VIA Email

September 14, 2015

Wendy Cleland-Hamnett, Director

Office of Pollution Prevention and Toxics

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, NW

Washington, D.C. 20460

Re: American Petroleum Institute Comments on the Center for Biological Diversity 

TSCA Section 21 Petition for Rulemaking Concerning the Regulation of Carbon 

Dioxide

Dear Ms. Cleland-Hamnett:

The American Petroleum Institute (API) respectfully submits these comments on the petition 

from the Center for Biological Diversity (the Petitioner or CBD) for rulemaking pursuant to 

Section 21 of the Toxic Substances Control Act (TSCA), 15 U.S.C. § 2601, et seq., concerning 

the regulation of carbon dioxide (CO2) (“CBD Petition” or “the Petition”). The Petition asks the 

United States (U.S.) Environmental Protection Agency (EPA or “the Agency”) to promulgate

regulations under TSCA Section 6 to protect “public health and the environment from the serious 

harms associated with anthropogenic emissions of carbon dioxide, including ocean 

acidification.” The Petition alternately requests that EPA adopt a rule under TSCA Section 4 to 

require “testing to determine toxicity, persistence, and other characteristics which affect health 

and the environment and are necessary to determine if there is an unreasonable risk of injury to 

health or the environment.”

API represents over 630 oil and natural gas companies, leaders of a technology-driven industry 

that supplies most of America’s energy and supports more than 9.8 million jobs and eight percent 

of the U.S. economy. API members include producers, refiners, suppliers, pipeline operators, 

and marine transporters of oil and natural gas, as well as service and supply companies that 

support all segments of the industry. API and its members are dedicated to protecting human 

health and the environment while developing and supplying energy resources. Over the 2000 -

2012 period, the U.S.-based oil and natural gas industry invested over $165 billion in greenhouse 

gas mitigating technologies.

1

 The most recent data from the U.S. Energy Information 

1 T2 and Associates. Key Investments in Greenhouse Gas Mitigation Technologies from 2000 through 2012 by 

Energy Firms, Other Industry and the Federal Government. (Sept., 2013). Available at: 

Derek D. Swick, PHD

Manager

Regulatory and Scientific Affairs

1220 L Street, NW

Washington, DC 20005-4070

USA

Telephone 202-682-8341

Email swickd@api.org

www.api.org

 
Wendy Cleland-Hamnett

September 14, 2015

Page 2

Administration show that CO2 greenhouse gas emissions from U.S. industry, including oil and 

natural gas companies, have declined and are now below 1990 levels.

I. Summary

API urges EPA to deny the Petition. There are many reasons that compel EPA to deny the 

petition, which API addresses in these comments and summarizes as follows.

• The Petition does not meet the legal standard for granting a TSCA Section 21 

petition for a Section 6(a) rule. The Petitioner has failed to set forth with sufficient 

particularity the facts that EPA is required to consider in deciding whether to issue a 

Section 6(a) rule. The Petition does not present adequate information on industrial 

processes that would be subject to rulemaking, the magnitude of the exposure, the 

benefits of the requested action, the availability of alternatives, or the economic 

consequences of regulation, among other things. The Petitioner is unclear regarding 

whether the requests are focused on the manufacture of CO2 as a commercial product, the 

manufacture of hydrocarbon substances and products, and/or the use of hydrocarbons, 

which results in generation of CO2 byproducts, emissions, and wastes. The Petitioner

fails to explain why it would be efficient and in the public interest to address the 

perceived risks of CO2 emissions under TSCA. It also disregards that TSCA is not 

intended to supplant environmental statutes. There is an unbroken line of precedent 

where EPA has concluded—in response to Section 21 petitions asking the Agency to use 

its Section 6(a) authority to address risks associated with emissions or discharges of 

chemicals to the environment—that it was not necessary or in the public interest to 

proceed with a Section 6 rule under TSCA. 

• The Petitioner has not attempted to conform its request for testing to TSCA, and the 

Petition does not address the applicable TSCA Section 4 findings. No facts are 

provided that would allow EPA to find that the information already available to the 

Agency is insufficient to permit a reasoned evaluation of the health or environmental 

effects of CO2 emissions. The Petition also improperly asks EPA to use TSCA Section 4 

to collect feasibility and cost/benefit data in order to shore up deficiencies in the Petition.

• The Petition’s discussion of current science on ocean acidification is highly 

inaccurate and incorrect in many respects. With these comments, API transmits an 

independent scientific review of the Petition, performed by Golder Associates in 

partnership with the Danish Hydraulic Institute (“Golder Report”).

2 The review 

identifies critical flaws that bring into question many of the major conclusions in the 

http://www.api.org/~/media/files/ehs/climate-change/2013-key-investments-ghg-mitigation.pdf. Accessed on Aug. 

24, 2015. 

2 Golder Associates. Scientific Evaluation of Center for Biological Diversity’s Petition Dated June 30, 2015 

Regarding Ocean Acidification (Sept., 2015). Transmitted as an attachment with this letter and thus incorporated 

into these API comments.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 3

Petition. The Petition refers to only those studies that might support the Petition’s

conclusions; misquotes or overstates certain studies; neglects studies that show lower, 

insignificant, or no impacts, or “positive” biological responses from the effects of ocean 

acidification; and has other deficiencies.

3

• Existing methods are not sufficient to account for pH variability or to project ocean 

acidification rates. The field of ocean acidification study does not yet allow for 

effective evaluation of long-term fluctuations in pH on a broad scale. Thus, the 

assertions in the Petition regarding future ocean pH are not reliable. There is significant 

temporal variability of pH even at single-point coastal locations due to regional changes 

influenced by changes in temperature, ocean circulation, seasonal climate variability, 

pressure, salinity, depth, nutrients, dissolved oxygen, photosynthesis, and respiration, as 

well as stochastic changes due to diurnal tides, seasonal currents, periodic storms, and 

other similar phenomenon. These variables for the most part are not taken into account in 

current long-term models.

• Current science does not support CBD’s assertions that CO2 poses unreasonable 

risk due to a relationship to ocean acidification. The Petition discusses drivers behind 

ocean acidification such as upwelling, but only in the context of negative impacts. 

Multiple factors such as local sources and local hydrographic processes (e.g., upwelling, 

mixing) can affect pH by amplifying or counteracting ocean acidification effects. 

Scientists studying ocean acidification have been able to identify natural processes that 

contribute to local pH variability (including temperature, salinity, nutrients, etc.), but they 

do not understand all the potential natural or site-specific causes of local pH variability, 

nor are they able to allocate or quantify those potential inputs with any measured 

certainty. 

• Many scientific uncertainties remain concerning the consequences of ocean 

acidification and appropriate mitigation strategies. Contrary to the Petitioner’s

assertions about the impacts of ocean acidification, many uncertainties exist regarding the 

effects of ocean acidification on marine life and complex ecosystems, and even less is 

known about the cumulative, lifelong effects of a lower pH environment. As discussed in 

the Golder Report, available ocean acidification studies typically rely on extrapolating 

results from small scale laboratory or in-site observation on individual species, to model 

effects on entire populations without accounting for the interim acclimation changes and 

adaptation that take place in a more gradually changing real world environment.

4

• Ocean acidification is a global process that cannot be significantly affected by 

regulation under TSCA. The action envisioned by the Petitioner would not provide the 

relief it seeks, as TSCA action would not significantly affect global CO2 concentrations.

3 Id.

4 Id.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 4

• EPA has already initiated efforts to better understand ocean acidification. The 

Petitioner’s call for a rulemaking to compel testing ignores the work EPA is already 

doing on ocean acidification. EPA has a technical workgroup tasked with contributing to 

“a better understanding of the scale of the potential impacts on aquatic life, relative 

contribution of drivers and sources, and the most meaningful metrics for assessing 

potential trends.” 5 EPA also actively partners with other agencies to identify and fill 

data gaps and looks for ways to comprehensively deepen its understanding of the science 

on ocean acidification. The field of research on ocean acidification is relatively young, 

and it is most appropriate that EPA focus its efforts at this time on understanding and 

advancing the science.

• Therefore, API urges EPA to deny the Petition.

The points above are discussed in the remainder of this letter and its attachments. These 

comments make clear that there is neither legal nor scientific support for granting the CBD 

Petition.

II. The Petition does not meet the legal standard for granting a TSCA Section 21 

petition.

A. The showings required in a petition to initiate rulemaking under Section 6 of 

TSCA

Section 21(b)(1) of TSCA requires that the petition “set forth the facts which it is claimed 

establish that it is necessary to issue” the rule or order requested.6 TSCA Section 21 implicitly 

incorporates the statutory standards that apply to the requested actions. Accordingly, a valid

petition requesting a rulemaking under TSCA Section 6(a) must contain all of the information 

needed by EPA to find that there is a “reasonable basis to conclude that the manufacture, 

processing, distribution in commerce, use, or disposal of a chemical substance or mixture, or that 

any combination of such activities, presents or will present an unreasonable risk of injury to 

health or the environment.”7 

Under TSCA Section 6(c), EPA is required to consider when promulgating a Section 6(a) rule: 

(A) the effects of such substance or mixture on health and the magnitude of the exposure 

of human beings to such substance or mixture, 

(B) the effects of such substance or mixture on the environment and the magnitude of the 

exposure of the environment to such substance or mixture, 

5 Letter from Nancy Stoner, Acting Administrator EPA, to Miyoko Sakashita, CBD. (May 17, 2013). 

6 15 U.S.C. § 2620(b)(1).

7 Id. at § 2605(a).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 5

(C) the benefits of such substance or mixture for various uses and the availability of 

substitutes for such uses, and 

(D) the reasonably ascertainable economic consequences of the rule, after consideration 

of the effect on the national economy, small business, technological innovation, the 

environment, and public health.8

Moreover, if EPA determines that the risk could be eliminated or reduced to a sufficient extent 

by actions taken under another Federal law(s) administered in whole or in part by the EPA, the 

Agency may not promulgate a Section 6(a) rule unless it finds, in the Agency’s discretion, that it 

is in the public interest to protect against the risk under TSCA.9 In making this determination, in 

summary, EPA must consider: 

(i) All relevant aspects of the risk, as determined by the EPA in the Agency’s discretion; 

(ii) A comparison of the estimated costs of complying with actions taken under TSCA 

and under the other EPA-administered law(s); and 

(iii) The relative efficiency of actions under TSCA and under the other EPAadministered law(s) to protect against such risk of injury.10

B. The showings required in a petition to initiate rulemaking under Section 4 of 

TSCA

The Petitioner must show that there are insufficient data and experience on the health or 

environmental effects of a particular chemical or mixture.11 The petitioner also must show that 

the testing requested will actually fill the data gap. In short, there must be a scientific need for 

the data in order for EPA to conduct a reasoned evaluation of the health or environmental effects 

of the chemical at issue. If there is scientific uncertainty as to how the tests are to be conducted, 

the Petitioner must develop appropriate scientific guidelines for such testing.12

III. There are numerous legal deficiencies in the petition.

A. The Petition does not provide support for action under TSCA Section 6(a).

EPA cannot promulgate Section 6(a) rules in isolation. Carbon dioxide is emitted as a byproduct 

of industrial processes. Any Section 6(a) rule would need to be process-specific. The statutory 

findings made concerning the magnitude of the exposure, the benefits, the availability of 

8 Id. at § 2605(c)(1)(A)-(D).

9 Id. at § 2605(c)(1).

10 Id. at § 2605(c)(1)(i)-(iii).

11 Id. at § 2603(1).

12 Citizens for a Better Environment v. Reilly, No. 85C8000, 1991 WL 95040, at p. 5 (N.D. Ill. May 24, 1991).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 6

alternatives, and the economic consequences of regulation would need to be process-specific. 

Indeed, given the findings that EPA is required to make in order to promulgate Section 6(a) 

rules, it would not be possible for EPA to issue such rules to cover CO2 emissions from broad 

industry sectors. However, the Petition asks that EPA do precisely that by referencing broad 

segments of the economy such as energy suppliers, industry, land use and forestry, agriculture, 

transportation, commercial and residential buildings, and waste and wastewater.13 It does not 

identify with specificity the discrete industrial processes that generate CO2 emissions and would 

be the subject of the requested rulemaking.

Similarly, the Petition fails to describe with sufficient particularity the magnitude of CO2

emissions from discrete industrial processes, demonstrate that regulation of any specific 

industrial process under TSCA would have a significant benefit, and set forth sufficient facts 

bearing on the risk reduction that would be achieved from regulation of any given industrial 

process. Most significantly, aside from generalization to the effect that many industries could 

achieve meaningful emission reductions “affordably,”14 the Petition provides no information that 

would allow EPA to ascertain the economic and other social consequences of regulatory action 

under TSCA Section 6(a). 

EPA has properly denied other TSCA Section 21 petitions on the basis that the petitions 

provided insufficient information on the cost, degree of availability of alternatives, and potential 

to reduce risk of unspecified risk management action.15 These factors are integral to EPA’s 

assessment of whether a rulemaking under TSCA Section 6(a) is necessary and, even more 

fundamentally, the Agency’s assessment of whether a particular risk is in fact an unreasonable 

risk. The deficiencies in the CBD Petition cannot be cured by asking that the cost/benefit data 

needed to make an unreasonable risk finding be developed under TSCA Section 4.

The Petitioner also fails to explain why they believe it would be efficient and in the public 

interest to address the perceived risks of CO2 emissions under TSCA. The Agency’s discretion 

in deciding such matters is not subject to judicial review.16 The Petition also does not make a 

showing that existing regulations are not adequately addressing CO2 emissions. One of 

Congress’ major concerns in drafting TSCA was to avoid overlapping or duplicative regulation 

of chemicals.17 TSCA is not intended to supplant environmental statutes that are designed to 

address combustion byproducts. To conclude otherwise would read Section 6(c)(1)(i)-(iii) out of 

the statute.

13 Petition at p. 5.

14 Petition at p. 30.

15 See EPA’s Denial of Petition Concerning Discarded Polyvinyl Chloride, 79 Fed. Reg. 64,722, 64,725 (Oct. 31, 

2014).

16 Senate Conf. Rep. (1976). S. Rep. No. 94-1302 at p. 76.

17 House Committee on Interstate and Foreign Commerce, 94th Congress, 2d Session, Legislative History of the 

Toxic Substances Control Act. (Committee Print; Dec., 1976). pp. 167, 197. 

 
Wendy Cleland-Hamnett

September 14, 2015

Page 7

There is an unbroken line of precedent where EPA has concluded—in response to Section 21 

petitions asking the Agency to use its Section 6(a) authority to address risks associated with 

emissions or discharges of chemicals to the environment—that it was not necessary or in the 

public interest to proceed with a Section 6 rulemaking under TSCA. For example, in the case of 

Central Michigan Citizen’s 1983 Petition to address risks from contaminated wastes at a Dow 

facility in central Michigan, EPA concluded that the issue was more appropriately addressed 

under other Federal law(s) rather than TSCA Section 6.

18

Even where EPA has initially considered promulgating a TSCA Section 6(a) rule on its own 

initiative, it has ultimately concluded that regulation under another of its statutory authorities 

would be more appropriate. For example, in 1991, EPA considered issuing a proposed TSCA 

rule to regulate dioxin levels in land-applied mill pulp and paper sludge, but ultimately decided 

to proceed under its Resource Conversation and Recovery Act (RCRA) authority.

The Courts have upheld EPA’s decision not to proceed under TSCA in light of the other 

statutory authorities available to the Agency. In Environmental Defense Fund v. Thomas, 657 F. 

Supp. 302 (1987), the District Court upheld EPA’s denial of a petition to regulate the disposal of 

dioxin-contaminated wastes because such wastes were more appropriately managed under other 

Federal laws. 

The Petition contains little that would guide the Agency’s exercise of discretion in this area. It

does not include a comparison of the estimated costs of complying with actions taken under 

TSCA and under other EPA-administered law(s). The Petition also does not discuss the relative 

efficiency of actions under TSCA and under the other EPA-administered law(s) to protect 

against the perceived risks associated with CO2 emissions.

Finally, although industrial/commercial product uses of CO2 are not the primary subject of the 

TSCA Section 21 Petition, the Petition mentions that CO2 is produced for commercial purposes 

including for uses in fertilizer, beverage carbonation, dry ice, refrigeration, pressurization, fire 

extinguishment, and packaging.19 The Petition provides no information that would allow EPA to 

conclude that emissions of CO2 from such products pose an unreasonable risk.

18 48 Fed. Reg. 33,739, 33,744 (Jul. 25, 1983). See also 49 Fed. Reg. 43,764, 43,765 (Oct. 31, 1984) (EPA’s denial 

of 1984 petition by Citizens for a Better Environment and Irondalers Against the Chemical Threat to issue a TSCA 

Section 6 rule to control unreasonable risk from multiple toxic substances from multiple sources through the air, 

land, and water where EPA concluded that other Federal laws could adequately address the issues raised in the 

petition and were more appropriate than TSCA.) See also 54 Fed. Reg. 52,993 (Dec. 26, 1989) (The 1989 petition 

by Browning-Ferris Industries (BFI) to specify the types of materials to be used in constructing monitoring wells at 

PCB disposal facilities where EPA stated it would be neither necessary nor productive for it to develop TSCA rules 

for PCB disposal facilities in light of the then on-going Office of Solid Waste and Emergency Response (OSWER) 

efforts to establish standards for monitoring well construction.)

19 Petition at p. 6.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 8

B. The Petition does not set forth sufficient facts for EPA to find a TSCA 

Section 4 rule is warranted.

Apparently anticipating that EPA might deny its request to issue a TSCA Section 6 rule, the 

Petitioner asks EPA to alternatively adopt a rule under TSCA Section 4 to require manufacturers 

and processors to:

• test CO2 reduction strategies;

• conduct a vulnerability assessment for marine and coastal species and ecosystems;

• forecast species’ responses to ocean acidification using modeling tools; and

• determine the economic values of ecosystems that are [allegedly] at risk from ocean 

acidification and the costs of reducing CO2 emissions to preserve those ecosystems.20

TSCA Section 4 test rules are limited to filling data gaps where there are insufficient data or 

experience to determine the “effects” of commercial activity concerning a substance or mixture 

“on health or the environment” provided that testing is necessary to fill the gaps. TSCA Section

4 test rules are not for the purpose of compelling projects to address the type of research 

questions enumerated in the Petition. Further, the Petition is unclear regarding whether the 

requests are focused on the manufacture of CO2 as a commercial product, the manufacture of 

hydrocarbon substances and products, and/or the use of hydrocarbons, which results in 

generation of CO2 byproducts, emissions, and wastes. It contains no reasoning on what entities 

could be required to do such testing under TSCA authority. 

The Petitioner does not attempt to conform its request to TSCA—it does not address the 

applicable TSCA Section 4 findings. The Petition provides no facts that would allow EPA to 

find that the information already available to the Agency is insufficient to permit a reasoned 

evaluation of the health or environmental effects of CO2 emissions. To the contrary, the Petition 

purports to set forth in detail what the Petitioner asserts is an extensive body of scientific 

support. The Petitioner has failed to provide a persuasive rationale as to why conducting a 

vulnerability assessment or forecasting species’ responses to ocean acidification is necessary to 

fill data gaps. Moreover, if promulgating a test rule, EPA is required to specify “[s]tandards for 

the development of test data” in the case of a single-phase test rule,21 or “[a] reference to 

appropriate guidelines for the development of test data” in the case of a two-phase test rule.

