I highlighted a few sections from the CO2 science article. Lough and Barnes refer to increases in calcification per year. Would this not then take into account the ocean acidity effect given that the studies were conducted over a time of elevated CO2 levels?

I don't think so, but I'm no expert. Calcification seems to refer to the laying down of calcium. Acidity wouldn't necessary prevent that, it would just gradually leach it away. Hence the sourcewatch comments:

It doesn't matter how quickly these clever little polyps can secrete the stuff, the overall determining factor is the pKa of the bicarbonate/carbonate system in seawater. If the stuff is going to simply dissolve away then the increased activity is to no avail.

Their work contradicts the Kleypas study which claims to show that calcification rates are decreasing on the GBR, which has been widely trumpeted by environmentalists.

Strawman. What environmentalists have been trumpetting is coral bleaching and the impact of acidity on things like oysters.

Well it appears that Lough and Barnes didn't just look at rates of calcification but also density and extention of the reef. If the latter two are increasing it would be safe to assume that Muso's theory (ie about the calcification rate not being able to keep up with the negative effect of CO2 induced ocean acidity), has not been demonstated so far. Indeed quite the opposite:


Historical Coral Growth at the Great Barrier Reef
--------------------------------------------------------------------------------

Reference
Lough, J.M. and Barnes, D.J.  1997.  Several centuries of variation in skeletal extension, density and calcification in massive Porites colonies from the Great Barrier Reef: A proxy for seawater temperature and a background of variability against which to identify unnatural change.  Journal of Experimental and Marine Biology and Ecology 211: 29-67.
What was done
Annual density, linear extension and calcification rates were determined from several coral cores retrieved from 35 sites at the Great Barrier Reef from 9° to 23°S, providing information about long-term variability in coral growth there since the late 15th century.

What was learned
All three of the parameters studied showed a general decrease in values from the north to the south.  Temporally, the authors' results indicated that growth characteristics for Porites are "highly variable," with extension and calcification rates varying "as much as ±20-30% about the mean, both from year to year and over the 10-30-year periods."  The temporal variability of density was much less at ±10% about the mean, both inter-annually and over 10-30 year periods.  The authors also note that their data showed frequent and extended periods of coral growth characteristics that were above or below the long-term mean, cautioning that "it would be unwise to rely on short-term values (say averages over less than 30 years) to assess mean conditions," adding it would be "rash to compare one year's value with another and it would be reckless to compare individual years in different decades without analyzing the long-term trends."

Analysis of average annual calcification rates revealed a statistically significant correlation with available sea surface temperature records, suggesting (though not confirming) that long-term variations in Porites calcification rates on the Great Barrier Reef are driven by variations in sea surface temperatures.  Using this relationship, the authors calculated that a rise in sea surface temperature from 20° to 21°C would increase the calcification rate by about 3.5%.

What it means
Because calcification, extension and density were shown to decrease with increasing latitude (or with decreasing water temperature), the authors suggested that calcification rate in Porites may not be an acceptable proxy for assessing the health of coral reef communities.  "Unfortunately," they note, "declines in calcification in Porites on the Great Barrier Reef over recent decades have been interpreted to be as a result of degradation of the marine environment."  And true it is, their record indicates a recent decline in calcification rates for this region.  However, their data show that "a decline in calcification equivalent to the recent decline occurred earlier this century and much greater declines occurred in the 18th and 19th centuries."  Furthermore, analyses of annual density banding from the coral samples "indicate that the 20th century has witnessed the second highest period of above average calcification in the past 237 years."  As a result, the authors conclude that "the observed decline in coral growth in recent decades may be, simply, a return to more 'normal' conditions."


Reviewed 1 August 1999

freediver wrote on Aug 28^th, 2008 at 5:41pm:


No it says "the twentieth century has witnessed", that does not mean the whole century. If you look back a line you will find this:

However, their data show that "a decline in calcification equivalent to the recent decline occurred earlier this century and much greater declines occurred in the 18th and 19th centuries."

pjb05 wrote on Aug 28^th, 2008 at 4:55pm:


Oh so it's my theory? That's almost as laughable as the quote from the front page of "CO2 science" that says  "contrasting the fantasy world of Al Gore and James Hansen with the factual findings of real-world science"


Are you really so naive that you can't see through that sort of thing? Al Gore is a public presenter - an ex politician, not a serious worker in the field.

