Constraints on the adjustment of tidal marshes to accelerating sea level rise

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 Holoce...

Full description

Saved in:

Bibliographic Details
Published in:	Science (American Association for the Advancement of Science) 2022-07, Vol.377 (6605), p.523-527
Main Authors:	Saintilan, Neil, Kovalenko, Katya E., Guntenspergen, Glenn, Rogers, Kerrylee, Lynch, James C., Cahoon, Donald R., Lovelock, Catherine E., Friess, Daniel A., Ashe, Erica, Krauss, Ken W., Cormier, Nicole, Spencer, Tom, Adams, Janine, Raw, Jacqueline, Ibanez, Carles, Scarton, Francesco, Temmerman, Stijn, Meire, Patrick, Maris, Tom, Thorne, Karen, Brazner, John, Chmura, Gail L., Bowron, Tony, Gamage, Vishmie P., Cressman, Kimberly, Endris, Charlie, Marconi, Christina, Marcum, Pamela, St. Laurent, Kari, Reay, William, Raposa, Kenneth B., Garwood, Jason A., Khan, Nicole
Format:	Article
Language:	eng
Subjects:	Accretion Climate change Deposition Holocene Land use Marshes Sea level Sea level rise Sediments Subsidence Tidal marshes
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	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. Will marshes rise up or sink? Marsh ecosystems are vulnerable to rising sea level, in addition to land-use change and other human activities. Studies have shown that some marshes are gaining elevation, making them remarkably resilient to rising seas; however, results vary across locations and between contemporary and Holocene records. Comparing data from 97 sites on four continents, Saintilan et al . found that the relationship between sediment accretion and marsh subsidence explains the variable responses to sea-level rise. Marshes accrete more sediment, keeping up with sea-level rise up to a point, but sediment subsidence increases nonlinearly with accretion such that at higher rates of sea-level rise, marshes begin to sink. Marshes are unlikely to keep up with rising seas under current climate change projections. —BEL Comparing marsh elevation change across four continents provides an explanation for variable marsh responses to sea-level rise.
ISSN:	0036-8075 1095-9203