Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos
Stable isotopes of oxygen (δ18O) in seawater reflect the combined influences of ocean circulation and atmospheric moisture balance. However, it is difficult to disentangle disparate ocean and atmosphere influences on modern seawater δ18O values, partly because continuous time series of seawater δ18O...
| Main Authors: | , , , , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
PO.DAAC, CA, USA
2023
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| Subjects: | |
| Online Access: | https://hdl.handle.net/2027.42/175878 https://doi.org/10.1029/2022GL102074 |
| _version_ | 1835008603843461120 |
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| author | Conroy, Jessica L. Murray, Nicole K. Patterson, Gillian S. Schore, Aiden I. G. Ikuru, Ima Cole, Julia E. Chillagana, David Echeverria, Fernando |
| author_facet | Conroy, Jessica L. Murray, Nicole K. Patterson, Gillian S. Schore, Aiden I. G. Ikuru, Ima Cole, Julia E. Chillagana, David Echeverria, Fernando |
| author_sort | Conroy, Jessica L. |
| collection | Unknown |
| description | Stable isotopes of oxygen (δ18O) in seawater reflect the combined influences of ocean circulation and atmospheric moisture balance. However, it is difficult to disentangle disparate ocean and atmosphere influences on modern seawater δ18O values, partly because continuous time series of seawater δ18O are rare. Here we present a nearly nine-year, continuous record of seawater δ18O values from the Galápagos. Seawater δ18O values faithfully track sea surface salinity and salinity along the equator at 50 m depth. Zonal current velocity within the Equatorial Undercurrent (EUC), directly west of the Galápagos, is strongly correlated with Galápagos surface seawater δ18O values with a 1-month lag. Reconstructions of Galápagos seawater δ18O values could thus provide a window into past variations in the strength of the EUC, an important influence on large-scale tropical Pacific climate.Plain Language SummaryThe Equatorial Undercurrent (EUC) flows beneath the surface of the equatorial Pacific Ocean from west to east, transporting cold, salty, nutrient rich waters. When this current hits the Galápagos, it rises to the surface. Its high nutrient levels serve as the foundation for the diverse Galápagos ecosystem and its colder temperature helps set up a strong sea surface temperature gradient that is the foundation of the tropical Pacific climate system. Despite its importance, little is known about how this current has varied prior to the short period of instrumental observations, and it remains challenging to reproduce in climate models. Here we show how Galápagos seawater stable isotope values track the strength of the EUC. Our findings open up possibilities to extend the record of the EUC back in time with isotope-based paleoclimate proxies from the Galápagos region.Key PointsGalápagos seawater δ18O values strongly covary with equatorial cold tongue salinity valuesSeawater δ18O values are higher with a stronger Pacific Equatorial Undercurrent west of Galápagos Peer Reviewed ... |
| format | Article in Journal/Newspaper |
| genre | Antarctica Journal |
| genre_facet | Antarctica Journal |
| geographic | Pacific |
| geographic_facet | Pacific |
| id | ftumdeepblue:oai:deepblue.lib.umich.edu:2027.42/175878 |
| institution | Open Polar |
| language | unknown |
| op_collection_id | ftumdeepblue |
