simplistic experiment, followed by broad disclaimers about it, emphasis mine.
Ocean acidification leaves clownfish deaf to predators
Press release issued 1 June 2011
Baby clownfish use hearing to detect and avoid predator-rich coral reefs during the daytime, but new research from the University of Bristol demonstrates that ocean acidification could threaten this crucial behaviour within the next few decades.
Since the Industrial Revolution, over half of all the CO2 produced by burning fossil fuels has been absorbed by the ocean, making pH drop faster than any time in the last 650,000 years and resulting in ocean acidification. Recent studies have shown that this causes fish to lose their sense of smell, but a new study published today in Biology Letters shows that fish hearing is also compromised.
Working with Professor Philip Munday at James Cook University, lead author Dr Steve Simpson of the School of Biological Sciences at the University of Bristol reared larvae straight from hatching in different CO2 environments.
“We kept some of the baby clownfish in today’s conditions, bubbling in air, and then had three other treatments where we added extra CO2 based on the predictions from the Intergovernmental Panel on Climate Change for 2050 and 2100,” Dr Simpson said.
After 17-20 days rearing, Dr Simpson monitored the response of his juvenile clownfish to the sounds of a predator-rich coral reef, consisting of noises produced by crustaceans and fish.
(click for MP3 file)
“We designed a totally new kind of experimental choice chamber that allowed us to play reef noise through an underwater speaker to fish in the lab, and watch how they responded,” Dr Simpson continued. “Fish reared in today’s conditions swam away from the predator noise, but those reared in the CO2 conditions of 2050 and 2100 showed no response.”
This study demonstrates that ocean acidification not only affects external sensory systems, but also those inside the body of the fish. The ears of fish are buried deep in the back of their heads, suggesting lowered pH conditions may have a profound impact on the entire functioning of the sensory system.
The ability of fish to adapt to rapidly changing conditions is not known. Dr Simpson said: “What we have done here is to put today’s fish in tomorrow’s environment, and the effects are potentially devastating. What we don’t know is whether, in the next few generations, fish can adapt and tolerate ocean acidification. This is a one-way experiment on a global scale, and predicting the outcomes and interactions is a major challenge for the scientific community.”
‘Ocean acidification erodes crucial auditory behaviour in a marine fish’ by Steve Simpson, Philip Munday, Matt Wittenrich, Rachel Manassa, Danielle Dixson, Monica Gagliano and Hong Yan in Biology Letters.
Translation: “we put the fish in a significantly different water environment, and they reacted differently”. Anyone who has ever owned a freshwater or saltwater aquarium can tell you about what happens when you transfer fish from the water environment they are used to, to one they aren’t. pH shock and Osmotic shock often often result from the abrupt change. The key is abrupt change, whether embryo or adult, the fish are wired for a specific ocean environment, change that environment abruptly and the fish change too. What they’ve done here is take 40 years of gradual change and compress it to the here and now.
And I have to think, these guys chose the absolute worst fish for the experiment, because I’m betting they didn’t go out and get wild embryos, but rather took the easy path of tank raised clown fish embryos. From Wikipedia:
Clownfish are now reared in captivity by a handful of marine ornamental farms in the USA. Clownfish were the first species of Saltwater fish to successfully be Tank-raised. Tank-raised fish are a better choice for aquarist, because wild-caught fish are more likely to die soon after purchasing them due to the stress of capture and shipping. Also, tank-bred fish are usually more disease resistant and in general are less affected by stress when introduced to the aquarium. Captive bred clownfishes may not have the same instinctual behavior to live in an anemone. They may have to be coaxed into finding the anemone by the home aquarist. Even then, there is no guarantee that the anemone will host the clownfish.
The “may not have the same instinctual behavior to live in an anemone.” is troubling. It suggests that tank raised clownfish may not be “normal”. And of course when I backtrack to the source method (from the Simpson paper) for obtaining embryos (Munday et al, 2008, referenced in the current paper) I find this:
Clownfish were reared at James Cook University’s experimental aquarium facility where the pH of unmanipulated seawater was 8.15 ± 0.07. This is similar to the pH that pelagic larvae would experience during development in the open ocean (1).
