Constraints on the adjustment of tidal marshes to accelerating sea level rise
Neil Saintilan, Katya E. Kovalenko, Glenn R. Guntenspergen, Kerrylee Rogers, James C. Lynch, Donald R. Cahoon, Catherine E. Lovelock, Daniel A. Friess, Erica Ashe, Ken W. Krauss, Nicole Cormier, Tom Spencer, Janine B. Adams, Jacqueline L. Raw, Carles Ibáñez, Francesco Scarton, Stijn Temmerman, Patrick Meire, Tom Maris, Karen M. Thorne, John C. Brazner, Gail L. Chmura, Tony Bowron, Vishmie Palepitiya Gamage, Kimberly Cressman, Charlie Endris, Christina M Marconi, Pamela Marcum, Kari St. Laurent, William G. Reay, Kenneth B. Raposa, Jason A. Garwood, Nicole S. Khan
Abstract
Much uncertainty exists about the vulnerability of valuable tidal marsh ecosystems to relative sea level rise. Previous assessments of resilience to sea level rise, to which marshes can adjust by sediment accretion and elevation gain, revealed contrasting results, depending on contemporary or Holocene geological data. By analyzing globally distributed contemporary data, we found that marsh sediment accretion increases in parity with sea level rise, seemingly confirming previously claimed marsh resilience. However, subsidence of the substrate shows a nonlinear increase with accretion. As a result, marsh elevation gain is constrained in relation to sea level rise, and deficits emerge that are consistent with Holocene observations of tidal marsh vulnerability.