| op_relation | https://hdl.handle.net/2027.42/175878 doi:10.1029/2022GL102074 Geophysical Research Letters Shen, G. T., Cole, J. E., Lea, D. W., Linn, L. J., McConnaughey, T. A., & Fairbanks, R. G. ( 1992 ). Surface ocean variability at Galapagos from 1936–1982: Calibration of geochemical tracers in corals. Paleoceanography, 7 ( 5 ), 563 – 588. https://doi.org/10.1029/92pa01825 Liu, Y., Xie, L., Morrison, J. M., Kamykowski, D., & Sweet, W. V. ( 2014 ). Ocean circulation and water mass characteristics around the Galápagos Archipelago simulated by a multiscale nested ocean circulation model. International Journal of Oceanography, 2014, 1 – 16. https://doi.org/10.1155/2014/198686 Martin, N. J., Conroy, J. L., Noone, D., Cobb, K. M., Konecky, B. L., & Rea, S. ( 2018 ). Seasonal and ENSO influences on the stable isotopic composition of Galápagos precipitation. Journal of Geophysical Research: Atmospheres, 123 ( 1 ), 261 – 275. https://doi.org/10.1002/2017JD027380 Rustic, G. T., Koutavas, A., Marchitto, T. M., & Linsley, B. K. ( 2015 ). Dynamical excitation of the tropical Pacific ocean and ENSO variability by little ice age cooling. Science, 350 ( 6267 ), 1537 – 1541. https://doi.org/10.1126/science.aac9937 Trueman, M., & d’Ozouville, N. ( 2010 ). Characterizing the Galápagos terrestrial climate in the face of global climate change. Galápagos Research, 67, 26 – 37. Walter, R. M., Sayani, H. R., Felis, T., Cobb, K. M., Abram, N. J., Arzey, A. K., et al. ( 2022 ). The CoralHydro2k database: A global, actively curated compilation of coral δ 18 O and Sr/Ca proxy records of tropical ocean hydrology and temperature for the common era. Earth System Science Data Discussions, 1 – 56. Wellington, G. M., Dunbar, R. B., & Merlen, G. ( 1996 ). Calibration of stable oxygen isotope signatures in Galapagos corals. Paleoceanography, 11 ( 4 ), 467 – 480. https://doi.org/10.1029/96pa01023 Yin, Y., Alves, O., & Oke, P. R. ( 2011 ). An ensemble ocean data assimilation system for seasonal prediction. Monthly Weather Review, 139 ( 3 ), 786 – 808. https://doi.org/10.1175/2010mwr3419.1 Garcia, A. M., Winemiller, K., Hoeinghaus, D., Claudino, M., Bastos, R., Correa, F., et al. ( 2017 ). Hydrologic pulsing promotes spatial connectivity and food web subsidies in a subtropical coastal ecosystem. Marine Ecology Progress Series, 567, 17 – 28. https://doi.org/10.3354/meps12060 IAEA/WMO. ( 2022 ). International atomic energy agency/world meteorological organization global network for isotopes in precipitation. The GNIP Database. Retrieved from https://www.iaea.org/services/networks/gnip Behringer, D. W., & Xue, Y. ( 2004 ). Evaulation of the global ocean data assimilation system at NCEP: The Pacific Ocean. In Eighth symposium on integrated observing and assimilation systems for atmosphere, oceans, and land surface, AMS 84th annual meeting. Biddle, L. C., Loose, B., & Heywood, K. J. ( 2019 ). Upper ocean distribution of glacial meltwater in the Amundsen Sea, Antarctica. Journal of Geophysical Research: Oceans, 124 ( 10 ), 6854 – 6870. https://doi.org/10.1029/2019jc015133 Caldwell, P. C., Merrifield, M. A., & Thompson, P. R. ( 2015 ). Sea level measured by tide gauges from global oceans—The joint archive for sea level holdings (NCEI accession 0019568), version 5.5. Dataset. NOAA National Centers for Environmental Information. https://doi.org/10.7289/V5V40S7W Cheung, A. H., Cole, J. E., Thompson, D. M., Vetter, L., Jimenez, G., & Tudhope, A. W. ( 2021 ). Fidelity of the coral Sr/Ca paleothermometer following heat stress in the northern Galápagos. Paleoceanography and Paleoclimatology, 36 ( 12 ), e2021PA004323. https://doi.org/10.1029/2021PA004323 Conroy, J. L. ( 2023 ). Galápagos temporal seawater isotope and salinity data, version 1.0. Interdisciplinary Earth Data Alliance (IEDA). https://doi.org/10.26022/IEDA/112750 Craig, H., & Gordon, L. I. ( 1965 ). Deuterium and oxygen 18 variations in the ocean and the marine environment. In E. Tongiorgi (Ed.), Stable isotopes in oceanographic studies and paleotempertures, Consiglio nazionale delle richerche (pp. 9 – 130 ). DeLong, K. L., Atwood, A., Moore, A., & Sanchez, S. ( 2022 ). Clues from the sea paint a picture of Earth’s water cycle. Eos, 103. https://doi.org/10.1029/2022EO220231 Dunbar, R. B., Wellington, G. M., Colgan, M. W., & Glynn, P. W. ( 1994 ). Eastern Pacific SST since 1600 AD the δ 18 Ο record of climate variability in Galápagos corals. Paleoceanography, 9 ( 2 ), 