Wallace, C. D.. Eastern Michigan University, none
Neely, R. D.. Eastern Michigan University, bob.neely@emich.edu

Diatom densities in sediment samples collected along a transect through a small, forested vernal wetland in Michigan were used as a means of determining the wetland's periphery in the absence of hydrophytic vegetation and surface water. The mass of biogenic silica and organic matter in the sediment samples were also used in conjunction with changes in the diatom community. Virtually every characteristic of the diatom community clearly demonstrated the extent of the wetland. The diatom flora was dominated by 15 taxa, virtually all of which declined from the wetland center to the wetland edge. Total diatom density near the center of the wetland exceeded 533,000 diatoms/gm of sediment, a 2,860% increase from the wetland periphery; total diatom density was positively correlated with distance from the wetland edge (0=0.76, p=0.0007). Diatom diversity increased by about 30% from the wetland edge to the wetland center (Shannon Weiner index). Furthermore, biogenic silica increased from levels below detection outside of the wetland to concentrations greater than 257.9 mg Si/kg sediment in the wetland interior. The same patterns were illustrated by percent organic matter composition of the sediment, i.e., approximately 15% at the wetland periphery and >80% in the wetland interior.
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
Code: CS63TH0498S