World Library  
Flag as Inappropriate
Email this Article
 

Ocean acidification

World map showing varying change to pH across different parts of different oceans
Estimated change in sea water pH caused by human created CO
2
between the 1700s and the 1990s, from the Global Ocean Data Analysis Project (GLODAP) and the World Ocean Atlas

NOAA provides evidence for upwelling of "acidified" water onto the Continental Shelf. In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) pCO2 on transect line 5 off Pt. St. George, California. The potential density surfaces are superimposed on the temperature section. The 26.2 potential density surface delineates the location of the first instance in which the undersaturated water is upwelled from depths of 150 to 200 m onto the shelf and outcropping at the surface near the coast. The red dots represent sample locations.[1]

Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere.[2] An estimated 30–40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes.[3][4] To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion, thus increasing ocean acidity (H+ ion concentration). Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14,[5] representing an increase of almost 30% in H+ ion concentration in the world's oceans.[6][7] Earth System Models project that within the last decade ocean acidity exceeded historical analogs[8] and in combination with other ocean biogeochemical changes could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean.[9]

Increasing acidity is thought to have a range of possibly harmful consequences, such as depressing metabolic rates and immune responses in some organisms, and causing coral bleaching. This also causes decreasing oxygen levels as it kills off algae.

Other chemical reactions are triggered which result in a net decrease in the amount of coral and some plankton, to form biogenic calcium carbonate, and such structures become vulnerable to dissolution.[10] Ongoing acidification of the oceans threatens food chains connected with the oceans.[11][12] As members of the InterAcademy Panel, 105 science academies have issued a statement on ocean acidification recommending that by 2050, global CO2 emissions be reduced by at least 50% compared to the 1990 level.[13]

Ocean acidification has been called the "evil twin of global warming"[14][15][16][17][18] and "the other CO2 problem".[15][17][19]

Ocean acidification has occurred previously in Earth's history. The most notable example is the Paleocene-Eocene Thermal Maximum (PETM),[20] which occurred approximately 56 million years ago. For reasons that are currently uncertain, massive amounts of carbon entered the ocean and atmosphere, and led to the dissolution of carbonate sediments in all ocean basins.

Contents

  • Carbon cycle 1
  • Acidification 2
    • Rate 2.1
  • Calcification 3
    • Overview 3.1
    • Mechanism 3.2
    • Saturation state 3.3
  • Possible impacts 4
    • Impacts on oceanic calcifying organisms 4.1
    • Other biological impacts 4.2
    • Nonbiological impacts 4.3
    • Impact on human industry 4.4
    • Impact on indigenous peoples 4.5
  • Possible responses 5
    • Reducing CO2 emissions 5.1
    • Climate engineering 5.2
      • Iron fertilization 5.2.1
    • Carbon negative fuels 5.3
  • Gallery 6
  • See also 7
  • References 8
  • Further reading 9
  • External links 10
    • Carbonate system calculators 10.1

Carbon cycle

The CO
2
cycle between the atmosphere and the ocean

The carbon cycle describes the fluxes of carbon dioxide (CO
2
) between the oceans, terrestrial biosphere, lithosphere,[21] and the atmosphere. Human activities such as the combustion of fossil fuels and land use changes have led to a new flux of CO
2
into the atmosphere. About 45% has remained in the atmosphere; most of the rest has been taken up by the oceans,[22] with some taken up by terrestrial plants.[23]

Distribution of (A) aragonite and (B) calcite saturation depth in the global oceans[24]
The map was created by the National Oceanic and Atmospheric Administration and the Woods Hole Oceanographic Institution using Community Earth System Model data. This map was created by comparing average conditions during the 1880s with average conditions during the most recent 10 years (2003–2012). Aragonite saturation has only been measured at selected locations during the last few decades, but it can be calculated reliably for different times and locations based on the relationships scientists have observed among aragonite saturation, pH, dissolved carbon, water temperature, concentrations of carbon dioxide in the atmosphere, and other factors that can be measured. This map shows changes in the amount of aragonite dissolved in ocean surface waters between the 1880s and the most recent decade (2003–2012). Aragonite saturation is a ratio that compares the amount of aragonite that is actually present with the total amount of aragonite that the water could hold if it were completely saturated. The more negative the change in aragonite saturation, the larger the decrease in aragonite available in the water, and the harder it is for marine creatures to produce their skeletons and shells. The global map shows changes over time in the amount of aragonite dissolved in ocean water, which is called aragonite saturation.

The carbon cycle involves both

The following packages calculate the state of the carbonate system in seawater (including pH):

Carbonate system calculators

  • The Other CO
    2
    Problem
    , an EPOCA-commissioned educational animation created by students from Ridgeway School, Plymouth
  • Acid Test: The Global Challenge of Ocean Acidification, by Natural Resources Defense Council
  • A Sea Change: Imagine a world without fish, an award-winning documentary and related blog about ocean acidification
  • Ocean Acidification in a Nutshell, by Greenpeace Aotearoa New Zealand
  • Ocean Acidification: An Ecosystem Facing Dissolution by GEOMAR I Helmholtz-Centre for Ocean Research Kiel
  • Lethal SeasNOVA , visit a unique coral garden in Papua New Guinea that offers a glimpse of what the seas could be like a half-century from now.

Videos on Ocean Acidification:

Popular media sources:

  • Effects of Climate Change and Ocean Acidification on Living Marine Organisms: Hearing before the Subcommittee on Oceans, Atmosphere, Fisheries, and Coast Guard of the Committee on Commerce, Science, and Transportation, United States Senate, One Hundred Tenth Congress, First Session, May 10, 2007
  • The Environmental and Economic Impacts of Ocean Acidification: Hearing before the Subcommittee on Oceans, Atmosphere, Fisheries, and Coast Guard of the Committee on Commerce, Science, and Transportation, United States Senate, One Hundred Eleventh Congress, Second Session, April 22, 2010
  • Ocean Acidification Congressional Research Service

Government sources:

  • – Smithsonian Ocean PortalDr. Francisco Chavez on Ocean Acidification
  • European Project of Ocean Acidification (EPOCA), a 4-year-long EU initiative to investigate ocean acidification (initiated June 2008)
  • Biological Impacts of Ocean Acidification (BIOACID), a German initiative funded by BMBF
  • Ocean Acidification Research Programme (UKOARP), a 5-year-long UK initiative funded by NERC, Defra and DECC
  • Research Program on Ocean Acidification at the Cluster of Excellence "Future Ocean", Kiel
  • Ocean Acidification Research Center at University of Alaska Fairbanks