291 – 315. https://doi.org/10.1029/93pa03501 Good, S. A., Martin, M. J., & Rayner, N. A. ( 2013 ). EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates. Journal of Geophysical Research: Oceans, 118 ( 12 ), 6704 – 6716. https://doi.org/10.1002/2013jc009067 Google Earth Pro. ( 2022 ). “Santa Cruz, Galápagos” version 7.3.4.8642. Jimenez, G., Cole, J. E., Thompson, D. M., & Tudhope, A. W. ( 2018 ). Northern Galápagos corals reveal twentieth century warming in the eastern tropical Pacific. Geophysical Research Letters, 45 ( 4 ), 1981 – 1988. https://doi.org/10.1002/2017GL075323 Karnauskas, K. B., Jakoboski, J., Johnston, T. M. S., Owens, W. B., Rudnick, D. L., & Todd, R. E. ( 2020 ). The Pacific equatorial undercurrent in three generations of global climate models and glider observations. Journal of Geophysical Research: Oceans, 125 ( 11 ), e2020JC016609. https://doi.org/10.1029/2020JC016609 Karnauskas, K. B., Murtugudde, R., & Busalacchi, A. J. ( 2010 ). Observing the Galápagos–EUC interaction: Insights and challenges. Journal of Physical Oceanography, 40 ( 12 ), 2768 – 2777. https://doi.org/10.1175/2010jpo4461.1 Kessler, W. S. ( 2006 ). The circulation of the eastern tropical Pacific: A review. Progress in Oceanography, 69 ( 2–4 ), 181 – 217. https://doi.org/10.1016/j.pocean.2006.03.009 Lea, D. W., Pak, D. K., & Spero, H. J. ( 2000 ). Climate impact of late quaternary equatorial Pacific Sea surface temperature variations. Science, 289 ( 5485 ), 1719 – 1724. https://doi.org/10.1126/science.289.5485.1719 LeGrande, A. N., & Schmidt, G. A. ( 2006 ). Global gridded data set of the oxygen isotopic composition in seawater. Geophysical Research Letters, 33 ( 12 ), L12604. https://doi.org/10.1029/2006GL026011 |
| op_rights | IndexNoFollow |
| publishDate | 2023 |
| publisher | PO.DAAC, CA, USA |
| record_format | openpolar |
| spelling | ftumdeepblue:oai:deepblue.lib.umich.edu:2027.42/175878 2025-06-15T14:13:39+00:00 Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos Conroy, Jessica L. Murray, Nicole K. Patterson, Gillian S. Schore, Aiden I. G. Ikuru, Ima Cole, Julia E. Chillagana, David Echeverria, Fernando 2023-02-28 application/pdf https://hdl.handle.net/2027.42/175878 https://doi.org/10.1029/2022GL102074 unknown PO.DAAC, CA, USA Wiley Periodicals, Inc. https://hdl.handle.net/2027.42/175878 doi:10.1029/2022GL102074 Geophysical Research Letters Shen, G. T., Cole, J. E., Lea, D. W., Linn, L. J., McConnaughey, T. A., & Fairbanks, R. G. ( 1992 ). Surface ocean variability at Galapagos from 1936–1982: Calibration of geochemical tracers in corals. Paleoceanography, 7 ( 5 ), 563 – 588. https://doi.org/10.1029/92pa01825 Liu, Y., Xie, L., Morrison, J. M., Kamykowski, D., & Sweet, W. V. ( 2014 ). Ocean circulation and water mass characteristics around the Galápagos Archipelago simulated by a multiscale nested ocean circulation model. International Journal of Oceanography, 2014, 1 – 16. https://doi.org/10.1155/2014/198686 Martin, N. J., Conroy, J. L., Noone, D., Cobb, K. M., Konecky, B. L., & Rea, S. ( 2018 ). Seasonal and ENSO influences on the stable isotopic composition of Galápagos precipitation. Journal of Geophysical Research: Atmospheres, 123 ( 1 ), 261 – 275. https://doi.org/10.1002/2017JD027380 Rustic, G. T., Koutavas, A., Marchitto, T. M., & Linsley, B. K. ( 2015 ). Dynamical excitation of the tropical Pacific ocean and ENSO variability by little ice age cooling. Science, 350 ( 6267 ), 1537 – 1541. https://doi.org/10.1126/science.aac9937 Trueman, M., & d’Ozouville, N. ( 2010 ). Characterizing the Galápagos terrestrial climate in the face of global climate change. Galápagos Research, 67, 26 – 37. Walter, R. M., Sayani, H. R., Felis, T., Cobb, K. M., Abram, N. J., Arzey, A. K., et al. ( 2022 ). The CoralHydro2k database: A global, actively curated compilation of coral δ 18 O and Sr/Ca proxy records of tropical ocean hydrology and temperature for the common era. Earth System Science