Capacidad Financiera y Comercial

Observations of ocean acidification are not yet on a fully global scale, not only because of the relatively short time of awareness of the importance of such changes, but also due to the high cost of research expeditions; the inaccessibility of many regions; the relative unavailability of highly accurate and reliable pH sensors; and the current limitations of autono- mous monitoring techniques. There is also a need to collect data on other environmental variables for

valid interpretation.Nevertheless, long time series

do exist on the changing marine carbon system in the central Pacific (Hawaii Ocean Time series, HOT) and North Atlantic (Bermuda Atlantic Time-series Study, BATS; European Station for Time-series in the Ocean, ESTOC), quantifying surface pH decline over the last several decades (over the range -0.0016 to -0.0019 yr-1₎[35-37]_{. The observed decline in surface}

pH at these three open-ocean stations is consis- tent with a surface ocean that is closely tracking the increase in atmospheric CO2 levels over the past three decades[38]_.

Synthesis products on observations of ocean pCO2 and

air-sea CO2 fluxes have been developed by the Global

Ocean Data Analysis Project (GLODAP)[16]_{, CARbon}

in the Atlantic Ocean (CARINA)[17]_{, the Surface}

Carbon CO2 Atlas (SOCAT)[18]_{, and PACIFICA}[39]_.

These initiatives include analyses of the penetration of anthropogenic carbon to the ocean interior, due to entrainment, mixing, and deep-water formation. In the North Atlantic and Southern oceans, signals of decreasing pH have already been observed at the

ocean floor[40-43]_{. Such changes involve more than a}

simple shoaling of aragonite and calcite saturation horizons, since the zone of low pH water may be extending downwards as well as upwards (Figure 3.7).In the Pacific and the South Atlantic, signals of anthropogenic carbon have also been observed in intermediate waters[44,45]_{. For all ocean basins, model}

projections indicate that ocean acidification will occur throughout the water column by 2100.

Recent international effort has been directed at extending and complementing these exist- ing programmes to more explicitly address ocean acidification and its impacts, with increased atten-

tion to shelf seas and coastal regions.Relevant

activities are being initiated and implemented at

Figure 3.7. Measured pH profiles in the north-east Atlantic along a 3,400 km transect from south-east Greenland to Portugal in 2002 (left) and 2008 (right).Additional transect data were collected in 1991, 1993, 2004 and 2006, and were fully consistent with this rapid expansion in the volume of low-pH intermediate water, and associated changes in seafloor conditions. From[40]_.

3. GLOBAL STATUS AND FUTURE TRENDS OF OCEAN ACIDIFICATION 33

the regional level, for example, through the US Ocean Margin Ecosystems Group for Acidification

Studies (OMEGAS)[46]_{, and also on a worldwide}

basis, through the recently established Global Ocean

Acidification Observing Network (GOA-ON)[47]

(Figure 3.8).GOA-ON aims to provide an under-

standing of ocean acidification conditions and the ecosystem response, as well as to deliver the data needed to optimize ocean acidification modelling. Since the potential scope for biological observ- ing is extremely wide, GOA-ON will build on, and work in close liaison with, the Global Ocean

Observing System (GOOS) and its Framework for Ocean Observation. Other bodies contributing to the development of the network include the IAEA Ocean Acidification International Coordination Centre (OA-ICC), IOC-UNESCO, the International Ocean Carbon Coordination Project (IOCCP), and a range of national funding agencies. To date, most ocean acidification observations have been ship-

based.However, increasing use is expected to be

made of pH sensors on profiling floats[48] _{and using}

underwater gliders; such issues are also considered in Chapter 9.

Figure 3.8. Components of the developing Global Ocean Acidification Observing Network (GOA-ON), including moorings, time-series stations, and ship-based surveys, by voluntary observing ships (VOS), ships of opportunity (SOO) and research vessels.Status at May 2014 from GOA-ON Requirements and Governance Plan[47]_.

References

1. Friedrich T, Timmermann A, Abe-Ouchi A, Bates NR, Chikamoto MO, et al. (2012) Detecting regional anthropogenic trends in ocean acidification against natural variability. Nature Climate Change 2: 167-171. 2. Hofmann GE, Smith JE, Johnson KS, Send U, Levin

LA, et al. (2011) High-frequency dynamics of ocean pH: A multi-ecosystem comparison. PLoS ONE 6 (12): e28983.

3. Duarte CM, Hendriks IE, Moore TS, Olsen YS, Steckbauer A, et al. (2013) Is ocean acidification an open-ocean syndrome? Understanding anthropogenic impacts on seawater pH. Estuaries and Coasts 36: 221-236.

4. Provoost P, Van Heuven S (2010) Long-term record of pH in the Dutch coastal zone: a major role for eutrophication-induced changes. Biogeosciences 7: 4127-4152.

5. Johnson ZI, Wheeler BJ, Blinebry SK, Carlson CM, Ward CS, 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.

6. Wootton JT, Pfister CA (2012) Carbon system measurements and potential climatic drivers at a site of rapidly declining ocean pH. PLoS ONE 7(12): e53396.

