Sediment-based reconstruction of submersed aquatic vegetation distribution in the Severn River, a sub-estuary of Chesapeake Bay

摘要: A paleo-ecological reconstruction of long-term changes in the distribution submersed aquatic vegetation (SAV) a Chesapeake sub-estuary was made using dated sediment cores on transects going from shallow ( 2 m) waters. Maynedier and Saltworks Creeks, branches Severn River, have had substantial losses SAV, similar to many parts upper Bay. Dating via  210 Pb established that accretion rates were 0.5-0.7 cm yr -1 these two systems, double rate sea level rise this region. Seeds only SAV species found sediments despite evidence others present at one time or another other tributaries Estuary. Of found, Zannichellia palustris seeds much more abundant than Ruppia maritima seeds, reflecting high dispersibility former species. The vertical pattern seed indicates over past 100 years, (particularly Z. ) has been increasingly confined shallower water depths. Although there is less riverine pulsing study creeks, head Bay (where previous records are available), both data sets consistent with hypothesis decreasing light availability due eutrophication erosion problem for Bay, particularly last several decades. Furthermore suggests historically low diversity may be attributable chronic longer term stress shallows River beds