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Threats to Coral Reefs of Bermuda

  • Struan R. SmithEmail author
  • Samia Sarkis
  • Thad J. T. Murdoch
  • Ernesto Weil
  • Aldo Croquer
  • Nicholas R. Bates
  • Rodney J. Johnson
  • Samantha de Putron
  • Andreas J. Andersson
Chapter
Part of the Coral Reefs of the World book series (CORW, volume 4)

Abstract

Bermuda’s reefs have endured the impact of 400 years of human settlement and resource extraction. Although the reef system has benefited from pro-active regulation and control of fishing and pollution since the twentieth century, the nearshore environment and lagoon reefs are threatened by ongoing and planned activities. Coastal development, including cruise ship ports, marinas and shipping channel expansion are significant potential threats through reef removal and sedimentation. The dense human population on Bermuda has produced chronic chemical and nutrient pollution in nearshore bays and harbours. Sewage has reduced water quality in some enclosed bays but is generally not a major threat. Coral bleaching has occurred repeatedly since the 1980s, in response to elevated seawater temperatures, but these events have not resulted in significant mortality. Corals diseases are prevalent at low levels of infection in a large number of species but do not appear to have caused significant mortality. The invasive lionfish (Pterios volitans) is present and the population is growing but culling and harvesting efforts are conducted. There is great concern for the potential impacts of climate-related changes, in particular ocean acidification. Bermuda’s corals grow at reduced rates compared with Caribbean conspecifics and there is evidence that some corals are already growing slower, under the current condition of declining aragonite saturation state in reef waters. The potential for reduced coral and reef growth, in combination with rising sea level, may compromise the effectiveness of the reef as a natural barrier to storm waves, resulting in greater coastal erosion.

Keywords

Coral Reef Ocean Acidification North Atlantic Ocean Subtropical Gyre Crustose Coralline Alga 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This is Contribution #200 of the Bermuda Biodiversity Project (BBP), Bermuda Aquarium, Museum and Zoo, in the Department of Conservation Services.

References

  1. Agassiz A (1894) Visit to the Bermudas. Bull Mus Comp Zool 26:209–281Google Scholar
  2. Andersson AJ, Bates NR, and de Putron SJ (2010) BEACON: Bermuda ocean acidification and coral reef investigation – overview and early results. ASLO/AGU Meeting, Portland, Feb 2010Google Scholar
  3. Andersson AJ, de Putron SJ, Bates NR, Collins A, Garley R, Noyes T, Dexter E (2011) Bermuda ocean acidification and coral reef investigation: temporal and spatial changes in seawater carbonate chemistry and calcification. Abstract, IPCC meeting, Okinawa, Feb 2011Google Scholar
  4. Antonius A (1982) The ‘band’ diseases in coral reefs. In: Proceedings of the 4th international coral reef symposium, vol 2. Manila, pp 7–14Google Scholar
  5. Bates NR (2001) Interannual variability of oceanic CO2 and biogeochemical properties in the Western North Atlantic subtropical gyre. Deep-Sea Res II 48:1507–1528CrossRefGoogle Scholar
  6. Bates NR (2002) Seasonal variability of the impact of coral reefs on ocean CO2 and air-sea CO2 exchange. Limnol Oceanogr 47(1):43–52CrossRefGoogle Scholar
  7. Bates NR (2012) Multi-decadal uptake of carbon dioxide into subtropical mode waters of the North Atlantic Ocean. Biogeosciences 9:2649–2659. doi: 10.5194/bg-9-2649-2012 CrossRefGoogle Scholar
