HR: 11:45h
AN: NB52A-06    [Abstracts]
TI: Influence of Multiple Disturbances on Ecosystem Structure and Function of a Headwater Stream
AU: * Lottig, N R
EM: nlottig@vt.edu
AF: Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 United States
AU: Valett, H M
EM: mvalett@vt.edu
AF: Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 United States
AU: Webster, J R
EM: jwebster@vt.edu
AF: Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 United States
AU: Schreiber, M E
EM: mschreib@vt.edu
AF: Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 United States
AB: Many studies in lotic systems have focused on pulse disturbances such as floods, while others have centered on press disturbances like chronic pollution. This research explores the combined effects of press and pulse disturbances on ecosystem structure and function in a headwater stream adjacent to an abandoned arsenic mine. Influences of floods were compared between an upstream (reference) reach and a `disturbed' reach adjacent to the arsenic mine. Average base flow discharge was 1.2 L/s. Floods were categorized as events with discharge more than 3x base flow. Arsenic in stream water was < 10 ppb in the reference reach and increased to 1000 ppb at the bottom of the mine-influenced reach. Phosphorus solute injections, ecosystem metabolism, and standing crop estimates of organic matter were determined monthly from April to December 2004 and ranged from 4 to 44 days post-flood event. We used regression analysis to explore relationships between type and intensity of disturbance and response variables such as spiraling metrics, standing crops, and ecosystem metabolism.
DE: 0400 Biogeosciences
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly