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Tectonic Subsidence of California Estuaries Increases Forecasts of Relative Sea-Level Rise


Even along the generally uplifting coast of the Pacific US, local geologic structures can cause subsidence. In this study, we quantify Holocene-averaged subsidence rates in four estuaries (Carpinteria Slough, Goleta Slough, Campus Lagoon, and Morro Bay) along the southern and central California coast by comparing radiocarbon-dated estuarine material to a regional sea-level curve. Holocene-averaged rates of vertical motion range from subsidence of 1.4 ± 2.4, 1.2±0.4, and 0.4 ± 0.3 mm/year in Morro Bay, Carpinteria Slough, and Goleta Slough, respectively, to possible uplift in Campus Lagoon (−0.1 ± 0.9 mm/year). The calculated rates of subsidence are of the same magnitude as rates of relative sea-level rise experienced over the late Holocene and effectively double the ongoing rates of relative sea-level rise experienced over the last five decades on other parts of the coast. The difference in rates of vertical motion among these four estuaries is attributed to their geological settings. Estuaries developed in subsiding geological structures such as synclines and fault-bounded basins are subsiding at much higher rates than those developed within flooded river valleys incised into marine terraces. Restoration projects accounting for future sea-level rise must consider the geologic setting of the estuaries and, if applicable, include subsidence in future sea-level rise scenarios, even along the tectonically uplifting US Pacific Coast.

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  • Bard, E., B. Hamelin, M. Arnold, L. Montaggioni, G. Cabioch, G. Faure, and F. Rougerie. 1996. Deglacial sea-level record from Tahiti corals and the timing of global meltwater discharge. Nature 382: 241–244.

    CAS  Article  Google Scholar 

  • Brew, D.S., and P.B. Williams. 2010. Predicting the impact of large-scale tidal wetland restoration on morphodynamics and habitat evolution in south San Francisco Bay, California. Journal of Coastal Research 26: 912–924.

    Article  Google Scholar 

  • Bromirski, P.D., A.J. Miller, R.E. Flick, and G. Auad. 2011. Dynamical suppression of sea level rise along the Pacific coast of North America: indications for imminent acceleration. Journal of Geophysical Research 116: C07005.

    Article  Google Scholar 

  • Clark, J.A., J.X. Mitrovica, and J. Alder. 2014. Coastal paleogeography of the California-Oregon-Washington and Bering sea continental shelves during the latest Pleistocene and Holocene: implications for the archaeological record. Journal of Archaeological Science 52: 12–23.

    Article  Google Scholar 

  • Coan, E.V., and P. Valentich-Scott. 2012. Bivalve seashells of tropical west America: marine mollusks from Baja California to Northern Peru. Santa Barbara: Santa Barbara Museum of Natural History.

    Google Scholar 

  • Dibblee, T.W. 1966. Geology of the Central Santa Ynez Mountains, Santa Barbara County, California. California Division of Mines and Geology Bulletin 186: 1–99.

    Google Scholar 

  • Draut, A.E., P.E. Hart, T.D. Lorenson, H.F. Ryan, F.L. Wong, R.W. Sliter, and J.E. Conrad. 2009. Late Pleistocene to Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, souther California, USA. Marine Geophysical Researches 30: 193–206.

    Article  Google Scholar 

  • Ferren Jr., W.R. 1985. Carpinteria salt marsh: environment, history, and botantical resources of a southern California estuary. The Herbarium, Department of Biological Sciences, University of California, Santa Barbara, CA. Publication 4: 1–300.

    Google Scholar 

  • Gallagher, J. 1996. Late Holocene evolution of the Chorro delta, Morro Bay, California. In Geography, 258. Los Angeles: University of Califoria Los Angeles.

  • Gesch, D., M. Oimoen, S. Greenless, C. Nelson, M. Steuck, and D. Tyler. 2002. The national elevation dataset. Photogrammetric Engineering and Remote Sensing 68: 5–11.

    Google Scholar 

  • Gurrola, L.D., E.A. Keller, J.H. Chen, L.A. Owen, and J.Q.D. Spencer. 2014. Tectonic geomorphology of marine terraces: Santa Barbara fold belt, California. Geological Society of America Bulletin 126: 219–233.

