THE ECOLOGICAL QUESTION
How does phosphorus fertilization affect long-term community structure in an arctic stream?
nutrient enrichment, limiting factor, bottom-up effects, cascade effects, herbivory, food webs, community structure, river community structure
WHAT STUDENTS DO
Students make Microsoft Excel bar graphs to assess effects of phosphorus addition on epilithic algae, epibenthic moss, mayflies, and arctic grayling fish in the Kuparuk River, in the foothills of the North Slope of Alaska. Data were taken over 15 years at the ARC LTER site at the Toolik field station. With these data, students: 1) hypothesize the influence of nutrient limitation in the community, 2) predict community response to nutrient fertilization, 3) test predictions by analyzing the long term data set, and 4) assess validity of hypotheses. In the process students appreciate the value of long-term ecological data sets.
Using a computer spreadsheet to make simple graphs, working in groups, oral presentation of analysis, writing a research paper, hypothesizing, analyzing, interpreting, and drawing conclusions.
Graphs from spreadsheet data, written or oral analyses, interpretations, conclusions, and hypotheses.
Slavik, K., Peterson, B. J., Deegan, L. A., Bowden, W. B., Hershey, A. E., Hobbie, J. E. 2004. Long-term responses of the Kuparuk River ecosystem to phosphorus fertilization. Ecology: Vol. 85, No. 4, pp. 939–954.
The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, Phone: 508-289-7487, Fax: 508-457-1548, firstname.lastname@example.org
Dr. Bruce Peterson conceived the idea of adding P to the stream to investigate the long-term consequences of small changes in the availability of a limiting nutrient. The National Science Foundation funded the original research and the development of this activity through the Long-Term Ecological Research Program. Karie Slavik developed the original data set and Jonathan Benstead provided the two photographs. Charlene D'Avanzo suggested this would be an appropriate data set for TIEE and was instrumental in bringing this exercise to fruition.
Deegan, Linda. March 2005, posting date.
The Kuparuk River
Copyright: Jonathan Benstead, The Ecosystems Center at MBL