How Old Are Marshes on the East Coast, USA? Complex Patterns in Wetland Age Within and Among Regions

Authors

Anna E. Braswell
James B. Heffernan
Matthew L. Kirwan, Virginia Institute of Marine ScienceFollow

Document Type

Article

Department/Program

Virginia Institute of Marine Science

Publication Date

10-16-2020

Journal

Geophysical Research Letters

Volume

47

Issue

19

First Page

e2020GL089415

Abstract

Sea‐level dynamics, sediment availability, and marine energy are critical drivers of coastal wetland formation and persistence, but their roles as continental‐scale drivers remain unknown. We evaluated the timing and spatial variability of wetland formation from new and existing cores collected along the Atlantic and Gulf coasts of the United States. Most basal peat ages occurred after sea‐level rise slowed (after ~4,000 years before present), but predominance of sea‐level rise studies may skew age estimates toward older sites. Near‐coastal sites tended to be younger, indicating creation of wetlands through basin infilling and overwash events. Age distributions differed among regions, with younger wetlands in the northeast and southeast corresponding to European colonization and deforestation. Across all cores, wetland age correlated strongly with basal peat depth. Marsh age elucidates the complex interactions between sea‐level rise, sediment supply, and geomorphic setting in determining timing and location of marsh formation and future wetland persistence.

DOI

DOI: 10.1029/2020GL089415

Keywords

Marsh, wetland formation, geomorphology

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

Recommended Citation

Braswell, Anna E.; Heffernan, James B.; and Kirwan, Matthew L., How Old Are Marshes on the East Coast, USA? Complex Patterns in Wetland Age Within and Among Regions (2020). Geophysical Research Letters, 47(19), e2020GL089415.

DOI: 10.1029/2020GL089415