22 

The Petitioner has cited no testing standards or appropriate test guidelines for conducting the 

requested vulnerability assessment or forecasting of species’ responses to ocean acidification. 

As the Court in Citizens for a Better Environment v. Reilly has admonished, a petitioner must 

20 Petition at p. 36.

21 40 C.F.R. § 790.40(b)(iv).

22 Id. at § 790.40(2)(iv).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 9

develop appropriate scientific guidelines for its proposed testing in order for the petitioner 

to sustain its claim that EPA should promulgate a Section 4 test rule.

23

The suggested testing of CO2 reduction strategies and the development of cost/benefit 

information is outside the scope of TSCA Section 4, as this information does not relate to the 

health or environmental effects of CO2. Rather, CO2 reduction strategies and cost/benefit 

information are part of the showing that the Petitioner needs to make concerning the economic 

consequences of a TSCA Section 6(a) rule. The purpose of TSCA Section 4 is not for EPA to 

collect feasibility or cost/benefit data in order to shore up deficiencies in a Section 21 petition.

IV. Current science does not support CBD’s assertions that CO2 poses unreasonable 

risk due to a relationship to ocean acidification.

Ocean acidification refers to the decrease in the pH of the oceans caused by the uptake by 

seawater of CO2 from the atmosphere.24 More precisely, once dissolved in seawater, CO2 reacts 

with water to form the bicarbonate ion, HCO3

- (a weak base) and to yield the H+ ion (proton).25 

Seawater (from the surface down to a depth that varies with local conditions) is naturally 

supersaturated with a related stronger base, the carbonate ion (CO3

-2

), which acts as a buffer by 

neutralizing some of the protons forming more bicarbonate ions. The net reaction is: CO2 + H2O 

+ CO3

-2

→ 2HCO3

-

.

26 As not all of the protons from the initial CO2 absorption reaction are so 

neutralized, the local proton concentration increases and the local ocean pH slightly declines as a 

result. The magnitude of these chemical changes depends on local conditions, varying with 

depth, distance from shore, temperature, local seawater chemistry, atmospheric CO2

concentration, biological activity, and other factors such as seawater mixing patterns.

The CBD Petition does not support the conclusion that CO2 poses an unreasonable risk of injury 

to health or the environment based on harm from ocean acidification. The sections below 

explain why the assertions of the Petition are not supported by current science. Science also 

does not support the notion that any type of TSCA regulation would significantly affect ocean 

acidification processes. EPA has already committed to work to better understand the science of 

ocean acidification and its impacts, and API supports the Agency’s efforts in that regard.

A. The Petition’s discussion of current science on ocean acidification is highly 

inaccurate and incorrect in many respects.

23 Citizens for a Better Environment v. Reilly, No. 85C8000, 1991 WL 95040 (N.D. Ill. May 24, 1991), emphasis 

added.

24 Memorandum from Denise Keehner, Director, Office of Wetlands, Oceans, Watersheds, EPA to Water Division 

Directors, Regions 1-10, entitled Integrated Reporting and Listing Decisions Related to Ocean Acidification. Nov. 

15, 2010. (“2010 EPA Memo”).

25 A small fraction of the dissolved CO2, about 0.12 percent on a molar basis in seawater, reacts with water to form 

carbonic acid, H2CO3. In equilibrium calculations, convention is to consider non-ionized CO2 as the sum of 

dissolved CO2 and non-dissociated H2CO3, which reacts with water to form HCO3

-

as noted. 

26 See: http://theotherco2problem.wordpress.com/what-happens-chemically. (Accessed on Aug. 24, 2015).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 10

The Golder Report, transmitted as an attachment as part of API comments, identifies many

critical flaws that bring into question the major assertions in the Petition. It is clear that the 

Petition does not constitute adequate scientific information to provide or lead to a reasonable 

basis to conclude that there is an unreasonable risk of injury to health or the environment from 

ocean acidification due to CO2 emissions.

The Golder Report enumerates many instances of deficiency and mischaracterization in the 

Petition, including but not limited to the following:

• The Petition draws on only selected literature that shows the highest adverse

impacts. It entirely ignores study results that show lower, insignificant, or no impacts; or 

“positive” biological responses from the effects of ocean acidification.

27 This 

exaggerates the magnitude and scale of ocean acidification. As counterexamples, the 

Golder Report includes twenty-eight examples of recent peer-reviewed papers (2010-

2015) showing lower, insignificant, or no impacts; or “positive” biological responses

from the effects of ocean acidification on marine life, and which are not included in the 

Petition.28

• The Petition selects studies with maximal impacts and misquotes or overstates study 

results. The Golder Report includes six examples of studies cited in the Petition for 

which the Petitioner exaggerates ocean acidification studies by selecting studies with

maximal impacts, or by misquoting or overstating study results.

29

• The Petition does not appropriately discuss the uncertainties, inappropriate 

experimental designs, and low statistical power present in the majority of studies. 

The Golder Report includes a brief review of publications on ocean acidification, 

showing that 50% to 60% of the publications focused on “impacts” to species (ranging 

from single cell organisms to vertebrates), populations, and communities.30 

Approximately 25% of the impact studies are based on observational in situ data (e.g.,

coral bleaching, coral and shell corrosions/dissolutions) combined with either site 

observations of pH, dissolved CO2, or trends in such variables along with atmospheric 

27 Golder Report at pp. 1-2.

28 Id. at Appendix A for abstract summaries of the studies. The Petition offers only studies with negative impacts of 

ocean acidification on marine animals such as molluscs, echinoderms, crustaceans, corals, plankton, ceplopods, and 

fish. The Golder Report includes other studies that suggest variations as summarized in Appendix A. For example, 

one study found gastropods T. japonicus (type of mollusc) showed high resistance to elevated pCO2 throughout the 

life cycle (Kita et al., 2013). Another study’s field and laboratory data in combination suggest that ocean 

acidification levels up to a pHT of 7.8 will have little effect on the sensitivity of tropical corals to thermal bleaching 

(Noonan et al., 2015). One study’s results suggest that long-term acclimation or adaptation could change or even 

reverse negative calcification responses in E. huxleyi (type of plankton) and its feedback to the global carbon cycle 

(Benner et al., 2015).

29 Id. at Appendix B. 

30 Id. at pp. 2-3.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 11

pCO2 obtained from other sites.”31 By their very nature, these studies have a high degree 

of uncertainty because multiple confounding factors such as local sources are ignored.

32

The other 75% of impact studies are experimental in nature, ranging from phytoplankton 

growth experiments carried out in small containers to large mesocosms (i.e., experimental 

tools used rarely, which incorporate a small part of the natural environment where 

conditions such as pH, pCO2

33, temperature, salinity, light, and mixing can be 

controlled).

34 The quality of these studies is at best questionable because of incomplete 

experimental conditions and designs and poor documentation of exposure conditions.35 

Furthermore, meta-analysis of ocean acidification experiments also have limits in terms 

of “uncritical reliance on the available body of published studies,” leading to exaggerated 

ocean acidification effects due to so-called “publication bias.”36 The Petition disregards

that the natural variation in pCO2 and pH in coastal waters often exceeds the projected 

change and findings in experiments.37

• The Petition disregards that ocean models do not accurately predict future pCO2

and pH in coastal waters and on the continental shelf, because there are key

influences not included in the models (e.g., from watersheds, local sources etc.).

Future ocean pH has little influence on coastal habitats. The Golder Report notes that 

several examples of the ocean acidification impacts claimed in the Petition are based on

examples from coastal or shelf waters.38 The Petition neglects that pCO2 and pH 

variation and trends in coastal waters differ profoundly from trends in deep ocean 

waters.

39 Many factors influence variations and trends in pH in coastal ecosystems, 

including but not limited to watershed processes, nutrient inputs, changes in ecosystem 

structure and processes, and emissions of SO2 and NOX from international shipping 

activity.

40

31 Id.

32 Id.

33 pCO2 is the partial pressure of CO2 in air, where the dissolved CO2 concentration in the water under consideration 

is in equilibrium with the air. However, since the marine waters under consideration are often not in equilibrium 

with the air, and hence the concentrations of carbonate species in the marine waters is subject to change, pCO2 is 

often used as a convenient alternate measurement to that of dissolved CO2 concentration in marine waters. When 

atmospheric CO2 levels rise, pCO2 typically rises. Along with pH, it is an important parameter for understanding 

carbonate chemistry in marine ecosystems.

34 Id.

35 Id.

36 Id. at p. 4.

37 Id. at p. 1. The Golder Report provides examples of studies that are also discussed below.

38 Id.

39 Id.

40 Id.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 12

• The Petition neglects the potential for physiological plasticity and biological 

adaptation to higher pCO2 and lower pH as demonstrated in recent literature.

CBD’s claim that high CO2 waters injure the growth, survival, fitness, and reproduction 

of marine animals does not take into account a growing number of studies that show 

examples of physiological acclimation and capacity to adapt to higher pCO2 and lowered 

pH.41 Also, in the majority of ex situ experiments, test animals are transferred abruptly 

from control conditions to tanks with reduced pH (increased CO2 concentrations), which 

may create shock effects that are different from effects of a gradual change in seawater 

chemistry, depending on the coping ability of an organism.42 Some studies suggest 

capacity for a physiological acclimation because the sensitivity to lowered pH if certain 

organisms are exposed gradually to lowered pH rather than exposed to an abrupt

change.43

• The CBD Petition includes a bibliography, but the bibliography omits 74 of the 

papers/reports that are cited in the text of the Petition.

44 API believes this is an 

indicator of the overall low quality of the information in the Petition, which clearly is an 

insufficient basis on which to initiate any TSCA action.

API refers to the attached Golder Report for full discussion of the above and additional serious 

problems with the assertions in the Petition. 

B. Existing methods are not sufficient to characterize pH variability or to 

project ocean acidification rates.

As EPA has noted, “the majority of the States do not have detailed monitoring protocols, 

assessment methods, or the high-resolution equipment needed to measure and implement the 

marine pH criteria.”45 EPA has stated, “in most coastal regions data are not readily available to 

characterize short-term marine pH diurnal and seasonal variability, or to quantify a normally 

occurring pH ‘baseline’ necessary to identify variation from natural and any long-term trends.”46 

Monitoring is key to understanding the fundamental processes that occur in complex coastal 

ecosystems. Of those processes, pH is a key variable that needs to be monitored in order to 

understand carbonate chemistry in such waters. 

There are significant limitations on pH measurement techniques. Defining baseline pH 

conditions and measuring the potential impacts of ocean acidification require technology that, at

41 Id. at pp. 4-5.

42 Id. at p. 4.

43 Id.

44 Id. at Appendix C for a complete listing of references cited in the Petition text but not found in the bibliography.

45 The National Research Council, Ocean Acidification: A National Strategy to Meet the Challenges of a Changing 

Ocean. (2010) at p. 4.

46 Id. citing NRC, 2010.

 
Wendy Cleland-Hamnett

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a minimum, has an ability to detect and accurately measure the pH changes that are estimated to 

be occurring or projected to occur. Estimates suggest ongoing pH changes of approximately 

0.002 pH units per year,

47 which is far below what can be routinely and accurately monitored 

through existing technology. Although there are recent developments in more accurate pH 

measurements using spectrophotometric methods, they have not yet been widely deployed in the 

field.

48

Relative to the technological limits of monitoring, important additional considerations include 

process control system limitations, electrode limitations, and flow rate variability limitations. 

Field controls are an important factor, including proper temperature control. Temperature and 

contact with atmospheric CO2 can affect the measured pH.49 Therefore, proper field controls are 

essential. Monitoring limitations are even more pronounced when monitoring is used to measure 

changes from baseline pH conditions that are not presently understood in waterbodies that 

experience significant temporal and spatial pH variability, in order to gauge the largely unstudied 

biological responses to such changes. These variability issues are discussed below.

1. Daily/Hourly Variability

There is significant variability in near-shore pH, and it is not possible to definitively determine a 

naturally occurring range of pH, which can vary in a waterbody on a daily or even hourly basis. 

Indeed, in some waterbodies, pH changes of 0.5 units have been reported within a single day. 

Consider the following results from 24,519 measurements spanning eight years of observing 

coastal ocean pH off Tatoosh Island, WA:

First, in contrast to the historical perspective that the ocean is well buffered, pH 

exhibited a pronounced 24-hour cycle, spanning 0.24 units during a typical day . . 

. This diurnal oscillation is readily explained by daily variation in photosynthesis 

and background respiration: water pH increases as CO2 is taken up, via 

photosynthesis, over the course of the day, and then declines as respiration and 

diffusion from the atmosphere replenish CO2 overnight . . . Second, pH 

47 Friis, K., et al. (2004). Spectrophotometric pH Measurement in the Ocean: Requirements, Design, and Testing of 

an Autonomous Charge-Coupled Device Detector System. Limmol. Oceanogr.; Methods Vol. 2. pp. 126-136 ("The 

increase of surface water due to the pCO2 uptake of atmospheric pCO2 drives a pH decrease of about 0.002 pH 

measurements is therefore of the same order." p. 126).

48 Abmann, S., et al. (2011). Spectrophotometric High-Precision Seawater pH Determination for Use in Underway

Measuring Systems. Ocean Sci.: Vol. 7. pp. 597–607.

49 “Because pH is dependent upon temperature, the temperature of the pH sample must be carefully controlled, or at 

least accurately measured before pH is determined. In addition, the pH of a seawater sample changes as CO2 is lost 

or gained on contact with the atmosphere. This is a concern particularly with deepwater samples where CO2 

concentrations are high. It is therefore important that samples be drawn as soon as possible after arrival of the 

rosette on deck. Furthermore, contact with the atmosphere should be avoided during sampling and sample bottles 

should remain tightly sealed until pH measurements are made.” Available at:

http://hahana.soest.hawaii.edu/hot/protocols/chap23.html. (Accessed on Aug. 24, 2015).

 
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September 14, 2015

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fluctuated substantially among days and years, ranging across a unit or more 

within any given year and 1.5 units over the study period.50

The National Oceanic and Atmospheric Administration (NOAA) has recently begun collecting 

time-resolved data on pH in addition to pCO2 at certain moorings in open ocean waters of the 

Pacific and coastal waters of the U.S.51 While the dataset is limited, the pH measurements 

indicate variability.52 As noted by Sutton et al.:

In 2010 we began equipping coastal moorings currently measuring pCO2 with pH 

and other biogeochemical sensors to measure ocean acidification parameters at 3

hour intervals in the surface water. Here we present the magnitude and diurnal to 

seasonal variability of pCO2 and pH during the first year of observations at 2 sites 

in the Atlantic and Pacific coastal margins of the U.S.—the Gulf of Maine and 

outer coast of Washington state.

53

See Figures and accompanying quotes below.54

Both the magnitude and range of pCO2 and pH values were greater at the coastal 

sites (Gulf of Maine and La Push) compared to open ocean Station Papa and also 

varied between coastal sites (Table 1). The range of pCO2 and pH values during 

50 Wootton, J.T., et al. Dynamic Patterns and Ecological Impacts of Declining Ocean pH in a High-Resolution 

Multi-Year Dataset. (2008). PNAS. Vol. 105. No. 48. p.18848.

51See: http://www.pmel.noaa.gov/co2/story/OA+Observations+and+Data. (Accessed on Aug. 24, 2015).

52 NOAA’s pH measurements for select sampling sites are reproduced in Attachment 2 to these comments. A full 

set of current data for all 21 mooring sites can be accessed at:

http://www.pmel.noaa.gov/co2/story/OA+Observations+and+Data.

53 Sutton, A.J., et al. (2011). Natural Variability of pCO2 and pH in the Atlantic and Pacific Coastal Margins of the 

U.S. American Geophysical Union. OS33B-1650.

54 Id.

 
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the coastal time series were as much as 4.5 times the range observed at Papa. We 

observed pCO2 and pH values in coastal waters predicted to occur in the open 

ocean at 2x pre-industrial CO2 levels . . .55

Only a few studies in coastal systems have documented short-term variability of 

carbon chemistry and the factors governing ocean acidification variability 

(Cullison et al., 2011 and Yu et al., 2011). The largest variance we observed in 

pH and pCO2 occurred at the La Push mooring off the Washington coast in 

September 2010. Values fluctuated as much as 200 uatm pCO2 and 0.2 pH 

between 3-hour cycles and >300 uatm pCO2 and 0.5 pH within one day (Figure 

3). Much of the variability at this site is likely due to a combination of high 

biological productivity and strong winds that can drive localized upwelling. 

Although seasonal fluctuations are apparent in the Station Papa time-series, 

values remained stable during this short time period.56

Researchers at Duke University have noted that “estuary systems in general and the US East 

Coast in particular are poorly characterized in terms of the temporal variability of their carbonate 

55 Id.

56 Id.

 
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systems.”57 The researchers found that “changes in pH on sub-year time scales exceed the 

magnitude of long-term projections . . . [0.3 units].”58 They also recorded frequent daily 

variations of ~0.1 units.59 Other very recent studies of near-shore carbonate chemistry have 

similarly identified both the short-term pH variability of such systems and the critical need for 

further research.60

2. Natural Causes of Ocean Acidity Changes and Variability

There are many factors that affect ocean acidity—oceanic uptake of atmospheric CO2 is only

one. This is especially true in coastal waters where there can be many, site-specific, local, or 

regional factors.61 A comprehensive understanding of naturally occurring local or regional 

contributions to ocean acidification and pH variability is important, and presently lacking. As 

noted by Hofmann, et al. (2011):

The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at 

best. While perturbation studies, in the form of incubations under elevated pCO2, 

reveal sensitivities and responses of individual species, one missing link in the 

OA story results from a chronic lack of pH data specific to a given species’ 

natural habitat . . . These observations reveal a continuum of month-long pH 

variability with standard deviations from 0.004 to 0.277 and ranges spanning 

0.024 to 1.430 pH units. The nature of the observed variability was also highly 

site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of 

varying amplitudes.

62 [internal citations omitted, emphasis added]

Hofmann, et al. (2014) subsequently noted that “[f]or coastal regions, the scientific community is 

just now assessing the longer-term variability in pH,” and that, heretofore, “no coordinated innershelf time series were available that would allow evaluation of the frequency, intensity and 

spatial expanse with which coastal ecosystems experience rapid acidification.”63

The importance of natural variability is also noted by Hofmann and others:

57 Johnson, Z.I., et al. (2013). Dramatic Variability of the Carbonate System at a Temperate Coastal Ocean Site 

(Beaufort, North Carolina, USA) is Regulated by Physical and Biogeochemical Processes on Multiple Timescales. 

PLoS ONE 8(12): e85117. p. 3.

58 Id.

59 Id.

60 Waldbusser, G.G., Salisbury, J.E. (2014) Ocean Acidification in the Coastal Zone from an Organism’s 

Perspective: Multiple System Parameters, Frequency Domains, and Habitats. Annual Review of Marine Science 

Vol. 6: 221-247; Hofmann et al. (2014). Exploring Local Adaptation and the Ocean Acidification Seascape –

Studies in the California Current Large Marine Ecosystem. Biogeosciences. Vol. 11. pp. 1053-1064.

61 Golder Report citing the following studies: Duarte et al. (2013) and Hassellȍv et al. (2013) at p. 1.

62 Hofmann, G.E, et al. (2011). High-Frequency Dynamics of Ocean pH: A Multi-Ecosystem Comparison. PLoS

ONE 6(12): e28983. 