Scientific projects:

  • Ocean Acidification overview from the Smithsonian Ocean Portal
  • Understanding Ocean Acidification -- Educational Site from Channel Islands National Marine Sanctuary -- Education Team

Educational sites:

  • Ocean Acidification International Coordination Centre (OA-ICC), a project operated by the International Atomic Energy Agency through its Environment Laboratories (Monaco)
  • A news stream provided by the Ocean Acidification International Coordination Centre (OA-ICC), provides daily information on ocean acidification (scientific papers, jobs, media coverages, meeting announcements etc.). Subscribe free of charge via email, RSS or Twitter.
  • How Acidification Threatens Oceans from the Inside Out Scientific American August 9, 2010 by Marah J. Hardt and Carl Safina
  • Ocean acidification due to increasing atmospheric carbon dioxide, report by the Royal Society (UK)
  • AR4 WG1 Chapter 5: Oceanic Climate Change and Sea Level, IPCC
  • State of the Science FACT SHEET: Ocean acidification, NOAA
  • Carbon Dioxide Information Analysis Center (CDIAC), the primary data analysis center of the U.S. Department of Energy (located at Oak Ridge National Laboratory)
  • Ocean acidification introduction, USGS
  • Climate change threatening the Southern Ocean, report by CSIRO
  • WorldCO
    2
    The Ocean in a High , an international science symposium series
  • EmissionCO
    2
    The Acid Ocean – the Other Problem with , David Archer (scientist), a RealClimate discussion
  • Regularly updated "blog" of ocean acidification publications and news, Jean-Pierre Gattuso
  • Task Force on Ocean Acidification in the Pacific, including recent presentations on ocean acidification, Pacific Science Association
  • Ocean Acidification, a multimedia, interactive site from The World Ocean Observatory
  • Acidic Oceans: Why should we care? Perspectives in ocean science, Andrew Dickson, Scripps Institution of Oceanography
  • Climate Change: Coral Reefs on the Edge A video presentation by Prof. Ove Hoegh-Guldberg on impact of ocean acidification on coral reefs
  • Life in the Sea Found Its Fate in a Paroxysm of Extinction April 30, 2012
  • Ocean acidification virtual lab
  • Ocean Acidification: Starting with the Science, a booklet from the Division on Earth & Life Studies of the United States National Research Council (released April 2011)
  • Ocean Acidification, a United States National Academy of Sciences/ National Research Council website that includes downloadable figures and interviews with ocean scientists
  • Ancient Ocean Acidification Intimates Long Recovery from Climate Change, July 22, 2010
  • Acidification alters fish behavior: higher carbon dioxide in oceans may affect brain chemistry February 25, 2012 Science News
  • Coordination of international research efforts and synthesis activities in ocean acidification. IMBER/SOLAS

Scientific sources:

External links

  • Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC) (2008). emissions and climate change: Ocean impacts and adaptation issues.2Position analysis: CO ISSN: 1835–7911. Hobart, Tasmania.
  • Cicerone, R.; et al.; J. Orr, P. Brewer (2004). World"CO
    2
    "The Ocean in a High (PDF).  
  • Doney, S. C. (2006). "The Dangers of Ocean Acidification".  , (Article preview only).
  • Drake, J.L.; Mass, T.; Falkowski, P. G. (2014). "The evolution and future of carbonate precipitation in marine invertebrates: Witnessing extinction or documenting resilience in the Anthropocene?". Elementa 2: 000026.  
  • Feely, R. A.; Sabine, Christopher L.; Lee, Kitack; Berelson, Will; Kleypas, Joanie; Fabry, Victoria J.; Millero, Frank J. (2004). System in the Oceans"CaCO
    3
    on the CO
    2
    "Impact of Anthropogenic .  
  • Harrould-Kolieb, E.; Savitz, J. (2008). ?"2"Acid Test: Can We Save Our Oceans From CO. Oceana. 
  •  
  • Jacobson, M. Z. (2005). "Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry".  
  • Kim, Rakhyun E. (2012). "Is a New Multilateral Environmental Agreement on Ocean Acidification Necessary?" (PDF). Review of European Community & International Environmental Law 21 (3): 243–258.  
  • Kleypas, J. A., R. A. Feely, V. J. Fabry, C. Langdon, C. L. Sabine, and L. L. Robbins. (2006). Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers: A Guide for Further Research, report of a workshop held 18–20 April 2005, St. Petersburg, FL, sponsored by National Science Foundation, NOAA and the U.S. Geological Survey, 88pp.
  •  
  • Mathis, J.T.; Feely, R. A. (2014). "Building an integrated coastal ocean acidification monitoring network in the U.S.". Elementa 1: 000007.  
  • Riebesell, U., V. J. Fabry, L. Hansson and J.-P. Gattuso (Eds.). (2010). Guide to best practices for ocean acidification research and data reporting, 260 p. Luxembourg: Publications Office of the European Union.
  • Sabine, C. L.; Feely, Richard A.; Gruber, Nicolas; Key, Robert M.; Lee, Kitack; Bullister, John L.; et al. (2004). "CO
    2
    "The Oceanic Sink for Anthropogenic . Science 305 (5682): 367–371.  
  • Stone, R. (2007). "A World Without Corals?".  