James Cook University in Townsville QLD has direct access to the ocean, so it would seem right that they have direct access to “unmanipulated seawater”. Still, they were tank raised, and that’s a different environment than the ocean and their wild cousins.
Let’s have a look at the paper.
Ocean acidification erodes crucial auditory behaviour in a marine fish
Ocean acidification is predicted to affect marine ecosystems in many ways, including modification of fish behaviour. Previous studies have identified effects of CO2-enriched conditions on the sensory behaviour of fishes, including the loss of natural responses to odours resulting in ecologically deleterious decisions. Many fishes also rely on hearing for orientation, habitat selection, predator avoidance and communication. We used an auditory choice chamber to study the influence of CO2-enriched conditions on directional responses of juvenile clownfish (Amphiprion percula) to daytime reef noise. Rearing and test conditions were based on Intergovernmental Panel on Climate Change predictions for the twenty-first century: current-day ambient, 600, 700 and 900 µatm pCO2. Juveniles from ambient CO2-conditions significantly avoided the reef noise, as expected, but this behaviour was absent in juveniles from CO2-enriched conditions. This study provides, to our knowledge, the first evidence that ocean acidification affects the auditory response of fishes, with potentially detrimental impacts on early survival.
- Received March 14, 2011.
- Accepted May 10, 2011.
- This Journal is © 2011 The Royal Society
Full paper here
First, note the time-line; it was fast tracked. It went from submission to approval in two months. It seems that according to this journal statement, they go for “fast track science” as a matter of policy:
Articles submitted to Biology Letters benefit from its broad scope and readership, dedicated media promotion and we aim for a turnaround time of within 4 weeks to first decision.
Looks like a paper mill to me.
And, this may indicate the paper was chosen on something other than scientific merit, emphasis mine:
Selection Publishing Criteria
The criteria for acceptance are: scientific excellence, work of outstanding quality and international importance, originality and interest across disciplines within biology. To be acceptable for publication a paper should represent a significant advance in its field, rather than something incremental.
All manuscripts are assessed by a member of the Editorial Board, who advises the Handling Editor on the suitability of the manuscript for Biology Letters. Based on this, the Handling Editor decides whether the paper should be rejected or sent for full peer-review. Many good papers are rejected at this stage on the grounds that they are insufficiently novel, due to high competition for space.
So, “novelty” is primary acceptance criteria and peer review is on a 4 week fast track. Check.
It seems volume of peer review is celebrated at this journal. That’s something I’ve never seen before in any other journal.
Quantity, not quality. Check.
What really seems to be missing from this clownfish experiment is a control experiment. For example, did they test the fish by putting them in water that represents the CO2/ ocean environment of 10-40 years ago? I seems they only tested for the future representing 600, 700 and 900 µatm pCO2. Here’s what they say about the method:
The CO2-conditions of our rearing and test environments were current-day ambient (∼390 µatm), and elevated-CO2 treatments (approx. 600, 700 and 900 µatm), consistent with the range of Intergovernmental Panel on Climate Change predictions for CO2 concentrations at the end of the twenty-first century .
This is very important, because the paper assumes that only an increase of CO2 will change clownfish behavior. Did they test for decreasing CO2 levels and what the fish would do then? Apparently not, and that basic use of a control seemed to have escaped those high volume peer reviewers racing to meet the 4 week deadline.
By not testing for a decreased CO2 situation, they invalidate their own premise. And that’s on top of the fact that they aren’t using wild clownfish embryos and they are making abrupt changes in the water chemistry that generations of the fish have not experienced and doing it only in one direction, up.
This is high school science stuff guys. I wait for an explanation as to why you didn’t test for a decrease to CO2 and the resultant pH on clownfish embryos.
So I wonder, if we take 10 peer reviewers from the “wilds” of science, put them in a think tank, increase the ambient CO2 levels to more than double they are used to, and then tell them they have 4 weeks to review 100 papers, will they still produce good science?
Maybe they need more peer reviewers in that clown car to be sure.