63 Hofmann et al. (2014) at p. 1055. 

 
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Recently, a deeper consideration of ecosystem-specific variation in seawater 

chemistry has emerged, one that is pertinent to the study of biological 

consequences of OA. Specifically, assessments of environmental heterogeneity 

present a nuanced complement to current laboratory experiments. The dynamics 

of specific natural carbonate chemistry on local scales provide critical context 

because outcomes of experiments on single species are used in meta-analyses to 

project the overall biological consequences of OA, to forecast ecosystem-level 

outcomes, and ultimately to contribute to policy decisions and the management of 

fisheries. As noted earlier, natural variability in pH is seldom considered when 

effects of ocean acidification are considered. Natural variability may occur at 

rates much higher than the rate at which carbon dioxide is decreasing ocean pH, 

about -0.0017 pH/year. This ambient fluctuation in pH may have a large impact 

on the development of resilience in marine populations, or it may combine with 

the steady effects of acidification to produce extreme events with large impacts. 

In either case, understanding the environmental variability in ocean pH is 

essential.

Although data on the natural variation in the seawater CO2 system are emerging, 

nearly all high-resolution (e.g., hourly) time series are based on pCO2 sensors, 

with comparatively few pH time series found in the literature. From a research 

perspective, the absence of information regarding natural pH dynamics is a 

critical data gap for the biological and ecological arm of the multidisciplinary 

investigation of OA.

64 [emphasis added] [internal citations omitted]

In addition to contributions from nutrient runoff, ocean upwelling is an important contributor to 

local pH levels and the variability of local pH, and it can be highly localized. Feely and others 

have observed that:

To better understand the extent of this ocean acidification in coastal waters, we 

conducted hydrographic surveys along the continental shelf of western North 

America from central Canada to northern Mexico. We observed seawater that is 

undersaturated with respect to aragonite upwelling onto large portions of the 

continental shelf, reaching depths of ~40 to 120 meters along most transect lines 

and all the way to the surface on one transect off northern California. Although 

seasonal upwelling of the undersaturated waters onto the shelf is a natural 

phenomenon in this region, the ocean uptake of anthropogenic CO2 has increased 

the areal extent of the affected area.65 [emphasis added]

64 Hofmann et al. (2011) at p. 2.

65 Feely, R.A., et al. (2008). Evidence for Upwelling of Corrosive “Acidified” Water onto the Continental Shelf. 

Science Vol. 320. p. 1490. Available at: http://www.pmel.noaa.gov/pubs/outstand/feel3087/feel3087.html.

(Accessed Aug. 27, 2015).

 
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September 14, 2015

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More recently, a report by the Congressional Research Service noted the role of several natural 

variables that can affect ocean acidification levels in a localized manner:

All gases, such as CO2, are less soluble in water as temperature increases. Thus, 

marine waters near the poles have a much greater capacity for dissolving CO2

than do ocean waters in the tropics. In addition, dissolved CO2 is transported into 

ocean depths at these high latitudes (i.e., deep water formation mechanism) since 

the lower-temperature waters are of higher density, causing greater convection to 

occur than happens in the more stratified tropical oceans. If temperature were the 

only factor affecting the rate of ocean acidification and its impacts on physical 

and biological features, these impacts might be more likely to occur in marine 

waters nearer the poles. However, in addition to temperature, other factors 

modulate the impact of CO2 on marine waters. Cellular respiration and organic 

decomposition add CO2 to seawater, and photosynthesis removes it. Deep 

oceanic water is enriched in CO2 due to respiration in the absence of 

photosynthesis and, when brought to the surface by equatorial currents (i.e.,

upwelling), can place CO2-enriched seawater in contact with the atmosphere 

where it can absorb even more CO2. Hence, the tropics, and most notably tropical 

coral reefs, are also vulnerable to near-term effects. An additional factor is the 

potential increase in storm activity at higher latitudes, as some climate models 

suggest. CO2 and other acidic gasses such as nitrogen dioxide are also dissolved 

in rainwater. An increase in North Atlantic or western North Pacific storms could 

significantly accelerate the pH decrease of surface ocean waters in these 

regions.66 [internal citations omitted]

Wootton and collaborators have also studied the impact of multiple factors in attempting to 

model ocean pH, as shown in the table and discussion below.67

As noted by Wootton and others describing the results of their study:

66 Upton, H.F. & Folger, P. (Jul. 30, 2013). Ocean Acidification. pp. 1-2. Congressional Research Service. 

Available at: http://www.fas.org/sgp/crs/misc/R40143.pdf. (Accessed on Aug. 27, 2015).

67 Wootton et al. (2008) at p. 18849.

 
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Our data demonstrate that ocean pH exhibits strong dynamic patterns over 

multiple temporal scales, which can be linked to variation in key physical and 

biological drivers with known mechanistic ties to pH. Across years, pH declined 

strongly in association with increases in atmospheric CO2. Over diurnal 

timescales, pH also showed strong systematic variation as a result of the interplay 

between uptake of CO2 via photosynthesis and release of CO2 via respiration. 

Ocean pH also exhibited variability at the seasonal time scale, but these patterns 

were more complex, with some years showing systematic increases and some 

showing systematic declines. This complexity is linked to annual variability in the 

seasonal patterns of drivers of pH . . . Two factors tend to increase pH seasonally: 

atmospheric CO2 declines during the summer as it is removed by terrestrial 

photosynthesis, and increased solar radiation tends to increase water temperature, 

which reduces CO2 solubility. Two other factors tend to decrease pH seasonally: 

phytoplankton frequently decline through the summer . . . reducing 

photosynthetic CO2 uptake, and upwelling generally increases through the 

summer, which brings high concentrations of CO2, arising from subsurface 

respiration, to the surface water, and also offsets seasonal increases in water 

temperature. In general, the effect of upwelling appears to predominate at the 

seasonal scale, but varies strongly among years.68

Researchers studying carbonate system variability in yet another near-shore region (Beaufort 

Inlet, N.C.) very recently reached similar conclusions on the multiple causes of dramatic pH 

variability:

In the oligotrophic open ocean, the larger spatial and temporal scales of physical 

processes in conjunction with the relatively lower biomass and biogeochemical 

activity including photosynthesis and respiration rates result in relatively small 

diurnal and annual variation in pH and DIC.

69 Yet in mesotrophic or eutrophic 

coastal oceans recent observations demonstrate that some ecosystems already 

experience annual or daily pH and DIC variability that vastly exceeds observed or 

predicted long-term change in open ocean regions. This dramatic hourly to 

annual variability in pH in the coastal ocean occurs over a wide range of temporal 

and spatial scales and encompasses physical and biogeochemical drivers 

photosynthesis and respiration and tidal mixing of water masses with different 

fluxes of CO2 (e.g., benthic, atmospheric, low biomass oligotrophic waters, high 

biomass mesotrophic waters). In addition to regular annual and daily cycles, 

episodic weather events increase the flux of fresh water into estuarine systems, 

and alter the carbonate systems at the land-sea interface over multiple timescales; 

68 Id.

69 Dissolved inorganic carbon (DIC).

 
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and this data suggests that coastal ecosystems and organisms already experience 

significant periodic (annual or diurnal) or episodic variability in pH and DIC.70

In sum, the Petition neglects that pH variation and trends in coastal waters differ substantially 

from ocean trends. Available monitoring data and studies have demonstrated that ocean 

acidification is highly variable, with the highest variability in the coastal and near shore region. 

Scientists studying ocean acidification have been able to identify the presence of some natural 

processes that contribute to local pH variability; however, they by no means understand all the 

potential natural or site-specific inputs to local pH variability, nor are they able to allocate or 

quantify those potential inputs.

C. Many uncertainties remain in current science regarding the causes of ocean 

acidification and about the role of various drivers in complex ecosystems.

The Petition includes definitive statements about the causes of ocean acidification without a 

robust discussion of the uncertainties associated with the science of ocean acidification. As 

discussed above, the magnitude of the chemical changes involved depends on local conditions—

varying with depth, distance from shore, temperature, local seawater chemistry, atmospheric CO2

concentrations, seawater mixing patterns, and other factors. Other potential causes of ocean 

acidification include upwelling of CO2-rich deep ocean waters, underwater vents of CO2, 

biological respiration activities, and the effects of river plumes and other land-source impacts in 

coastal waters. In specific locations, almost none of these inputs are fully characterized or well 

understood. 

EPA recently stated:

EPA recognizes that a growing body of research indicates the seriousness of 

global ocean acidification risks and the potential that conditions relate to [ocean 

acidification] may have significant adverse impacts on aquatic life in the coastal 

waters of Washington and Oregon, and elsewhere. However, the science is 

complex – and experts agree that more research and analyses are needed to fully 

understand the sources, causes and impacts of [ocean acidification] in different 

aquatic environments.

71 [emphasis added]

EPA has stated that the science is in the early stages, especially in regard to coastal waters of the 

territorial seas and estuarine waters, and EPA has referenced a number of studies that point to: 

1) significant shortcomings in understanding the effects of ocean acidification, and 2) an “urgent 

70 Johnson (2013).

71 United States's Cross Motion for Summary Judgment and Combined Memorandum in Support of Cross-Motion 

for Summary Judgment and in Opposition to Plaintiff's Motion for Summary Judgment ("United States Cross 

Motion"). Center for Biological Diversity v. EPA, Case No. 13-cv-1866 JLR (W.D. Wash. Aug. 15, 2014). p. 1.

 
Wendy Cleland-Hamnett

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Page 21

need” for more studies of ocean pH dynamics and their underlying causal mechanisms and 

consequences.72

As discussed in the Golder Report, “this inherent variability and its multiple, complex 

associations with pH implies that the concept of ocean acidification caused by anthropogenic 

CO2 emissions cannot be transposed to coastal ecosystems (Duarte et al., 2013).”73 Moreover, 

“[d]epending on the location-specific balance among different drivers, the pH of some coastal 

ecosystems will decline while the pH of others will increase.”74 As examples, the Golder Report 

highlights the following studies:

• In the mid-Atlantic, the pH trends in the Chesapeake Bay differ by season and the 

influence of freshwater (Waldbusser et al. 2011).75

• In Europe, the pH of the Southern North Sea and in the Danish Straits peaked at 8.3 

around 1980-1985 when eutrophication was at the highest level. However, since then pH 

has decreased—at a rate 10 times higher than acidification in the Pacific Ocean—as a 

result of nutrient management actions and a reversal of eutrophication in coastal waters 

(Duarte et al. 2013).76

• Diurnal variation can exceed 1.5 pH units in shallow benthic systems populated by 

seagrass and macroalgae (Duarte et al., 2013; Table 2) underlining that sessile organisms

(i.e., permanently attached to a solid substrate) in such habitats are adapted to short term 

yet recurring variation in pH that majorly exceeds the predicted change in a future 

ocean.77 

In addition, “because of very coarse spatial resolution in oceanographic models (typically 100 

km x 100 km), model predictions of future effects of ocean acidification (including aragonite 

saturation) do not resolve the issue of pH variability found in coastal waters.”78 Ocean

acidification studies typically rely on extrapolating results from small-scale laboratory or in-site 

observation studies on individual species to model effects on entire populations. However, 

multiple factors such as local sources can affect pH and/or local hydrographic processes 

(upwelling, mixing) by amplifying or counteracting ocean acidification effects.79 The Golder 

72 Id. at p. 6; See studies cited in footnote 6.

73 Golder Report at p. 1.

74 Id. at p. 2.

75 Id.

76 Id.

77 Id.

78 Id.

79 Id. at p. 3.

 
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Report finds that one cannot rely on present ocean models to predict future changes in pH and 

aragonite saturation in coastal waters.

80

Scientists studying the ocean acidification issue have been able to identify the presence of some 

natural processes that contribute to local pH variability. However, they do not yet understand all 

the potential natural or site-specific inputs to local pH variability, nor are they able to allocate or 

quantify those potential inputs. 

D. Many scientific uncertainties remain concerning the consequences of ocean 

acidification and appropriate mitigation strategies. 

A significant portion of the CBD Petition focuses on the consequences of ocean acidification and 

makes broad assertions that high CO2 waters injure the growth, survival, fitness and reproduction 

of marine animals, including molluscs, echinoderms and crustaceans; corals; and plankton, 

cephalopods and fish.81 Yet, many scientific uncertainties remain concerning the impacts of 

ocean acidification on marine life and the ecosystem. The Petition fails to consider that 

biological response and associated uncertainty in measured response varies greatly by species 

and stressor. Single-stressor studies have limited value in comparison to studies of the effects of 

multiple stressors in site-specific ambient conditions.

EPA has properly noted that in the case of ocean acidification and associated aquatic life

impacts, information is largely absent or limited at this point in time.82 EPA has referred to a 

2010 report by the National Research Council (“NRC”),83 which concluded that:

[o]verall, the acidification of seawater should prove unfavorable for most 

calcifying organisms, and this is likely to constitute a major negative effect on the 

marine biota. But it must be emphasized that despite extensive research efforts we 

still have a poor understanding of the mechanisms and regulation of the 

calcification process in marine organisms.

84 [emphasis added]

Similarly, discussing the impact of potential acidification on internal pH control and other 

metabolic processes, the NRC stated that:

[t]o date, the state of knowledge concerning the effects of decreasing pH and 

increasing CO2 on most marine organisms is sparse. Although many of the 

underlying physiological mechanisms are understood in some detail, knowledge 

of the metabolic consequences for individual performance remains weak. 

80 Id. at p. 2.

81 Petition at pp. 13-26.

82 EPA 2010 Memo at p. 1.

83 Id. at p. 3.

84 The National Research Council, Ocean Acidification: A National Strategy to Meet the Challenges of a Changing 

Ocean. (2010) at pp. 48-50.

 
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Understanding is particularly poor concerning the sensitivities of various life 

stages of marine organisms . . . Even less is known about the cumulative, lifelong 

effects of a lower pH environment in terms of how it will affect the performance, 

growth, survival, and fitness of individuals, especially when combined with other 

likely stressors.85

The 2010 NRC report also discussed the ecosystem effects of ocean acidification for various 

potentially vulnerable ecosystems, including coastal ecosystems. At the outset, the NRC 

recognized the complexity of such coastal ecosystems: 

[C]oastal ecosystems exhibit naturally high variability in pH and seawater 

chemistry due to biological activity, freshwater input, upwelling, atmospheric 

deposition, and other factors. They are also subject to a diversity of stresses 

caused by human activities, such as organic matter and nutrient inputs, pollution 

by toxic organic compounds and metals, acid rain, sea level rise and other climate 

change effects, and overfishing. The effects of ocean acidification on coastal 

ecosystems may be small relative to the effects of these natural and humaninduced stresses.86 

After providing a summary of the literature through 2010, the NRC concluded: 

However, existing research in coastal ecosystems, as is the case with other 

ecosystems, has been focused on individual organisms, not on the population, 

community, or ecosystem levels. Consequently, it is unknown whether 

populations sensitive to changes in ocean chemistry will be able to adapt through 

behavioral or physiological changes. For example, populations with individuals 

possessing genetic variations that tolerate the expected changes in ocean 

chemistry may result in higher survival or reproductive success because of morerapid-than-expected adaptation to the new conditions . . . It is not known whether 

coastal ecosystems that do not currently experience natural hypoxic and low pH 

events are less susceptible to incremental shifts in regional ocean chemistry due to 

ocean acidification. Areas along the U.S. eastern seaboard, the Gulf of Maine, 

and others have weaker oxygen minimum zones and higher pH waters along 

coastal zones. Organisms inhabiting these ecosystems may tolerate larger shifts 

in ocean chemistry caused by ocean acidification than those in ecosystems 

overlying more hypoxic upwelling waters, but this hypothesis requires study.87 

In part, to address such uncertainties and data gaps in biological responses, the NRC made 

several recommendations in its 2010 report. One key recommendation was:

85 Id. at pp. 51-52.

86 Id. at p. 70.

87 Id. at pp. 71-72.

 
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[T]he National Program should support an adaptive monitoring program to 

identify biological response variables specific to ocean acidification. In the 

meantime, measurements of general indicators of ecosystem change, such as 

primary productivity, should be supported as part of a program for assessing the 

effects of acidification.88

In addition, as part of its recommendation that “federally-funded research on ocean acidification 

should focus on the following eight unranked priorities” the NRC highlighted the need to 

“understand the physiological mechanisms of biological responses,” “assess the potential for 

acclimation and adaptation,” “investigate the response of individuals, populations, and 

communities,” and “understand ecosystem-level consequences.”89 That is, four of its eight 

priorities addressed biological responses.

The NRC work highlights the limits on the current understanding of biological responses to 

ocean acidification, especially on coastal species and ecosystems. There is further discussion in 

a 2011 Intergovernmental Panel on Climate Change (IPCC) document, with extensive U.S. 

authorship.90 Other studies have noted the lack of information on biological responses but also 

found that marine biota seem to be more resilient to ocean acidification than has been previously 

presumed.91

EPA appropriately determined that neither Washington nor Oregon were required to list their 

coastal waters as “impaired” under Section 303(d) of the Clean Water Act for ocean 

acidification. CBD had asked EPA to disapprove Washington’s and Oregon’s lists for failure to 

include waters allegedly impaired by ocean acidification. In considering the lists, EPA reviewed 

and assessed the applicability of each of the 173 studies cited by CBD.92 With respect to 

biological response issues, EPA provided detailed responses to CBD on the inability of 

laboratory and hatchery studies to establish linkages between biological and oceanographic data. 

EPA noted the continued need for more information “on the biological condition within the 

waterbody (e.g., in situ field studies documenting the health of aquatic life populations) or 

88 Id. at p. 7.

89 Id. at pp. 109-110.

90 IPCC Workshop on Impacts of Ocean Acidification on Marine Biology and Ecosystems, Workshop Report. (Jan., 

2011). In particular, see the extensive discussion of biological uncertainties discussed in the Synthesis Plenary 

Report IV-2: Impacts of Ocean Acidification for Individual Organisms: The State of Knowledge, Key Uncertainties, 

and the Way Forward and the Synthesis Plenary Report IV-3: Scaling up to Ecosystems: The State of Knowledge, 

Key Uncertainties, and the Way Forward.

91 Hendriks I.E., et al. (2010). Vulnerability of Marine Biodiversity to Ocean Acidification: A meta-analysis. 

Estuarine Coastal & Shelf Science, 86, pp. 157-164. While the meta-analysis of 372 experimentally evaluated 

responses has been critiqued, it is a comprehensive data review of potential biological responses to ocean 

acidification and, at a minimum, demonstrates that the potential biological responses to ocean acidification remain 

uncertain.

92 Appendix A to EPA Answer in Center for Biological Diversity v. EPA, Case No. 13-cv-1866 JLR (W.D. Wash. 

Jan. 15, 2014).