Further reading

  • Clarke, L.; et al. (July 2007). "Scenarios of Greenhouse Gas Emissions and Atmospheric Concentrations. Sub-report 2.1A of Synthesis and Assessment Product 2.1 by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research". Washington, DC., USA: Department of Energy, Office of Biological & Environmental Research 
  • Good, P.; et al. (2010). "An updated review of developments in climate science research since IPCC AR4. A report by the AVOID consortium" (PDF). London, UK: Committee on Climate Change . Report website.
  • UK Royal Society (September 2009). "Geoengineering the climate: science, governance and uncertainty" (PDF). London: UK Royal Society. , RS Policy document 10/09. Report website.  
  • UNEP (November 2010). "The Emissions Gap Report: Are the Copenhagen Accord pledges sufficient to limit global warming to 2°C or 1.5°C? A preliminary assessment". Nairobi, Kenya: United Nations Environment Programme (UNEP).  
  • US NRC (2011). America's Climate Choices. A report by the Committee on America's Climate Choices, US National Research Council (US NRC). Washington, DC, USA: National Academies Press.  
  • WBGU (2006). Special Report: The Future Oceans – Warming Up, Rising High, Turning Sour (PDF). Berlin, Germany: WBGU. . Report website.  
  1. ^ "Feely et al. - Evidence for upwelling of corrosive "acidified" water onto the Continental Shel". pmel.noaa.gov. Retrieved 2014-01-25. 
  2. ^ a b c Caldeira, K.; Wickett, M. E. (2003). "Anthropogenic carbon and ocean pH".  
  3. ^ Millero, Frank J. (1995). "Thermodynamics of the carbon dioxide system in the oceans". Geochimica et Cosmochimica Acta 59 (4): 661–677.  
  4. ^ Feely, R. A.; et al. (July 2004). "Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans". Science 305 (5682): 362–366.  
  5. ^ Jacobson, M. Z. (2005). "Studying ocean acidification with conservative, stable numerical schemes for nonequilibrium air-ocean exchange and ocean equilibrium chemistry".  
  6. ^ a b c Hall-Spencer, J. M.; et al.; Rodolfo-Metalpa, R.; Martin, S. (July 2008). "Volcanic carbon dioxide vents show ecosystem effects of ocean acidification".  
  7. ^ a b Report of the Ocean Acidification and Oxygen Working Group, International Council for Science's Scientific Committee on Ocean Research (SCOR) Biological Observatories Workshop
  8. ^ Mora, C (2013). "The projected timing of climate departure from recent variability". Nature 502: 183–187.  
  9. ^ a b c d e f Mora, C.; et al. (2013). "Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century". PLoS Biology 11: e1001682.  
  10. ^ a b c d e f g h Orr, James C.; et al. (2005). "Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms" (PDF).  
  11. ^ Cornelia Dean (January 30, 2009). "Rising Acidity Is Threatening Food Web of Oceans, Science Panel Says". New York Times. 
  12. ^ Robert E. Service (13 July 2012). "Rising Acidity Brings and Ocean Of Trouble". Science 337 (6091): 146–148.  
  13. ^ a b c d IAP (June 2009). "Interacademy Panel (IAP) Member Academies Statement on Ocean Acidification". , Secretariat: TWAS (the Academy of Sciences for the Developing World), Trieste, Italy.
  14. ^ a b Huffington Post, 9 July 2012, "Ocean Acidification Is Climate Change's 'Equally Evil Twin,' NOAA Chief Says," http://www.huffingtonpost.com/2012/07/09/ocean-acidification-reefs-climate-change_n_1658081.html?utm_hp_ref=green
  15. ^ a b The other carbon dioxide problem http://www.rsc.org/chemistryworld/2014/07/ocean-acidification
  16. ^ Global warming’s evil twin: ocean acidification http://theconversation.com/global-warmings-evil-twin-ocean-acidification-19017
  17. ^ a b Hennige, S.J. (2014). "Short-term metabolic and growth responses of the cold-water coral Lophelia pertusa to ocean acidification". Deep-Sea Research II 99: 27–35.  
  18. ^ Pelejero, C. (2010). "Paleo-perspectives on ocean acidification". Trends in Ecology and Evolution 25 (6): 332–344.  
  19. ^ Doney, S.C. (2009). Problem"2"Ocean Acidification: The Other CO. Annual Review of Marine Science 1: 169–192.  
  20. ^ Zachos, J.C.; Röhl, U.; Schellenberg, S.A.; Sluijs, A.; Hodell, D.A.; Kelly, D.C.; Thomas, E.; Nicolo, M.; Raffi, I.; Lourens, L. J.; McCarren, H.; Kroon, D. (2005). "Rapid acidification of the ocean during the Paleocene-Eocene thermal maximum". Science 308 (5728): 1611–1615.  
  21. ^ "carbon cycle".  
  22. ^ Raven, J. A.; Falkowski, P. G. (1999). "Oceanic sinks for atmospheric CO2".  
  23. ^ Cramer, W.; et al. (2001). "Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models".  
  24. ^ "Feely et al. - Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans". pmel.noaa.gov. Retrieved 2014-01-25. 
  25. ^ Kump, Lee R.;  
  26. ^ IPCC (2005). "IPCC Special Report on Carbon Dioxide Capture and Storage" (PDF). p. 390. 
  27. ^ a b c d e f g Raven, J. A. et al. (2005). Ocean acidification due to increasing atmospheric carbon dioxide. Royal Society, London, UK.
  28. ^ Bows, Kevin; Bows, Alice (2011). "Beyond 'dangerous' climate change: emission scenarios for a new world" (PDF).  
  29. ^ Turley, C. (2008). "Impacts of changing ocean chemistry in a high-CO
    2
    world".  
  30. ^ a b Feely, R. A.; Sabine, C. L.; Hernandez-Ayon, J. M.; Ianson, D.; Hales B. (June 2008). "Evidence for upwelling of corrosive "acidified" water onto the continental shelf".  
  31. ^ a b Key, R. M.; Kozyr, A.; Sabine, C. L.; Lee, K.; Wanninkhof, R.; Bullister, J.; Feely, R. A.; Millero, F.; Mordy, C. and Peng, T.-H. (2004). "A global ocean carbon climatology: Results from GLODAP".  
  32. ^ "Ocean acidification and the Southern Ocean" by the Australian Antarctic Division of the Australian Government
  33. ^ EPA weighs action on ocean acidification post at official blog of EPOCA, the European Project on Ocean Acidification
  34. ^ Review of Past IPCC Emissions Scenarios, IPCC Special Report on Emissions Scenarios (ISBN 0521804930).
  35. ^ Wootton, J. T.; Pfister, C. A. and Forester, J. D. (2008). "Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset".  
  36. ^ "Ocean Growing More Acidic Faster Than Once Thought; Increasing Acidity Threatens Sea Life".  
