By Rud Istvan,
This short post is drawn from the introductory section of essay Shell Games in my ebook Blowing Smoke, foreword from Prof. Judith Curry of Georgia Tech. The thrust of that essay was scientific misconduct by Fabricius concerning Milne Bay coral reefs and by PMEL concerning the Netarts Bay oyster hatchery. Both were hyped by a deeply misleading ‘fake news’ climate alarm series in the Seattle Times. This redrafted and reillustrated essay introduction section concerns neither of those misconduct examples. As discussed with Charles the Moderator, it hopefully accomplishes two things I have not seen at WUWT despite being a regular contributor and reader since 2011. First, it provides seawater chemistry basics with ‘deep dive’ links. Second, it sets that basic understanding against published pH measurements and background ocean biology, something even Jim Steele’s excellent coral posts did not fully provide.
Obiter dictum. We acknowledge that seawater is basic and cannot truly acidify (pH<7). But that is a losing semantic quibble, not a winning skeptical argument. The generally accepted linguistic convention—for better or worse–is that lowering seawater pH means ‘acidification’. There is no doubt that adding dissolved CO2 does lower pH. The relevant questions are how much and whether that amount matters. This post answers both questions (a little, not much) without the two specific false alarms that motivated the ebook version.
There are certainly some ocean related AGW consequences beyond any scientific doubt. Henry’s Law requires that the partial pressures of atmospheric and dissolved ocean CO2 equilibrate. Rising atmospheric CO2 must increase dissolved seawater CO2. That is long established simple physical chemistry.
This lowers pH by increasing carbonic acid. NOAA PMEL has documented this in the central Pacific at Station Aloha off Mauna Loa where sea surface pH has declined from 8.11 to 8.07 since 1991, as dissolved pCO2 increased from ≈325 to ≈360μatm while atmospheric CO2 increased from about 355 to 395 ppm. That is Δ0.04 pH in 24 years.
But for two reasons, Station Aloha cannot be linearly extrapolated into the future as IPCC AR4 erroneously did. First and foremost, ocean pH is not a linear chemical system driven only by Henry’s law; it is a system highly buffered by dissolved minerals and seafloor carbonates. Taking seawater chemical buffering into account, IPCC AR5 3.8.2 suggested that doubled atmospheric CO2 might cause surface pH to decline by Δ0.15-0.2, less than half of AR4. This is well within the normal diurnal and seasonal biological seawater pH variation for almost all ocean waters. It is no cause for the alarms sounded by the Seattle Times series Sea Change.
Ocean surface pH is not uniform. It varies diurnally, seasonally, by ecosystem, and by underlying ocean depth. At the deep ocean and biologically barren PMEL Station Aloha site north of tropical Hawaii, seasonal surface variation is only Δ0.1 pH. Moderately fertile Southern Ocean surface seasonality is Δ0.5 pH. Seasonal surface variation is as high as biologically fertile Δ1.43 pH depending on which of and where the Pacific’s 8 biological marine ecosystems are evaluated.[i]
How marine creatures do under experimental aquarium conditions of roughly doubled CO2 (with food, light, and temperature held constant) depends on species. [ii] Crustaceans, temperate urchins, calcifying (coralline) algae, limpets, and mussels do well. Oysters, conch, bay scallops, and some tropical corals don’t. But aquariums do not reflect the important interplay of many other ecosystem factors also affecting these creatures.
For a specific example, Florida Bay conchs thrive amidst complex interactions between seasonal pH and salinity that drive extreme pH swings, even though Woods Hole aquarium studies suggest they should not. The Everglades mangrove fringe in Florida Bay has a low salinity winter pH 5.8 yet serves as a crucial ‘predator safe’ nursery ecosystem for many Florida Bay marine species. Yet toward Key West (the ‘Conch Republic’) pH peaks as high as 9.8 during sunny summer days with elevated (from evaporation) salinity.[iii] The maximum geographic separation is just 90 miles, the average only 25 miles. Such extreme pH changes come from Thallassia sea grass photosynthesis consuming dissolved CO2, plus evaporative high salinity (>50ppt) driving calcium carbonate precipitation. Florida Bay demonstrates the enormous variability and resilience of actual marine ecosystem biodiversity.
