Coastal marsh degradation into ponds induces irreversible elevation loss relative to sea level

Geophysical Research Letters
By: , and 

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Abstract

Coastal marshes and their valuable ecosystem services are feared to be lost by sea level rise, yet the mechanisms of marsh degradation into ponds and potential recovery are poorly understood. We quantified and analyzed elevations of marsh surfaces and pond bottoms along a marsh loss gradient (Blackwater River, Maryland, USA). Our analyses show that ponds deepen with increasing tidal channel width connecting the ponds to the river, indicating a new feedback mechanism where channels lead to enhanced tidal export of pond bottom material. Pond elevations also decrease with increasing pond size, consistent with previous work identifying a positive feedback between wind wave erosion and pond size. These two positive feedbacks, combined with bimodal elevation distributions and sharp topographic boundaries between interior ponds and the marsh platform, indicate alternative elevation states and imply that marsh loss by pond formation is nearly irreversible once pond deepening exceeds a critical level.

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Publication type Article
Publication Subtype Journal Article
Title Coastal marsh degradation into ponds induces irreversible elevation loss relative to sea level
Series title Geophysical Research Letters
DOI 10.1029/2020GL089121
Volume 47
Issue 18
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Patuxent Wildlife Research Center
Description e2020GL089121, 10 p.
Country United States
State Maryland
Other Geospatial Blackwater River
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