Madfronter
New member
I thought others would like to read this as well...
http://news.bbc.co.uk/2/hi/science/nature/7936137.stm
http://news.bbc.co.uk/2/hi/science/nature/7936137.stm
Acidic Ocean
- Thread starter Madfronter
- Start date
Folks reading this should recognize that the "30% more acidic" they mention corresponds to a drop of 0.11 pH unit.
So however you choose to interpret it, folks with reef tanks at pH 7.7 to 7.9 are experiencing conditions much more acidic than the article is referring to.
pH 7.7 is more than 300% more acidic than NSW at pH 8.2.
So however you choose to interpret it, folks with reef tanks at pH 7.7 to 7.9 are experiencing conditions much more acidic than the article is referring to.
pH 7.7 is more than 300% more acidic than NSW at pH 8.2.
greenbean36191
Premium Member
Yes, but hobbyists should also keep in mind that we don't have the major contributors to negative reef growth like large parrotfish, scores of rock boring urchins, boring sponges, hurricanes, etc. In an aquarium, net growth is usually very strongly positive so a minor drop in calcification isn't a big deal. In the wild, net growth is often just marginally positive (and negative for many reefs recently), so a very small reduction in positive growth, especially with increasing sources of negative growth like WBD or frequent bleaching can shift the balance.
We also try to maintain a proper balance of Ca and alk for optimal calcification. The ocean doesn't do that, so small shifts in pH can result in big shifts in the range where the aragonite saturation state is suitable for reef growth.
We also try to maintain a proper balance of Ca and alk for optimal calcification. The ocean doesn't do that, so small shifts in pH can result in big shifts in the range where the aragonite saturation state is suitable for reef growth.
ctenophors rule
New member
its a shame what we have done to our oceans, good thing i want to study sea grasses. lol
i read that at our current atmospheric co2 levels, even if green house gas emmisions greatly dimminished, or even halted all together, our oceans would still become to acidic to suport coral growth, is this true? because it goes against other information i found.
thanks
i read that at our current atmospheric co2 levels, even if green house gas emmisions greatly dimminished, or even halted all together, our oceans would still become to acidic to suport coral growth, is this true? because it goes against other information i found.
thanks
ctenophors rule
New member
i do, maybe not in the near future, but probably. then later wghen the oceans ph goes back up we can repopulate the oceans.
one can hope, right?
one can hope, right?
greenbean36191
Premium Member
Not a chance. We aren't talking about waiting for a few years and things will get better. We are talking about conditions that will take several hundred if not thousands of years to return to normal once the tipping point is reached. Beyond that the diversity we have in the hobby, especially what we can actually breed in captivity, isn't anything close to what it would require to recreate a functioning ecosystem.
power boat jim
Well-known member
I would not be so quick to say "not a chance" The ecosystems have shown a remarkable ability to rebound after disasters. Look at how fast things return after forest fires . The scars from Mt St Helens eruption are about gone. Lake Erie has recovered from being, for all practical purposes, dead in less then 30 years.
Though none of these are on the scale on the earths oceans, I believe the pattern shows natures ability to bounce back fairly fast if conditions permit.
AND DONT BE SUCH A PESSIMiST
LockeOak
New member
<a href=showthread.php?s=&postid=14646430#post14646430 target=_blank>Originally posted</a> by power boat jim
I would not be so quick to say "not a chance" The ecosystems have shown a remarkable ability to rebound after disasters. Look at how fast things return after forest fires . The scars from Mt St Helens eruption are about gone. Lake Erie has recovered from being, for all practical purposes, dead in less then 30 years.
Though none of these are on the scale on the earths oceans, I believe the pattern shows natures ability to bounce back fairly fast if conditions permit.
AND DONT BE SUCH A PESSIMiST
That's not a good analogy. A better analogy would be a forest fire and, perhaps, the damage done to a reef by a major hurricane. Yes, damage is done, but it's a single, very brief event and the underlying conditions that supported the original ecosystem remain in place. What's more, there are outside populations to repopulate the damaged areas. Ocean acidification is an entirely different situation, where the conditions to which the reefs are adapted are changing. The brief severe disturbances (hurricanes, El Nino / Southern Oscillation bleaching events) will still occur, while the reef's ability to recover are greatly diminished. And since acidification is a more or less global phenomenon, there are no potential founding populations. If the ocean dropped to, say, 7.8 (on the bad end of projections) reefs would probably recover, but not on a timescale relevant to humanity.
power boat jim
Well-known member
I guess my point was we have an iffy track record in predicting daily local changes for most atmospheric events. Our record is even worse for predicting long range global climatic/oceanic changes. There are far too many varibles,known and unknown, to account for in these models.