 
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September 14, 2015

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laboratory studies that are designed to account for natural variability and ecological complexity 

within a particular system.”93 

In its answer to CBD’s complaint challenging EPA’s approval of Washington’s and Oregon’s 

303(d) lists, EPA defended its determinations and, with respect to CBD’s claims, denied that the 

information before it was sufficient to make determinations regarding nonattainment with 

applicable water quality standards.94 In 2014, EPA’s motion confirmed its position:

There were no in situ field studies documenting adverse effects on the health of 

aquatic life populations in either state [Washington and Oregon]. Nor was there 

any other information documenting effects on indigenous populations of aquatic 

life in state waters indicating stressors attributable to ocean acidification. The 

only information available regarding aquatic life in ambient waters under natural 

conditions was inconclusive. CBD relies only upon anecdotal observations, 

laboratory experiments, and data collected at artificial habitats, specifically, onshore oyster seed hatcheries.95

In March 2015, Judge Robart rejected CBD’s arguments and agreed with the EPA: 

The science surrounding ocean acidification and its causes and effects is 

complicated and still-developing. “[I]n an area characterized by scientific and 

technological uncertainty . . . this court must proceed with particular caution, 

avoiding all temptation to direct the agency in a choice between rational 

alternatives.” [citations omitted]. Accordingly, this court will not second guess 

EPA’s decision to require more conclusive evidence before identifying coastal 

waters as acidified-impaired.96

API has reviewed the recent planning documents and reports on ocean acidification by various 

Federal governmental agencies such as the United State Geological Service, NOAA, the National 

Ocean Council, the Interagency Working Group on Ocean Acidification, as well as similar plans 

and reports by various states such as those on the West and Gulf coasts. None of these entities 

have begun to address the need for more sound science on biological responses, both at the 

species, and certainly at the ecosystem level, that can link ocean acidification parameters such as 

pH or pCO2 to biologic outcomes. However, the existence of a multi-agency task group,

including these agencies and their published agendas, makes clear that strategies to address 

marine pH are under consideration.

93 United States Cross Motion at p. 18.

94 Id. 

95 United States’ Combined Memorandum at p. 18. Center for Biological Diversity v. EPA, Case No. 13-cv-1866 

JLR (W.D. Wash. Jan. 15, 2014).

96 Amended Order on Cross Motions for Summary Judgment, at p. 54. Center for Biological Diversity v. EPA, Case 

No. 13-cv-1866 JLR (W.D. Wash. Mar. 2015); citing Ctr. for Biological Diversity v. EPA, 749 F.3d 1079, 1088 

(D.C. Cir. 2014 (quoting Envl. Def. Fund, Inc. v. Costle, 578 F.2d 337, 339 (D.C. Cir. 1978).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 26

While the science is developing over time, there is a growing body of work that is beginning to 

expand out of laboratory settings to study the role adaptation plays in real-time marine 

ecosystems. One study from the West Coast Ocean Acidification and Hypoxia Science Panel 

(“OAH Panel”) examined ocean acidification responses within the California Current Large 

Marine Ecosystem, where there are multiple biotic interactions that are variable and complex, 

instead of in laboratories, and where historically pH responses have been studied in isolation.97 

Importantly, this study addresses major questions “regarding whether marine species currently 

possess functional traits that would allow the tolerance of a changing environment, or whether 

they will be able to adapt to rapidly changing ocean conditions in the future.”98

Hofmann and others (2014) focused on sea urchins and mussels because, in lab experiments, 

those two species experienced differing levels of resilience to pH changes (sea urchins were 

generally resilient and mussels experienced decreased shell growth and strength).99 The field 

studies in the California Current Large Marine Ecosystem found that sea urchins were unaffected 

by increases in pCO2 and, surprisingly, adult mussels of the species Mytilus californianus

showed “faster growth at sites with more extreme exposures to pH.”100 

In its review of scientific literature, the Golder Report finds that experimental studies commonly 

found in ocean acidification research have limited insights into long-term projections of impacts 

because they have failed to taken into consideration variables such as an organism’s capacity for 

physiological acclimation and ability to adapt to varying water chemistry.101 As the Golder 

Report summarizes:

However, the scientists in these primary studies have abruptly exposed today’s 

test organisms to an assumed future seawater chemistry without accounting for 

the interim changes and adaptation periods that would take place in the real world. 

It is therefore not surprising that they “observed” adverse effects including 

increased mortality, reduced growth and calcification rates in short-term 

experiments.102

The Golder Report finds that these sudden transfers—which are found in the majority of in situ

experiments—“may create inherent shock-effects exceeding or overshadowing effects of a 

gradual change in seawater chemistry depending on the coping ability of the organism.”103 In 

fact, “[s]ome studies suggest capacity for a physiological acclimation because the sensitivity to 

lowered pH becomes reduced if certain organisms (e.g., isopod, coralline algae) are exposed 

97 Hofmann et al. (2014) at pp. 1153-1164.

98 Id. at p. 1054.

99 Id. at p. 1057.

100 Id. at pp. 1057-58.

101 Golder Report at pp. 3-5.

102 Id. at pp. 4-5.

103 Id. at p. 4.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 27

gradually to lowered pH rather than exposed to an abrupt change (e.g., Munguea & Alenius,

2013 and Kamenos et al., 2013).”104 

Newer studies also suggest that adaptive evolutionary change can take place across year-todecade timescales:

• Well-calcified morphotypes of coccolithosphore have been found in low pH regions of 

the ocean (Beaufort et al., 2011);

105

• After culturing the wide-occurring coccolithophore Emiliania huxleyi over more than 700 

generations at high pCO2 and elevated temperature, inorganic carbon content, primary 

production, and calcification rate did not differ from present (ambient) conditions 

(Benner et al., 2013);

106

• For benthic invertebrates, recent studies from the California Current Marine Ecosystem 

showed that larvae of a key sea urchin species collected in areas characterized by 

upwelling and variable pCO2 had more resilient metabolic responses to pCO2 than larvae 

from other regions with stable conditions (Kelly et al., 2013);

107 and

• Significant genetic changes were observed in larvae from seven adult populations of sea 

urchins cultured under different CO2 levels. Changes were found in genes for biomineralization, lipid metabolism, and ion homeostasis—gene classes that build skeletons 

and participate in pH regulation (Pespeni et al., 2013).108

While evidence of resilience is welcome, these studies do not come close to fully addressing the 

needed additional research on biological response.109 They are one step toward addressing these 

complex biologic responses within their intricate marine environments. As noted, ocean 

acidification researchers have found, “[t]he effect of Ocean Acidification (OA) on marine biota 

is quasi-predictable at best.”110

104 Id.

105 Id. at p. 5.

106 Id.

107 Id.

108 Id.

109 In May 2013, the Arctic Monitoring and Assessment Programme (AMAP), in conjunction with the Arctic 

Council, issued AMAP Assessment 2013: Arctic Ocean Acidification, which noted that “[t]here is an almost 

complete lack of information on the effects of ocean acidification (in isolation or in combination with other 

environmental stressors) on keystone species and processes in the Arctic. Accordingly, there is an urgent need for 

focused research on the likely impacts of ocean acidification on a range of taxa and processes.” p. 53.

110 Hofmann et al. (2011). See also The West Coast Ocean Acidification and Hypoxia Science Panel, Multiple 

Stressor Considerations: Ocean Acidification in a Deoxygenating Ocean and Warming Climate. (Jul., 2015).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 28

The Petition argues that ocean acidification “may” already be increasing the toxicity of harmful 

algal blooms known as “red tides.”111 Petitioners claim that the increase in the toxicity of 

harmful algal blooms in Southern California may be due, in part, to acidified waters.112 

However, the Golder Report notes two other studies that offer different conclusions:

• A study regarding the effect of pH on growth and domoic acid production by potentially 

toxic diatoms of the genera Pseudo-nitzschia and Nitzschia found an opposite response to 

pH-change: that the domoic acid production and concentration increased with pH 

increase (Lundholm et al., 2004).113

• The 5-year project “A Regional Comparison of Upwelling and Coastal Land Use 

Patterns on the Development of HAB Hotspots Along the California Coast” funded 

through NOAA’s Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) 

Program did not identify ocean acidification as a trigger for Pseudo-nitzschia blooms 

along the California coast.114

Citing two studies that are not in the bibliography, the Petition also asserts that ocean 

acidification can decrease the sound absorption of seawater, causing sounds to travel further with 

potential impacts to marine animals and other marine life sensitive to noise pollution.115 The 

Golder Report finds:

Sound propagation in the ocean is sufficiently complex that sophisticated 

computer models are needed to accurately assess the likely changes in lowfrequency noise levels due to the decrease in sound absorption caused by ocean 

acidification. A realistic calculation indicates that the expected increase in noise 

levels from 1960 to 2250 over the frequency range 50–2000 Hz is likely to be less 

than about 0.2 dB, for a scenario that gives a change in surface pH of 0.7 units 

over that time.116 

The science on the consequences of ocean acidification on marine animals is complex 

and does not support the assertions and conclusions of the Petition. Going forward, more 

carefully planned studies that take into account the effects of physiological plasticity and 

adaptation will provide a fuller understanding of the long-term effects of ocean 

acidification on marine life.

111 Petition at pp. 25-26.

112 Id.

113 Golder Report at Appendix B. 

114 Id.

115 Petition at p. 26.

116 Golder Report at Appendix B.

 
Wendy Cleland-Hamnett

September 14, 2015

Page 29

E. Ocean acidification is a global process that would not be significantly 

affected by TSCA regulation.

The Petition’s notion that there is a need for TSCA regulation because international measures to 

reduce greenhouse gas emissions are inadequate is misguided. Even if EPA had proper reason to 

regulate CO2 emissions under TSCA (which it does not), the action envisioned by the Petitioner 

would not provide the relief it seeks, as TSCA action would not measurably affect global CO2

concentrations.

Carbon dioxide emissions intermix freely in the atmosphere and, regardless of the location of the 

emission point, contribute to the overall global atmospheric CO2 concentration. Actual or 

modeled decreases in ocean pH are the cumulative result of all individual stationary and mobile 

source emissions, as well as all natural source emissions, from every nation in the world. A CO2 

source on the shore of Puget Sound has no more or less potential to harm oysters in the Sound 

than a source in Sichuan Provence, China. Even if the source on Puget Sound and thousands like 

it across the U.S. were able to reduce their CO2 emissions to zero, global increases in CO2 would 

more than make up the difference. The complexity inherent in a phenomenon caused in part by 

cumulative CO2 emissions across the globe is staggering—even more so considering that 

atmospheric CO2 concentration is but one of the many variables that impact ocean pH levels.

F. EPA has already initiated efforts to better understand ocean acidification.

API is aware of EPA’s efforts to better understand and respond to ocean acidification. EPA has 

taken appropriate and reasonable steps to begin to understand research gaps, quantify limitations, 

and inventory its statutory authorities. 

In response to CBD’s 2013 Petition, EPA announced that it was “convening a technical 

workgroup to evaluate data and research regarding water quality parameters most relevant for 

understanding and addressing ocean acidification and its causes.”117 EPA further explained that 

the workgroup will be tasked with contributing to “a better understanding of the scale of the 

potential impacts on aquatic life, relative contribution of drivers and sources, and the most 

meaningful metrics for assessing potential trends.”118 EPA also actively participates in efforts to 

better understand and advance the science of ocean acidification, including in partnership with 

other agencies.

119

As discussed in the sections above, much of the science surrounding ocean acidification and its

causes and impacts on marine life and complex ecosystems is uncertain. The ocean acidification 

research field is relatively young. Challenges include monitoring limitations, pH variability 

117 2013 Letter from Nancy Stoner. 

118 Id. 

119 For example, See Interagency Working Group on Ocean Acidification of the Subcommittee on Ocean Science 

and Technology, Third Report on Federally Funded Ocean Acidification Research and Monitoring Activities (Apr., 

2015).

 
Wendy Cleland-Hamnett

September 14, 2015

Page 30

based on a large suite of localized drivers, vastness of complex marine ecosystems, and 

improperly designed small-scale experiments. Thus, it is most appropriate that EPA focus its 

efforts at this time on understanding and advancing the science.

Regarding the technical workgroup, EPA has not yet provided much public information about it. 

While API supports EPA’s goal of using the technical workgroup to improve its understanding 

of fundamental aspects of ocean acidification, we strongly recommend that the technical 

workgroup conduct its research and proceedings in an open, transparent, and collaborative 

manner that is inclusive of all relevant stakeholders, including industry and the scientific 

community.

V. Conclusion

API supports EPA’s continuing efforts to further develop its understanding of ocean acidification 

and its sources, causes, and impacts. EPA has recognized that the science of ocean acidification 

is complex and uncertain and that more research and analyses are necessary to better understand 

the ocean acidification issue. API urges EPA to deny the CBD Petition. Denial clearly is 

warranted for both legal and scientific reasons, as explained in these comments.

API thanks the Agency for its attention to these comments on this important matter. Feel free to 

contact me with any questions or should you require additional information from API.

Sincerely,

Attachments (2)
ATTACHMENT 1
September 2015

SCIENTIFIC EVALUATION OF CENTER FOR 

BIOLOGICAL DIVERSITY'S PETITION 

DATED JUNE 30, 2015, REGARDING 

OCEAN ACIDIFICATION

REPORT

Report Number 1537019

Distribution:

API

Golder Associates

DHI 

Submitted to:

American Petroleum Institute
September 2015

Report No. 1537019 i

Table of Contents

1.0 BACKGROUND......................................................................................................................................................... 1

2.0 OVERALL EVALUATION OF PETITION .................................................................................................................. 1

3.0 CONCLUSION ........................................................................................................................................................... 5

4.0 CITED LITERATURE................................................................................................................................................. 6

5.0 APPENDICES 

5.1

APPENDIX A

28 examples of recent peer-reviewed papers (2010-2015) showing lower, insignificant, or no impacts; or “positive” 

biological responses from the effects of ocean acidification and which are not included in petition.

APPENDIX B

6 examples in the petition exaggerating ocean acidification effects by selecting studies with maximal impacts; or 

misquoting or overstating study results.

APPENDIX C

List of citations to scientific literature in the text of the petition that are not included in petition’s bibliography.
September 2015

Report No. 1537019 1

1.0 BACKGROUND

On the 30th of June 2015, the Center for Biological Diversity submitted a petition to the U.S. Environmental 

Protection Agency. The petition has been prepared by Donn J. Viviani, PhD requesting actions pursuant to 

section 21 of the Toxic Substances Control Act (“TSCA” or the “Act”), 15 U.S.C. § 2620, and section 553(e) 

of the Administrative Procedure Act (“APA”), 5 U.S.C. § 553(e), “to promulgate regulations protecting public 

health and the environment from serious harms associated with anthropogenic emissions of carbon dioxide, 

including ocean acidification” (“petition”).

Golder Associates, in partnership with Danish Hydraulic Institute, was retained by the American Petroleum 

Institute to conduct an independent scientific review of the petition. The focus of the review has been to 

conduct an unbiased scientific evaluation of the petition and to address issues that have been omitted or 

insufficiently addressed. 

2.0 OVERALL EVALUATION OF PETITION

Based on an independent assessment, the petition 

 is biased from “cherry-picking” selected information in the scientific literature that only includes those

studies showing or inferring the highest adverse impacts - and entirely neglecting study results that 

show lower, insignificant, or no impacts, or “positive” biological responses from the effects of ocean 

acidification. This bias exaggerates the magnitude and scale of ocean acid acidification.

 misquotes or overstates study results without appropriately discussing uncertainties, inappropriate 

experimental designs and low statistical power in the majority of studies.

 disregards that the natural variation in pCO2 and pH in coastal waters often exceeds the projected 

change and findings in experiments.

 neglects to consider that future pCO2 and pH in coastal waters and on the continental shelf regions will 

differ greatly from model predictions of ocean pH due to influences not included in the models (e.g., 

from watersheds, local sources etc.). 

 fails to consider the potential for biological adaptation to higher pCO2 and pH reduction as 

demonstrated in growing literature.

 includes a bibliography that is of limited utility because 74 of the cited papers/reports are not included in 

the bibliography. 

The petition neglects that pCO2 and pH variation and trends in coastal waters differ 

profoundly from trends in deep ocean waters - yet several examples of ocean 

acidification impacts in the petition build on examples from coastal or shelf waters.

Variation and trends in pH in coastal ecosystems are influenced by a large suite of drivers including but not 

limited to the following: 1) watershed processes; 2) nutrient inputs; 3) changes in ecosystem structure and 

processes (Duarte et al. 2013); and 4) emissions of SO2 and NOX from international shipping activity

(Hassellöv et al. 2013).

This inherent variability and its multiple, complex associations with pH implies that the concept of ocean 

acidification caused by anthropogenic CO2 emissions cannot be transposed directly to coastal ecosystems 

(Duarte et al. 2013). 
September 2015

Report No. 1537019 2

Depending on the location-specific balance among different drivers, the pH of some coastal ecosystems will 

decline while the pH of others will increase. For example:

 In the mid-Atlantic, the pH trends in Chesapeake Bay differ by season and the influence of freshwater 

(Waldbusser et al. 2011). 

 In Europe, the pH of the southern North Sea and in the Danish Straits peaked at 8.3 around 1980-1985

when localized eutrophication1 was at its highest level. However, since then, pH has decreased - at a 

rate 10 times higher than acidification in the Pacific Ocean - as a result of nutrient management actions 

and a reversal of eutrophication in coastal waters (Duarte et al. 2013). 

 Diurnal variation can exceed 1.5 pH units in shallow benthic systems populated by seagrass and 

macroalgae (Duarte et al. 2013, Table 2) underlining that sessile organisms (i.e. permanently attached 

to a solid substrate) in such habitats are adapted to short-term yet recurring variation in pH that majorly 

exceeds the predicted change in a future ocean. 

Because of very coarse spatial resolution in oceanographic models (typically 100 km x 100 km) model 

predictions of future effects of ocean acidification (including aragonite saturation) do not resolve the issue of 

pH variability found in coastal waters. Moreover, these models tend to not to include watershed drivers. In 

summary, we cannot rely on present ocean models to predict future changes in pH and aragonite saturation 

in coastal waters, or vice versa.

The petitions exaggerate ocean acidification impacts by neglecting study results 

showing lower, insignificant, or no impacts; or “positive” biological responses. 

The petition presents a biased impression by only referring to studies showing negative biological response 

to ocean acidification (pH-reduction, pCO2 increase). The petitioners have essentially “cherry-picked” 

published information showing the highest impacts and neglecting another important group of studies 

showing 1) lower impacts, 2) insignificant impacts, 3) no response or 4) "positive" biological responses. 

 Appendix A to these comments lists 28 examples of peer-reviewed journal articles (with abstracts) that 

do not appear in petition and are largely neglected in the petitioner’s ocean acidification literature 

review.

 Appendix B to these comments lists 6 examples where the petitioner exaggerates ocean acidification 

studies by selecting studies with maximal impacts; or misquoting or overstating study results.

Appendix C lists cited papers/reports in the petition that are not listed in the bibliography. In total, there 

were 90 citations referring to 74 papers/reports not listed in the bibliography. Lack of information on 

exact publications cited makes it difficult to examine concurrence between the petition on the one hand 

- and the primary study results and the authors’ interpretation of their own results on the other. 

The majority of ocean acidification experiments are improperly designed to address 

the complexity of ocean ecosystems and air interactions; consequently, their 

results should be viewed with caution.

The number of published scientific papers on ocean acidification has increased recently, with an annual

growth of 33% each year from 2004 – 2013. Statistically, they can be broken down as follows:

 Between 50% and 60% of the publications have focused on “impacts” (Scopus database search2

) to

species (ranging from single cell organism to vertebrates), populations and communities. 

 

1 Eutrophication refers to the over-enrichmentof an ecosystem from inorganic nutrients. This leads to increased algal production and CO2 depletion that then can drives up pH.