  37. ^ UN: Oceans are 30 percent more acidic than before fossil fuels
  38. ^ "What is Ocean Acidification". NOAA. Retrieved 24 August 2013. 
  39. ^ "Rate of ocean acidification the fastest in 65 million years". Physorg.com. 2010-02-14. Retrieved 2013-08-29. 
  40. ^ "An Ominous Warning on the Effects of Ocean Acidification by Carl Zimmer: Yale Environment 360". e360.yale.edu. Retrieved 2014-01-25. 
  41. ^ Report: Ocean acidification rising at unprecedented rate
  42. ^ United States National Research Council, 2010. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean
  43. ^ "The Geological Record of Ocean Acidification".  JournalistsResource.org, retrieved 14 March 2012
  44. ^ Hönisch, Bärbel; Ridgwell, Andy; Schmidt, Daniela N.; Thomas, E.; Gibbs, S. J.; Sluijs, A.; Zeebe, R.; Kump, L.; Martindale, R. C.; Greene, S. E.; Kiessling, W.; Ries, J.; Zachos, J. C.; Royer, D. L.; Barker, S.; Marchitto, T. M.; Moyer, R.; Pelejero, C.; Ziveri, P.; Foster, G. L.; Williams, B. (2012). "The Geological Record of Ocean Acidification".  
  45. ^ The Acid Ocean – the Other Problem with CO2 Emission
  46. ^ a b How Acidification Threatens Oceans from the Inside Out
  47. ^ Fiona Harvey, environment correspondent (2013-08-25). "Rising levels of acids in seas may endanger marine life, says study | Environment". The Guardian. Retrieved 2013-08-29. 
  48. ^ CO2 emissions threaten ocean crisis
  49. ^ Mitchell, M. J.; et al. (2010). "A model of carbon dioxide dissolution and mineral carbonation kinetics".  
  50. ^ Atkinson, M.J.; Cuet, P. (2008). "Possible effects of ocean acidification on coral reef biogeochemistry: topics for research".  
  51. ^ Thurman, H.V.; Trujillo, A.P. (2004). Introductory Oceanography. Prentice Hall.  
  52. ^ The Royal Society. Ocean Acidification Due To Increasing Atmospheric Carbon Dioxide, The Clyvedon Press Ltd. (2005): 11.
  53. ^ Marubini, F.; Ferrier-Pagès, C.; Furla, P.; Allemand, D. (2008). "Coral calcification responds to seawater acidification: a working hypothesis towards a physiological mechanism".  
  54. ^ a b Rosa, R.; Seibel, B. (2008). "Synergistic effects of climate-related variables suggest future physiological impairment in a top oceanic predator". P.n.a.s. 105 (52): 20776–20780.  
  55. ^ a b Bibby, R.; et al. (2008). "Effects of ocean acidification on the immune response of the blue mussel Mytilus edulis". Aquatic Biology 2: 67–74.  
  56. ^ Gooding, R.; et al. (2008). "Elevated water temperature and carbon dioxide concentration increase the growth of a keystone echinoderm". Proceedings of the National Academy of Sciences 106: 9316–21.  
  57. ^ Some like it acidic April 17, 2013 Science News
  58. ^ "Ocean Acidification Summary for Policymakers". IGBP. 
  59. ^ National Research Council. Overview of Climate Changes and Illustrative Impacts. Climate Stabilization Targets: Emissions, Concentrations, and Impacts over Decades to Millennia. Washington, DC: The National Academies Press, 2011. 1. Print.
  60. ^ Nienhuis, S.; Palmer, A.; Harley, C. (2010). affects shell dissolution rate but not calcification rate in a marine snail"2"Elevated CO.  
  61. ^ Gattuso, J.-P.; Frankignoulle, M.; Bourge, I.; Romaine, S. and Buddemeier, R. W. (1998). "Effect of calcium carbonate saturation of seawater on coral calcification".  
  62. ^ Gattuso, J.-P.; Allemand, D.; Frankignoulle, M. (1999). "Photosynthesis and calcification at cellular, organismal and community levels in coral reefs: a review on interactions and control by carbonate chemistry".  
  63. ^ Langdon, C.; Atkinson, M. J. (2005). "Effect of elevated pCO2 on photosynthesis and calcification of corals and interactions with seasonal change in temperature/irradiance and nutrient enrichment".  
  64. ^ Riebesell, Ulf; Zondervan, Ingrid; Rost, Björn; Tortell, Philippe D.; Zeebe, Richard E. and François M. M. Morel (2000). "Reduced calcification of marine plankton in response to increased atmospheric CO
    2
    ".  
  65. ^ Zondervan, I.; Zeebe, R. E., Rost, B. and Rieblesell, U. (2001). "Decreasing marine biogenic calcification: a negative feedback on rising atmospheric CO2". Global Biogeochemical Cycles 15 (2): 507–516.  
  66. ^ Zondervan, I.; Rost, B. and Rieblesell, U. (2002). "Effect of CO2 concentration on the PIC/POC ratio in the coccolithophore Emiliania huxleyi grown under light limiting conditions and different day lengths".  
  67. ^ Delille, B.; Harlay, J., Zondervan, I., Jacquet, S., Chou, L., Wollast, R., Bellerby, R.G.J., Frankignoulle, M., Borges, A.V., Riebesell, U. and Gattuso, J.-P. (2005). "Emiliania huxleyi during experimental blooms of the coccolithophorid 2"Response of primary production and calcification to changes of pCO. Global Biogeochemical Cycles 19 (2): GB2023.  
  68. ^ Kuffner, I. B.; Andersson, A. J., Jokiel, P. L., Rodgers, K. S. and Mackenzie, F. T. (2007). "Decreased abundance of crustose coralline algae due to ocean acidification".  
  69. ^ Phillips, Graham; Chris Branagan (2007-09-13). "Ocean Acidification – The BIG global warming story". ABC TV Science: Catalyst (Australian Broadcasting Corporation). Retrieved 2007-09-18. 
  70. ^ Gazeau, F.; Quiblier, C.; Jansen, J. M.; Gattuso, J.-P.; Middelburg, J. J. and Heip, C. H. R. (2007). on shellfish calcification"CO
    2
    "Impact of elevated .  
  71. ^ Comeau, C.; Gorsky, G., Jeffree, R., Teyssié, J.-L. and Gattuso, J.-P. (2009). "Impact of ocean acidification on a key Arctic pelagic mollusc ("Limacina helicina")".  
  72. ^ Buitenhuis, E. T.; de Baar, H. J. W. and Veldhuis, M. J. W. (1999). "Photosynthesis and calcification by Emiliania huxleyi (Prymnesiophyceae) as a function of inorganic carbon species".  
  73. ^ Nimer, N. A.; Merrett, M. J. (1993). "Calcification rate in Emiliania huxleyi Lohmann in response to light, nitrate and availability of inorganic carbon".  
  74. ^ a b Iglesias-Rodriguez, M. D.; Halloran, P. R., Rickaby, R. E. M., Hall, I. R., Colmenero-Hidalgo, E., Gittins, J.R., Green, D.R.H., Tyrrell, T., Gibbs, S.J., von Dassow, P., Rehm, E., Armbrust, E.V. and Boessenkool, K.P. (2008). "Phytoplankton Calcification in a High-CO2 World".  