Florida Bay. Photo courtesy South Florida Water Management District
[i] Hofmann et. al., High-frequency dynamics of ocean pH: a multi ecosystem comparison, PLoS One 6: e28983 (2011)
[ii] Oceanus 48 (2010), the Woods Hole Oceanographic Institution publication.
[iii] NOAA/National Park Service Joint Report: NOAA Technical Memorandum NOS NCCOS CCMA154, same as NPS Special Report 01-02. Page 64.
Thanks, Rud, very useful.
There is an easy way to determine whether acidification of a high-volume, high-density, highly buffered and turbulent system by atmospheric CO2 is feasible, and that is to compare its pH to that of a shallow, low-volume, relatively calm and unbuffered fresh water pond and lake system. It should be obvious that the latter would be a virtual acid bath well before any ocean system showed meaningful changes in pH. Also, notably, the article did not address localized and temporary changes in pH due to submarine volcanic activity, which comes to mind when papers publish data on ocean acidification localized near the Pacific Ring of Fire.
I don’t know for a fact that atmospheric CO2 is that important to ocean pH.
Yeah, I said that.
My view is that of a limnologist. The organic content in most fresh water streams makes them acidic. Land runoff into the oceans would lower the pH of the surrounding waters. I can’t quantify the effect, nor the atmospheric CO2 effect, so I don’t know which is bigger. I can say the atmospheric CO2 isn’t acting alone.
Could someone show me the data that shows the ocean is actually becoming less basic? All I ever see is assumptions based on an increase in atmospheric CO2
Someone a few months ago posted this image of all known ocean surface pH readings since about 1900
ZERO TREND
Bottom line is, the bulk of the global-warmers have a chemical viewpoint that can briefly be described thus: “Carbon dioxide dissolve in water and make Acid. Teacher say Acid bad. Acid dissolve chalky stuff and make it go fizz fizz. Coral reef thingies made of chalky stuff so CO2 double bad, just like orange man.”
And that’s about it, even at Christmas.
Michael: thanks for the global warmer’s chemical viewpoint – it gave a good laugh. Sadly, I think you’re right.
The article perfectly describes the biological aspects of the problem of acidification of sea water. I would like to briefly discuss the question of whether an increase in CO2 concentration in the atmosphere can significantly affect the acidity of seawater.
The concentration of CO2 in sea water is very low. Extrapolation of data by J.Carrol et al (1991) https://www.researchgate.net/publication/253858692_The_Solubility_of_Carbon_Dioxide_in_Water_at_Low_Pressure to the partial pressures of CO2 0.03 kPa and 0.04 kPa at 20oC gives the values of solubility 12.8 and 16 micromole CO2/kg H2O correspondingly. This means that the increase in CO2 concentration over the past 100 years was only 0.13 mg/kg. Can such a change in concentration affect the pH even in the absence of buffer salts?
The formation of hydrogen ions in water when CO2 is dissolved takes place in two stages:
СO2 + H2O H2CO3 (1)
H2CO3 H+ + HCO3- (2)
It’s known that for the 1st stage (hydration) equilibrium constant [H2CO3]/[CO2] is of 0.0017 in pure water and 0.0012 in seawater. https://en.wikipedia.org/wiki/Carbonic_acid
In other words, only one CO2 molecule from 830 is converted to carbonic acid. The equilibrium constant for stage (2) [H+] [HCO3-] /[H2CO3] = 0.00025. Consequently, the concentration of hydrogen ions formed in water due to CO2. is negligible, and other reasons for the change in seawater acidity need to be considered.
You are mistaken regarding the conversion of CO2 to carbonic acid, carbonic acid is a minor intermediate stage between CO2 and bicarbonate ions. The overall equilibrium can be described by the following equation:
[H+] = Sqrt(10^-14 + KhHa1*pCO2/kH)
Kh≈ 1.2×10−3, Ka1 = 2.5×10−4, kH = 29.76 , KhHa1/kH= ~10^-8
Here’s my conjecture – others more able than me can check the numbers.
“Even if earth’s atmosphere suddenly changed to 100% CO2, nothing but CO2, there would still no be enough CO2 (at one atmospheric pressure at sea level) to acidify the whole volume of the ocean.”