2 www.scopus.com - Online database available to Elsevier costumers. Within life science, the search basis includes more than 7.300 titles (journals, books).
September 2015

Report No. 1537019 3

o About 25% of the “impact” studies are based on observational in situ data (e.g. coral 

bleaching, coral and shell corrosions/dissolutions) combined with either site-observations of 

pH, dissolved CO2 or trends in such variables along with atmospheric pCO2 obtained from 

other sites (Scopus database search). 

o About 75 % of “impact” studies are experimental in nature ranging from phytoplankton 

growth experiments carried out in small containers to large mesocosms (experimental tools 

used rarely where conditions such as pH, pCO2, temperature, salinity, light, and mixing can 

be controlled).

Regarding the first 25% of the impact studies, ocean acidification research relying on in situ observations 

(e.g. shell dissolutions/corrosion) and correlative analysis to physico-chemical conditions is by its very nature 

associated with high uncertainty. This is because multiple confounding factors such as local sources can 

affect pCO2 and pH and/or local hydrographic processes (upwelling, mixing) can amplify or counteract 

acidification signals. Consequently, sustained local (and regional scale) monitoring (pH, pCO2, temperature 

etc.) is of paramount importance (e.g., Reum et al. 2014) in understanding any patterns. 

Regarding the other 75% of the impact studies, taking the ex situ experimental approach, the quality of many 

studies is questionable at best. Significant concerns include incomplete descriptions of experimental 

conditions, insufficient experimental designs and poor documentation of essential exposure conditions (e.g.,

pH, pCO2, temperature and salinity) such that the relevance of the studies to the conditions in the field 

cannot be estimated.

One recent assessment (that is not mentioned in the petition), Cornwall & Hurd (2015), evaluated 465 peerreviewed ocean acidification studies between 1993 and 2014 against a “checklist” defining appropriate 

experimental conditions to arrive at reliable results. The checklist included (but was not limited to):

 how seawater carbonate chemistry was manipulated and characterized in tanks (Dickson 2010; Gattuso 

et al. 2010); and

 to what extent true replicate exposures (as opposed to pseudo-replicates) were applied (Hurlbert 1984).

Cornwall and Hurd found that most researchers did not follow internationally accepted procedures to ensure 

quality and thereby impeded the reliability of the results. As Cressey states: “Only in 27 cases could they 

(Cornwall and Hurd) be certain that an appropriate experimental design had been used, and in 279 cases, 

the design was clearly inappropriate. The remaining studies had insufficient detail on experimental set-up”

(Cressey 2015). The high percentage of non-ideal experiments does not completely disqualify the validity of 

their results, but should lead to a cautious use of such results for policy or regulatory decisions, such as 

setting environmental targets.

Cornwall & Hurd (2015) did not evaluate statistical power in their analysis of ocean acidification publications; 

however, with less than 2.5 experimental units per treatment (true replicates or pseudo-replicates) on 

average; it is our opinion that statistical power in the 465 studies must have been much lower than the usual 

target at 0.8. The statistical power is expressed as "1 - β", where β expresses the probability of "type II 

errors" (also called the false negative rate), i.e. the risk that we (incorrectly) evaluate an unaffected organism 

to be affected in an experiment. Many scientists seem confident if their experiments show a significant 

difference (at α = 0.05) between control and treatment, but if power is low, the likelihood that a statistically 

significant result reflects a true effect will be low. In contrast to most ocean acidification experiments, the 

number of true replicates is high (typically 5) and/or number of test concentrations is high (typically 8) in 

aquatic ecotoxicological standard tests carried out under Good Laboratory Practice (GLP) following OECD, 

EPA and ISO guidelines. Standardized test protocols, extensive documentation, high statistical power and 

thus confidence of results are required for supporting regulatory frameworks such as developing 

environmental quality standards. 
September 2015

Report No. 1537019 4

Physiological plasticity and shock effects

In the majority of ex situ experiments (i.e., laboratory-based), test animals are transferred abruptly from 

control conditions to tanks with reduced pH (increased CO2 concentrations). These sudden transfers may

create inherent shock-effects exceeding or overshadowing effects of a gradual change in seawater chemistry

depending on the coping ability of an organism. For example, vertical migrating copepods naturally are 

exposed to large variation in seawater chemistry, and accordingly, are more likely to adapt to relatively rapid

pH-CO2 changes (Lewis et al. 2013). In contrast, sedentary benthic organisms are less robust - with larvae 

stages and calcifiers such as corals, molluscs, echinoderms generally being the most sensitive even though 

large inter-group variation in sensitivity exists (Byrne 2011). Some studies suggest capacity for a 

physiological acclimation because the sensitivity to lowered pH becomes reduced if certain organisms (e.g.,

isopods, coralline algae) are exposed gradually to lowered pH rather than exposed to an abrupt change 

(e.g., Munguia & Alenius 2013, Kamenos et al. 2013). Implications for impact predictions may be important 

and such mechanisms should be further examined before they are relied on for regulatory decisions.

Meta-analysis of Ocean Acidification experiments

Meta-analysis of ocean acidification research has become increasingly popular in the past 4-5 years (Dupont 

et al. 2010, Hendriks et al. 2010, Kroeker et al. 2010, Liu et al. 2010, Kroeker et al. 2013, Harvey et al. 2013, 

De Vries et al. 2013, Azevedo et al. 2015). Meta-analysis can be seen as an advanced approach to 

synthesize results from previous ocean acidification research and ultimately achieve a higher statistical 

power for impacts of interest. The majority of meta-analyses quantify the response (as % of control) to 

increases in pCO2 or reduction in pH within a limited exposure range - e.g. pH ≤ 0.5 or future levels 

complying with the IPCC "business-as-usual" prediction for year 2100. In contrast, two studies (De Vries et 

al. 2013, Azevedo et al. 2015) attempted to estimate dose-response relations using Species Sensitivity 

Distribution (SSD) functions. SSDs are used extensively within ecotoxicology to predict no-effect 

concentrations or estimate the percentage of species affected at a specific pCO2 concentration or pH level.

In performing reviews and meta-analyses, scientists must make several choices (e.g., how to select studies, 

what endpoints to analyze) and many of those choices can determine the outcome of analysis.

A serious potential pitfall is an uncritical reliance on the available body of published studies (e.g., including 

peer-reviewed papers only). This may lead to exaggerated ocean acidification effects due to so-called 

"publication bias" - meaning that experiments with insignificant (or negative) results are less likely to be 

published in peer-reviewed literature (Song et al. 2010). Kroeker et al. (2013) and Harvey et al. (2013) did 

consider publication bias although specific test results such as “funnel” plot was not presented. Other 

choices in data handling can also influence final conclusions - e.g., in the meta-analysis carried out by 

Azevedo et al. (2015), the highest levels of pH for a given impact (pH10 and pH50, affecting 10% and 50% of 

a process, survival etc., respectively) was selected when more than one dose-response relation was 

available for a species. Such an approach will tend to exaggerate effects of acidification.

Long-term projections of impacts should take adaptive capacity into account.

The majority of ocean acidification studies and practically all reviews on ocean acidification refer to future 

impact based on short-term studies with seawater chemistry in a future environment (year 2100) following 

the IPCC A1FI3(worst-case scenario) - i.e., pH = 7.6 in the world oceans. If this approach is accepted, that 

decision should be made with the recognition that it will likely lead to a projection of massive adverse 

impacts to marine life from ocean acidification. See e.g., reviews by Dupont et al. 2010, Liu et al. 2010, 

Kroeker et al. 2013, De Vries et al. 2013, Azevedo et al. 2015 showing up to 80 % reduction in abundance 

of calcifying algae, or up 50 % reduction in coral abundance and so forth. However, scientists in these

primary studies have abruptly exposed today’s test organisms to an assumed future seawater chemistry 

 

3 Scenario A1FI (very rapid economic growth, global population that peaks in mid-century and declines thereafter, followed by rapid introduction of new and more efficient 

technologies; extensive use of fossils).
September 2015

Report No. 1537019 5

without accounting for the interim changes and adaptation periods that would take place in the real world. It 

is therefore not surprising that they “observed” adverse effects including increased mortality, reduced growth 

and calcification rates in short-term experiments. 

The above approach has been criticized for neglecting both physiological plasticity (see above) and genetic 

adaptation (Kelly & Hofmann 2012, Kelly et al. 2013, Collins et al. 2014). For example, large population size 

and a large gene pool in a species or genus are signs of potential adaptation through evolution (Reusch 

2014). Marine phytoplankton is thought to possess key characteristics, such as rapid cell division rates and 

large population sizes that give them the capacity to evolve in response to global change on timescales of 

weeks to decades. Previously, the general view was that an increase in CO2 leads to inefficient calcification 

in coccolithophores (thereby affecting the biological pump, i.e. the transfer by sedimentation of CaCO3 to the 

deep sea). However, more recently, well-calcified morphotypes of coccolithophores have been found in low 

pH regions of the ocean (Beaufort et al. 2011) and after culturing the wide-occurring coccolithophore 

Emiliania huxleyi over more than 700 generations at high pCO2 and elevated temperature, inorganic carbon 

content, primary production and calcification rate did not differ from present (ambient) conditions (Benner et 

al. 2013). These newer studies suggest that adaptive evolutionary change can take place across year-todecade timescales.

Recent studies in the “California Current Large Marine Ecosystem” have documented adaptation to elevated 

pCO2 in several benthic marine invertebrates at sites characterized by episodic upwelling of cold, low-pH 

water under-saturated with CaCO3 (Hofmann et al. 2014). (For example, larvae of a key sea urchin species 

collected in areas characterized by upwelling and variable pCO2 had more resilient metabolic responses to 

pCO2 than larvae from other regions with stable conditions (Kelly et al. 2013)). Additionally, significant 

genetic changes were observed in larvae from seven adult populations of the sea urchins cultured under 

different CO2 levels (Pespeni et al. 2013). Changes were found in genes for bio-mineralization, lipid 

metabolism, and ion homeostasis - gene classes that build skeletons and participate in pH regulation, 

indicating that genetic changes (and adaptation) can occur within one generation exposed to elevated pCO2

(Pespeni et al. 2013). Other examples of successful adaptation to increased pCO2 include non-calcifying 

polychaetes (Calosi et al. 2015).

Although examples from the marine environment are few, wider climate adaptation via evolutionary 

processes has been documented in the terrestrial environment (Hoffmann and Sgrõ 2011). The real 

challenges are to understand and predict which species and traits will be able to adapt (those with large 

genetic variation or large population size) and those with low adaptation potential. Species and populations 

interact with other species and populations through competition for space and food, through predation and 

so forth. Probably it will be climate-induced modification of interactions rather than direct (proximate) effect 

of acidification on individuals that can lead to local extinction of species (Gaylord et al. 2015). The 

knowledge in this field is rather limited and instead of relying primarily only on physiological effects and 

mortality in short-term ocean acidification experiments, research efforts may be better spent on carefully

planned combined scientific studies that also allow for acclimation to take place and consider other localized 

variables. 

3.0 CONCLUSION

Lowering of pH in the oceans is driven, in part, by the ongoing increase in CO2 emission to the atmosphere 

and subsequent CO2 absorption in oceans. Based on most studies, lowered pH in a future ocean suggests 

impacts on marine organisms, their physiology and survival – especially for those that build shells of calcium 

carbonate. Ocean acidification was recognized rather late and the associated research field must be 

regarded as immature with several unsolved questions that partly can be traced to improper study methods 

leading to conflicting predictions on future (at lower pH in oceans) impacts on marine life. As an example, 

most impact studies have abruptly exposed test organisms to a future seawater chemistry without 

accounting for the interim changes and adaptation periods that would take place in the real world. But even 

comparable studies exposing identical species to identical pH conditions find conflicting results. Recent 
September 2015

Report No. 1537019 6

reviews have clearly documented that the vast majority of ocean acidification studies are characterized by 

improper experimental design that invariably will weaken the confidence of their study results. 

The petition presents a distinctly biased view on impacts of ocean acidification by neglecting the 

uncertainties inherently being a consequence of improper study designs in most ocean acidification 

experiments; completely overlooking the peer-reviewed research that contradict the results from the 

“mainstream” ocean acidification; “cherry-picking” study results that show the largest effects of pH 

reductions; and ignoring the growing number of studies that show clear examples of adaptation to lowered 

pH.

4.0 CITED LITERATURE 

Azevedo LB, De Schryver AnM, Hendriks AJ, Huijbregts MAJ (2015) Calcifying species sensitivity 

distributions for ocean acidification. Environ. Sci. Technol. 49: 1495−1500.

Beaufort L, Probert I, de Garidel-Thoron T, Bendif EM, Ruiz- Pino D, Metzl N, Goyet C (2011) Sensitivity of 

coccolithophores to carbonate chemistry and ocean acidification. Nature 476: 80–83.

Benner I, Diner RE, Lefebvre SC, Li D, Komada T, Carpenter EJ, Stillman JH (2013) Emiliania huxleyi

increases calcification but not expression of calcification-related genes in long-term exposure to elevated 

temperature and pCO2. Phil Trans R Soc B 368: 20130049.

Byrne M (2011) Impact of ocean warming and ocean acidification on marine invertebrate life history stages: 

vulnerabilities and potential for persistence in a changing ocean. Oceanography and Marine Biology: An 

Annual Review 49: 1–42.

Calosi P, Rastrick SPS, Lombardi C, de Guzman HJ, Davidson L, Jahnke M, Giangrande A, Hardege JD,

Schulze A, Spicer JI, Gambi M-C (2015) Adaptation and acclimatization to ocean acidification in marine 

ectotherms: an in situ transplant experiment with polychaetes at a shallow CO2 vent system. Phil Trans R 

Soc B 368: 20120444.

Collins S, Rost B, Rynearson TA (2014) Evolutionary potential of marine phytoplankton under ocean 

acidification. Evol Appl. 7(1): 140–155.

Cressey D (2015) Crucial ocean-acidification models come up short - Poorly designed studies leave future 

uncertain for sea dwellers. Nature 524: 18–19 (06 August 2015) doi:10.1038/524018a.

De Vries P, Tamis JE, Foekema EM, Klok C, Murk AJ (2013) Towards quantitative ecological risk 

assessment of elevated carbon dioxide levels in the marine environment. Mar. Pollut. Bull. 73 (2): 516−523.

Dickson, AG. 2010. The carbon dioxide system in seawater: equilibrium chemistry and measurements. In 

(Eds: Riebesell U, Fabry VJ, Hansson L, Gattuso JP): Guide to best practices for ocean acidification 

research and data reporting, pp. 17–40. Publications Office of the European Union, Luxembourg.

Duarte CM, Hendriks IE, Moore TS, Olsen YS, Steckbauer A, Ramajo L, Carstensen J, Trotter JA, 

McCulloch M. (2013) Is ocean acidification an open-ocean syndrome? Understanding anthropogenic impacts 

on seawater pH. Estuar. Coast. 36: 221–236. (doi:10.1007/s12237-013-9594-3).

Dupont S, Ortega-Martinez O, Thorndyke M (2010) Impact of near-future ocean acidification on 

echinoderms. Ecotoxicology 19: 449–462.

Gattuso JP, Gao K, Lee K, Rost B, Schulz KG (2010) Approaches and tools to manipulate the carbonate 

chemistry. In (Eds: Riebesell U, Fabry VJ, Hansson L, Gattuso JP): Guide to best practices for ocean 

acidification research and data reporting, pp. 41–51. Publications Office of the European Union, 

Luxembourg.
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Gaylord B, Kroeker KJ, Sunday JM, Anderson KM, Barry JP, Brown NE, Connell SD, Dupont S, Fabricius 

KE, Hall-Spensen JM, Klinger T, Milazzo M, Munday PL, Russell BD, Sanford E, Schreiber SJ, Thiyagarajan 

V, Vaughan MLH, Widdicombe (2015) Ocean acidification through the lens of ecological theory. Ecology 

96(1): 3–15.

Harvey BP, Gwynn-Jones D, Moore PJ (2013) Meta-analysis reveals complex marine biological responses to 

the interactive effects of ocean acidification and warming. Ecology and Evolution 3(4): 1016–1030.

Hendriks IE, Duarte CM, Alvarez MA (2010) Vulnerability of marine biodiversity to ocean acidification: a 

meta-analysis. Estuarine, Coastal and Shelf Science 86: 157–164.

Hassellöv I-M, Turner DR, Lauer A, Corbett JJ (2013) Shipping contributes to ocean acidification, Geophys. 

Res. Lett. 40: 2731–2736, doi:10.1002/grl.50521.

Hofmann GE, Evans TG, Kelly MW, Padilla-Gamino JL, Blanchette CA, Washburn L, Chan F, McManus MA, 

Menge BA, Gaylord, B, Hill TM, Sanford E, LaVigne M, Rose JM, Kapsenberg L, Dutton JM (2014) Exploring 

local adaptation and the ocean acidification seascape – studies in the California Current Large Marine 

Ecosystem. Biogeosciences 11: 1053–1064.

Hoffmann AA and Sgrõ, CM (2011) Climate change and evolutionary adaptation. Nature 470: 479-485.

Hurlbert SH (1984) Pseudoreplication and the design of ecological field experiments. Ecological Monographs 

54: 187–211.

Kamenos NA et al. (2013) Coralline algal structure is more sensitive to rate, rather than the magnitude, of 

ocean acidification. Global Change Biology 19: 3621–3628.

Kelly MW, Hofmann, GE (2012) Adaptation and the physiology of ocean acidification. Funct Ecol. 27: 980–

990.

Kelly MW, Padilla-Gamiño JL, Hofmann GE (2013) Natural variation, and the capacity to adapt to high pCO2

in a keystone species. Global Change Biol., 19, 2536–2546.

Kroeker KJ, Kordas RL, Crim RN, Singh GG (2010) Meta-analysis reveals negative yet variable effects of 

ocean acidification on marine organisms. Ecology Letters 13: 1419–1434.

Kroeker et al. (2013) Impacts of ocean acidification on marine organisms: quantifying sensitivities and 

interaction with warming. Global Change Biology 19: 1884–1896.

Lewis CN, Brown KA, Edwards LA, Cooper G, Findlay HS (2013) Sensitivity to ocean acidification parallels 

natural pCO2 gradients experienced by Arctic copepods under winter sea ice. PNAS 110 no. 51 E4960-

E4967.

Liu J, Weinbauer MG, Maier C, Dai M, Gattuso J-P (2010) Effect of ocean acidification on microbial diversity, 

and on microbe-driven biogeochemistry and ecosystem functioning. Aquatic Microbial Ecology 61: 291–305.

Munguia P, Alenius B (2013) The role of preconditioning in ocean acidification experiments: a test with the 

intertidal isopod Paradella dianae. Marine and Freshwater Behaviour and Physiology 46(1): 33-44, DOI: 

10.1080/10236244.2013.788287.

Pespeni MH, Sanford E, Gaylord BV, Hill TM, Hosfelt JD, Jaris HK, LaVigne M, Lenz EA, Russell AD, Young 

MK, Palumbi SR (2013) Evolutionary change during experimental ocean acidification. Proceedings of the 

National Academy of Sciences USA 110: 6937–6942.

Reum JCP, Alin SR, Feely RA, Newton J, Warner M, McElhany P (2014) Seasonal carbonate chemistry 

covariation with temperature, oxygen, and salinity in a fjord estuary: Implications for the design of ocean 

acidification experiments. PLoS ONE 9(2): e89619. doi:10.1371/journal.pone.0089619.

Reusch TBH (2014) Climate change in the oceans: evolutionary versus phenotypically plastic responses of 

marine animals and plants. Evol Appl. 7(1): 104–122.
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Song F, Parekh S, Hooper L, Loke YK, Ryder J, Sutton AJ (2010) Dissemination and publication of research 

findings: an updated review of related biases. Health Technol. Assess. 2010; 14 (8):iii, ix–xi.