    Article  Google Scholar 

  • Hanson, K.L., W.R. Lettis, J.R. Wesling, K.I. Kelson, and L. Mezger. 1992. Quaternary marine terraces, south-central coastal California: implications for crustal deformation and coastal evolution. In Quaternary coasts of the United States: marine and lacustrine systems, ed. C.H.I. Fletcher and J.F. Wehmiller, 323–332. Tulsa: Society for Sedimentary Geology (SEPM).

    Chapter  Google Scholar 

  • Holmquist, J., L. Reynolds, L. Brown, J. Southon, A.R. Simms, and G. MacDonald. 2015. Marine radiocarbon reservoir values in southern California estuaries: interspecies, latitudinal, and interannual variability. Radiocarbon 57: 449–458.

    CAS  Article  Google Scholar 

  • Jackson, J.A., ed. 1997. Glossary of Geology. American Geological Institute. 769 p.

  • Jackson, P.A., and R.S. Yeats. 1982. Structural evolution of Carpinteria Basin, Western Transverse Ranges, California. American Association of Petroleum Geologists Bulletin 66: 805–829.

    Google Scholar 

  • Kolker, A.S., M.A. Allison, and S. Hameed. 2011. An evaluation of subsidence rates and sea-level variability in the northern Gulf of Mexico. Geophysical Research Letters 38: L21404.

    Article  Google Scholar 

  • Lajoie, K.R., J.P. Kern, J. Wehmiller, G.L. Kennedy, S.A. Mathieson, A.M. Sarna-Wojcicki, R.F. Yerkes, and P.F. McCrory. 1979. Quaternary marine shoreline and crustal deformation San Diego to Santa Barbara, California. In Geological excursions in the southern California area, ed. P.L. Abbott, 3–15. San Diego: San Diego State University Department of Geological Sciences.

    Google Scholar 

  • Lambeck, K., Y. Yokoyama, and A. Purcell. 2002. Into and out of the Last Glacial Maximum: sea-level change during oxygen isotope stages 3 and 2. Quaternary Science Reviews 21: 343–360.

    Article  Google Scholar 

  • Lettis, W.R., and N.T. Hall. 1994. Los Osos fault zone, San Luis Obispo County, California. In Seismotectonics of the Central California Coast Ranges, ed. I.B. Alterman, R.B. McMullen, L.S. Cluff, and D.B. Slemmons. Boulder: Geological Society of America.

    Google Scholar 

  • Lohmar, J.M., K.B. Macdonald, and S.A. Janes. 1980. Late Pleistocene-Holocene sedimentary infilling and faunal change in a southern California coastal lagoon. In Quaternary depositional environments of the pacific coast: pacific coast paleogeography symposium 4, ed. M.E. Field, A.H. Bouma, I.P. Colburn, R.G. Douglas, and J.C. Ingle, 231–240. Pacific Section SEPM.

  • Minor, S.A., K.S. Kellogg, R.G. Stanley, L.D. Gurrola, E.A. Keller, and T.R. Brandt. 2009. Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California. In United States Geological Survey Scientific Investigations Map, 1–38. Denver, CO: USGS.

  • Nardin, T.R., R.H. Osborne, D.J. Bottjer, and R.C.J. Sheidemann. 1981. Holocene sea-level curves for Santa Monica Shelf, California continental borderland. Science 213: 331–333.

    CAS  Article  Google Scholar 

  • Page, H.M., D.C. Reed, M.A. Brzezinski, J.M. Melack, and J.E. Dugan. 2008. Assessing the importance of land and marine sources of organic matter to kelp forest food webs. Marine Ecology Progress Series 360: 47–62.

    Article  Google Scholar 

  • Reeder-Myers, L.A., J.M. ERlandson, D.A. Muhs, and T.C. Rick. 2015. Sea level, paleogeography, and archeology on California’s Northern Channel Islads. Quaternary Research 83: 263–272.

    Article  Google Scholar 

  • Reimer, P.J., E. Bard, A. Bayliss, J.W. Beck, P.G. Blackwell, C.B. Ramsey, C.E. Buck, H. Cheng, R.L. Edwards, M. Friedrich, P.M. Grootes, T.P. Guilderson, H. Haflidason, I. Hajdas, C. Hatte, T.J. Heaton, D.L. Hoffmann, A.G. Hogg, K.A. Hughen, K.F. Kaiser, B. Kromer, S.W. Manning, M. Niu, R.W. Reimer, D.A. Richards, E.M. Scott, J.R. Southon, R.A. Staff, C.S.M. Turney, and J. Van der Plicht. 2013. INTCAL13 and MARINE13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55: 1869–1887.