Let me offer some perspective. Folks keep talking like the expected changes in alkalinity are large. Let me start with my local situation on the coast of California.
pH measurements at the inlet pipe to the Monterey Bay Aquarium. Inlet depth is 50′ (15 metres). Light yellow hairlines show standard error of each month’s measurements, indicating a wide spread of pH values in each month. Red interval at the top right shows the theoretical pH change which would have occurred over the time period of the dataset. Photo shows kids at the Aquarium looking at the fish.
Next, here’s the natural variation of pH in different parts of the ocean:
pH in different marine environments. DATA SOURCE: PLOS
The average pH ranges from 7.6 to 8.2, and the one standard deviation data runs from 7.2 to 8.4 … here’s a quote from the source of the figure above:
Heck, over coral reefs the pH can change by 0.2 pH units in SIX HOURS … and per the head post, “IPCC AR5 3.8.2 suggested that doubled atmospheric CO2 might cause surface pH to decline by Δ 0.15-0.2 …”.
Finally, we tend to think that the ocean all has the same pH … not true. pH in the ocean around Alaska is about 8.05 … and in the ocean around Hawaii it is on the order of 7.65.
So no, I am not concerned that a slight neutralization is going to even be noticed by the ocean creatures.
w.
Let me offer some perspective. Folks keep talking like the expected changes in alkalinity are large.
The ocean alkalinity is not the same as pH, it is given by:
TA ≡ 2[CO3-2] + [HCO3-] + [H2BO3-] + 2[HBO3-2] + 3[BO3-3]
+ [OH-] + [organic/inorganic H+ acceptors] – [H+]
So the H+ is only a very minor contributor to alkalinity. If you want to call it something other than pH just call it hydrogen ion concentration.
Willis
I think that it should be noted that the Monterey Bay Aquarium is situated at the head of the Monterey submarine canyon. The area is noted for frequent and erratic upwelling of the water. The reason that the aquarium started monitoring the intake was because they had lost specimens when the upwelling water was anoxic. The bottom line is that the variance in pH at the aquarium results from low-pH water coming from great depths, and is not typical of what occurs in areas that lack significant upwelling. That is, low-pH water is more common in upwelling zones.
Thanks, Clyde. I know that the upwelling is the reason for the fast changes in the pH. It’s not limited to the Monterrey Aquarium, however. It occurs all along this coast. My point was simple. All of the creatures living along the coast of California, Oregon, and Washington regularly undergo swings in pH much larger than the gradual change expected by the year 2100 …
w.
So, a late maybe dead thread set of final comments on my simple guest post.
I tried to defuse the semantic pedantic ‘acidification’ quibble at the outset. Failed abjectly. But that failure teaches IMO a much bigger skeptical failure. No different than prolife means actually antiabortion. If you lose the popular terminology symbology, stop fighting a lost battle and move on. The battle is political for genersl populace minds. Not static. Not purist.
Depressingly Few appreciated the two simple main science guestpost points:
1. Seawater is highly buffered, so all the alarmist ‘acidification/neutralization/debasification projections are physically (chemically) impossible. See how silly word games are in the greater chemical debate context?
2. Ocean biology creates much more seasonal variability than warmunists project would be catastrophic. Jim Steele’s comment takes the biological gold metal, paraphrased: ‘freshwater averages pH5.5, but freshwater mollusc shells do NOT dissolve because protected by protein coats…’
That is a warmunist killer biological argument. Kudos, Jim Steele.
So, the next time an all knowing commentator on your favorite MSM news outlet announces how the water is getting more acidic at an alarming rate, are you going to answer with a somewhat oblique truth about mollusc coatings, or are you going to answer with the more direct truth that there is no acid/acidity in the water at all? Maybe it is OK if both those truths are brought forward to the extent possible?
To put it another way, what makes you think that the “there’s more acid all the time” promoters are OK to win, it’s good to go for *that* idea, while the more subtle truth about the ability of the wilderness to adapt to even relatively large changes over time, why *that* is going to put the alarmists in their place, they would *never* lie about *that*!
