WHAT IS STRESSING OUT OUR STREAMS?
Jennifer Wong-Ala1, Aaron Stoler2.
1College of Arts and Sciences, Kapi`olani Community College, Honolulu, HI, 2Oakland University, Rochester, MI.
The conversion of forest into other uses such as agriculture is known to cause harmful effects to streams in the surrounding area, including increased water temperature and changes in organic matter inputs (e.g., woody debris). This study sought to assess the independent and interactive effects of organic matter input on ecosystem processes such as primary productivity in a tropical montane stream system. We hypothesized that changes in woody debris inputs associated with agricultural activity would increase rates of ecosystem processes, particularly primary productivity. To test this hypothesis, we conducted a controlled experiment using streamside flow-through mesocosms within the secondary forest of the Las Cruces Biological Station in San Vito, Costa Rica. Our mesocosm experiment contained 8 flow-through channels. Treatments consisted of either rock substrate or rock, leaf litter, and woody-debris substrate. These treatments simulated agricultural and forested stream substrates, respectively. We then estimated primary productivity by measuring algal biomass within each mesocosm once a week for a total of 2 weeks. We expect that decreases in organic matter inputs increase primary productivity, which in turn increased the algal biomass.