  8. Bates NR, Samuels L, Merlivat L (2001) Biogeochemical and physical factors influencing seawater fCO2 and air-sea CO2 exchange on the Bermuda coral reef. Limnol Oceanogr 46(4):833–846CrossRefGoogle Scholar
  9. Bates NR, Amat A, Andersson AJ (2011) Feedbacks and responses of coral calcification on the Bermuda reef system to seasonal changes in biological processes and ocean acidification. Biogeosciences 7:1–22Google Scholar
  10. Bates NR, Best MH, Neely K, Garley R, Dickson AG, Johnson RJ (2012) Indicators of anthropogenic carbon dioxide uptake and ocean acidification in the North Atlantic Ocean. Biogeosciences 9:2509–2522. doi: 10.5194/bg-9-2509-2012 CrossRefGoogle Scholar
  11. Bodungen BV, Jickells TD, Smith SR, Ward JAD, Hillier GB (1982) The Bermuda Marine Environment – Vol. III. The final report of the Bermuda Inshore Waters Investigation. B.B.S.R. Spec. Publ. No. 18., p. 123Google Scholar
  12. Boyer JN, Briceno HO (2010) Water quality monitoring program for Bermuda’s coastal resources. Technical report #T-473 of the Southeast Environmental Research Center (FIU), prepared for Bermuda Government Department of Conservation Services, 57ppGoogle Scholar
  13. Burke L, Reytar K, Spaulding M, Perry A (2011) Reefs at risk revisited. World Resources Institute, Washington, DC, p 130Google Scholar
  14. Burns KA, Ehrhardt MG, MacPherson J, Tierney JA, Kananen G, Connelly D (1990) Organic and trace metal contaminants in sediments, seawater and organisms from two Bermudan harbours (GEEP Workshop, September 1988). JEMBE 138:9–34CrossRefGoogle Scholar
  15. Butler JN, Burnett-Herkes J, Barnes JA, Ward J (1993) Bermuda fisheries, a tradgedy of the commons averted? Environment 35:7–33CrossRefGoogle Scholar
  16. CARICOMP (2000) Status and temporal trends at the CARICOMP reef site. In: Proceedings of 9th international coral reef symposium, vol 1, Bali. pp 325–330Google Scholar
  17. Cohen AL, Smith SR, McCartney MS, van Etten J (2004) How brain corals record climate: an integration of skeletal structure, growth and chemistry of Diploria labyrinthiformis from Bermuda. MEPS 271:147–158CrossRefGoogle Scholar
  18. Cook CB, Logan A, Ward J, Luckhurst BE, Berg CJ Jr (1990) Elevated temperatures and bleaching on a high-latitude reef: the 1988 Bermuda event. Coral Reefs 9:45–49CrossRefGoogle Scholar
  19. Cook CB, Dodge RE, Smith SR (1994) Fifty years of impacts on coral reefs in Bermuda. In: Proceedings of the colloquium on coral reefs, 1993, R.S.M.A.S, Miami. pp 160–166Google Scholar
  20. Connelly DP, Readman JW, Knap AH, Davies J (2001) Contamination of the coastal waters of Bermuda by organotins and the triazine herbicide Irgarol 1051. Mar Pollut Bull 42:409–441Google Scholar
  21. Croquer A, Weil E (2009) Spatial variability in distribution and prevalence of Caribbean scleractinian coral and octocoral diseases. II. Genera-level analysis. Diseas Aquat Orgs 83:209–222CrossRefGoogle Scholar
  22. Curry RG, McCartney MS (2001) Ocean gyre circulation changes associated with the North Atlantic Oscillation. J Phys Oceanogr 31:3374–3400CrossRefGoogle Scholar
  23. de Putron SJ, McCorkle DC, Cohen AL, Dillon AB (2011) The impact of seawater saturation state and bicarbonate ion concentration on calcification by new recruits of two Atlantic corals. Coral Reefs 30:321–328CrossRefGoogle Scholar
  24. Dodge RE, Vaisnys JR (1977) Coral populations and growth patterns: responses to sedimentation and turbidity associated with dredging. J Mar Res 35:715–730Google Scholar
  25. Dodge RE, Logan A, Antonius A (1982) Quantitative reef assessment studies in Bermuda: a comparison of methods and preliminary results. Bull Mar Sci 32:745–760Google Scholar
  26. Dodge RE, Jickells TD, Knap AH, Boyd S, Bak RPM (1984) Reef-building coral skeletons as chemical pollution (phosphorus) indicators. Mar Poll Bull 15:178–187CrossRefGoogle Scholar
  27. Dryer S, Logan A (1978) Holocene reefs and sediments in Castle Harbour, Bermuda. J Mar Res 36:399Google Scholar
  28. Environment Statistics Compendium (2009) Bermuda Government Department of Statisitics. Bermuda Government 90ppGoogle Scholar
  29. European Union (2006) Directive 2006/7/EC of the European Parliament and of the Council of 15th February 2006 concerning the management of bathing water quality and repealing Directive 76/160/EECGoogle Scholar
  30. Flood V, Pitt JM, Smith SR (2005) Historical and ecological analysis of coral communities in Castle Harbour (Bermuda) after more than a century of perturbation. Mar Poll Bull 51:545–557CrossRefGoogle Scholar
  31. Garret P, Ducklow H (1975) Coral diseases in Bermuda. Nature 253:349–350CrossRefGoogle Scholar
  32. Garrett P, Smith DL, Wilson AO, Patriquin D (1971) Physiography, ecology and sediments of two Bermuda patch reefs. J Geol 79:647–668CrossRefGoogle Scholar
  33. Goodkin NF, Hugen KA, Curry WB, Doney SC, Ostermann DR (2008) Sea surface temperature and salinity variability at Bermuda during the end of the little ice age. Paleooceanography 23(PA3202):1–13Google Scholar
  34. Grist JP, Josey SA, Marsh R, Good SA, Coward AC, de Cuevas BA, Alderson SG, New AL, Madec G (2010) The roles of surface heat flux and ocean heat transport convergence in determining Atlantic Ocean temperature variability. Ocean Dyn 60(4):771–790. doi: 10.1007/s10236-010-0292-4 CrossRefGoogle Scholar
  35. Gunther JA (1999) Bioaccumulation of metals in the turkey-wing mussel, Arca zebra, off the coast of Bermuda. M.Sc. thesis, Villanova University, 59ppGoogle Scholar
  36. Harvell CD, Altizer S, Cattadori IM, Harrington L, Weil E (2009) Climate change and wildlife diseases: when does the host matter the most? Ecology 90(4):912–920CrossRefGoogle Scholar
  37. Hayward SJ, Gomez VH, Sterrer WE (eds) (1981) Bermuda’s delicate balance. Bermuda National Trust, Bermuda, p 402Google Scholar
  38. Hurrell JW (1995) Decadal trends in the North Atlantic Oscillation: regional temperatures and precipitation. Science 269:676–679Google Scholar
  39. Hurrell JW, Deser C (2009) North Atlantic climate variability: the role of the North Atlantic Oscillation. J Mar Syst 79(3–4):231–244. doi: 10.1016/j.marsys.2009.11.002 Google Scholar
  40. IPCC (2007) Climate change 2007: the physical science basis. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge/New York, 996ppGoogle Scholar
  41. Jaap WC (2000) Coral reef restoration. Ecol Eng 15:345–364CrossRefGoogle Scholar
  42. Jickells TD, Knap AH (1984) The distribution and geochemistry of some trace metals in the Bermuda coastal environment. Estuar Coast Shelf Sci 18:245–262CrossRefGoogle Scholar
  43. Jickells TD, Knap AH, Smith SR (1986) Trace metal and nutrient fluxes through the Bermuda inshore waters. Rapp P-v Reun Cons Int Explor Mer 186:251–262Google Scholar
  44. Johnson RJ, Knap AH, Bates NR, Whitefield JD, Kadko D, Lomas MW (2008) Coordinated change in the heat, salinity and CO2 budgets of the mesopelagic zone at the Bermuda time-series sites. Abstract ASLO/AGU Ocean Sciences meeting, Orlando, March 2008Google Scholar
  45. Jones RJ (2010) Environmental contamination associated with a marine landfill (‘seafill’) beside a coral reef. Mar Pol Bull 60:1993–2006CrossRefGoogle Scholar
  46. Jones RJ (2011) Environmental effects of the cruise tourism boom: sediment resuspension from cruise ships and the possible effects of increased turbidity and sediment deposition on corals (Bermuda). Bull Mar Sci 87:659–679CrossRefGoogle Scholar