  75. ^ Sciandra, A.; Harlay, J.; Lefevre, D.; et al. (2003). "Response of coccolithophorid Emiliania huxleyi to elevated partial pressure of CO2 under nitrogen limitation".  
  76. ^ Langer, G.; et al.; Geisen, M., Baumann, K. H. (2006). "Species-specific responses of calcifying algae to changing seawater carbonate chemistry".  
  77. ^ "Acidification Of Oceans May Contribute To Global Declines Of Shellfish, Study By Stony Brook Scientists Concludes" (Press release). School of Marine and Atmospheric Sciences at Stony Brook University. 27 September 2010. Retrieved 4 June 2012. 
  78. ^ Ruttiman, J. (2006). "Sick Seas".  
  79. ^ Cohen, A.; Holcomb, M. (2009). "Why Corals Care About Ocean Acidification: Uncovering the Mechanism" (PDF). Oceanography 24 (4): 118–127.  
  80. ^ Hannah L. Wood, John I. Spicer and Stephen Widdicombe (2008). "Ocean acidification may increase calcification rates, but at a cost".  
  81. ^ Fabricius, Katharina (2011). "Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations". Nature Climate Change.  
  82. ^ Dixson, D. L.; et al. (2010). "Ocean acidification disrupts the innate ability of fish to detect predator olfactory cues". Ecology Letters 13 (1): 68–75.  
  83. ^ Simpson, S. D.; et al. (2011). "Ocean acidification erodes crucial auditory behaviour in a marine fish". Biology Letters 7 (6): 917–20.  
  84. ^ Hester, K. C.; et al. (2008). "Unanticipated consequences of ocean acidification: A noisier ocean at lower pH" (PDF). Geophysical Research Letters 35 (19).  
  85. ^ Acid In The Oceans: A Growing Threat To Sea Life by Richard Harris. All Things Considered, 12 August 2009.
  86. ^ Kwok, Roberta. "Ocean acidification could make squid develop abnormally". University of Washington. Retrieved 2013-08-24. 
  87. ^ "Swiss marine researcher moving in for the krill". The Australian. 2008. 
  88. ^ "Ocean Acidification Promotes Disruptive and Harmful Algal Blooms on Our Coasts". 2014. 
  89. ^ Ridgwell, A.; Zondervan, I.; Hargreaves, J. C.; Bijma, J.; Lenton, T. M. (2007). "Assessing the potential long-term increase of oceanic fossil fuel CO2 uptake due to CO2-calcification feedback".  
  90. ^ Tyrrell, T. (2008). "Calcium carbonate cycling in future oceans and its influence on future climates".  
  91. ^ "Effects of Ocean Acidification on Marine Species & Ecosystems". Report. OCEANA. Retrieved October 13, 2013. 
  92. ^ a b Lischka S., B ̈ udenbender J., Boxhammer T., Riebesell U. (15 April 2011). "Impact of ocean acidification and elevated temperatures on early juveniles of the polar shelled pteropod Limacina helicina : mortality, shell degradation, and shell growth" (PDF). Report. Biogeosciences. pp. 919–932. Retrieved 14 November 2013. 
  93. ^ "Comprehensive study of Arctic Ocean acidification". Study. CICERO. Retrieved 14 November 2013. 
  94. ^ "Antarctic marine wildlife is under threat, study finds". BBC Nature. Retrieved October 13, 2013. 
  95. ^ V. J. Fabry, C. Langdon, W. M. Balch, A. G. Dickson, R. A. Feely, B. Hales, D. A. Hutchins, J. A. Kleypas, and C. L. Sabine. "Present and Future Impacts of Ocean Acidification on Marine Ecosystems and Biogeochemical Cycles" (PDF). Report of the Ocean Carbon and Biogeochemistry Scoping Workshop on Ocean Acidification Research. 
  96. ^ "Canada's State of the Oceans Report, 2012". Report. Fisheries and Oceans Canada. 2012. Retrieved 21 October 2013. 
  97. ^ Robert J. Foy, Mark Carls, Michael Dalton, Tom Hurst, W. Christopher Long, Dusanka Poljak, André E. Punt, Michael F. Sigler, Robert P. Stone, Katherine M. Swiney (Winter 2013). "CO 2 , pH, and Anticipating a Future under Ocean Acidification" (PDF).  
  98. ^ "Bering Sea Crab Fishery". Report. Seafood Market Bulletin. November 2005. Retrieved 10 November 2013. 
  99. ^ Snyder, John. "Tourism in the Polar Regions: The Sustainability Challenge" (PDF). Report. UNEP, The International Ecotourism Society. Retrieved 13 October 2013. 
  100. ^ Muniz, I. P. (May 1984). "The Effects of Acidification on Scandinavian Freshwater Fish Fauna". Series B, Biological Sciences 305 (1124): 517–528.  
  101. ^ Table TS.2 (p.9) and Figure TS.10 (p.20), in: Technical Summary, in Clarke & others 2007
  102. ^ a b Halting ocean acidification in time, in: Summary for Policymakers, in WBGU 2006, p. 3
  103. ^ UNFCCC. Conference of the Parties (COP) (15 March 2011). "Report of the Conference of the Parties on its sixteenth session, held in Cancun from 29 November to 10 December 2010. Addendum. Part two: Action taken by the Conference of the Parties at its sixteenth session" (PDF). Geneva, Switzerland: United Nations , p.3, paragraph 4. Documen available in UN languages and text format.
  104. ^ Ch 2: Which emission pathways are consistent with a 2 °C or 1.5 °C temperature limit?, in UNEP 2010, pp. 28–29
  105. ^ Good & others 2010, Executive Summary
  106. ^ Summary, in UK Royal Society 2009, pp. ix-xii
  107. ^ "Ch 5: Key Elements of America's Climate Choices". Box 5.1: Geoengineering.  , in US NRC 2011, pp. 52–53
  108. ^ Trujillo, Alan (2011). Essentials of Oceanography. Pearson Education, Inc. p. 157.  
  109. ^ Cao, L.; Caldeira, K. (2010). "Can ocean iron fertilization mitigate ocean acidification?".  
  110. ^ Sec 2.3.1 Ocean fertilisation methods, in Ch 2: Carbon dioxide removal techniques, in UK Royal Society 2009, pp. 16–19
  111. ^ Table 2.8, in: Sec 2.3.1 Ocean fertilisation methods, in Ch 2: Carbon dioxide removal techniques, in UK Royal Society 2009, p. 18
  112. ^ DiMascio, Felice;  
  113. ^ Willauer, Heather D.; DiMascio, Felice; Hardy, Dennis R.; Lewis, M. Kathleen; Williams, Frederick W. (April 11, 2011). Extraction of Carbon Dioxide from Seawater by an Electrochemical Acidification Cell. Part 2 - Laboratory Scaling Studies (PDF) (memorandum report). Washington, DC: Chemistry Division, Navy Technology Center for Safety and Survivability, U.S. Naval Research Laboratory. Retrieved September 7, 2012. 
  114. ^ Eisaman, Matthew D.; et al. (2012). extraction from seawater using bipolar membrane electrodialysis"2"CO (PDF). Energy and Environmental Science 5 (6): 7346–52.  

