HR: 1330h
AN: B33C-05    [Abstracts]
TI: The Longitudinal Effects of Impoundment on Periphyton Biomass and δ¹³C in a Northern Michigan Stream
AU: * Mulder, J D
EM: jmulder@kent.edu
AF: Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855 United States
AU: Rebertus, A
EM: arebertu@nmu.edu
AF: Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855 United States
AB: Autochthonous production is often altered upstream of small impoundments, such as beaver dams, but few studies have examined how such impoundments affect downstream production. A better understanding is needed of how production and organic matter dynamics are affected by natural impoundments. In this study we examined the effects of a beaver impoundment on periphyton biomass and δ¹³C in a low-order, forested stream. Periphyton samples were cultured at locations every 200 meters starting at a beaver dam and continuing 800 meters downstream. Samples were analyzed for biomass and carbon and nitrogen stable isotopes. By using additions of macrophyte biomass, the system was manipulated in an attempt to alter natural production levels and isotopic signatures of periphyton. Statistically significant effects were not detected; however, the results did indicate trends. Production decreased with distance from the impoundment, and detrital additions increased production. The amount of increase, however, was inversely related to distance from the impoundment. A shift in isotopic ratios of periphyton was detected, suggesting effects on the inorganic carbon pool, and perhaps shortening of carbon turnover lengths.
DE: 1845 Limnology
DE: 9901 NABS Student Award - Basic Research
SC: Biogeosciences [B]
MN: 2005 Joint Assembly