Let's say you disagreed with the reporting of the Russian Georgian conflict on Channel 9 news. I don't know where you live but if you're in Melbourne, it would be like saying, " This guy Tony Jones is totally wrong about the Georgian situation - he's living in a fantasy world. Or in Queensland - Bruce Paige (9 anchorman)  is totally deluded about the situation in Georgia.

The question you have to ask is just who are they trying to kid? Certainly not serious workers in the field. They would find the Al Gore analogy as amusing as I do. Maybe the odd member of the general public who didn't bother to think too deeply on the subject would be caught out by it.

The point is that the Ocean pH has already dropped by 0.1 from 8.3 to 8.2. (That's a logarithmic scale by the way. pH is the negative log of the Hydrogen ion activity). Most of that drop has occurred during the last 40 years or so, so any studies previous to that are totally irrelevant.

As the buffering capacity of the ocean drops, the atmospheric CO2 levels will rise even faster. Remember that currently 50% of the excess CO2 produced is taken up by the oceans. That figure will drop as time goes on.

PJB, These are old papers, cherry picked to make them look more significant than they are,  and a great deal of work has been done since that time. 

If this paper, written in 2001 was so significant in indicating that ocean acidification was a non issue (it wasn't), why then do we have such an emphasis on ocean acidification today (seven years later) by the same researchers ? Did they forget about their own research in 2001, or has there been more extensive work done since then? What do you think?

Same group:

http://www.aims.gov.au/docs/media/news2008/20080306.html

"All media are invited to visit AIMS on Tuesday 11 March to meet scientists participating in a workshop on the growing issue of ocean acidification.

The consequences of increased greenhouse gases in the atmosphere have already been seen in, for example, the coral bleaching that has afflicted the Great Barrier Reef in recent years.

A subtle but potentially more serious effect of climate change is arising as the oceans absorb much of the extra atmospheric carbon dioxide. This is making the oceans more acidic and will reduce the ability of marine organisms to form their skeletons and shells.

AIMS has assembled some prominent national and international experts who will be at the Institute’s headquarters at Cape Ferguson near Townsville 11-14 March to discuss research directions over the coming years as this phenomenon develops.

Please come to AIMS at 10am on Tuesday 11 March 2008 to meet with AIMS scientists and their colleagues from other research organisations. Among the scientists present will be AIMS climate change team leader Dr Janice Lough, AIMS research manager Dr Lyndon Llewellyn, Dr Joanie Kleypas from the Institute for Study of Society and Environment in Boulder, Colorado and Dr Bronte Tilbrook from CSIRO Marine Laboratories in Hobart."


I mean let's lose the tunnel vision of the denialist sites for a change and take a look at the real world for a change. This is a major issue.

It is certainly a more extensive and rigorous study than the Keyplas research.

That hardly makes it significant.

pjb05 wrote on Sep 1^st, 2008 at 4:07pm:


You're missing the point. You imply that Barnes and Lough are somehow showing in their paper that ocean acidification is not an issue. The fact is that they are among the top researchers in the field, and that the paper was just one of many papers that investigated the nature and rate of calcification in marine organisms.

The problem is that denialists latch on to this kind of thing and use the research to design arguments that are totally 180 degrees out of phase with the findings of the original researchers. It's a form of 'cherry picking'. Don't look behind that curtain!  I am the great wizard of obfuscation.

Ask Barnes or Lough how significant they think ocean acidification to be.

What do you think would be their answer?  I'll email them if you like and let you know.

Do you really think that there exists two groups on researchers - one of which thinks that ocean acidification is a non issue, and the other  believes it to be significant?

If you believe that then you're living in cloud cuckoo land.