Waldbusser GG, Voigt EP, Bergschneider H, Green MA, Newell RI (2011) Biocalcification in the eastern 

oyster (Crassostrea virginica) in relation to long-term trends in Chesapeake Bay pH. Estuaries and Coasts 

34(2): 221–231.
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Report Signature Page

GOLDER ASSOCIATES A/S

Hans Christian Krarup

Director

Registered in Denmark at Maglebjergvej 6, 1. sal, DK-2800 Kgs. Lyngby, Denmark. CVR 29 62 42 24

Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation.

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Report No. 1537019

APPENDIX A

28 examples of recent peer-reviewed papers (2010-2015) 

showing lower, insignificant, or no impacts; or “positive” 

biological responses from the effects of ocean acidification

and which are not included in petition. 
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The petition presents a biased impression by only referring to studies showing negative biological responses

to ocean acidification (pH-reduction, pCO2 increase), generally choosing published information showing the 

highest impacts and neglecting the group of studies showing lower, insignificant, or no impacts; or "positive" 

biological response. To demonstrate that low-response studies were excluded in the petition, a literature 

search4 was conducted of ocean acidification studies published in peer-reviewed journals and the search 

identified 28 studies out of approximately 220 (encompassing clear information of ocean acidification - pCO2

– pH impacts or no impacts in abstracts) showing lower, insignificant, or no impacts; or “positive” biological 

responses. Study conclusions are shown in Bold. The Impact Factor (a measure of how frequently 

published papers are cited in scientific literature) of listed and not cited papers vary between 1.12 and 28.1.

Summaries of Abstracts Reference

1. The authors examined how the physiology of the giant kelp 

Macrocystis pyrifera is affected by elevated pCO2/low pH. Growth 

and photosynthetic rates, external and internal carbonic anhydrase 

(CA) activity, HCO3 - versus CO2 use were determined over a 7-

day incubation at ambient pCO2 400 μatm/pH 8.00 and a future OA 

treatment of pCO2 1200 μatm/pH 7.59. Neither the 

photosynthetic nor growth rates were changed by elevated 

CO2 supply in the OA treatment. Our results suggest that 

photosynthetic Ci uptake and growth of Macrocystis will not 

be affected by elevated pCO2/low pH predicted for the future, 

but the combined effects with other environmental factors like 

temperature and nutrient availability could change the 

physiological response of Macrocystis to OA.

Fernández PA, Roleda MY, Hurd CL 

(2015) Effects of ocean acidification 

on the photosynthetic performance, 

carbonic anhydrase activity and 

growth of the giant kelp Macrocystis 

pyrifera. Photosynthesis Research 

124 (3): 293-304

(impact factor 2014: 3.50)

2. This study tested the ability of coral heterotrophy to mitigate 

reductions in growth due to climate change stress in the critically 

endangered Caribbean coral Acropora cervicornis via changes in 

feeding rate and lipid content. Corals were either fed or unfed and 

exposed to elevated temperature (30°C), enriched pCO2 (800 

ppm), or both (30°C/800 ppm) as compared to a control (26°C/390 

ppm) for 8 weeks. Feeding rate and lipid content both increased in 

corals experiencing OA vs. present-day conditions, and were

significantly correlated. Fed corals were able to maintain 

ambient growth rates at both elevated temperature and 

elevated CO2, while unfed corals experienced significant 

decreases in growth with respect to fed conspecifics. Our 

results show for the first time that a threatened coral species 

can buffer OA-reduced calcification by increasing feeding 

rates and lipid content.

Towle EK, Enochs IC, Langdon C 

(2015) Threatened Caribbean coral is 

able to mitigate the adverse effects of 

ocean acidification on calcification by 

increasing feeding rate. PLoS ONE 

10 (4), e0123394

(impact factor 2013/14: 3.53)

3. The goal of the present study was to assess the long-term 

impact of ocean acidification on a suite of physiological parameters 

of the sea urchin Echinometra mathaei in more realistic food 

conditions. A long-term experiment was conducted in mesocosms 

provided with an artificial reef in which the urchins principally fed on 

algae attached to the reef calcareous substrate. Contrasted pH 

conditions (pH 7.7 vs control) were established gradually over six 

months and then maintained for seven more months. Acid-base 

Moulin L, Grosjean P, Leblud J, (...), 

Collard M, Dubois P (2015) Longterm mesocosms study of the effects 

of ocean acidification on growth and 

physiology of the sea urchin 

Echinometra mathaei. Marine 

Environmental Research 103: 103-

 

4 www.scopus.com (search term: ”ocean acidification” and (growth or calcification or mortality or survival or acclimation or adaptation). 
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parameters of the coelomic fluid, growth and respiration rate were 

monitored throughout the experiment. Results indicate that 

E.mathaei should be able to regulate its extracellular pH at 

long-term, through bicarbonate compensation. Growth, 

respiration rate and mechanical properties of the test were not 

affected. This ability to resist OA levels expected for 2100at 

long-term could determine the future of coral reefs, 

particularly reefs where E.mathaei is the major bioeroder.

114

(impact factor 2014: 2.33)

4. A 7-month CO2 perturbation experiment was performed on one 

of the most CaCO3 dependent species, the Antarctic brachiopod 

Liothyrella uva, which inhabits the Southern Ocean where 

carbonate ion saturation levels are amongst the lowest on Earth. 

The effects of the predicted environmental conditions in 2050 and 

2100 on the growth rate and ability to repair shell in L. uva were 

tested with four treatments; a low temperature control (0°C, pH

7.98), a pH control (2°C, pH 8.05), mid-century scenario (2°C, pH

7.75) and end-century scenario (2°C, pH 7.54). Environmental 

change impacts on shell repair are rarely studied, but here 

repair was not affected by either acidified conditions or 

temperature. Growth rate was also not impacted by low pH. 

Elevated temperature did, however, increase growth rates. The 

ability of L. uva to continue, and even increase shell 

production in warmer and acidified seawater suggests that 

this species can acclimate to these combined stressors and 

generate suitable conditions for shell growth at the site of 

calcification.

Cross EL, Peck LS, Harper EM 

(2015) Ocean acidification does not 

impact shell growth or repair of the 

Antarctic brachiopod Liothyrella uva

(Broderip, 1833). Journal of 

Experimental Marine Biology and 

Ecology 462: 29-35

(impact factor 2014: 1.87)

5. The authors evaluated the impact of ocean acidification on the 

early development of sea cucumber Apostichopus japonicus. The 

effect of pH-levels (pH 8.04, 7.85, 7.70 and 7.42) were tested on 

post-fertilization success, developmental (stage duration) and 

growth rates. Post-fertilization success decreased linearly with pH 

leading to a 6% decrease at pH 7.42 as compared to pH 8.1. The 

impact of pH on developmental time was stage-dependent: (1) 

stage duration increased linearly with decreasing pH in earlyauricularia stage; (2) decreased linearly with decreasing pH in the 

mid-auricularia stage; but (3) pH decline had no effect on the lateauricularia stage. At the end of the experiment, the size of doliolaria 

larvae linearly increased with decreasing pH. In conclusion, a 

0.62 unit decrease in pH had relatively small effects on A. 

japonicus early life-history compared to other echinoderms, 

leading to a maximum of 6% decrease in post-fertilization 

success and subtle effects on growth and development.

Yuan X et al. (2015) Impact of CO2-

driven acidification on the 

development of the sea cucumber 

Apostichopus japonicus (Selenka) 

(Echinodermata: Holothuroidea). 

Marine Pollution Bulletin 95 (1): 195-

199.

(impact factor 2013/14: 2.79)

6. The ecological, physiological, and skeletal characteristics of the 

calcifying green alga Halimeda grown at CO2 seeps (pH-total~7.8) 

was investigated and compared them to those at control reefs with 

ambient CO2 conditions (pHtotal~8.1). Six species of Halimeda

were recorded at both the high CO2 and control sites. For Halimeda 

digitata and Halimeda opuntia in situ light and dark oxygen fluxes 

and calcification rates, carbon contents and stable isotope 

Vogel N et al. (2015) Calcareous 

green alga Halimeda tolerates ocean 

acidification conditions at tropical 

carbon dioxide seeps. Limnology and 

Oceanography 60 (1): 263-275
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signatures were determined. In both species, rates of calcification 

in the light increased at the high CO2 site compared to controls 

(131% and 41%, respectively). Calculated net calcification of both 

species was similar between seep and control sites. Significantly, 

lighter carbon isotope signatures of H. digitata and H. opuntia

phylloids at high CO2 (1.01 ppt and 1.94 ppt, respectively) indicate 

increased photosynthetic uptake of CO2 over HCO3-potentially 

reducing dissolved inorganic carbon limitation at the seep site. 

Moreover, H. digitata and H. opuntia specimens transplanted for 14 

d from the control to the seep site exhibited similar δ13C signatures 

as specimens grown there. These results suggest that the 

Halimeda spp. investigated can acclimatize and will likely still 

be capable to grow and calcify in pCO2 conditions exceeding 

most pessimistic future CO2 projections.

(impact factor 2014: 3.79)

7. The study focused on Crepidula fornicata, an invasive gastropod 

which colonized shallow waters around European coasts during the 

20th century. Authors investigated the effects of 10 weeks' 

exposure to current (380 μatm) and elevated (550, 750, 1,000 

μatm) pCO2 on this engineer species using an acute temperature 

increase (1°C 12 h-1) as the test. Respiration rate in C. fornicata

increased linearly with temperature between 18 and 34 °C, but 

no differences were detected between the different pCO2

conditions either in the regressions between respiration rate 

and temperature or in Q10 values. In the same way, condition 

indices were similar in all the pCO2 treatments at the end of 

the experiment, but decreased from the beginning of the 

experiment. This species was highly resistant to acute 

exposure to high temperature regardless of pCO2 levels, even 

though food was limited during the experiment. Crepidula fornicata

appears to have either developed resistance mechanisms or a 

strong phenotypic plasticity to deal with fluctuations of 

physicochemical parameters in its habitat. This suggests that 

invasive species may be more resistant to future 

environmental changes than its native competitors.

Noisette F et al. (2015) Metabolic 

responses to temperature stress 

under elevated pCO2 in Crepidula 

fornicate. Journal of Molluscan 

Studies 81 (2): 238-246

(impact factor 2014: 1.39)

8. The effect of ocean warming and acidification was investigated 

on a natural plankton assemblage from an oligotrophic area, the 

bay of Villefranche (NW Mediterrean Sea). Under nutrientdepleted conditions in the Mediterranean Sea [control: 360 

μatm, elevated temperature and pCO2: ∼410 μatm & 610 μatm, 

respectively], ocean acidification has a very limited impact on 

the plankton community but that small species will benefit from 

warming with a potential decrease of the export and energy 

transfer to higher trophic levels.

Maugendre et al. (2015) Effect of 

ocean warming and acidification on a 

plankton community in the NW 

Mediterranean Sea. ICES J. Mar. Sci.

72 (6): 1744-1755.

(impact factor 2014/15: 2.53)

9. Authors carried out 3 experiments on the larvae of mahi-mahi 

Coryphaena hippurus, a large pelagic tropical fish species of high 

economic value. Mahi-mahi larvae were raised for up to 21 d under 

either ambient seawater conditions (350 to 490 μatm pCO2) or 

projected scenarios of ocean acidification (770 to 2170 μatm 

pCO2). Evaluation of hatch rate, larval size, development, 

Bignami, S., Sponaugle, S., Cowen,

R.K. (2014) Effects of ocean 

acidification on the larvae of a highvalue pelagic fisheries species, Mahimahi Coryphaena hippurus. Aquatic 
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swimming activity, swimming ability (Ucrit), and otolith (ear 

stone) formation produced few significant effects. However, 

larvae unexpectedly exhibited significantly larger size-at-age and 

faster developmental rate during 1 out of 3 experiments, possibly 

driven by metabolic compensation to elevated pCO2 via a 

corresponding decrease in routine swimming velocity. Furthermore, 

larvae had significantly larger otoliths at 2170 μatm pCO2, and a 

similar but non-significant trend also occurred at 1200 μatm pCO2, 

suggesting potential implications for hearing sensitivity. The lack of 

effect on most variables measured in this study provides an 

optimistic indication that this large tropical species, which 

inhabits the offshore pelagic environment, may not be overly 

susceptible to ocean acidification.

Biology 21 (3): 249-260

(impact factor 2014: 1.12)

10. The authors examined the photosynthetic physiology of 

Phaeocystis globosa while growing it under different pH levels 

induced by CO2 enrichment and investigated its acclimation to 

carbonate chemistry changes under different light levels. Shortterm exposure to reduced pH (7.70) decreased the alga's 

photosynthesis and light use efficiency. However, acclimation to 

the reduced pH level for 1-19 generations led to recovered 

photosynthetic activity, being equivalent to that of cells grown 

under pH 8.07 (control), though such acclimation required a 

different time span under different light regimes. The low-pHgrown cells increased their contents of chlorophyll and carotenoids 

with prolonged acclimation to the acidification, with increased 

photosynthetic quantum yield and decreased non-photochemical 

quenching. The specific growth rate of the low-pH-grown cells 

also increased to emulate that grown under the ambient pH 

level. This study clearly shows that Phaeocystis globosa is 

able to acclimate to seawater acidification by increasing its 

energy capture and decreasing its non-photochemical energy 

loss.

Chen S, Beardall J, Gao K (2014) A 

red tide alga grown under ocean 

acidification upregulates its tolerance 

to lower pH by increasing its 

photophysiological functions. 

Biogeosciences 11 (17): 4829-4838

(impact factor 2013/14: 3.98)

11. The blue mussel, Mytilus galloprovincialis, was used as a 

model species to test how ocean acidification affects the growth of 

a calcifying invertebrate across a wide range of temperatures 

encompassing their thermal optimum. Mussels were exposed in the 

laboratory to a factorial combination of low and high pCO2 (400 and 

1200 μatm CO2) and temperatures (12, 14, 16, 18, 20, and 24°C) 

for one month. Results indicate that the effects of ocean 

acidification on shell growth are highly dependent on temperature. 

Although high CO2 significantly reduced mussel growth at 

14°C, this effect gradually lessened with successive warming 

to 20°C, illustrating how moderate warming can mediate the 

effects of ocean acidification through temperature's effects on 

both physiology and seawater geochemistry. Furthermore, the 

mussels grew thicker shells in warmer conditions independent 

of CO2 treatment. 

Kroeker KJ et al. (2014). The role of 

temperature in determining species' 

vulnerability to ocean acidification: A 

case study using Mytilus 

galloprovincialis. PLoS ONE 9 (7), 

e100353

(impact factor 2013/14: 3.53)

12. Two separate experiments showed that larval development of 

the barnacle Amphibalanus (Balanus) improvisus was not 

Pansch C, Schlegel P, and 

Havenhand J (2013) Larval 
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significantly affected by the level of reduced pH that has been 

projected for the next 150 years. After 3 and 6 days of 

incubation, no consistent effects was found of reduced pH on 

developmental speed or larval size at pH 7.8 compared with the 

control pH of 8.1. After 10 days of incubation, there were no net 

changes in survival or overall development of larvae raised at pH 

7.8 or 7.6 compared with the control pH of 8.0.

development of the barnacle 

Amphibalanus improvisus responds 

variably but robustly to near-future 

ocean acidification. ICES Journal of 

Marine Science, 70: 805–811

(impact factor 2014/15: 2.53)

13. The study combined in situ study bleaching surveys around 

three tropical CO2 seeps with a 2-month two-factor (CO2 and 

temperature) tank experiment in order to investigate how ocean 

acidification and sea surface temperature (SST) affected the 

bleaching susceptibility of tropical reef corals. Surveys at CO2

seep and control sites during a minor regional bleaching event 

gave little indication that elevated pCO2 influenced the bleaching 

susceptibility of the wider coral community, the four most common 

coral families (Acroporidae, Faviidae, Pocilloporidae, or Poritidae), 

or the thermally sensitive coral species Seriatopora hystrix. In the 

tank experiment, sublethal bleaching was observed at 31°C after 5 

d in S. hystrix and 12 d in Acropora millepora, whereas controls 

(28°C) did not bleach. None of the measured proxies for coral 

bleaching were negatively affected by elevated pCO2 at pHT

7.79 (vs. 7.95 pHT in controls), equivalent to ∼780 μatm pCO2

and an aragonite saturation state of 2.5. On the contrary, high 

pCO2 benefitted some photophysiological measures (although 

temperature effects were much stronger than CO2 effects) -

maximum photosystem II quantum yields and light-limited electron 

transport rates increased in both species at high pCO2, whereas 

gross photosynthesis and pigment concentrations increased in S.

hystrix at high pCO2. The field and laboratory data in 

combination suggest that OA levels up to a pHT of 7.8 will 

have little effect on the sensitivity of tropical corals to thermal 

bleaching.

Noonan SHC & KE Fabricius (2015) 

Ocean acidification affects 

productivity but not the severity of 

thermal bleaching in some tropical 

corals. ICES J. Mar. Sci. (in press)

(impact factor 2014/15: 2.53)

14. Effects of OA on embryos and unfed larvae of the great scallop 

(Pecten maximus Lamarck) were studied at pCO2 levels of 469 

(ambient), 807, 1164, and 1599 μatm until seven days after 

fertilization. OA affected both survival and shell growth negatively 

after seven days. Survival was reduced from 45% in the ambient 

group to 12% in the highest pCO2 group. Shell length and height 

were reduced by 8 and 15%, respectively, when pCO2 increased

from ambient to 1599 μatm. Development of normal hinges was 

negatively affected by elevated pCO2 levels in both trochophore 

larvae after two days and veliger larvae after seven days. Results 

show that P. maximus embryos and early larvae may be 

negatively affected by elevated pCO2 levels within the range of 

what is projected towards year 2250, although the initial drop 

in pCO2 level may have overestimated the effect of the highest 

pCO2 levels.

Andersen S, Grefsrud ES, Harboe T 

(2013) Effect of increased pCO2 level 

on early shell development in great 

scallop (Pecten maximus Lamarck) 

larvae Biogeosciences 10: 6161–

6184

(impact factor 2013/14: 3.98)

15. Calcifying organisms such as coccolithophores that fix and Benner I, Diner RE, Lefebvre SC, Li 
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export carbon into the deep sea provide feedbacks to increasing

atmospheric pCO2. Acclimation experiments suggest negative 

effects of warming and acidification on coccolithophore

calcification, but the ability of these organisms to adapt to future 

environmental conditions is not well understood. The authors 

tested the combined effect of pCO2 and temperature on the 

coccolithophore Emiliania huxleyi over more than 700 generations. 

Cells increased inorganic carbon content and calcification rate 

under warm and acidified conditions compared with ambient 

conditions, whereas organic carbon content and primary production 

did not show any change. In contrast to findings from shortterm experiments, our results suggest that long-term 

acclimation or adaptation could change, or even reverse, 

negative calcification responses in E. huxleyi and its feedback 

to the global carbon cycle. Genome-wide profiles of gene 

expression using RNA-seq revealed that genes thought to be 

essential for calcification are not those that are most strongly 

differentially expressed under long-term exposure to future ocean 

conditions. Rather, differentially expressed genes observed here 

represent new targets to study responses to ocean acidification 

and warming.

D, Komada T, Carpenter EJ, Stillman 

J (2013) Emiliania huxleyi increases 

calcification but not expression of 

calcification-related genes in longterm exposure to elevated 

temperature and pCO2. Phil Trans R 

Soc B 368: 20130049.

