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By Charles Rhodes, P.Eng., Ph.D.

This web page outlines the problem of CO2 induced ocean acidification which poses a near term threat to about 15% of the world human food protein supply and is the cause of a present precipitous decline in the British Columbia wild fish population. The term "ocean acidification" is a fancy name for an increased ocean (HCO3)- ion concentration resulting from an increased atmospheric CO2 concentration. Ocean acidification causes a large reduction in the ocean (CO3)-- ion concentration which ion concentration is crucial for the survival of numerous marine organisms that are at the base of the ocean food chain. Due to the limited ocean turnover in the British Columbia Inside Passage (water between the mainland and the off-shore islands) this issue of low pH is now causing fish starvation in the inside passage. The observable consequences include a collapse of the wild salmon fishery and starvation of the resident orca population.

For many millions of years Earth's atmospheric CO2 concentration stayed within the range 180 ppmv to 300 ppmv and as a consequence the ocean (CO3)-- ion concentration was sufficient to enable simple marine life to form bone and shell material. Over time these marine organisms died and their CaCO3 bone and shell components sunk to the bottom of the ocean where they gradually accumulated to form a layer of limestone. Core drilling of this layer of limestone and isotopic analysis of the drill cores reveals the geophysical history of Earth going back over one hundred million years.

The problem is that recent combustion of fossil fuels has increased the atmospheric CO2 concentration to 413.5 ppmv which causes a corresponding increase in the concentration of dissolved (HCO3)- ions in ocean water which in turn causes a much larger fractional decrease in the concentration of (CO3)-- ions in ocean water. This decrease in (CO3)-- ion concentration prevents many simple marine organisms from forming bone and shell material. Since these marine organisms are near the bottom of the ocean food chain, loss of these simple marine organisms causes starvation in the entire ocean food chain and will soon cause starvation of humans.

This problem of ocean acidification is particularly acute in coastal sea water where, due to a continental shelf and off-shore islands and/or long inlets, there is relatively little mixing between the CO2 absorbing near surface water and the deeper water of the major ocean. Due to ocean mixing the ocean acidification problem is presently less acute over the deep ocean but will continue to get worse during the coming decades. Presently the BC wild salmon population is collapsing because wild salmon have to swim hundreds of km through the food depleted Inside Passage while transiting to and from the rivers in which they were born and in which they spawn. Similarly resident orca are not reproducing due to lack of their principal food (salmon).

The problem of collapse of the ocean food chain due to long term ocean acidification by CO2 was predicted by scientists decades ago, but has been overlooked by the IPCC and most other parties studying CO2 triggered climate change. However, this collapse of the ocean fishery has major near term human consequences. The time for irresponsible political and legal decisions relating to building more fossil fuel energy infrastructure instead of more nuclear power infrastructure has long past.

The important chemical reactions are as follows:

Decomposition of volcanic rock under water:
1) CaSiO3(a portion of volcanic rock) + H2O > Ca(OH)2 + SiO2 (sand)
2) Ca(OH)2 > Ca++ + 2(OH)-
(The (OH)- ions make sea water slightly basic)

Dissolving a small amount of CO2 from the atmosphere into ocean water causes the reaction:
CO2 + H2O = 2 H+ + (CO3)--
The low resulting small H+ ion concentration is cancelled by the larger (OH)- ion concentration via the reaction:
2 H+ + 2 (OH)- = 2 H2O
so the sea water remains basic but at a slightly lower pH.

Recall that a pH of 7.0 is a neutral solution, a larger pH is basic, a smaller pH is acidic. Before combustion of fossil fuels the ocean pH was about 8.2, which is basic. Increasing the atmospheric CO2 concentration causes the ocean pH to drop below 8.0 which is still basic but is more acidic than at a pH of 8.2. Hence the process is known as ocean acidification. At pH values below 8.0 many forms ocean marine life dependent on CaCO3 for formation of bone and shell material cannot survive.

Increasing the atmospheric CO2 concentration sharply reduces the ocean (CO3)-- ion concentration by converting (CO3)-- ions into (HCO3)- ions via the reaction:
3) H2O + CO2 + (CO3)-- > 2 (HCO3)-
(Since the equilibrium concentration of (CO3)-- ions is much less than the equilibrium concentration of (HCO3)- ions a small fractional change in (HCO3)- ion concentration causes a large fractional change in the (CO3)-- ion concentration.)

Formation of CaCO3 by tiny marine organisms:
4) Ca++ + (CO3)-- > CaCO3
(This is the chemical reaction used by marine species to form bone and shell material)

Ocean heating:
5) 2 (HCO3)- > H2O + CO2 + (CO3)--
(Water temperatures that are high enough to reverse the ocean acidification process are over 45 degrees C and are incompatible with most marine life)

As long as the atmospheric CO2 concentration is low the (CO3)-- ion concentration in ocean water is sufficiently high that reaction #4 operates which allows CaCO3 to form in the bones and shells of simple marine organisms.

