Historical rates of sediment and nutrient accumulation in marshes of the Upper St. Johns River Basin, Florida, U.S.A. |
| |
| Authors: | Mark Brenner Claire L Schelske Lawrence W Keenan |
| |
| Institution: | (1) Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA;(2) Department of Fisheries and Aquatic Sciences, University of Florida, 7922 NW 71st Street, Gainesville, FL 32653, USA;(3) St. Johns River Water Management District, PO Box 1429, Palatka, FL 32178, USA |
| |
| Abstract: | We used 210Pb-dated sediment cores from wetlands and Blue Cypress Lake, in the Upper St. Johns River Basin (USJRB), Florida, USA, to measure historical accumulation rates of bulk sediment, total carbon (C), total nitrogen (N), and total phosphorus (P). Marsh cores displayed similar stratigraphies with respect to physical properties and nutrient content. Wetland sediments typically contained > 900 mg organic matter (OM) g–1 dry mass, > 500 mg C g–1, and 30–40 mg N g–1. OM, C, and N concentrations were slightly lower in uppermost sediments of most cores, but displayed no strong stratigraphic trends. Total P concentrations were relatively low in bottommost deposits (0.01–0.11 mg g–1), but ranged from 0.38–2.67 mg g–1 in surface sediments. The mean sediment accretion rate in the marsh since ~ 1900, 0.33 ± 0.05 cm yr–1, was calculated from ten 210Pb-dated cores. All sites displayed increases in accumulation rates of bulk sediment, C, N, and P since the early part of the 20th century. These trends are attributed to recent hydrologic modifications in the basin combined with high nutrient loading from agricultural, residential, and urban sources. |
| |
| Keywords: | accumulation rates Florida 210Pb dating nutrients paleolimnology sediment wetlands |
| 本文献已被 SpringerLink 等数据库收录！ |
|