References

See also

Gallery

[114].
2
CO

Carbon negative fuels

A report by the UK's Royal Society (2009)[110] reviewed the approach for effectiveness, affordability, timeliness and safety. The rating for affordability was "medium", or "not expected to be very cost-effective." For the other three criteria, the ratings ranged from "low" to "very low" (i.e., not good). For example, in regards to safety, the report found a "[high] potential for undesirable ecological side effects," and that ocean fertilization "may increase anoxic regions of ocean ('dead zones')."[111]

Iron fertilization of the ocean could stimulate photosynthesis in phytoplankton (see Iron Hypothesis). The phytoplankton would convert the ocean's dissolved carbon dioxide into carbohydrate and oxygen gas, some of which would sink into the deeper ocean before oxidizing. More than a dozen open-sea experiments confirmed that adding iron to the ocean increases photosynthesis in phytoplankton by up to 30 times.[108] While this approach has been proposed as a potential solution to the ocean acidification problem, mitigation of surface ocean acidification might increase acidification in the less-inhabited deep ocean.[109]

Iron fertilization

Reports by the WGBU (2006),[102] the UK's Royal Society (2009),[106] and the US National Research Council (2011)[107] warned of the potential risks and difficulties associated with climate engineering.

Mitigation approaches such as adding chemicals to counter the effects of acidification are likely to be expensive, only partly effective and only at a very local scale, and may pose additional unanticipated risks to the marine environment. There has been very little research on the feasibility and impacts of these approaches. Substantial research is needed before these techniques could be applied.

(mitigating temperature or pH effects of emissions) has been proposed as a possible response to ocean acidification. The IAP (2009)[13] statement cautioned against climate engineering as a policy response:

Climate engineering

Climate engineering

Limiting global warming to below 2 °C would imply a reduction in surface ocean pH of 0.16 from pre-industrial levels. This would represent a substantial decline in surface ocean pH.[105]

One policy target related to ocean acidity is the magnitude of future global warming. Parties to the United Nations Framework Convention on Climate Change (UNFCCC) adopted a target of limiting warming to below 2 °C, relative to the pre-industrial level.[103] Meeting this target would require substantial reductions in anthropogenic CO2 emissions.[104]

In order to prevent disruption of the calcification of marine organisms and the resultant risk of fundamentally altering marine food webs, the following guard rail should be obeyed: the pH of near surface waters should not drop more than 0.2 units below the pre-industrial average value in any larger ocean region (nor in the global mean).

The German Advisory Council on Global Change[102] stated:

Stabilizing atmospheric CO2 concentrations at 450 ppm would require near-term emissions reductions, with steeper reductions over time.[101]

  • Acknowledge that ocean acidification is a direct and real consequence of increasing atmospheric CO2 concentrations, is already having an effect at current concentrations, and is likely to cause grave harm to important marine ecosystems as CO2 concentrations reach 450 [parts-per-million (ppm)] and above;
  • [...] Recognise that reducing the build up of CO2 in the atmosphere is the only practicable solution to mitigating ocean acidification;
  • [...] Reinvigorate action to reduce stressors, such as overfishing and pollution, on marine ecosystems to increase resilience to ocean acidification.

Members of the InterAcademy Panel recommended that by 2050, global anthropogenic CO2 emissions be reduced less than 50% of the 1990 level.[13] The 2009[13] statement also called on world leaders to:

Reducing CO2 emissions

Possible responses

Acidification could damage the Arctic tourism economy and affect the way of life of indigenous peoples. A major pillar of Arctic tourism is the sport fishing and hunting industry. The sport fishing industry is threatened by collapsing food webs which provide food for the prized fish. A decline in tourism lowers revenue input in the area, and threatens the economies that are increasingly dependent on tourism.[99] Acidification is not merely a threat but has significantly declined whole fish populations. For example, In Scandinavia studies conducted on acidic water revealed that 15% of species populations had disappeared and that many more populations were limited in numbers or declining.[100] The rapid decrease or disappearance of marine life could also affect the diet of Indigenous peoples.

Impact on indigenous peoples

The threat of acidification includes a decline in American Lobster, Ocean Quahog, and scallops means there is less shellfish meat available for sale and consumption.[96] Red king crab fisheries are also at a serious threat because crabs are calcifiers and rely on carbonate ions for shell development. Baby red king crab when exposed to increased acidification levels experienced 100% mortality after 95 days.[97] In 2006 Red King Cab accounted for 23% of the total guideline harvest levels and a serious decline in red crab population would threaten the crab harvesting industry.[98] Several ocean goods and services are likely to be undermined by future ocean acidification potentially affecting the livelihoods of some 400 to 800 million people depending upon the emission scenario.[9]

Impact on human industry

Leaving aside direct biological effects, it is expected that ocean acidification in the future will lead to a significant decrease in the burial of carbonate sediments for several centuries, and even the dissolution of existing carbonate sediments.[89] This will cause an elevation of ocean alkalinity, leading to the enhancement of the ocean as a reservoir for CO2 with implications for climate change as more CO2 leaves the atmosphere for the ocean.[90]

Nonbiological impacts

Another possible effect would be an increase in anchovies and shellfish, in turn increasing occurrences of amnesic shellfish poisoning, neurotoxic shellfish poisoning and paralytic shellfish poisoning.[88]

Aside from the slowing and/or reversing of calcification, organisms may suffer other adverse effects, either indirectly through negative impacts on food resources,[27] or directly as reproductive or physiological effects. For example, the elevated oceanic levels of CO2 may produce CO
2
-induced acidification of body fluids, known as ecosystems.[87]

Other biological impacts

In some places carbon dioxide bubbles out from the sea floor, locally changing the pH and other aspects of the chemistry of the seawater. Studies of these carbon dioxide seeps have documented a variety of responses by different organisms.[6] Coral reef communities located near carbon dioxide seeps are of particular interest because of the sensitivity of some corals species to acidification. In Papua New Guinea, declining pH caused by carbon dioxide seeps is associated with declines in coral species diversity.[81] However, in Palau carbon dioxide seeps are not associated with reduced species diversity of corals, although bioerosion of coral skeletons is much higher at low pH sites.