We have overestimated changes on most of the gloom and doom forecasts. Though the present trend is cause for study and concern, it is way too early to say there is no way for things to recover in a time scale relavent to humanity (The entire "relevant to humanity statement" is one that could be its own discussion).
I dont disgree with what you said about the analogy being weak since there isnt much to compare global scale with. All the more reason to not count out the possibility of a recovery that may be different then predicted.
Jim
We have overestimated changes on most of the gloom and doom forecasts. Though the present trend is cause for study and concern, it is way too early to say there is no way for things to recover in a time scale relavent to humanity (The entire "relevant to humanity statement" is one that could be its own discussion).
I dont disgree with what you said about the analogy being weak since there isnt much to compare global scale with. All the more reason to not count out the possibility of a recovery that may be different then predicted.
Jim
Poorcollegereef
Future Doc
Actually, the climate change projections are getting to be quite accurate in many cases. While the projections in the '70 were "funky" and discredited the climate models in public opinion, my research into the models is that we might be underestimating the speed of change within the model. The "too many variable" argument has very little merit within these models. Not only is it an appeal to ignorance (a logical fallacy), but variables such as volcanic activity and cloud cover are included with amazing precision. Yes, I do acknowledge that models are imperfect reproductions, but as both computing technology and recording technology increases the precision of the models will also increase.
Now, when working on my master's thesis, my trans-arctic shipping routes prediction was based on IPCC 2007 reports in determining the likely time period that would allow seasonal trans-oceanic shipping between SE asia and the eastern seaboard(US). Now, between completing the thesis and presenting it at a national conference, my data was dated and I had to update it because the ice melt in the arctic what much faster than originally projected. This does not make the models wrong, but many assume "out of date" with wrong.
Plus, I would not consider Lake Erie any "better" sure some pollutant are lower and it is less toxic to humans, but the zebra mussel and other human related activity has drastically alter Erie, the great lakes, and nearly every ecosystem in the planet. I consider invasive species the most permanent and destructive forms of pollution.
Now, when working on my master's thesis, my trans-arctic shipping routes prediction was based on IPCC 2007 reports in determining the likely time period that would allow seasonal trans-oceanic shipping between SE asia and the eastern seaboard(US). Now, between completing the thesis and presenting it at a national conference, my data was dated and I had to update it because the ice melt in the arctic what much faster than originally projected. This does not make the models wrong, but many assume "out of date" with wrong.
Plus, I would not consider Lake Erie any "better" sure some pollutant are lower and it is less toxic to humans, but the zebra mussel and other human related activity has drastically alter Erie, the great lakes, and nearly every ecosystem in the planet. I consider invasive species the most permanent and destructive forms of pollution.
Beaun
It's pronounced Bone
Erring on the side of caution should be the way we approach these situations though. When a forest fire breaks out, we dont let it burn down the whole forest, we try and combat it. That is if it gets out of hand, forest fires can be a good thing after all. But to simply claim that no matter what happens, or what we do to the planet, it can bounce back and recover is foolish. This is a problem humanity has made much too often in our history with the environment.
power boat jim
Well-known member
Where did I say" no matter what happens, or what we do to the planet, it can bounce back and recover "? Before you call some foolish please read what is written. All I did was bring up three examples of environmental recovery from three seperate incidents. The degree of recovery in each case is a debateable item. It was just to point out that recovery is possible in a short time if the environment is given the chance.
power boat jim
Well-known member
The reason I made statement about the long range predictions was based on the problem of getting all the reliable data that is needed put into the program. Im sure the computers of today can crunch the data and come up with a spot on forecast IF it is given bulletproof data to start with. Im not sure that yet exists.
Please correct me if Im wrong, but some computer programs can "fudge" numbers if a hole in the data exists. If the computer cant the programmer certainly can. Im not saying this is wrong, but it sometimes data for a certain perameter in a certain place does not exist. So you now do your best to extrapolate. This is where the variable I was talking about comes into play. The more unknowns there are the more extrapolation that is needed.
As is evident from the seventies, predictions of a coming ice age were prevelant then, things prediction wise are much better. One reason, some of the "holes" in the data that existed then are now filled in. So, as soon as we know everything and can get into a computer we will have a perfect long range prediction. Until then I believe the predictions are only a reflection of what we know-and thats not everything.
I agree 100% about the invasive species, My point with the lake was in regard to water quality only. One must also note improvement in eco systems when conditions are improved even though they are not complete or dont meet everyones expectations.