(impact factor 2014/15: 6.31)

16. While strong evidence suggests calcification by tropical reefbuilding corals containing algal symbionts (zooxanthellae) will 

decline over the next century, likely responses of azooxanthellate 

corals to ocean acidification are less well understood. Because 

azooxanthellate corals do not obtain photosynthetic energy from 

symbionts, they provide a system for studying the direct effects of 

acidification on energy available for calcification. The solitary 

azooxanthellate orange cup coral Balanophyllia elegans often lives 

in low-pH, upwelled waters along the California coast. In an 8-

month factorial experiment, we measured the effects of three pCO2

treatments (410, 770, and 1220 μatm) and two feeding frequencies 

(3-day and 21-day intervals) on "planulation" (larval release) by 

adult B. elegans, and on the survival, skeletal growth, and 

calcification of newly settled juveniles. Planulation rates were 

affected by food level but not pCO2. Juvenile mortality was 

highest under high pCO2 (1220 μatm) and low food (21-day 

intervals). Feeding rate had a greater impact on calcification of 

B. elegans than pCO2. While net calcification was positive 

even at 1220 μatm (~3 times current atmospheric pCO2), overall 

calcification declined by ~25-45%, and skeletal density declined by 

~35-45% as pCO2 increased from 410 to 1220 μatm. Aragonite 

crystal morphology changed at high pCO2, becoming significantly 

shorter but not wider at 1220 μatm. The authors concluded that 

food abundance is critical for azooxanthellate coral calcification, 

and that B. elegans may be partially protected from adverse 

consequences of ocean acidification in habitats with abundant 

heterotrophic food.

Crook ED, Cooper H, Potts DC, 

Lambert T and Paytan A (2013) 

Impacts of food availability and pCO2

on planulation, juvenile survival, and 

calcification of the azooxanthellate 

scleractinian coral Balanophyllia 

elegans, Biogeosciences, 10: 7599-

7608

(impact factor 2013/14: 3.98)

17. Marine bacteria are the main consumers of freshly produced 

organic matter. Many enzymatic processes involved in the 

bacterial digestion of organic compounds were shown to be pH 

Endres S, Galgani L, Riebesell U, 

Schulz K-G, Engel A (2014) 

Stimulated Bacterial Growth under 
September 2015

Report No. 1537019

sensitive in previous studies. The authors studied the effects of 

elevated seawater pCO2 on a natural plankton community during a 

large-scale mesocosm study in a Norwegian fjord. Nine Kiel OffShore Mesocosms for Future Ocean Simulations (KOSMOS) were 

adjusted to different pCO2 levels ranging initially from ca. 280 to 

3000 μatm and sampled every second day for 34 days. The first 

phytoplankton bloom developed around day 5. On day 14, 

inorganic nutrients were added to the enclosed, nutrient-poor 

waters to stimulate a second phytoplankton bloom, which occurred 

around day 20. These results indicate that marine bacteria benefit 

directly and indirectly from decreasing seawater pH. During the first 

phytoplankton bloom, 5–10% more transparent exopolymer 

particles were formed in the high pCO2 mesocosms. 

Simultaneously, the efficiency of the protein-degradingenzyme 

leucine aminopeptidase increased with decreasing pH resulting in 

up to three times higher values in the highest pCO2/lowest pH 

mesocosm compared to the controls. In general, total and cellspecific aminopeptidase activities were elevated under low pH 

conditions. The combination of enhanced enzymatic hydrolysis of 

organic matter and increased availability of gel particles as 

substrate supported up to 28% higher bacterial abundance in the 

high pCO2 treatments. It was therefore concluded that ocean 

acidification has the potential to stimulate the bacterial 

community and facilitate the microbial recycling of freshly 

produced organic matter, thus strengthening the role of the 

microbial loop in the surface ocean.

Elevated pCO2: Results from an OffShore Mesocosm Study. PLoS ONE 

9(6): e99228 

doi:10.1371/journal.pone.0099228

(impact factor 2013/14: 3.53)

18. The aim of the study was to test the sensitivity of selected 

seaweed macrofoulers to transient elevation of pCO2 in their 

natural microenvironment, i.e. the boundary layer covering the 

thallus surface of brown seaweeds. Fragments of the macroalga 

Fucus serratus bearing an epibiotic community composed of the 

calcifiers Spirorbis spirorbis (Annelida) and Electra pilosa (Bryozoa) 

and the non-calcifier Alcyonidium hirsutum (Bryozoa) were 

maintained for 30 days under three pCO2 conditions: natural 460 ± 

59 μatm, present-day upwelling1193 ± 166 μatm and future 

upwelling 3150 ± 446 μatm. Only the highest pCO2 caused a 

significant reduction of growth rates and settlement of S. spirorbis 

individuals. Additionally, S. spirorbis settled juveniles exhibited 

enhanced calcification of 40% during daylight hours compared to 

dark hours, possibly reflecting a day-night alternation of an 

acidification-modulating effect by algal photosynthesis as opposed 

to an acidification-enhancing effect of algal respiration. E. pilosa

colonies showed significantly increased growth rates at 

intermediate pCO2 (1193 μatm) but no response to higher pCO2. 

No effect of acidification on A. hirsutum colonies growth rates was 

observed. The results suggest a remarkable resistance of the 

algal macro-epibionts to levels of acidification occurring at 

present day upwellings in the Baltic. Only extreme future 

upwelling conditions impacted the tubeworm S. spirorbis, but 

not the bryozoans.

Saderne V, Wahl M (2013) 

Differential Responses of Calcifying 

and Non-Calcifying Epibionts of a 

Brown Macroalga to Present-Day and 

Future Upwelling pCO2. PLoS ONE 

8(7): e70455

(impact factor 2013/14: 3.53)

19. The effect of elevated seawater carbon dioxide (CO2) on the Piontek J, Borchard, C, Sperling M, 
September 2015

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activity of a natural bacterioplankton community in an Arctic fjord 

system was investigated by a mesocosm perturbation study in the 

frame of the European Project on Ocean Acidification (EPOCA). A 

pCO2 range of 175-1085 μatm was set up in nine mesocosms 

deployed in the Kongsfjorden (Svalbard). The activity of natural 

extracellular enzyme assemblages increased in response to 

acidification. Rates of glucosidase and leucine-aminopeptidase 

increased along the gradient of mesocosm pCO2. A decrease in 

seawater pH of 0.5 units almost doubled rates of both enzymes. 

Heterotrophic bacterial activity was closely coupled to 

phytoplankton productivity in this experiment. The bacterioplankton 

community responded to rising chlorophyll a concentrations after a 

lag phase of only a few days with increasing protein production and 

extracellular enzyme activity. Time-integrated primary production 

and bacterial protein production were positively correlated, strongly 

suggesting that higher amounts of phytoplankton-derived organic 

matter were assimilated by heterotrophic bacteria at increased 

primary production. Primary production increased under high 

pCO2 in this study, and it can be suggested that the efficient 

heterotrophic carbon utilisation had the potential to 

counteract the enhanced autotrophic CO2 fixation. However, 

these results also show that beneficial pCO2-related effects on 

bacterial activity can be mitigated by the top-down control of 

bacterial abundances in natural microbial communities.

Schulz, KG, Riebesell U, Engel A 

(2013) Response of bacterioplankton 

activity in an Arctic fjord system to 

elevated pCO2: results from a 

mesocosm perturbation study. 

Biogeosciences, 10: 297–314

(impact factor 2013/14: 3.98)

20. The authors investigated the effects of elevated pCO2 in 

seawater both on the acute mortality and the reproductive 

properties of the benthic copepod Tigriopus japonicus and 

gastropod Babylonia japonica with the purpose of accumulating 

basic data for assessing potential environmental impacts of subsea geological storage of anthropogenic CO2 in Japan. Acute 

tests showed that nauplii of T. japonicus have a high tolerance to 

elevated pCO2 environments. Full life cycle tests on T. japonicus

indicated NOEC (No Observed Effect Concentration) = 5800 μatm 

and LOEC (Lowest Observed Effect Concentration) = 37,000 μatm. 

Adult B. japonica showed remarkable resistance to elevated 

pCO2 in the acute tests. Embryonic development of B. 

japonica showed a NOEC=1500 μatm and LOEC = 5400 μatm. 

T. japonicus showed high resistance to elevated pCO2

throughout the life cycle and B. japonica are rather sensitive 

during the veliger stage when they started to form their shells.

Kita J, Kikkawa T, Asai T, Ishimatsu 

A (2013) Effects of elevated pCO2 on 

reproductive properties of the benthic 

copepod Tigriopus japonicus and 

gastropod Babylonia japonica. Mar 

Pollut Bull. 73(2): 402-8.

(impact factor 2013/14: 2.79)

21. Predictions of future impact of climate change on coral reefs 

indicate that bleaching mortality due to higher temperature will be 

the major factor in the decline of coral reefs. Ocean acidification is 

increasingly considered to be an important contributing factor, but 

estimates of its importance vary widely in the literature. Models of 

future reef decline due to ocean acidification generally involve four 

simplifying assumptions that can lead to contradictions. The 

assumptions are: (i) Oceanic conditions of Ωarag control or are at 

least highly correlated with net calcification rate (Gnet) on coral 

reefs;(ii) Calcification rate is driven by bulk water carbonate ion 

concentration [CO3

2− ] expressed as Ωarag; (iii) Changes in coral 

Jokiel PL (2015) Predicting the 

impact of ocean acidification on coral 

reefs: evaluating the assumptions 

involved. – ICES Journal of Marine 

Science, doi: 

10.1093/icesjms/fsv091.

(impact factor 2014/15: 2.53)
September 2015

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calcification rate can be used to estimate future changes in coral 

reef calcification rate; and (iv) The impact of OA is additive and not 

synergistic with other environmental factors such as increased 

temperature. The assumption that aragonite saturation state 

(Ωarag) of seawater drives calcification is the most widely used 

and needs to be further evaluated. An alternate hypothesis is 

that calcification is limited by the ability of the system to rid 

itself of the protons generated by calcification. Recent studies 

allow further testing of the assumptions and point the way to 

resolving shortcomings in our understanding of how OA 

impacts coral reefs.

22. The authors investigated the effects of an increase in dissolved 

CO2 on the microbial communities of the Mediterranean Sea during 

two mesocosm experiments in two contrasting seasons - winter, at 

the peak of the annual phytoplankton bloom, and summer, under 

low nutrient conditions. The experiments included treatments with 

acidification and nutrient addition, and combinations of the two. We 

followed the effects of ocean acidification on the abundance of the 

main groups of microorganisms (diatoms, dinoflagellates, 

nanoeukaryotes, picoeukaryotes, cyanobacteria, and heterotrophic 

bacteria) and on bacterial activity, leucine incorporation, and 

extracellular enzyme activity. Our results showed a clear 

stimulation effect of OA on the abundance of small phytoplankton 

(pico- and nanoeukaryotes), independently of the season and 

nutrient availability. A large number of the measured variables 

showed significant positive effects of acidification in summer 

compared with winter, when the effects were sometimes negative. 

Effects of OA were more conspicuous when nutrient concentrations 

were low. Our results therefore suggest that microbial 

communities in oligotrophic waters are considerably affected 

by OA, whereas microbes in more productive waters are less 

affected. The overall enhancing effect of acidification on 

eukaryotic pico- and nanophytoplankton, in comparison with 

the non-significant or even negative response to nutrient-rich 

conditions of larger groups and autotrophic prokaryotes, 

suggests a shift towards medium-sized producers in a future 

acidified ocean.

Sala et al. (2015) Contrasting effects 

of ocean acidification on the microbial 

food web under different trophic 

conditions 

ICES J. Mar. Sci. (2015) doi: 

10.1093/icesjms/fsv130

(impact factor 2014/15: 2.53)

23. Rising levels of atmospheric CO2 are responsible for a change 

in the carbonate chemistry of seawater with associated pH drops 

(acidification) projected to reach 0.4 units from 1950 to 2100. The 

authors investigated possible indirect effects of seawater 

acidification on the feeding, fecundity, and hatching success of 

the calanoid copepod Acartia grani, mediated by potential CO2-

induced changes in the nutritional characteristics of their prey. The 

authors used as prey the autotrophic dinoflagellate Heterocapsa

sp., cultured at three distinct pH levels (control: 8.17, medium: 

7.96, and low: 7.75) by bubbling pure CO2 via a computer 

automated system. Acartia grani adults collected from a laboratory 

culture were acclimatized for 3 d at food suspensions of 

Heterocapsa from each pH treatment (ca. 500 cells ml−1; 300 μg C 

l

−1). Feeding and egg production rates of the preconditioned 

Isari S, Zervoudaki S, Peters J, 

Papantoniou, Pelejero C, Saiz E 

(2015) Lack of evidence for elevated 

CO2-induced bottom-up effects on 

marine copepods: a dinoflagellate–

calanoid prey–predator pair. ICES J. 

Mar. Sci. (2015) doi: 

10.1093/icesjms/fsv078

(impact factor 2014/15: 2.53)
September 2015

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females did not differ significantly among the three Heterocapsa

diets. Egg hatching success, monitored once per day for the 72 h, 

did not reveal significant difference among treatments. These 

results are in agreement with the lack of difference in the cellular 

stoichiometry (C : N, C : P, and N : P ratios) and fatty acid 

concentration and composition encountered between the three 

tested Heterocapsa treatments. The findings disagree with 

those of other studies using distinct types of prey, suggesting 

that this kind of indirect influence of acidification on copepods 

may be largely associated with interspecific differences 

among prey items with regard to their sensitivity to elevated 

CO2 levels.

24. Effects of ocean acidification on the composition of the active 

bacterial and archaeal community within Arctic surface sediment 

were analyzed in detail using 16S rRNA 454 pyrosequencing. 

Intact sediment cores were collected and exposed to one of five 

different pCO2 concentrations [380 (present day), 540, 750, 1120 

and 3000 μatm] and RNA extracted after a period of 14 days 

exposure. Measurements of diversity and multivariate similarity 

indicated very little difference between pCO2 treatments. Only 

when the highest and lowest pCO2 treatments were compared 

were significant differences evident, namely increases in the 

abundance of operational taxonomic units most closely 

related to the Halobacteria and differences to the 

presence/absence structure of the Planctomycetes. The 

relative abundance of members of the classes Planctomycetacia 

and Nitrospira increased with increasing pCO2 concentration, 

indicating that these groups may be able to take advantage of 

changing pH or pCO2 conditions. The modest response of the 

active microbial communities associated with these sediments may 

be due to the low and fluctuating pore-water pH already 

experienced by sediment microbes, a result of the pH buffering 

capacity of marine sediments, or due to currently unknown factors. 

Further research is required to fully understand the impact of 

elevated CO2 on sediment physicochemical parameters, 

biogeochemistry and microbial community dynamics.

Tait K, Laverock B, Shaw J,

Somerfield PJ, Widdicombe S (2013) 

Minor impact of ocean acidification to 

the composition of the active 

microbial community in an Arctic 

sediment. Environmental 

Microbiology Reports 

doi:10.1111/1758-2229.12087

(impact factor 2013/14: 3.264)

25. The ocean captures a large part of the anthropogenic carbon 

dioxide emitted to the atmosphere. As a result of the increase in 

CO2 partial pressure the ocean pH is lowered as compared to preindustrial times and a further decline is expected. Ocean 

acidification has been proposed to pose a major threat for marine 

organisms, particularly shell-forming and calcifying organisms. The 

authors showed, on the basis of meta-analysis of available 

experimental assessments, differences in organism responses 

to elevated pCO2 and propose that marine biota may be more 

resistant to ocean acidification than expected. Calcification is 

most sensitive to ocean acidification while it is questionable if 

marine functional diversity is impacted significantly along the 

ranges of acidification predicted for the 21st century. Active 

biological processes and small-scale temporal and spatial 

variability in ocean pH may render marine biota far more 

Hendriks IE, Duarte CM, Alvarez MA 

(2010) Vulnerability of marine 

biodiversity to ocean acidification: a 

meta-analysis. Estuarine, Coastal 

and Shelf Science 86: 157–164.

(impact factor 2013/14: 2.25)
September 2015

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resistant to ocean acidification than hitherto believed.

26. Marine phytoplankton have many obvious characters, such as 

rapid cell division rates and large population sizes, that give them 

the capacity to evolve in response to global change on timescales 

of weeks, months or decades. However, few studies directly 

investigate if this adaptive potential is likely to be realized. Because 

of this, evidence of to whether and how marine phytoplankton may 

evolve in response to global change is sparse. There is limited 

support from experimental evolution that some taxa of marine 

phytoplankton may adapt to ocean acidification, and strong 

indications from studies of variation and structure in natural 

populations that selection on standing genetic variation is 

likely.

Collins S, Rost B, Rynearson TA 

(2014) Evolutionary potential of 

marine phytoplankton under ocean 

acidification. Evol Appl. 7(1): 140–

155.

(impact factor 2013/14: 4.23)

27. The ongoing ocean acidification associated with a changing 

carbonate system may impose profound effects on marine 

planktonic calcifiers. The authors showed that a coccolithophore, 

Gephyrocapsa oceanica, evolved in response to an elevated CO2 

concentration of 1000 μatm (pH reduced to 7.8) in a long-term 

(∼670 generations) selection experiment. The high CO2-selected 

cells showed increases in photosynthetic carbon fixation, growth 

rate, cellular particulate organic carbon (POC) or nitrogen (PON) 

production, and a decrease in C:N elemental ratio, indicating a 

greater upregulation of PON than of POC production under the 

ocean acidification condition. Cells from the low CO2 selection 

process shifted to high CO2 exposure showed an enhanced cellular 

POC and PON production rates. The data suggest that the 

coccolithophorid could adapt to ocean acidification with 

enhanced assimilations of carbon and nitrogen but decreased 

C:N ratios.

Jin P, Gao K, Beardall J (2013) 

Evolutionary responses of a 

coccolithophorid

Geophyrocapsa oceanica to ocean 

acidification. Evolutionary Biology 

67:1869–1878.

(impact factor 2013/14: 4.23)

28. Ocean acidification in response to rising atmospheric CO2

partial pressures is widely expected to reduce calcification by 

marine organisms. From the mid-Mesozoic, coccolithophores have 

been major calcium carbonate producers in the world's oceans, 

today accounting for about a third of the total marine CaCO3

production. The authors present laboratory evidence that 

calcification and net primary production in the coccolithophore 

species Emiliania huxleyi are significantly increased by high 

CO2 partial pressures. Field evidence from the deep ocean is 

consistent with these laboratory conclusions, indicating that 

over the past 220 years there has been a 40% increase in 

average coccolith mass. The study shows that coccolithophores 

are already responding and will probably continue to respond to 

rising atmospheric CO2 partial pressures, which has important 

implications for biogeochemical modeling of future oceans and 

climate.

Iglesias-Rodriguez MD, Halloran PR, 

Rickaby REM, Hall IR, ColmeneroHidalgo E, Gittins JR, Green DRH, 

Tyrrell T, Gibbs SJ, von Dassow P et 

al.

(2008) Phytoplankton calcification in 

a high CO2 world. Science 320: 336–

340.