7. Shaw EC, McNeil BI, Tilbrook B, Matear R, Bates ML (2013) Anthropogenic changes to seawater buffer capacity combined with natural reef metabolism induce extreme future coral reef CO2 conditions. Global Change Biology 19: 1632-1641.

8. Feely RA, Sabine CL, Hernandez-Ayon JM, Ianson D, Hales B (2008) Evidence for upwelling of corrosive “acidified” water onto the continental shelf. Science 320: 1490-1492.

9. Findlay HS, Artioli Y, Navas JM, Hennige SJ, Wicks LC, et al. (2013) Tidal downwelling and implications for the carbon biogeochemistry of cold-water corals in relation to future ocean acidification and warming. Global Change Biology 19: 2708-2719.

10. Zhai W-D, Zheng N, Huo C, Xu Y, Zhao H-D, et al. (2014) Subsurface pH and carbonate saturation state of aragonite on the Chinese side of the North Yellow Sea: seasonal variations and controls. Biogeosciences 11: 1103-1123.

11. Doney SC, Mahowald N, Lima I, Feely RA,

Mackenzie FT, et al. (2007) Impact of anthropogenic atmospheric nitrogen and sulfur deposition on ocean acidification and the inorganic carbon system. Proceedings of the National Academy of Sciences of the United States of America 104: 14580-14585.

12. Roberts DA, Birchenough SNR, Lewis C, Sanders MB, Bolam T, et al. (2013) Ocean acidification increases the toxicity of contaminated sediments. Global Change Biology 19: 340-351.

13. Greenwood N, Pearce D (Figure 2). In: Williamson P, Turley CM, Brownlee C, Findlay HS, Ridgwell A et al., Impacts of Ocean Acidification . MCCIP Science Review 2013: 34-48.

14. Artioli Y, Blackford J, Butenschon M, Holt JT, Wakelin SL, et al. (2012) The carbonate system of the NW European shelf: sensitivity and model validation. Journal of Marine Systems 102-104: 1-13.

15. Artioli Y, Blackford J, Nondal G, Bellerby RGJ, Wakelin SL, et al. (2014) Heterogeneity of impacts of high CO2 on the North Western European Shelf. Biogeosciences 11: 601-612.

16. Key RM, Kozyr A, Sabine CL, Lee K, Wanninkhof R, et al. (2004) A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Global Biogeochemical Cycles 18: GB4031.

17. Key RM, Tanhua T, Olsen A, Hoppema M, Jutterstrom S, et al. (2010) The CARINA data synthesis project: introduction and overview. Earth Systems Science Data 2: 105-121.

18. Bakker D.C.E. and 80 others. 2014. _{An update to}

the Surface Ocean CO2 Atlas (SOCAT version 2). Earth System Science Data, 6, 69-90; doi: 10.5194/ essd-6-69-2014

19. Zeebe RE (2012) History of seawater carbonate chemistry, atmospheric CO2, and ocean acidification Annual Review of Earth and Planetary Sciences, 40: 141-165.

20. Caldeira K, Wickett ME (2005) Ocean model predictions of chemistry changes from carbon dioxide emissions to the atmosphere and ocean. Journal of Geophysical Research-Oceans 110: C09S04. 21. Steinacher M, Joos F, Froelicher TL, Plattner GK,

Doney SC (2009) Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model. Biogeosciences 6: 515-533.

22. Denman K, Christian JR, Steiner N, Poertner H-O, Nojiri Y (2011) Potential impacts of future ocean acidification on marine ecosystems and fisheries: current knowledge and recommendations for future research. ICES Journal of Marine Science 68: 1019-1029.

23. Bopp L, Resplandy L, Orr JC, Doney SC, Dunne JP, et al. (2013) Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models. Biogeosciences 10: 6225-6245.

3. GLOBAL STATUS AND FUTURE TRENDS OF OCEAN ACIDIFICATION 35

24. Orr JC, Fabry VJ, Aumont O, Bopp L, Doney SC, et al. (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437: 681-686.

25. McNeil BI, Matear RJ (2007) Climate change feedbacks on future oceanic acidification. Tellus Series B-Chemical and Physical Meteorology 59: 191-198.

26. Moss RH, Edmonds JA, Hibbard KA, Manning MR, Rose SK, et al. (2010) The next generation of scenarios for climate change research and assessment. Nature 463: 747-756.

27. IGBP, IOC, SCOR (2013). Ocean Acidification Summary for Policymakers 2013. _{International}

Geosphere-Biosphere Programme.Stockholm, Sweden.

28. McNeil B, Matear R (2008) Southern Ocean

acidification: A tipping point at 450-ppm atmospheric CO2. Proceedings of the National Academy of Science 105: 18860-18864.

29. Loose B, Schlosser P (2011) Sea ice and its effect on CO2 flux between the atmosphere and the Southern Ocean interior. Journal of Geophysical Research- Oceans 116: C11019.