If I’m putting some in here it is only because we’re still facing a genuinely alarming situation of the eco-extremists in our society seizing the air of authority, broadcasting their alarm from the chairmanship positions of most of the world’s science organizations, and all of this with the hearty support of the mainstream/leftstream media! If the most basic “spin” or “slant” terminology in support of alarm is therefore somehow held to be a lost cause, unchallengeable really, then aren’t the more subtle points of anti-alarm sure to be lost as well?
In case there is a misunderstanding here, note that I for one am not complaining about the simple use of the phrase “Ocean Acidification”, as in the title of your article, for instance. For me, at least, the real trigger for the current terminology discussion was your immediate dissing of what you yourself said was the truth, as in, I quote;
“We acknowledge that seawater is basic and cannot truly acidify (pH<7). But that is a losing semantic quibble, not a winning skeptical argument"
Since when is the truth a mere quibble, and since when is a lie to be fully accepted as the presumably valid or unbiased terminology that everyone must necessarily work with? Go right ahead and use the word acidification in the alarmist context, but please don't go out of your way to excuse it either.
Ocean pH levels
Several years ago, I visited the Monterey Bay Aquarium. One of the docents was excited enough about OA to tell us that Scripps Institute was about to launch several autonomous mini subs which would cruise the oceans taking measurements. She pointed out that one of the items that these vehicles would measure would be pH and she went on to explain how this data would show the impact of OA.
When I heard this, I began thinking that the data would most likely show that there are wide variations in ocean pH levels (diurnal, seasonal and local). Based on the routes these vehicles take they might find pH trends in either direction or possibly no discernable pH trend.
Recently I searched for this data, but I have not found it. Does anyone have a link to this data?
See my comment above, along with my posts on the subject (below).
w.
The Electric Oceanic Acid Test 2010-06-19
I’m a long-time ocean devotee. I’ve spent a good chunk of my life on and under the ocean as a commercial and sport fisherman, a surfer, a blue-water sailor, and a commercial and sport diver. So I’m concerned that the new poster-boy of alarmism these days is sea-water “acidification” from…
The Reef Abides 2011-10-25
I love the coral reefs of the planet. In my childhood on a dusty cattle ranch in the Western US, I decorated my mental imaginarium of the world with images of unbelievably colored reefs below white sand beaches, with impossibly shaped fish and strange, brilliant plants. But when I finally…
The Ocean Is Not Getting Acidified 2011-12-27
There’s an interesting study out on the natural pH changes in the ocean. I discussed some of these pH changes a year ago in my post “The Electric Oceanic Acid Test“. Before getting to the new study, let me say a couple of things about pH. The pH scale measures…
The Reef Abides … Or Not 2014-07-06
I’ve written a few times on the question of one of my favorite hangouts on the planet, underwater tropical coral reefs. Don’t know if you’ve ever been down to one, but they are a fairyland of delights, full of hosts of strange and mysterious creatures. I’ve seen them far from…
pH Sampling Density 2014-12-30
A recent post by Anthony Watts highlighted a curious fact. This is that records of some two and a half million oceanic pH samples existed, but weren’t used in testimony before Congress about ocean pH. The post was accompanied by a graph which purported to show a historical variation in ocean…
A Neutral View of Oceanic pH 2015-01-02
Following up on my previous investigations into the oceanic pH dataset, I’ve taken a deeper look at what the 2.5 million pH data points from the oceanographic data can tell us. Let me start with an overview of oceanic pH (the measure of alkalinity/acidity, with neutral being a pH of…
The Kavachi Sharcano 2015-07-11
The Solomon Islands, where I lived for eight years, is just north of Australia and just south of the Equator. It is part of the “Ring Of Fire”, the area of strong earthquake and volcanic activity that encircles the Pacific. You can see below that the islands are on …
Carbon And Carbonate 2016-01-30
I’ve spent a good chunk of my life around, on, and under the ocean. I worked seasonally for many years as a commercial fisherman off of the western coast of the US. I’ve frozen off my begonias setting nets in driving sleet up in the Bering Sea. I’m also a …
That’s great, thanks.
What I would like is contextual numbers for how much CO2 there is in the oceans, in the atmosphere, and in the lithosphere, so that the changes can be given relative scale and hence significance. I feel that if the things are put ob ne a comparable global scale the realities can be discussed more rationally.