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HighlandReefer
06/01/2011, 02:20 PM
http://www.sciencedaily.com/releases/2011/05/110531201221.htm

ScienceDaily (May 31, 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 behavior 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 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.

"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."

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I don't know what the expected ocean acidification is for 2050 and 2100. Perhaps in some tanks it may compare. :)

Randy Holmes-Farley
06/01/2011, 02:33 PM
The full text is free here. The low pH they are referring to is around pH 7.7-7.8 based on the paragraphs below, which is reported by some hobbyists in this forum.

http://rsbl.royalsocietypublishing.org/content/early/2011/05/25/rsbl.2011.0293.full

from it:

"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"


and

"Since the Industrial Revolution, approximately 142 billion tonnes of anthropogenic CO2 has been absorbed by the oceans, resulting in ocean acidification at a rate far faster than any time in the last 650 000 years [1], and causing the average pH of the ocean to drop by 0.1 units [2]. If global emissions continue on the current trajectory, atmospheric CO2, currently at 390 ppm, is predicted to reach 730–1020 ppm by 2100 [2,3], causing a further drop in ocean pH of 0.3–0.4 units"

Boomer
06/01/2011, 02:48 PM
Cliff

I was contacted by some NOAA Blue Crab larvae researches in Alaska doing the same with low pH. But I do not know if the article ever came out. They too where looking at survival rates in low seawater pH from increased atm CO2. I do have some issues with these so called increased ocean pH's for atm Co2.

We are at the lowest atm CO2 in the history of the earth. During the rain of the Dinosaurs and those higher tropical forest CO2 was wayyy many times higher than now. Same for the Cambrian explosion and all the inverts.

Here is what I mean:

http://files.abovetopsecret.com/uploads/ats41378_image277.gif

HighlandReefer
06/01/2011, 02:49 PM
Thanks Randy. ;)

So the lower pH is a concern in many tanks.

Randy Holmes-Farley
06/01/2011, 02:50 PM
Maybe clownfish were deaf for millions of years during the dino age. :D

HighlandReefer
06/01/2011, 02:51 PM
Thanks Boomer. ;)

Nice graph and explanation. :)

HighlandReefer
06/01/2011, 02:51 PM
Maybe clownfish were deaf for millions of years during the dino age. :D

:lol:

Boomer
06/01/2011, 03:54 PM
:rollface::rollface::rollface::rollface::rollface:

Boomer
06/01/2011, 04:00 PM
OK, I have to shut off this PC. I'm still laughing from Randy's last comment. It is just so funny and can not think straight right now :lol:

Paco
06/02/2011, 07:21 AM
Wow, my poor clownfish. I'm sure she can't hear at all as I rarely have a pH above 7.8 due to indoor CO2 levels.