MCsaxmaster
New member
It seems there's a bit of confusion here between climate scenarios and ocean acidification scenarios. While climate is indeed a complex systems influenced by many factors, oceanic pH (and associated carbonate chemistry) is not. The effects of adding CO2 to seawater are very well understood, very well quantified, and easily tested. I mean, if you dissolve a particular amount of CO2 into some seawater we can calculate and then verify the change in pH to within +/- 0.0004 units. That's pretty good 
Considering the entire Earth/ocean/atmosphere system and how the release of X amount of CO2 in Y period of time affects ocean chemistry is indeed a bit more complicated, but is still a *relatively* simple undertaking. The only truly meaningful uncertainty in projections of future ocean acidification are 1) the amount of CO2 released, and 2) the rate of release. The big picture is sharply in focus.
As for coral reefs and other ecosystems rebounding: I'm quite confident they will, eventually. A slug of 2000 GtC released by the end of the century ("business as usual") however will require on the order of tens of thousands of years to be neutralized through natural mechanisms (dissolution of carbonates, weathering of silicates, etc.). We actually have fairly good geological precedent on the timescale here, which is actually on the long end of what we would expect from modeling. During the Paleocene-Eocene Thermal Maximum (PETM) ~55 mya a similar amount of carbon was realeased to the atmosphere in two ~1000 yr pulses over the course of ~20,000 yrs. The recovery time for "normal" carbonate chemistry (meaning return to carbonate accumulation in sediments) was 100,000+ yrs. There were widespread marine extinctions, especially in benthic forams. Coral reefs disappeared for several million yrs.
We're creating a similar event today, albeit probably a bit worse since we're releasing a similar pulse of CO2 in the matter of 200-300 yrs instead of several thousand yrs. Since the ocean takes 800+ yrs to turn over, that means that less of that CO2 gets buried in the deep ocean, and most of it stays in the surface, causing worse acidification.
Hence, we can probably expect widespread marine extinctions, the global collapse of coral reefs for perhahps several million yrs, an eventual rebound of coral reefs sometime in the distant future (or course, that didn't work so well for the rugose corals, tabulate corals, rudist bivalves, etc., all of which were major reefbuilders for millions of yrs, and all of which are long extinct) and disrupted carbon cycling for 100,000+ yrs. We can expect this if geologic history is a good precedent and IF we do release all that CO2, that is.
That's the big question--will we release all of that CO2, resulting in a modern event similar to the PETM, or will we not? I hope not, and thankfully the tide seems to be turning in that direction (pun intended )
Chris
Considering the entire Earth/ocean/atmosphere system and how the release of X amount of CO2 in Y period of time affects ocean chemistry is indeed a bit more complicated, but is still a *relatively* simple undertaking. The only truly meaningful uncertainty in projections of future ocean acidification are 1) the amount of CO2 released, and 2) the rate of release. The big picture is sharply in focus.
As for coral reefs and other ecosystems rebounding: I'm quite confident they will, eventually. A slug of 2000 GtC released by the end of the century ("business as usual") however will require on the order of tens of thousands of years to be neutralized through natural mechanisms (dissolution of carbonates, weathering of silicates, etc.). We actually have fairly good geological precedent on the timescale here, which is actually on the long end of what we would expect from modeling. During the Paleocene-Eocene Thermal Maximum (PETM) ~55 mya a similar amount of carbon was realeased to the atmosphere in two ~1000 yr pulses over the course of ~20,000 yrs. The recovery time for "normal" carbonate chemistry (meaning return to carbonate accumulation in sediments) was 100,000+ yrs. There were widespread marine extinctions, especially in benthic forams. Coral reefs disappeared for several million yrs.
We're creating a similar event today, albeit probably a bit worse since we're releasing a similar pulse of CO2 in the matter of 200-300 yrs instead of several thousand yrs. Since the ocean takes 800+ yrs to turn over, that means that less of that CO2 gets buried in the deep ocean, and most of it stays in the surface, causing worse acidification.
Hence, we can probably expect widespread marine extinctions, the global collapse of coral reefs for perhahps several million yrs, an eventual rebound of coral reefs sometime in the distant future (or course, that didn't work so well for the rugose corals, tabulate corals, rudist bivalves, etc., all of which were major reefbuilders for millions of yrs, and all of which are long extinct) and disrupted carbon cycling for 100,000+ yrs. We can expect this if geologic history is a good precedent and IF we do release all that CO2, that is.
