Experiments

Past and present experiments conducted under the project

Experiment 1
As part of an SES project, undergraduate student Meg Yang is examining how resource availability affects community composition and dynamics.

Experiment 2
This is the first ¹³C labeling experiment. In this experiment duplicate chemostats inoculated with water collected from the surface of Siders Pond is fed a defined medium consisting of five substrates that include glucose, xylose, acetate, ethanol and methanol. Once respiration and other indicators of community function reach steady state, the glucose in the medium will be enriched with 100% ¹³C-Glucose, and samples will be collected for stable isotope probing to determine what fraction of the bacterial, protist and viral community depends on that particular substrate.

Experiment 3
This is basically Exp 2, but with new media design that is not N and P limited as it was in Exp. 2.

Experiment 4
This is similar to Exp 3, except we are running 6 chemostats simulaneously, where MC1 (called MC1-C12) is the control with no ¹³C labels and the next five chemostats (MC2,..., MC6) each have one of the five substrates (Methanol, MC2-Met; Ethanol, MC3-Eth; Acetate, MC4-Ace; Xylose, MC5-Xyl; Glucose, MC6-Glu) replaced with its ¹³C equivalent. Chemostat operation has also changed, in that we will start the experiment with ¹³C-labeled substrates (one substrate labeled in each MC) and follow ¹³C inclusion into the food web during batch phase (no media flow). Once the batch phase has finished (about 1 week), chemostat operation will begin, but the media will contain no ¹³C-labeled substrates so that the heavy isotope will be washed out. After approximately 10 days, we will switch to the media with individually ¹³C-labeled substrates and follow their inclusion into the food web under chemostat conditions at a dilution rate of 1 d^-1. This single experiment will allows us to track how the food web functions under both transient (batch) and steady state (chemostat) conditions.