However, reactions #1 and #2 are very slow which limits the rate at which Ca++ and (CO3)-- ions can form. When the atmospheric CO2 concentration is higher than normal the rate of (HCO3)- ion formation in reaction #3 exceeds the rate of (CO3)-- ion formation in rection #2. Under these circumstances the (HCO3)- ion concentration in the ocean water rises and the (CO3)-- ion concentration drops preventing CaCO3 formation via reaction #4. Thus one of the more immediate consequences of continued combustion of fossil fuels is extinction of marine life that relies on CaCO3 for production of bone or shell material.

Observations of ocean acidification via the distribution of CaCO3 on the ocean floor and via dissolved CO2 concentration are complicated by the natural flux of CO2 and CaCO3 through the ocean. Atmospheric CO2 preferentially dissolves in the ocean in cold near polar waters and comes out of solution in warm tropical waters. Thus, even with no combustion of fossil fuels the concentration of dissolved CO2 and the rate of deposition of CaCO3 on the ocean floor varies widely with latitude and water temperature. The practical way to observe and quantify ocean acidification is via precise measurements of ocean water pH using sophisticated chemical instrumentation. However, due to the complexity of the required instrumentation there are limited available ocean pH data sets.

Japan has long recognized the importance of ocean pH to fish and has carefully monitored Pacific Ocean pH at various points since about 1980. After the trend of decreasing ocean pH became obvious the Japanese ocean pH monitoring program was expanded in 1995. Japanese ocean pH data alerted the world to the link between atmospheric CO2 concentration and ocean pH. This issue, now called Ocean Acidification, was the subject of a world conference in Monaco in October 2008. That conference resulted in the Monaco Declaration On Ocean Acidification dated January 30, 2009.

Prior to the year 2008, the Scripps Institute of Oceanogrpahy confirmed by experiment that an ocean pH below 8.0 would prevent bone and shell formation in many marine organisms. Prior to 2008 the bulk ocean pH was still sufficiently high that ocean acidification was not an immediate threat.

While the ocean volume is very large the amount of CO2 dissolved in the ocean due to combustion of fossil fuels is also large and the fraction of CO2 in ocean water necessary to significantly lower the ocean pH is relatively small. The rate at which CO2 dissolved in the ocean is removed by formation of insoluble CaCO3 is much smaller than is the present rate of CO2 absorption by the ocean. Hence there is an increasing accumulation of (HCO3)- ions in ocean water. The mass of CO2 dissolved in ocean water via the reaction:
CO2 + H2O > H+ + (HCO3)-
is comparable to and follows the mass of CO2 in the atmosphere, which mass is constantly increasing. The increase in ocean (HCO3)- ion concentration is revealed via precise measurement of the pH of ocean water.

Note that historically the ocean pH was about pH = 8.20 and that an ocean food chain collapse occurs at a pH values below pH = 8.00.

To demonstrate the extent of the bulk ocean acidification problem it is necessary to plot ocean pH as a function of time over a period of decades. The following Jaspanese bulk ocean pH data was provided to this author by Dr. Alexander Cannara of Menlo Park, California. His contact information is:
Email: cannara@sbcglobal.net, Telephone: 650-400-3071

Cannara Supplied Data:
Japanese Pacific Ocean pH data

The following ocean pH information was provided to this author by Mr. Alex Rhodes, of Victoria, British Columbia, formerly a principal of the whale watching company Seacoast Expeditions:
Ocean pH data from an off-shore buoy by Washington State
US Ocean pH Data
Ocean Networks Canada

Ocean pH measurements made at Cambridge Bay, Nunavut in the high Arctic, during the period 2016 to 2019, show the following ocean pH as a function of time:


US ocean pH measurements made in 2014 near Prince Rupert, which is adjacent to the southern tip of the Alaska panhandle, show the following pH as a function of time:

The above data shows that near Prince Rupert in the later part of 2014 the ocean pH decreased to the point of causing a local ocean food chain collapse.

Available ocean pH measurements in the Salish Sea between Vancouver and Victoria show the following pH measurements as a function of time:

The Marine Technology Centre is near the Vancouver Island Swartz Bay ferry terminal, north of Victoria.

The recent pH data for the Salish Sea consistently indicates a pH of consistently less than 8.00 corresponding to a local ocean food chain collapse. This data explains the precipitous decline in the salmon population and the failure of resident orcas to successfully reproduce during recent years.

The US data from the buoy at La Push off the coast of Washington State shows a trend of gradually decreasing pH in the deep ocean off the coast of Washington State.

If present trends continue the Japanese data provided by Dr.Alexander Cannara and the data from the ocean buoy at La Push (Washington State) show that most major ocean fish species will be extinct before the year 2050. This extinction will be the result of acidification of ocean water caused by the increased atmospheric CO2 concentration. The relatively low ocean turnover in the BC Inside Passage, including the Salish Sea, exacerbates the ocean acidification problem. In the bulk Pacific Ocean part of the absorbed CO2 diffuses into the deep ocean. In the BC Inside Passage the average depth is of the order of (1 / 10) the depth of the main Pacific Ocean, so the absorbed CO2 is more concentrated, making the pH significantly lower than in the bulk ocean.

A 5 minute summary of Ocean Acidification presented by Dr.Alexander Cannara in 2015

A 56 minute lecture on Ocean Acidification and related chemistry presented in January 2009 by Dr. Andrew Dickson, a Scripps Institute marine chemist.
This video contains scanning electron microscope photos which demonstrate that at an ocean pH of less than 8.00 many marine organisms can no longer maintain bone and shell material. Note: The change from ocean pH = 8.15 to ocean pH = 8.05 represents a 25% increase in ocean acidity due to CO2 absorbed since 1980.

Ocean acidification is a major problem because the simple marine organisms directly impacted by a decrease in ocean (CO3)-- ion concentration are near the bottom of the ocean food chain. These simple marine organisms are the main source of food for small fish which in turn are the main source of food for larger fish which in turn are the main source of food for large marine mammals such as orcas and are an important source of food for land animals such as bears and humans. Bear excrement is an important source of micro-nutrients in many forests.

As the atmospheric CO2 concentration rises the ocean (CO3)-- ion concentration rapidly falls which causes the simple marine organisms to die, which leads to death by starvation species further up the food chain including fish, marine mammals, bears and ultimately humans. Ocean pH measurements indicate that there has been ocean starvation in the British Columbia Inside Passage since about 2014. If present trends continue Japanese data indicates that most major fish species in the bulk ocean will be extinct by the year 2050.

There is presently a rapid decline in wild fish stocks on both the east and west coasts of Canada. On the west coast ocean food chain starvation has caused a precipitous decline in the wild salmon population which has directly impacted the population of large marine mammals such as orcas. There is no practical remedy for this ocean acidification problem other than leaving fossil fuels in the ground.

Chemically correcting the ocean pH, even just in Canadian inshore waters, would require a fleet of nuclear reactors and many cubic km of mined material. The unwillingness of governments to face the reality and consequences of rising atmospheric CO2 concentration is rapidly leading to a human disaster. Much of the human population of south east Asia relies on sea food protein. As sea food protein supplies collapse there will be forced migration of about a billion people, many of whom will attempt to seek refuge North America.

In Canada the decision by the Canadian supreme court on January 16, 2020 to allow tripling of the capacity of the Transmountain Pipeline, against the will of the elected government of British Columbia, which sought to protect its environment, will quickly cause irreversible destruction of the fishing industry in British Columbia and the US Pacific North West, even without a major maritime bitumen spill. The existing Alberta oil sand production, if continued, will cause a further cumulative reduction in bulk ocean pH which, over about two decades, will drive most major fish species into extinction. The oceans are further threatened by both the increase in tar sand production capacity enabled by the Transmountain Pipeline capacity expansion and by a proposed new major oil sands development known as the Teck Frontier Mine.

Due to the limited ocean turnover in the BC Inside Passage, the pH in the Inside Passage, including the Salish Sea, is significantly higher than in the bulk ocean. By enabling expansion of tar sand oil extraction the courts and the Canadian federal government are permanently sacrificing the BC fishing industry and all it supports in order to realize a few years of oil profits. This is an extremely foolish decision that Canadians will regret for many years to come.

It is equally foolish for Indian bands to take an ownership position in the Transmountain Pipeline. By so doing these Indian bands are enabling their own economic destruction. How can they claim compensation for loss of the salmon fishery and marine mammals when they are owners of the pipeline that in the future will be the main Canadian enabler of ocean acidification?

Some Indian bands have fishing rights protected by treaty. Absent Indian ownership of the Transmountain Pipeline these Indian bands will likely have a strong legal case for long term financial compensation due to federal government enabled destruction of the BC salmon fishery by the Alberta fossil fuel industry.

The prudent thing for all parties to do right now is to cancel the Transmountain Pipeline capacity expansion, close tar sand oil production and obtain the required energy from emission free nuclear power. Unfortunately short term greed seems to be overwhelming long term prudence.

Our Daily Planet
Seattle times
Physics World
University of Technology, Sydney
California Natural Resources
Hakai Magasine
Motherboard Tech By Vice
Carbon Brief
You Tube
Investigate West
Science Daily
The Guardian
Sea-Bird Scientific
A Short History of Ocean Acidification Science

This web page last updated January 31, 2020.

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