The effects of stream flow on the carbon isotope value of the green filamentous algae, Dichotomosiphon tuberosis.

Abstract

The purpose of this experiment was to determine the ratio of carbon-13 to carbon-12 isotopes in green filamentous at different stream velocities and light exposures and supplement ongoing research to determine food web structures in the East Branch of the Maple River in specific reference to Brychius hungerfordi, the Hungerford's crawling water beetle. To perform the experiment, 40 samples of Dichotomosiphon tuberosis were planted in artificial stream troughs, 20 in a fast flow regime and 20 in a slow regime. Half of all the samples were placed under shaded covering. The alga was harvested after a two-week growing period with light, temperature and flow speeds taken daily and CO2 and nutrient levels in the water were collected weekly. After harvesting, the algae samples were cleaned and freeze dried in preparation for the carbon isotope analysis. Significantly higher 13C/12C values were found in samples growing in the slow regime compared to the fast regime, as well as signficant higher del-13C value sin algae grown in the sun, compared to those growing in the shade.