That's the big question--will we release all of that CO2, resulting in a modern event similar to the PETM, or will we not? I hope not, and thankfully the tide seems to be turning in that direction (pun intended
)Chris
greenbean36191
Premium Member
Not a chance. Your examples are all short-term disturbances and are not at all comparable to acidification. CO2 has a long lifetime in the ocean, so there's a lot of inertia in the system. The problem doesn't just quickly remedy itself within a few decades or so once you stop adding CO2. Once we reach the tipping point, we're talking timescales of several hundred to a few thousand years (depending on how bad we let things get) before conditions favorable to reef growth return.
Even if the timespan wasn't an issue, the diversity we can maintain in captivity is a huge problem. You can't just stick corals back out in the wild and expect a functional ecosystem. There are very few species that we can culture in captivity which is something you need to do for any restoration program, much less one that will occur a few centuries down the line.
I'm so pessimistic because scleractinian corals are only the most recent in a long line of reef building organisms- most of which are now extinct. In previous periods of low pH reefs have disappeared entirely for several million years.
Your confusing perfection with utility.
There's an old saying about models that none are perfect, but some are useful. You don't have to have complete knowledge of a system to produce a useful model. The models only get more certain as the data behind them improves.
And just FWIW even in the 70s there were only 6 peer reviewed papers predicting cooling, vs. 39 predicting warming, so it's not true that predictions of a coming ice age were ever prevalent.
Poorcollegereef
Future Doc
Here is the trick, we know the major variables that are driving the climate system. There really are not "unknown variables" that are driving factors. The only variable that is the "iffy" (if you could call it) is the rate of change based on human activity. There are variables in human activity that are more challenging to determine. It is much easier to take a positivist approach to nature or the traditional sciences. In the social sciences and related fields, the rate of change in human activity is a bit more difficult (and you don't have social construction theory in CO2 studies). But we do know one basic thing, things are changing and we know the factor contributing to the change. While the rate of change is more debatable, and as a result, good models project ranges rather than exact numbers based on some variables, even if the human race disappeared tomorrow, there would still be an increase in global temperatures in the 2-5 degree F in the next 30 years.
MCSaxMaster, its good hearing your reasoning again, I haven't read any of your posts in a while.
Greenbean, the peer review of global cooling is accurate, but the non-peer review/popular media actually focused on cooling more than warming. This was driven on both a temporary decline in global temps in the '70 that was just a variation in normal temperatures ranges, and that aerosols were receiving a lot of environmental critique. The media and public just concentrated on the "next iceage" idea rather than an idea of gradual warming. It is actually kind of funny to go back and look at some of the cooling models and the inputs. Icebergs are more marketable (and more personal) than... well Al Gore
MCSaxMaster, its good hearing your reasoning again, I haven't read any of your posts in a while.
Greenbean, the peer review of global cooling is accurate, but the non-peer review/popular media actually focused on cooling more than warming. This was driven on both a temporary decline in global temps in the '70 that was just a variation in normal temperatures ranges, and that aerosols were receiving a lot of environmental critique. The media and public just concentrated on the "next iceage" idea rather than an idea of gradual warming. It is actually kind of funny to go back and look at some of the cooling models and the inputs. Icebergs are more marketable (and more personal) than... well Al Gore
power boat jim
Well-known member
Thanks, Poorcollegereef, green bean and MCsax. Your answers together paint the clearest picture of how many of the pieces fit together that I have seen in a while. Excellent work all of you.
Thanks for endulging this old earth science major who might need a bit more "updating" in order to understand how complex and detailed some of these models have become.
Thanks for endulging this old earth science major who might need a bit more "updating" in order to understand how complex and detailed some of these models have become.
wld1783
Premium Member
<a href=showthread.php?s=&postid=14646430#post14646430 target=_blank>Originally posted</a> by power boat jim
I would not be so quick to say "not a chance" The ecosystems have shown a remarkable ability to rebound after disasters. Look at how fast things return after forest fires . The scars from Mt St Helens eruption are about gone. Lake Erie has recovered from being, for all practical purposes, dead in less then 30 years.
Though none of these are on the scale on the earths oceans, I believe the pattern shows natures ability to bounce back fairly fast if conditions permit.
AND DONT BE SUCH A PESSIMiST
Totally agree...look back to history.
WWII Thousands of boats (sorry navy guys) with millions of gallons of diesel were torpedoed over some of our most pristine reefs...Some have created awesome reefs...Truk Lagoon
Mother nature is wonderful in how she adapts. We tend to make things worse like putting out forest fires or driving a Chevy Prius...lota of heavy metals in that battery, not good for land fills.
Just the facts
Bill