    CAS  Article  Google Scholar 

  • Reynolds, L.C., and A.R. Simms. 2015. Late Quaternary relative sea level in Southern California and Monterey Bay. Quaternary Science Reviews 126: 57–66.

    Article  Google Scholar 

  • Shennan, I. 2015. Handbook of sea-level research: framing research questions. In Hanbook of sea-level research, ed. I. Shennan, A. Long, and B.P. Horton, 3–25. Wiley.

  • Simms, A.R., H. Rouby, and K. Lambeck. 2016. Marine terraces and rates of vertical tectonic motion: the importance of glacio-isostatic adjustment along the Pacific coast of central North America. Geological Society of America Bulletin 128: 81–93.

    Google Scholar 

  • Sommerfield, C.K., H.J. Lee, and W.R. Normark. 2009. Postglacial sedimentary record of the Southern California continental shelf and slope, point conception to Dana Point. In Earth science in the urban ocean: the southern California continental borderland, ed. H.J. Lee and W.R. Normark, 89–115. Denver: Geological Society of America.

    Chapter  Google Scholar 

  • Sousa, W.P. 1983. Host life history and the effect of parasitic castration on growth: a field study of Cerithidea California Haldeman (Gastropoda: Prosobranchia) and its rematode parasites. Journal of Experimental Marine Biology and Ecology 73: 273–296.

    Article  Google Scholar 

  • Törnqvist, T.E., S.J. Bick, K. van der Borg, and A.F.M. de Jong. 2006. How stable is the Mississippi Delta? Geology 34.

  • Törnqvist, T.E., D.J. Wallace, J.E.A. Storms, J. Wallinga, R.L. Van Dam, M. Blaauw, M.S. Derksen, C.J.W. Klerks, C. Meijneken, and E.M.A. Snijders. 2008. Mississippi Delta subsidence primarily caused by compaction of Holocene strata. Nature Geoscience 1: 173–176.

    Article  Google Scholar 

  • Wiegers, M.O. 2009. Geologic map of the Morro Bay South 7.5′ Quadrangle San Luis Obispo County, California: a digital database. California: California Department of Conservation/California Geological Survey.

    Google Scholar 

  • Yu, S.-Y., T.E. Törnqvist, and P. Hu. 2012. Quantifying lithospheric subsidence rates underneath the Mississippi Delta. Earth and Planetary Science Letters 331-332: 21-30.

  • Zong, Y., and Y. Sawai. 2015. Diatoms. In Handbook of Sea-Level Research, ed. I. Shennan, A. Long, and B.P. Horton, 233–248. Wiley.

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We would like to thank Johnathan Rice, Daniel Livsey, Lauren Simkins, and Elisabeth Steel for their help in the field. Gratitude is also expressed to Andrew Brooks of the Carpinteria Saltmarsh Reserve, Christine Thompson of the California Department of Fish and Wildlife, and Lisa Stratton from the Cheadle Center for Biodiversity and Ecological Restoration (CCBER) at UC-Santa Barbara for helping to facilitate permission to work in Carpinteria Slough, Goleta Slough, and Campus Lagoon, respectively. We also wish to thank John Southon of UC-Irvine for help with the 14C dating. Funding for this project was provided by the Santa Barbara Coastal Long-Term Ecological Research (LTER) program of the National Science Foundation. This research was also supported by the Southern California Earthquake Center (Contribution No. 6020). SCEC is funded by NSF Cooperative Agreement EAR-1033462 and USGS Cooperative Agreement G12AC20038.

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Communicated by Cathleen Wigand

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Simms, A., Reynolds, L.C., Bentz, M. et al. Tectonic Subsidence of California Estuaries Increases Forecasts of Relative Sea-Level Rise. Estuaries and Coasts 39, 1571–1581 (2016).

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  • Estuary
  • Marsh
  • Sea level
  • Compaction
  • Lagoon
  • Santa Barbara