(impact factor 2008: 28.1)
September 2015

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APPENDIX B

6 examples in the petition exaggerating ocean acidification 

effects by selecting studies with maximal impacts; or 

misquoting or overstating study results.
September 2015

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The primary study by Barton et al. 2008 (The Pacific oyster, Crassostrea gigas, shows negative 

correlation to naturally elevated carbon dioxide levels: Implications for near-term ocean acidification 

effects. Limnology and Oceanography, 57(3), pp.698–710.) is cited 5 times relating to 4 issues in the 

petition. 

We find 3 of 4 citations to the Barton et al. study problematic for the following reasons: either there is no 

background in the Barton et al. 2008 study for the petition claims or the generality and confidence of study 

results are exaggerated compared to Barton et al.'s presentation of the results.

1.

p.12

Petition citation: 

"The harmful effects of ocean acidification have already begun to occur. For example, ocean

acidification has caused:

 A massive die-off of oysters in the Pacific Northwest (Barton et al. 2012; R. A. Feely,

Sabine, et al. 2012; Washington State Blue Ribbon Panel 2012);”

Comment: This claim of a massive die-off of oysters in the Pacific Northwest cannot be found in 

Barton et al.’s publication. 

The closest we could find is:

"On the other hand, these larval mortality events often coincided with strong coastal upwelling and the 

presence of seawater thermodynamically unstable with respect to aragonite in Netarts Bay.”

5

2

p.13

Petition citation: 

"Corals, coralline algae, plankton, mollusks, and other shellfish exposed to future levels of ocean 

acidification have all experienced problems (Kleypas & Yates 2009; Kuffner et al. 2007; Barton et al.

2012; Talmage & Gobler 2011; Talmage & Gobler 2009; Orr et al. 2005; Riebesell et al. 2000).”

Comment: The problem (reduced growth in early larvae) in the Barton et al. 2008 study occurred 

when exposed to present day "ocean acidification" when intake water to the oyster hatchery was 

dominated of "upwelled CO2 rich water."

3

p.13

Petition citation: 

" Scientists have definitively linked oyster production failures to high-CO2 ocean waters that were 

used to raise larvae" (Barton et al. 2012)".

Comment: The authors are not as definite as claimed in petition (i.e. from last paragraph in 

Discussion section):

"Our study, relying on hatchery records and utilizing their production model, does potentially suffer 

from the lack of strict control as found in other more constrained experimental systems. We therefore 

acknowledge the correlative and suggestive nature of this study; however, it highlights the 

significance of current-day variable carbonate chemistry effects on commercially important species 

(and reliant regional economy) in surface waters and validates previous laboratory-based acidification 

experiments in which carbonate chemistry was manipulated. The significant effects on hatchery-

 

5 P. 699, second column
September 2015

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based oyster production indicates that local and regional acidification effects are already on us, and 

responses of these coupled natural human systems to increasing CO2 are likely unfavorable."6

p.14

Petition citation: 

"Unlike previous laboratory experiments, this study (Barton et al.) analyzed calcifying organism 

responses in the ambient-water CO2 chemistry of Oregon’s coastal waters. Larval production and 

mid-stage growth (~120 um to ~150 um) of the oyster, Crassostrea gigas, were both significantly 

negatively correlated with the chemistry of waters in which larval oysters were spawned and reared 

for the first 48 hours of life. Although the impact of the exposure was not immediate, the delayed 

reaction caused a significant decline in growth for mid-sized oyster larvae and reduced overall 

production.”

Comment: citation OK

 

6 Emphasis added.
September 2015

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4. The meta-analysis by Kroeker et al. (2013) is cited once in the petition on page 13 of the petition 

but this publication is not listed in the petition’s bibliography. Based on the description in petition,

we assume that the reference is to: Kroeker et al. (2013) Impacts of ocean acidification on marine 

organisms: quantifying sensitivities and interaction with warming. Global Change Biology 19: 1884–

1896. Kroeker (2011) is also not listed in the bibliography.

Overall, there are inconsistencies in the petition regarding the Kroeker studies; namely, neither of the 

Kroeker studies in 2013 or 2010 as cited by the petition analyzed "over 400 experiments" as stated in the 

petition.

p.13

Petition citation: 

"In a meta-analysis of over 400 experiments examining the impacts of ocean acidification on marine 

organisms, Kroeker et al. (2013) found the biological effects to be generally large and negative. This 

analysis was restricted to experiments with pH manipulations of less than 0.5 units, in order to reflect 

the predicted level of ocean acidification by the end of the century (IPCC 2007). By limiting the 

analysis to small variations in pH, this study shows that within the foreseeable future ocean 

acidification will have “profound repercussions for marine organisms” (Kroeker et al. 2010). While the 

negative effect of ocean acidification was most pronounced for calcification and survival (27% 

reductions in both responses), the study also revealed significant negative effects on growth and 

reproduction (11 to 19%, respectively). In addition, abundance was reduced by 15%. The strength of 

this analysis suggests that the patterns highlighted in this study are a robust representation of the 

current literature on ocean acidification.”

7

Comment: 

 The Kroeker et al. (2010) meta-analysis encompassed 73 studies and 251 experiments (not 

over 400 experiments).

 The Kroeker et al. (2013) meta-analysis encompassed 228 studies and 367 experiments (not 

over 400 experiments). The 2013 study included all experiments from the earlier Kroeker et 

al. (2010) study.

 The stated percentages underscored in citation above are without citations and appear to 

refer to the Kroeker et al. (2013) study.

It is noteworthy that the petition only refers to the two Kroeker meta-analyses but does not mention the 

comparable meta-analysis by Hendriks8et al. (2010) that was based on 372 experiments, and concluded the 

following; "Here we show, on the basis of meta-analysis of available experimental assessments, differences 

in organism responses to elevated pCO2 and propose that marine biota may be more resistant to ocean 

acidification than expected. Calcification is most sensitive to ocean acidification while it is questionable if 

marine functional diversity is impacted significantly along the ranges of acidification predicted for the 21st

century. Active biological processes and small-scale temporal and spatial variability in ocean pH may render 

marine biota far more resistant to ocean acidification than hitherto believed."9 

 

7 Emphasis added.

8 Hendriks IE, Duarte CM, Alvarez MA (2010) Vulnerability of marine biodiversity to ocean acidification: a meta-analysis. Estuarine, Coastal and Shelf Science 86: 157–164.

9

Id. In Abstract
September 2015

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5. Petition claims that ocean acidification may increase harmful algal bloom (HAB) and will increase 

toxin concentrations in cells; however, alternative hypotheses or studies are not considered.

Based on two primary studies by Tatters et al. 2012, 2013 (and by Fu et al. 2012) it is claimed in the petition 

(p. 26) as follows:

p.26

Petition citation: 

"High CO2 levels in seawater magnify the toxins of harmful algae. (Fu et al. 2012; Avery O. Tatters et 

al. 2012; Avery O. Tatters et al. 2013). Studies of the genus Pseudo-nitzscia show that the toxicity of 

diatoms which produce a neurotoxin increases significantly under ocean acidification conditions. A -

0.5pH change caused toxin production in the diatoms to increase 4.2-fold and a -0.3pH unit change 

increased the toxicity 2.5-fold. Many studies on the effects of ocean acidification and algal blooms 

have been conducted at CO2 levels that are already occurring in California, and the increase in the 

toxicity of harmful algal blooms in Southern California (and resulting mass mortalities of fish and 

marine mammals) may be due, in part, to acidified waters.

10 However, these studies suggest that the 

damage will become much worse.”

11

Comment:

 Different species and strains within Pseudo-nitzscia may differ in response to pH. However, it 

is highly surprising that Tatters et al. did not cite the study of Lundholm N, Hansen PJ, Kotaki 

Y (2004) Effect of pH on growth and domoic acid production by potentially toxic diatoms of the 

genera Pseudo-nitzschia and Nitzschia. Mar Ecol Prog Ser 273:1-15. They found an opposite 

response to pH-change: that the domoic acid production and concentration increased with pH 

increase.12

 The 5-year project "A Regional Comparison of Upwelling and Coastal Land Use Patterns on

the Development of HAB Hotspots Along the California Coast" funded through NOAA’s 

Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Program do not consider OA 

as a trigger for Pseudo-nitzschia blooms along the California coast.

13

At this website, “HAB Hotspots researchers have developed 3 hypotheses for Psuedo nitzchia 

bloom and toxin initiation: 

1. “Blooms start as subsurface accumulations (subsurface maxima) and eventually manifest 

as surface blooms.

2. Blooms are predominantly caused by advective processes and retention in eddy-like 

circulation; subsurface maxima are less important.

3. There are a unique set of environmental conditions leading from bloom initiation to toxicity 

that can be identified through a comparative approach, allowing us to contrast potential 

factors (such as stratification, nutrient load, nutrient type) between regions.

The alternate hypotheses are that HAB events in California are truly stochastic and/or the 

underlying ecophysiological responses are so complex that relatively simple conceptual models 

such as proposed here do not adequately explain bloom and toxin initiation.”

14

 

10 Id.

11 Emphasis added.

12 Emphasis added.

13 http://oceandatacenter.ucsc.edu/MBHAB/hotspots; last accessed August 29, 2015.

14 Id.
September 2015

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6. Petition claims that ocean acidification will increase noise pollution potentially affecting mammals

and other marine life; however, alternative studies are not considered.

Based on two primary studies by Hester et al. (2008)15, and Brewer et al. (2009)16 (neither appear in petition 

bibliography), it is claimed in the petition (p. 26) that ocean acidification can also decrease the sound 

absorption of seawater.

p.26

Petition citation: 

"Ocean acidification can also decrease the sound absorption of seawater, causing sounds to travel 

further with potential impacts on marine mammals and other marine life sensitive to the sounds of 

vessel traffic, seismic surveys, and other noise pollution (Hester et al. 2008). Sound travels 10-15 

percent further with a change of 0.1 pH, and it is predicted to increase about 40 percent by midcentury (Hester et al. 2008). Additionally, a decline of 0.3 pH units causes a 40 percent decrease in 

the sound absorption of surface seawater and sound may travel 70 percent farther, further affecting 

sensitive marine mammals (Brewer et al. 2009).”

Comment:

As stated at the “The Discovery of Sound in the Sea” website developed by the University of Rhode 

Island’s Graduate School of Oceanography (GSO) in partnership with Marine Acoustics, Inc,,

http://www.dosits.org/science/soundsinthesea/oceanacidification/ last accessed August 29, 2015):

 “Sound propagation in the ocean is sufficiently complex that sophisticated computer 

models are needed to accurately assess the likely changes in low-frequency noise levels 

due to the decrease in sound absorption caused by ocean acidification. A realistic 

calculation17 indicates that the expected increase in noise levels from 1960 to 2250 over 

the frequency range 50–2000 Hz is likely to be less than about 0.2 dB, for a scenario that 

gives a change in surface pH of 0.7 units over that time Another recent calculation18

results in a predicted change in noise levels of less than 0.5 dB for all frequencies in the 

deep ocean, and no observable change in shallow water, for a decrease in pH from 8.1 to 

7.4 pH units.”

 

15 We assume Petition refers to Hester KC, Peltzer ET, Kirkwood WJ, Brewer PG (2008) Unanticipated consequences of ocean acidification: A noisier ocean at lower pH. Geophys. Res. Lett. 35: 

19601.

16 We assume Petition refers to Brewer PG, Hester KC (2009) Ocean acidification and the increasing transparency of the ocean to low-frequency sound. Oceanography 22: 86–93.

17 Joseph JE, Chiu C-S ( 2010) A computational assessment of the sensitivity of ambient noise level to ocean acidification. J. Acoust. Soc. Am. 128, 144-149.

18 Reeder DB, Chiu C.-S. (2010) Ocean acidification and its impact on ocean noise: Phenomenology and analysis. J. Acoust. Soc. Am. 128, 137-143.
September 2015

Report No. 1537019

APPENDIX C

List of citations to scientific literature in the text of the petition 

that are not included in petition’s bibliography.
September 2015

Report No. 1537019

Page in 

Petition

74 unique references cited in the text of the petition but not found in petition’s 

bibliography

9 1. Sabine et al. 2004

2. Ishii et al. 2011

3. Joos et al. 2011

10 4. Harris, DeGrandpre et al. 2013

11 5. Fabry et al. 2009 (Fabry 2008 is provided in the bibliography.)

6. Mathis et al. 2011a

12 7. Dore et al. 2009

13 8. Bednarsek 2014

9. Kroeker et al. 2013

10. Kroeker et al. 2010

14 11. Kurihara & Shirayama 2004

12. Ross et al. 2011

13. Watson et al. 2009

14. Waldbusser et al. 2010

15. Hettinger et al. 2012

15 16. Dickinson et al. (2012)

Ross et al. 2011 (repeat cite)

17. Parker et al. 2010

18. Zippay and Hoffman 2010

19. Gazeau et al. 2007

20. Kurihara 2008

21. Findlay et al. 2010

22. Hauton et al. 2009

Ross et al. 2011 (repeat cite)

23. Gutowska et al. 2009

16 Kurihara 2008 (repeat cite)

Kurihara & Shirayama 2004 (repeat cite)

24. Suwa et al. 2010

25. Shirayama & Thornton 2005

17 26. Ellis et al. 2009

27. Arnold et al. 2009

28. Albright 2011

29. Bibby et al. 2008

30. Frieler et al. 2012

18 31. Caldeira & Archer 2007

19 32. Anthony et al. 2011

33. Anlauf et al. 2011

34.Hoegh-Guldberg et al. 2007

35. Van Hooidonk et al. 2014 (cited 2013)

36. Buddemeier et al. 2011

37. Abbasi & Abbasi 2011

38. Albright et al. 2010
September 2015

Report No. 1537019

20 39. Murubini et al. 2003

Albright et al. 2010 (repeat cite)

40. Cohen & Holcomb 2009

41. Renegar and Riegl 2005

42. De Mol et al. 2002

43. Kenyon et al. 2003

44. Roberts & Hirshfield 2012 

45. Cairns 2007

46. McDonough & Puglise 2003

Abbasi & Abbasi 2011 (repeat cite)

Kurihara 2008 (repeat cite)

47. Dupont & Thorndyke 2009 

Kroeker et al. 2010 (repeat cite)

48. Maier et al. 2009

21 49. Manzello et al. 2008

50. Wissshak et al. 2012

51. Feary et al. 2007

52. Madin et al. 2012

Maier et al. 2009

53. McCulloch et al. 2012

54. Wood et al. 2008 

Cohen & Holcomb 2009 (repeat cite)

55. Albright & Langdon 2011

22 Albright et al. 2010

Albright and Langdon 2011

Suwa et al. 2010

56. Doropoulos et al. 2012

57. Dupont et al. 2010 

Ross et al. 2011

58. Guinotte et al. 2006

Hoegh-Guldberg et al. 2007 (repeat cite)

23 59. Gattuso & Hansson 2011

60. Comeau et al. 2012

61. Comeau et al. 2009

Bednarsek 2014 (repeat cite)

62. Bednarsek 2012

63. Comeau et al. 2010 

64. Lishka 2012

65. Mathis 2011

24 66. Nilsson et al. 2012

67. Dickson et al. 2010

25 68. Devine et al. 2011

69. Haugan 2006

70. Roberts, Birchenough et al. 2013

71. Hester et al. 2008

72. Brewer et al. 2009

28 73. Cooley and Doney 2009
September 2015

Report No. 1537019

74. Brander et al. 2009a
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T: +45 70 27 47 57
1 API Comments on TSCA Section 21 Petition on Carbon Dioxide

ATTACHMENT 2

VARIABILITY IN pH: SELECT NOAA SAMPLING SITES MEASURING pH IN OPEN 

OCEAN WATERS OF THE PACIFIC AND COASTAL WATERS OF THE U.S.1

Ocean Station Papa (Station Papa). This site has one of the longest records of time-series 

measurements in the ocean. However, even for this site, the pH sensor was only installed on 

June 15, 2010. It is an open ocean site – hence the modest variability in pH.

 1 Note: http://www.pmel.noaa.gov/co2/story/OA+Observations+and+Data; last accessed Aug. 24, 2015. For full set 

of current data on all 21 mooring sites, please see NOAA website.
2 API Comments on TSCA Section 21 Petition on Carbon Dioxide

WHOTS. This station is the WHOI Hawaii Ocean Time-series Station Mooring. The mooring 

is located in open ocean waters roughly 100 km north of Oahu, Hawaii. On July 7, 2011, a 

surface seawater pH sensor was added to the WHOTS Mooring. Note the sparse pH data and the 

modest variability consistent with its open ocean location.

Gulf of Maine. This monitor is located in the coastal Western Gulf of Maine. The buoy is in 

approximately 65 meters of water. The pH sensor was added on September 9, 2010. Note the 

far greater variability at the station compared to Papa, above. (Incomplete chart available at 

pmel.noaa.gov; last accessed August 24, 2015).
3 API Comments on TSCA Section 21 Petition on Carbon Dioxide

La Push, Washington. The station is located on the NANOOS UW Mooring off of La Push, WA 

(47.97°N, 124.95°W). This monitor if off the outer coast of Washington near La Push. The 

surface seawater pH sensor were deployed on the buoy on July 16, 2010. Note the considerable 

variability in pH, especially compared to Papa. (Incomplete chart available at pmel.noaa.gov; 

last accessed August 24, 2015). 
4 API Comments on TSCA Section 21 Petition on Carbon Dioxide

Gray’s Reef. This station is located at the National Data Buoy Center (NDBC), approximately 

40 nautical miles Southeast of Savannah, Georgia in Gray's Reef National Marine Sanctuary. On 

September 19, 2011, a surface seawater pH sensor was added to the Grays Reef mooring. Note 

the high degree of variability in the measured pH values. (Chart as found on NOAA website 

with jumbled months on x axis).
5 API Comments on TSCA Section 21 Petition on Carbon Dioxide

CCE2. This station is the California Current Ecosystem Mooring 2 (CCE2). This mooring is 

part of a multi-investigator, multi-disciplinary project with two surface moorings in the 

California Current. CCE-2 is positioned on the shelf break on the California Coast, where 

localized upwelling processes are at their maximum. On March 24, 2012, a surface seawater pH 

sensor was added to the CCE2 mooring. Note the high degree of pH variability. (Incomplete 

chart available at pmel.noaa.gov; last accessed August 24, 2015).

]
6 API Comments on TSCA Section 21 Petition on Carbon Dioxide

Kaneohe Bay. The station is in Kaneohe Bay, located on the eastern side of Oahu, Hawaii, and 

is a complex estuarine system with a large barrier coral reef, numerous patch reefs, fringing 

reefs, and several riverine inputs. The Kaneohe buoy was deployed on September 29, 2011 in 

approximately 60 feet of water on the open ocean side of the barrier reef. On September 29, 

2011, a surface seawater pH sensor was added to the Kaneohe mooring.

Cheeca Rocks. The station is at Cheeca Rocks, which is an inshore patch reef within the Florida

Keys National Marine Sanctuary (FKNMS) off of Islamorada, Florida. On December 7, 2011, a 

surface seawater pH sensor was added to the Cheeca Rocks mooring. Note the high degree of 

pH variability.
7 API Comments on TSCA Section 21 Petition on Carbon Dioxide

La Parguera. The station at La Parguera is located on the southwestern coast of Puerto Rico in 

the municipality of Lajas. On December 2, 2011, a surface seawater pH sensor was added to the 

La Parguera mooring. The La Parguera Natural Reserve includes all the coastline of the 

municipality of Lajas extending 1 km towards land from the shore and 9 nautical miles offshore. 

Marine and coastal ecosystem including: mangroves, seagrass, reefs, bays and salt 

marshes. Note the high degree of pH variability.