30. Arctic Monitoring and Assessment Programme (2013).AMAP Assessment 2013: Arctic Ocean Acidification. AMAP, Oslo, Norway. 99p http://www. amap.no/documents/doc/AMAP-Assessment-2013- Arctic-Ocean-Acidification/881

31. Wahlstrom I, Omstedt A, Bjork G, Anderson LG (2013) Modeling the CO2 dynamics in the Laptev Sea, Arctic Ocean: Part II. Sensitivity of fluxes to changes in the forcing. Journal of Marine Systems 111: 1-10. 32. Wahlstrom I, Omstedt A, Bjork G, Anderson LG

(2012) Modelling the CO2 dynamics in the Laptev Sea, Arctic Ocean: Part I. Journal of Marine Systems 102: 29-38.

33. Biastoch A, Treude T, Rüpke LH, Riebesell U, Roth C, et al. (2011) Rising Arctic Ocean temperatures cause gas hydrate destabilization and ocean acidification. Geophysical Research Letters 38: L08602.

34. Archer D (2005) Fate of fossil fuel CO2 in geologic time. Journal of Geophysical Research-Oceans 110: C09S05.

35. Dore JE, Lukas R, Sadler DW, Church MJ, Karl DM (2009) Physical and biogeochemical modulation of ocean acidification in the central North Pacific. Proceedings of the National Academy of Sciences of the United States of America 106: 12235-12240. 36. Bates NR, Best MHP, Neely K, Garley R, Dickson AG,

et al. (2012) Detecting anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean. Biogeosciences 9: 2509-2522.

37. Santana-Casiano JM, Gonzalez-Davila M, Rueda M-J, Llinas O, Gonzalez-Davila E-F (2007) The interannual variability of oceanic CO2 parameters in the northeast Atlantic subtropical gyre at the ESTOC site. Global Biogeochemical Cycles 21: GB1015.

38. Intergovernmental Panel on Climate Change (2013) Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the IPCC (Stocker TF, Qin D, Plattner G-K, Tognor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V & Midgley PM (eds). Cambridge University Press, Cambridge UK and New York, USA.

39. Suzuki T. and 18 others. (2013) PACIFICA Data Synthesis Project. ORNL/CDIAC-159, NDP-092. Carbon Dioxide Information Analysis Center, Oak Ridge TN, USA; doi: 10.3334/CDIOAC/OTG. PACIFICA_NDP092.

40. Vazquez-Rodriguez M, Perez FF, Velo A, Rios AF, Mercier H (2012) Observed acidification trends in North Atlantic water masses. Biogeosciences 9: 5217-5230.

41. Vazquez-Rodriguez M, Touratier F, Lo Monaco C, Waugh DW, Padin XA, et al. (2009) Anthropogenic carbon distributions in the Atlantic Ocean: data- based estimates from the Arctic to the Antarctic. Biogeosciences 6: 439-451.

42. Hauck J, Hoppema M, Bellerby RGJ, Voelker C, Wolf-Gladrow D (2010) Data-based estimation of anthropogenic carbon and acidification in the Weddell Sea on a decadal timescale. Journal of Geophysical Research-Oceans 115: C03004.

43. Olafsson J, Olafsdottir SR, Benoit-Cattin A, Danielsen M, Arnarson TS, et al. (2009) Rate of Iceland Sea acidification from time series measurements. Biogeosciences 6: 2661-2668.

44. Byrne RH, Mecking S, Feely RA, Liu X (2010) Direct observations of basin-wide acidification of the North Pacific Ocean. Geophysical Research Letters 37: L02601.

45. Resplandy L, Bopp L, Orr JC, Dunne JP (2013) Role of mode and intermediate waters in future ocean acidification: Analysis of CMIP5 models. Geophysical Research Letters 40: 3091-3095.

46. Hofmann GE, Evans TG, Kelly MW, Padilla- Gamiño JL, Blanchette CA et al (2014) Exploring local adaptation and the ocean acidification seascape – studies in the California Current Large Marine Ecosystem. Biogeosciences 11: 1053-1064. 47. GOA-ON http://www.goa-on.org

As well as using models to project climate change, we can better understand the future impacts of ocean acidification by studying how biogeochemical cycles operated in the past, and the impact past events had on marine ecosystems.

In addition to variations in seawater acidity from place to place because of circulation patterns, biolog- ical activity, and other oceanographic processes (see previous chapter), the average state of the ocean can also change through time in response to natural variations in the global carbon cycle. Past changes in ocean acidity can be studied by chemical analysis of the skeletons of dead organisms such as molluscs,

foraminifera, corals and algae, or of ocean sedi- ments, which are accessible by drilling into the sea- bed. Deep-sea cores commonly contain abundant fossils of calcifying (carbonate producing) plankton, such as foraminifera and coccolithophores (Figure 4.1), which are among the groups considered most at risk in future ocean acidification.

The paleo-record can be used to extend the current record of acidity changes as it stretches back millions of years in time. Over the longer term, it contains evidence of: (1) cyclic changes in ocean chemis- try associated with glacial / interglacial cycles with sometimes abrupt transitions; (2) multi-million