  47. Jones R, Parsons R, Watkinson E, Kendall D (2010) Sewage contamination of a densely populated coral ‘atoll’ (Bermuda). Environ Monit Assess. doi: 10.1007/s10661-010-1738-3
  48. Jones RJ, Johnson R, Noyes T, Parsons R (2012) Spatial and temporal patterns of coral black band disease in relation to a major sewage outfall. MEPS 462:70–92CrossRefGoogle Scholar
  49. Joyce TM, Pickart TS, Millard RC (1999) Long-term hydrographic changes at 52 and 66 degrees W in the North Atlantic subtropical gyre and Caribbean. Deep-Sea Res II 46(1–2):245–278. doi: 10.1016/S0967-0645(98)00102-7 CrossRefGoogle Scholar
  50. Kleypas JA, Buddemeier RW, Gattuso J-P (2001) The future of corals reefs in an age of global change. Int J Earth Sci 90:426–437CrossRefGoogle Scholar
  51. Knap AH, Cook CB, Cook SB, Simmons JAK, Jones RJ, Murray AE (1991) Marine environmental studies to determine the impact of the mass burn incinerator proposed for Tynes Bay, Bermuda. BBSR report to Bermuda Government Ministry of Works & Engineering, Bermuda. 256ppGoogle Scholar
  52. Kuhnert H, Cruger T, Patzold J (2005) NAO signature in a Bermuda coral Sr/Ca record. Geochem Geophys Geosys 6(Q04004):11Google Scholar
  53. Leavitt DF, Lancaster BA, Lancaster AS, Capuzzo JM (1990) Changes in the biochemical composition of a subtropical bivalve, Arca zebra, in response to contaminant gradients in Bermuda (GEEP Workshop, September 1988). J Exp Mar Biol Ecol 138:85–98Google Scholar
  54. Linton D, Fisher T (eds) (2004) CARICOMP – Caribbean coastal marine productivity program: 1993–2003. Caribbean coastal data centre, centre for marine sciences, University of the West Indies, MonaGoogle Scholar
  55. Lomas MW, Steinberg DK, Dickey TD, Carlson CA, Nelson NB, Condon RH, Bates NR (2010) Increased ocean carbon export in the Sargasso Sea is countered by its enhanced mesopelagic attenuation. Biogeosciences 7(1):57–70CrossRefGoogle Scholar
  56. Luckhurst BE (1996a) Trends in commercial fishery landings of groupers and snappers in Bermuda from 1975 to 1992 and associated fishery management issues. In: Arreguin-Sanchez F, Munro JL, Balgos MC, Pauly D (eds) Biology, fisheries and culture of tropical groupers and snappers. ICLARM conference proceedings, vol 48, Manila. pp 277–288Google Scholar
  57. Luckhurst BE (1996b) A fishery-independent assessment of Bermuda’s coral reef fish stocks by diver census following the fish pot ban – a progress report. Proc Gulf Caribb Fish Inst 46:309–323Google Scholar
  58. Luckhurst BE (2010) Observations of a black grouper (Mycteroperca Bonaci) spawning aggregation in Bermuda. Gulf Caribb Res 22:43–49Google Scholar
  59. Luckhurst BE, Ward JAD (1996) Analysis of trends in Bermuda’s fishery statistical database from 1975 to 1990 with reference to fishery management measures implemented during this period. Proc Gulf Caribb Fish Inst 44:306–324Google Scholar
  60. McGillicuddy DJ, Robinson AR (1997) Eddy induced nutrient supply and new production in the Sargasso Sea. Deep Sea Res 44:1427–1450CrossRefGoogle Scholar
  61. McGillicuddy DJ, Johnson RJ, Siegel DA, Michaels AF, Bates NR, Knap AH (1999) Mesoscale variations of biogeochemical properties in the Sargasso Sea. J Geophys Res 104:13381–13394CrossRefGoogle Scholar
  62. McGillicuddy DJ, Anderson LA, Bates NR, Bibby T, Buesseler KO, Carlson CA, Davis CS, Ewart C, Falkowski PG, Goldthwait SA, Hansell DA, Jenkins WJ, Johnson R, Kosnyrev VK, Ledwell JR, Li QP, Siegel DA, Steinberg DK (2007) Eddy/wind interactions stimulate extraordinary mid-ocean plankton blooms. Science 316(5827):1016–1021. doi: 10.1126/science.1136256 CrossRefGoogle Scholar