Ocean acidification may force some organisms to reallocate resources away from productive endpoints such as growth in order to maintain calcification.[80]

The fluid in the internal compartments where corals grow their exoskeleton is also extremely important for calcification growth. When the saturation rate of aragonite in the external seawater is at ambient levels, the corals will grow their aragonite crystals rapidly in their internal compartments, hence their exoskeleton grows rapidly. If the level of aragonite in the external seawater is lower than the ambient level, the corals have to work harder to maintain the right balance in the internal compartment. When that happens, the process of growing the crystals slows down, and this slows down the rate of how much their exoskeleton is growing. Depending on how much aragonite is in the surrounding water, the corals may even stop growing because the levels of aragonite are too low to pump in to the internal compartment. They could even dissolve faster than they can make the crystals to their skeleton, depending on the aragonite levels in the surrounding water.[79]

When exposed in experiments to pH reduced by 0.2 to 0.4, larvae of a temperate brittlestar, a relative of the common sea star, fewer than 0.1 percent survived more than eight days.[46] There is also a suggestion that a decline in the coccolithophores may have secondary effects on climate, contributing to global warming by decreasing the Earth's albedo via their effects on oceanic cloud cover.[78] All marine ecosystems on Earth will be exposed to changes in acidification and several other ocean biogeochemical changes.[9]

The Royal Society published a comprehensive overview of ocean acidification, and its potential consequences, in June 2005.[27] However, some studies have found different response to ocean acidification, with coccolithophore calcification and photosynthesis both increasing under elevated atmospheric pCO2,[72][73][74] an equal decline in primary production and calcification in response to elevated CO2[75] or the direction of the response varying between species.[76] A study in 2008 examining a sediment core from the North Atlantic found that while the species composition of coccolithophorids has remained unchanged for the industrial period 1780 to 2004, the calcification of coccoliths has increased by up to 40% during the same time.[74] A 2010 study from Stony Brook University suggested that while some areas are overharvested and other fishing grounds are being restored, because of ocean acidification it may be impossible to bring back many previous shellfish populations.[77] While the full ecological consequences of these changes in calcification are still uncertain, it appears likely that many calcifying species will be adversely affected.

Corals,[61][62][63] coccolithophore algae,[64][65][66][67] coralline algae,[68] foraminifera,[69] shellfish[70] and pteropods[10][71] experience reduced calcification or enhanced dissolution when exposed to elevated CO
2
.

Although the natural absorption of CO
2
by the world's oceans helps mitigate the climatic effects of anthropogenic emissions of CO
2
, it is believed that the resulting decrease in pH will have negative consequences, primarily for oceanic coccolithophores, corals, foraminifera, echinoderms, crustaceans and molluscs.[9][59] As described above, under normal conditions, calcite and aragonite are stable in surface waters since the carbonate ion is at supersaturating concentrations. However, as ocean pH falls, the concentration of carbonate ions required for saturation to occur increases, and when carbonate becomes undersaturated, structures made of calcium carbonate are vulnerable to dissolution. Therefore, even if there is no change in the rate of calcification, the rate of dissolution of calcareous material increases.[60]

Impacts on oceanic calcifying organisms

The report "Ocean Acidification Summary for Policymakers 2013" describes research findings and possible impacts.[58]

Increasing acidity has possibly harmful consequences, such as depressing metabolic rates in jumbo squid,[54] depressing the immune responses of blue mussels,[55] and coral bleaching. However it may benefit some species, for example increasing the growth rate of the sea star, Pisaster ochraceus,[56] while shelled plankton species may flourish in altered oceans.[57]

refer to caption and image description
Video summarizing the impacts of ocean acidification. Source: NOAA Environmental Visualization Laboratory.

Possible impacts

[53] is directly proportional to its saturation state.CaCO
3
This decrease in saturation state is believed to be one of the main factors leading to decreased calcification in marine organisms, as the inorganic precipitation of [52] and raises the saturation horizons of both forms closer to the surface.CaCO
3
levels and the resulting lower pH of seawater decreases the saturation state of CO
2
Increasing [10] Calcium carbonate occurs in two common

The decrease in the concentration of CO32− decreases Ω, and hence makes CaCO
3
dissolution more likely.

Here Ω is the product of the concentrations (or activities) of the reacting ions that form the mineral (Ca2+
and CO2−
3
), divided by the product of the concentrations of those ions when the mineral is at equilibrium (K
sp
), that is, when the mineral is neither forming nor dissolving.[50] In seawater, a natural horizontal boundary is formed as a result of temperature, pressure, and depth, and is known as the saturation horizon, or lysocline.[27] Above this saturation horizon, Ω has a value greater than 1, and CaCO
3
does not readily dissolve. Most calcifying organisms live in such waters.[27] Below this depth, Ω has a value less than 1, and CaCO
3
will dissolve. However, if its production rate is high enough to offset dissolution, CaCO
3
can still occur where Ω is less than 1. The carbonate compensation depth occurs at the depth in the ocean where production is exceeded by dissolution.[51]

{\Omega} = \frac{\left[\textrm{Ca}^{2+}\right] \left[\textrm{CO}_{3}^{2-}\right]}{K_{sp}}

The saturation state (known as Ω) of seawater for a mineral is a measure of the thermodynamic potential for the mineral to form or to dissolve, and is described by the following equation:

Saturation state

These increases in concentrations of dissolved carbon dioxide and bicarbonate, and reduction in carbonate, are shown in a Bjerrum plot.

Of the extra carbon dioxide added into the oceans, some remains as dissolved carbon dioxide, while the rest contributes towards making additional bicarbonate (and additional carbonic acid). This also increases the concentration of hydrogen ions, and the percentage increase in hydrogen is larger than the percentage increase in bicarbonate,[49] creating an imbalance in the reaction HCO3 \leftrightarrow CO32− + H+. To maintain chemical equilibrium, some of the carbonate ions already in the ocean combine with some of the hydrogen ions to make further bicarbonate. Thus the ocean's concentration of carbonate ions is reduced, creating an imbalance in the reaction Ca2+ + CO32− \leftrightarrow CaCO3, and making the dissolution of formed CaCO
3
structures more likely.

