Open AccessShort-Term Accretional and Erosional Patterns in a Virginia Salt Marsh
Author(s) -
Thomas G. Reidenbaugh,
William C. Banta,
Michele Varricchio,
Robert P. Strieter,
Santoria Mendoza
Publication year - 1983
Publication title -
gulf research reports
Language(s) - English
Resource type - Journals
ISSN - 0072-9027
DOI - 10.18785/grr.0703.17
Subject(s) - salt marsh , spartina alterniflora , spartina , marsh , accretion (finance) , intertidal zone , brackish marsh , geology , environmental science , hydrology (agriculture) , tidal range , oceanography , erosion , sediment , geomorphology , estuary , wetland , ecology , physics , biology , geotechnical engineering , astrophysics
We estimated 3-year average rates of accretion and erosion in different vegetation zones of a juvenile Spartina alterniflora salt marsh at Wallops Island, Virginia, by precise releveling of a fixed grid. Seaward of the marsh there was extremely variable accretion and erosion in tidal flat, as a result of winter ice scouring and transport. At the lower limit of the marsh, tall Spartina edge marsh accreted at about 6.2 mm yr-1 , well in excess of relative sea level rise, supplied by mineral sediments. At the upper limit, levee Spartina and high marsh accreted at about 1.6 mm yr-1, in equilibrium with sea level rise. Accretion there was supplemented by organic sediments from tidal wrack. At mid-elevations, medium Spartina middle marsh eroded slightly at about -0.6 mm yr-1, and low-density Spartina and bare soil eroded rapidly at about -5.3 mm yr-1. These zones may be relatively sediment-starved. The most severe erosion resulted from vegetation diebacks beneath tidal wrack. Patterns of accretion and erosion show that this site is maturing topographically from a juvenile foreshore marsh to a creek-drained marsh.