  63. McKinney C (1998) Characterization of coral diseases and coral bleaching in Bermuda (Sept–Oct 1998). Research Experience for Undergraduates (REU) Report. Bermuda Biological Station for Research Inc. 50ppGoogle Scholar
  64. MEP (2004) Marine environmental program annual report, 2003–2004. Bermuda Institute of Ocean Sciences, 46ppGoogle Scholar
  65. MEP (2005) Marine environmental program annual report, 2004–2005. Bermuda Institute of Ocean Sciences, 136ppGoogle Scholar
  66. MEP (2006) Marine environmental program annual report, 2005–2006. Bermuda Institute of Ocean Sciences, 128ppGoogle Scholar
  67. MEP (2007) Marine environmental program annual report, 2006–2007. Bermuda Institute of Ocean Sciences, 80ppGoogle Scholar
  68. Ministry of Transport (2011) Study of Bermuda’s shipping channels to accommodate larger cruise ships. Public presentation, Bermuda Government, (www.gov.bm) 49ppGoogle Scholar
  69. Morgan MB, Edge SE, Snell TW (2005) Profiling differential gene expression of corals along a transect of waters adjacent to the Bermuda municipal dump. Mar Pollut Bull 51:524–533Google Scholar
  70. Morris B, Barnes J, Brown F, Markham J (1977) The Bermuda marine environment, vol 15. Bermuda Biological Station Special Publication, St. George’s WestGoogle Scholar
  71. Murdoch TJT, Glasspool AF, Outerbridge M, Manuel S (2007) Bermuda seagrass status report 2004. BREAM project. Bermuda Biodiversity Project Special Publication 2007–002. 84ppGoogle Scholar
  72. Owen R, Knap A, Toaspern M, Carberry K (2002) Inhibition of coral photosynthesis by the antifouling herbicide Irgarol 1051. Mar Poll Bull 44:623–632CrossRefGoogle Scholar
  73. Pandolfi JM, Bradbury RH, Sala E, Hughes TP, Bjorndal KA, Cooke RG, McArdel D, McClenachen L, Newman MJH, Paredes G, Warner RR, Jackson JBC (2003) Global trajectories of the long-term decline of coral reef ecosystems. Science 301:955–958CrossRefGoogle Scholar
  74. Price ARG (2006) Cruise ships and sustainability in Bermuda: a preliminary evaluation. Report prepared for the Bermuda National Trust. Industrial Economics, Inc., p. 44Google Scholar
  75. Quinn B, Gagne F, Weber J-P, Blaise C (2005) Ecotoxicological effects of a semi-submerged municipal dump (Castle Harbour, Bermuda) on the calico scallop Argopecten gibbus. Mar Poll Bull 51:534–544CrossRefGoogle Scholar
  76. Richardson PL, Cheney RE, Worthington LV (1978) A census of Gulf Stream rings, spring 1975. J Geophys Res 83:6136–6144CrossRefGoogle Scholar
  77. Rogers JC (1990) Patterns of low-frequency monthly sea level pressure variability (1899–1986) and associated wave cyclone frequencies. J Climate 3:1364–1379CrossRefGoogle Scholar
  78. Ruetzler K, Santavy DL, Antonius A (1983) The black band disease of Atlantic reef corals. The black band disease of Atlantic reef corals. III. Distribution, ecology and development. PSZNI Mar Ecol 4:329–358CrossRefGoogle Scholar
  79. Sarkis S (1999) Report on the potential impacts of cruise ships on Bermuda’s environment. Bermuda National Trust, p. 46CrossRefGoogle Scholar
  80. Sarkis S, van Beukering PJH, McKenzie E (2010) (eds) Total economic value of Bermuda’s coral reefs: valuation of ecosystem services. Technical report. Department of Conservation Services, Bermuda Government, (www.conservation.bm), 199ppGoogle Scholar
  81. Simmons JAK, Lyons WB (1994) The groundwater flux of nitrogen and phosphorous to Bermuda’s coastal waters. Water Res Bull 30:984–991CrossRefGoogle Scholar
  82. Smith SR (1985) Reef damage and recovery after ship groundings on Bermuda. In: Proc 5th Int Coral Reef Symp vol 6. Tahiti, pp 497–502Google Scholar
