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Title: Tidal Marshes across a Chesapeake Bay Subestuary Are Not Keeping up with Sea-Level Rise

Sea-level rise is a major factor in wetland loss worldwide, and inmuch of Chesapeake Bay (USA) the rate of sea-level rise is higher than the current global rate of 3.2 mmyr -1 due to regional subsidence.Marshes along estuarine salinity gradients differ in vegetation composition, productivity, decomposition pathways, and sediment dynamics, andmay exhibit different responses to sea-level rise. Coastal marshes persist by building vertically at rates at or exceeding regional sea-level rise. In one of the first studies to examine elevation dynamics across an estuarine salinity gradient, we installed 15 surface elevation tables (SET) and accretion marker-horizon plots (MH) in tidal freshwater, oligohaline, and brackish marshes across a Chesapeake Bay subestuary. Over the course of four years, wetlands across the subestuary decreased 1.8 ± 2.7 mmyr -1 in elevation on average, at least 5 mmyr -1 below that needed to keep pace with global sea-level rise. Elevation change rates did not significantly differ among themarshes studied, and ranged from-9.8 ± 6.9 to 4.5 ± 4.3 mmyr -1. Surface accretion of depositedmineral and organic matter was uniformly high across the estuary (~9–15 mmyr -1), indicating that elevation loss was not due to lack of accretionary input. Position in the estuary and associatedmore » salinity regime were not related to elevation change or surface matter accretion. In conclusion, previous studies have focused on surface elevation change inmarshes of uniformsalinity (e.g., salt marshes); however, our findings highlight the need for elevation studies inmarshes of all salinity regimes and different geomorphic positions, and warn that brackish, oligohaline, and freshwater tidal wetlands may be at similarly high risk of submergence in some estuaries.« less
 [1] ;  [2] ;  [2] ;  [3]
  1. Univ. of Maryland, College Park, MD (United States); Northwest Indian Fisheries Commission, Olympia, WA (United States)
  2. Univ. of Maryland, College Park, MD (United States)
  3. Univ. of South Alabama, Mobile, AL (United States)
Publication Date:
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Accepted Manuscript
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Additional Journal Information:
Journal Volume: 11; Journal Issue: 7; Journal ID: ISSN 1932-6203
Public Library of Science
Research Org:
Univ. of Maryland, College Park, MD (United States)
Sponsoring Org:
U.S. Department of Energy, National Institute for Climatic Change Research; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; marshes; salinity; estuaries; sediment; fresh water; wetlands; linear regression analysis; decomposition
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