Bjerrum plot: Change in carbonate system of seawater from ocean acidification.

Mechanism

Changes in ocean chemistry can have extensive direct and indirect effects on organisms and their habitats. One of the most important repercussions of increasing ocean acidity relates to the production of shells and plates out of calcium carbonate (CaCO
3
).[27] This process is called calcification and is important to the biology and survival of a wide range of marine organisms. Calcification involves the precipitation of dissolved ions into solid CaCO
3
structures, such as coccoliths. After they are formed, such structures are vulnerable to dissolution unless the surrounding seawater contains saturating concentrations of carbonate ions (CO32−).

Overview

Calcification

A 2013 study claimed acidity was increasing at a rate 10 times faster than in any of the evolutionary crises in Earth's history.[47] In a synthesis report published in Science in 2015, 22 leading marine scientists stated that CO2 from burning fossil fuels is changing the oceans' chemistry more rapidly than at any time since the Great Dying, Earth's most severe known extinction event, emphasizing that the 2 °C maximum temperature increase agreed upon by governments reflects too small a cut in emissions to prevent "dramatic impacts" on the world's oceans, with lead author Jean-Pierre Gattuso remarking that "The ocean has been minimally considered at previous climate negotiations. Our study provides compelling arguments for a radical change at the UN conference (in Paris) on climate change".[48]

In the 15-year period 1995–2010 alone, acidity has increased 6 percent in the upper 100 meters of the Pacific Ocean from Hawaii to Alaska.[46] According to a statement in July 2012 by Jane Lubchenco, head of the U.S. National Oceanic and Atmospheric Administration "surface waters are changing much more rapidly than initial calculations have suggested. It's yet another reason to be very seriously concerned about the amount of carbon dioxide that is in the atmosphere now and the additional amount we continue to put out."[14]

"The natural pH of the ocean is determined by a need to balance the deposition and burial of CaCO
3
on the sea floor against the influx of Ca2+
and CO2−
3
into the ocean from dissolving rocks on land, called weathering. These processes stabilize the pH of the ocean, by a mechanism called CaCO
3
compensation...The point of bringing it up again is to note that if the CO
2
concentration of the atmosphere changes more slowly than this, as it always has throughout the Vostok record, the pH of the ocean will be relatively unaffected because CaCO
3
compensation can keep up. The [present] fossil fuel acidification is much faster than natural changes, and so the acid spike will be more intense than the earth has seen in at least 800,000 years."

A review by climate scientists at the RealClimate blog, of a 2005 report by the Royal Society of the UK similarly highlighted the centrality of the rates of change in the present anthropogenic acidification process, writing:[45]

[44][43] examined the geological record in an attempt to find a historical analog for current global conditions as well as those of the future. The researchers determined that the current rate of ocean acidification is faster than at any time in the past 300 million years.Science A 2012 paper in the journal [42][41] A National Research Council study released in April 2010 likewise concluded that "the level of acid in the oceans is increasing at an unprecedented rate."[40] and the rate of increase is about ten times the rate that preceded the Paleocene–Eocene mass extinction. The current and projected acidification has been described as an almost unprecedented geological event.[39] Current rates of ocean acidification have been compared with the greenhouse event at the Paleocene–Eocene boundary (about 55 million years ago) when surface ocean temperatures rose by 5–6 degrees

One of the first detailed datasets to examine how pH varied over a period of time at a temperate coastal location found that acidification was occurring much faster than previously predicted, with consequences for near-shore benthic ecosystems.[35][36] Thomas Lovejoy, former chief biodiversity advisor to the World Bank, has suggested that "the acidity of the oceans will more than double in the next 40 years. This rate is 100 times faster than any changes in ocean acidity in the last 20 million years, making it unlikely that marine life can somehow adapt to the changes."[37] It is predicted that, by the year 2100, the level of acidity in the ocean will reach the levels experienced by the earth 20 million years ago.[9][38]

Rate

Average surface ocean pH[10]
Time pH pH change relative
to pre-industrial
Source H+ concentration change
relative to pre-industrial
Pre-industrial (18th century) 8.179 analysed field[31]
Recent past (1990s) 8.104 −0.075 field[31] + 18.9%
Present levels ~8.069 −0.11 field[6][7][32][33] + 28.8%
2050 (2×CO
2
= 560 ppm)
7.949 −0.230 model[10] + 69.8%
2100 (IS92a)[34] 7.824 −0.355 model[10] + 126.5%

Although the largest changes are expected in the future,[10] a report from spawned there, and though the study only dealt with the area from Vancouver to Northern California, the authors suggest that other shelf areas may be experiencing similar effects.[30]

Since the industrial revolution began, it is estimated that surface ocean pH has dropped by slightly more than 0.1 units on the logarithmic scale of pH, representing about a 29% increase in H+
. It is expected to drop by a further 0.3 to 0.5 pH units[9] (an additional doubling to tripling of today's post-industrial acid concentrations) by 2100 as the oceans absorb more anthropogenic CO
2
, the impacts being most severe for coral reefs and the Southern Ocean.[2][10][27] These changes are predicted to continue rapidly as the oceans take up more anthropogenic CO
2
from the atmosphere. The degree of change to ocean chemistry, including ocean pH, will depend on the mitigation and emissions pathways[28] society takes.[29]

Caldeira and Wickett (2003)[2] placed the rate and magnitude of modern ocean acidification changes in the context of probable historical changes during the last 300 million years.

CO2 (aq) + H2O \leftrightarrow H2CO3 \leftrightarrow HCO3 + H+ \leftrightarrow CO32− + 2 H+.

Dissolving CO
2
in seawater increases the hydrogen ion (H+
) concentration in the ocean, and thus decreases ocean pH, as follows:[26]

Acidification

The resistance of an area of ocean to absorbing atmospheric CO
2
is known as the Revelle factor.

When CO
2
dissolves, it reacts with water to form a balance of ionic and non-ionic chemical species: dissolved free carbon dioxide (CO
2(aq)
), carbonic acid (H
2
CO
3
), bicarbonate (HCO
3
) and carbonate (CO2−
3
). The ratio of these species depends on factors such as solubility pump.

[25] present in the Earth's oceans.
2
CO

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.