  83. Smith GW, Weil A (2004) Aspergillosis in gorgonians. In: Rosenberg E, Loya Y (eds) Coral reef health and diseases. Springer, Berlin, pp 279–286CrossRefGoogle Scholar
  84. Smith SR, Hellin DC, McKenna SA (1998) Marine environmental impact studies on the thermal effluent released from the Tynes Bay Incinerator and ash waste disposal in Castle Harbour. BBSR Spec Publ vol 35. Bermuda Biological Station for Research, Ferry Reach, 210ppGoogle Scholar
  85. Tilstone G, Smyth T, Poulton A, Hutson R (2009) Measured and remotely sensed estimates of primary production in the Atlantic Ocean from 1998 to 2005. Deep-Sea Res 56(15):918–930. doi: 10.1016/j.dsr2.2008.10.034 CrossRefGoogle Scholar
  86. Venti A, Kadko D, Andersson A, Langdon C, Bates NR (in press) A multi-tracer approach to estimate reef residence times. Global Biogeochem CyclesGoogle Scholar
  87. Verrill AE (1907) The Bermuda Islands. Part IV. Geology and paleontology, and part V. An account of the coral reefs. Trans Connect Acad Arts Sci 12:45–348Google Scholar
  88. Waltham A (1998) The effects of shipping traffic on adjacent coral reefs along the North Shore, Bermuda. Undergraduate thesis, Southampton University, 52ppGoogle Scholar
  89. Webster G, Smith SR (2002) Impact of a sewage outfall on juvenile coral populations in Bermuda. In: Proc 9th Int Coral Reef Symp vol 2. Bali, pp 1041–1045Google Scholar
  90. Weil E, Croquer A (2009) Spatial variability in distribution and prevalence of Caribbean scleractinian coral and octocoral diseases. I. Community-level analysis. Diseas Aquat Orgs 83:195–208CrossRefGoogle Scholar
  91. Weil E, Hooten A (2008) Underwater cards for assessing coral health on Caribbean coral reefs. GEF-CRTR-Currie Comm, Australia, 30ppGoogle Scholar
  92. Weil E, Urreiztieta I, Garzon-Ferreira J (2002) Geographic variability in the incidence of coral and octocoral diseases in the wider Caribbean. In: Proc 9th Int Coral Reef Symp vol 2. Bali, pp 1231–1237Google Scholar
  93. Whitfield PE, Gardner T, Vives SP, Gilligan MR, Courtenay WR Jr, Ray GC, Hare JA (2002) Biological invasion of the Indo-Pacific lionfish Pterois volitans along the Atlantic coast of North America. Mar Ecol Prog Ser 235:289–297CrossRefGoogle Scholar
  94. Widdows J, Burns KA, Menon NR, Page DS, Soria S (1990) Measurement of physiological energetics (scope for growth) and chemical contaminants in mussels (Arca zebra) transplanted along a contaminant gradient in Bermuda (GEEP Workshop, September 1988). JEMBE 138:99–117CrossRefGoogle Scholar
  95. Zhang LP, Wu LX, Zhang JX (2011) Freshwater loss/salinification: simulated response to recent freshwater flux change over the Gulf Stream and it’s extension: coupled ocean–atmosphere adjustment and Atlantic-Pacific teleconnection. J Climate 24(15):3971–3988. doi: 10.1175/2011JCL14020.1 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Struan R. Smith
    • 1
    Email author
  • Samia Sarkis
    • 2
  • Thad J. T. Murdoch
    • 3
  • Ernesto Weil
    • 4
  • Aldo Croquer
    • 5
  • Nicholas R. Bates
    • 6
  • Rodney J. Johnson
    • 6
  • Samantha de Putron
    • 6
  • Andreas J. Andersson
    • 7
  1. 1.Natural History Museum, Bermuda Aquarium, Museum and ZooHamilton ParishBermuda
  2. 2.Department of Conservation ServicesHamilton ParishBermuda
  3. 3.Bermuda Zoological SocietyHamilton ParishBermuda
  4. 4.Department of Marine SciencesUniversity of Puerto RicoMayaguesUSA
  5. 5.Departamento de Estudios AmbientalesUniversidad Simon BolivarCaracasVenezuela
  6. 6.Bermuda Institute of Ocean SciencesSt GeorgesBermuda
  7. 7.Scripps Institution of OceanographySan DiegoUSA

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