Data Discussions, 1 – 56. Wellington, G. M., Dunbar, R. B., & Merlen, G. ( 1996 ). Calibration of stable oxygen isotope signatures in Galapagos corals. Paleoceanography, 11 ( 4 ), 467 – 480. https://doi.org/10.1029/96pa01023 Yin, Y., Alves, O., & Oke, P. R. ( 2011 ). An ensemble ocean data assimilation system for seasonal prediction. Monthly Weather Review, 139 ( 3 ), 786 – 808. https://doi.org/10.1175/2010mwr3419.1 Garcia, A. M., Winemiller, K., Hoeinghaus, D., Claudino, M., Bastos, R., Correa, F., et al. ( 2017 ). Hydrologic pulsing promotes spatial connectivity and food web subsidies in a subtropical coastal ecosystem. Marine Ecology Progress Series, 567, 17 – 28. https://doi.org/10.3354/meps12060 IAEA/WMO. ( 2022 ). International atomic energy agency/world meteorological organization global network for isotopes in precipitation. The GNIP Database. Retrieved from https://www.iaea.org/services/networks/gnip Behringer, D. W., & Xue, Y. ( 2004 ). Evaulation of the global ocean data assimilation system at NCEP: The Pacific Ocean. In Eighth symposium on integrated observing and assimilation systems for atmosphere, oceans, and land surface, AMS 84th annual meeting. Biddle, L. C., Loose, B., & Heywood, K. J. ( 2019 ). Upper ocean distribution of glacial meltwater in the Amundsen Sea, Antarctica. Journal of Geophysical Research: Oceans, 124 ( 10 ), 6854 – 6870. https://doi.org/10.1029/2019jc015133 Caldwell, P. C., Merrifield, M. A., & Thompson, P. R. ( 2015 ). Sea level measured by tide gauges from global oceans—The joint archive for sea level holdings (NCEI accession 0019568), version 5.5. Dataset. NOAA National Centers for Environmental Information. https://doi.org/10.7289/V5V40S7W Cheung, A. H., Cole, J. E., Thompson, D. M., Vetter, L., Jimenez, G., & Tudhope, A. W. ( 2021 ). Fidelity of the coral Sr/Ca paleothermometer following heat stress in the northern Galápagos. Paleoceanography and Paleoclimatology, 36 ( 12 ), e2021PA004323. https://doi.org/10.1029/2021PA004323 Conroy, J. L. ( 2023 ). Galápagos temporal seawater isotope and salinity data, version 1.0. Interdisciplinary Earth Data Alliance (IEDA). https://doi.org/10.26022/IEDA/112750 Craig, H., & Gordon, L. I. ( 1965 ). Deuterium and oxygen 18 variations in the ocean and the marine environment. In E. Tongiorgi (Ed.), Stable isotopes in oceanographic studies and paleotempertures, Consiglio nazionale delle richerche (pp. 9 – 130 ). DeLong, K. L., Atwood, A., Moore, A., & Sanchez, S. ( 2022 ). Clues from the sea paint a picture of Earth’s water cycle. Eos, 103. https://doi.org/10.1029/2022EO220231 Dunbar, R. B., Wellington, G. M., Colgan, M. W., & Glynn, P. W. ( 1994 ). Eastern Pacific SST since 1600 AD the δ 18 Ο record of climate variability in Galápagos corals. Paleoceanography, 9 ( 2 ), 291 – 315. https://doi.org/10.1029/93pa03501 Good, S. A., Martin, M. J., & Rayner, N. A. ( 2013 ). EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates. Journal of Geophysical Research: Oceans, 118 ( 12 ), 6704 – 6716. https://doi.org/10.1002/2013jc009067 Google Earth Pro. ( 2022 ). “Santa Cruz, Galápagos” version 7.3.4.8642. Jimenez, G., Cole, J. E., Thompson, D. M., & Tudhope, A. W. ( 2018 ). Northern Galápagos corals reveal twentieth century warming in the eastern tropical Pacific. Geophysical Research Letters, 45 ( 4 ), 1981 – 1988. https://doi.org/10.1002/2017GL075323 Karnauskas, K. B., Jakoboski, J., Johnston, T. M. S., Owens, W. B., Rudnick, D. L., & Todd, R. E. ( 2020 ). The Pacific equatorial undercurrent in three generations of global climate models and glider observations. Journal of Geophysical Research: Oceans, 125 ( 11 ), e2020JC016609. https://doi.org/10.1029/2020JC016609 Karnauskas, K. B., Murtugudde, R., & Busalacchi, A. J. ( 2010 ). Observing the Galápagos–EUC interaction: Insights and challenges. Journal of Physical Oceanography, 40 ( 12 ), 2768 – 2777. https://doi.org/10.1175/2010jpo4461.1 Kessler, W. S. ( 2006 ). The circulation of the eastern tropical Pacific: A review. Progress in Oceanography, 69 ( 2–4 ), 181 – 217. https://doi.org/10.1016/j.pocean.2006.03.009 Lea, D. W., Pak, D. K., & Spero, H. J. ( 2000 ). Climate impact of late quaternary equatorial Pacific Sea surface temperature variations. Science, 289 ( 5485 ), 1719 – 1724. https://doi.org/10.1126/science.289.5485.1719 LeGrande, A. N., & Schmidt, G. A. ( 2006 ). Global gridded data set of the oxygen isotopic composition in seawater. Geophysical Research Letters, 33 ( 12 ), L12604. https://doi.org/10.1029/2006GL026011 IndexNoFollow Galápagos seawater salinity Pacific Equatorial Undercurrent stable isotope Geological Sciences Science Article 2023 ftumdeepblue 2025-06-04T05:59:23Z Stable isotopes of oxygen (δ18O) in seawater reflect the combined influences of ocean circulation and atmospheric moisture balance. However, it is difficult to disentangle disparate ocean and atmosphere influences on modern seawater δ18O values, partly because continuous time series of seawater δ18O are rare. Here we present a nearly nine-year, continuous record of seawater δ18O values from the Galápagos. Seawater δ18O values faithfully track sea surface salinity and salinity along the equator at 50 m depth. Zonal current velocity within the Equatorial Undercurrent (EUC), directly west of the Galápagos, is strongly correlated with Galápagos surface seawater δ18O values with a 1-month lag. Reconstructions of Galápagos seawater δ18O values could thus provide a window into past variations in the strength of the EUC, an important influence on large-scale tropical Pacific climate.Plain Language SummaryThe Equatorial Undercurrent (EUC) flows beneath the surface of the equatorial Pacific Ocean from west to east, transporting cold, salty, nutrient rich waters. When this current hits the Galápagos, it rises to the surface. Its high nutrient levels serve as the foundation for the diverse Galápagos ecosystem and its colder temperature helps set up a strong sea surface temperature gradient that is the foundation of the tropical Pacific climate system. Despite its importance, little is known about how this current has varied prior to the short period of instrumental observations, and it remains challenging to reproduce in climate models. Here we show how Galápagos seawater stable isotope values track the strength of the EUC. Our findings open up possibilities to extend the record of the EUC back in time with isotope-based paleoclimate proxies from the Galápagos region.Key PointsGalápagos seawater δ18O values strongly covary with equatorial cold tongue salinity valuesSeawater δ18O values are higher with a stronger Pacific Equatorial Undercurrent west of Galápagos Peer Reviewed ... Article in Journal/Newspaper Antarctica Journal Unknown Pacific |
| spellingShingle | Galápagos seawater salinity Pacific Equatorial Undercurrent stable isotope Geological Sciences Science Conroy, Jessica L. Murray, Nicole K. Patterson, Gillian S. Schore, Aiden I. G. Ikuru, Ima Cole, Julia E. Chillagana, David Echeverria, Fernando Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos |
| title | Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos |
| title_full | Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos |
| title_fullStr | Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos |
| title_full_unstemmed | Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos |
| title_short | Equatorial Undercurrent Influence on Surface Seawater δ18O Values in the Galápagos |
| title_sort | equatorial undercurrent influence on surface seawater δ18o values in the galápagos |
| topic | Galápagos seawater salinity Pacific Equatorial Undercurrent stable isotope Geological Sciences Science |
| topic_facet | Galápagos seawater salinity Pacific Equatorial Undercurrent stable isotope Geological Sciences Science |
| url | https://hdl.handle.net/2027.42/175878 https://doi.org/10.1029/2022GL102074 |