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Sediment transport‐based metrics of wetland stability
Author(s) -
Ganju Neil K.,
Kirwan Matthew L.,
Dickhudt Patrick J.,
Guntenspergen Glenn R.,
Cahoon Donald R.,
Kroeger Kevin D.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065980
Subject(s) - marsh , sediment , wetland , environmental science , hydrology (agriculture) , accretion (finance) , sediment transport , flood myth , oceanography , geology , ecology , geomorphology , geography , geotechnical engineering , physics , archaeology , astrophysics , biology
Despite the importance of sediment availability on wetland stability, vulnerability assessments seldom consider spatiotemporal variability of sediment transport. Models predict that the maximum rate of sea level rise a marsh can survive is proportional to suspended sediment concentration (SSC) and accretion. In contrast, we find that SSC and accretion are higher in an unstable marsh than in an adjacent stable marsh, suggesting that these metrics cannot describe wetland vulnerability. Therefore, we propose the flood/ebb SSC differential and organic‐inorganic suspended sediment ratio as better vulnerability metrics. The unstable marsh favors sediment export (18 mg L −1 higher on ebb tides), while the stable marsh imports sediment (12 mg L −1 higher on flood tides). The organic‐inorganic SSC ratio is 84% higher in the unstable marsh, and stable isotopes indicate a source consistent with marsh‐derived material. These simple metrics scale with sediment fluxes, integrate spatiotemporal variability, and indicate sediment sources.