Identifying sources of organic matter in sediments of shallow lakes using multiple geochemical variables |
| |
| Authors: | William F Kenney Mark Brenner Jason H Curtis Claire L Schelske |
| |
| Institution: | (1) Land Use and Environmental Change Institute (LUECI) and Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA |
| |
| Abstract: | We analyzed 210Pb-dated sediment cores from four relatively shallow lakes (zmax < 10 m) in the Upper Ocklawaha River Basin, Florida, USA to compare primary producer community structure before and after
anthropogenic impacts. We measured physical and chemical sediment variables including density, organic matter (OM), water-soluble
phosphorus, polyphosphate (Poly-P), total P (TP), total carbon to total nitrogen mass ratios of OM (TC:TN), biogenic silica
(diatoms, sponge spicules), total amorphous silica, and stable carbon and nitrogen isotope ratios of bulk OM. Principal component
analysis showed that diatom biogenic silica, TC:TN, Poly-P and TP displayed discernible stratigraphic changes associated with
the shift in the primary producer community. We applied k-means cluster analysis to these variables to identify macrophyte-derived,
transitional, and phytoplankton-derived sediments. Our approach provides an objective method for identifying sediment sources
that may be applied to shallow lakes in other regions. The four study lakes shifted from a macrophyte-dominated state to a
transitional state before major anthropogenic disturbances, and became phytoplankton-dominated after ~1950. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
