Updates on the Experiment!

This past week, I started Round 4 out of 5 for this experiment! I had a little pep in my step, since I knew I would have enough money to complete this experiment!! :) 

 

The experimental setup is a bit time consuming. Since we're in Oregon and well, the water is a bit colder and the water chemistry is different, we have to make up our own seawater. It takes a couple of days to mix the salt, make sure the salinity and pH are correct, and ensure all of the important chemicals (calcium, nitrate, etc.) are at the right levels. Once the system is ready, I take individual photographs of each coral fragment. I take a white light photograph and two fluorescence photographs to measure symbiont and coral host abundance (figure below). Taking pictures of every fragment for each round typically takes around 4-5 hours. 

 

Once all of the pictures are taken, I take an initial tissue sample from each fragment and place it in a buffer where it can be stored for long periods of time (months to years). This process usually takes about 2 hours, so my awesome undergraduate volunteers come in handy! :) 

Finally, the last step is to place the corals in the experimental tanks according to a random block design. This design ensures no confounding effects (a sort of bias), such as the tank the coral is in or their position within the tank. Below, you can see a view from the side of a tank, looking across all four experimental tanks! Pretty neat view! 

 

Then, the temperature ramp begins! I start at the ambient temperature of 27C and ramp up or down 1 degree Celsius to the final temperature. For this trial, I am testing 27C and 30C. Once the water temperature reaches the final acclimation temperature, the corals sit for two weeks (acclimation) before they are exposed to a thermal stress. 

After acclimation, I take photos and sample every coral again. I ramp both rooms to a final stress temperature of 32C and take pictures again throughout the stress to evaluate coral bleaching. I take an endpoint tissue sample to assess coral health across acclimation and stress - a measurement that will tell me if corals were able to acclimate or not. 

Below is a view of one my experimental rooms. Each room is identical with 4 tanks (where the corals are held) and a sump below the tanks. Water circulates from the top tanks down into the sump and then back up again - a system that keeps the water moving and allows us to remove algae and other waste. My advisor, Eli, and I built these systems ourselves, so it's homemade! I have to say, graduate school has taught me a lot about the use of PVC (apart from corals and molecular biology, of course), haha! 

 

Currently, I am starting to analyze tissue samples from previous experiments and have a couple undergraduates assisting me in the lab. We're almost finished extracting RNA and DNA and will soon start sequencing preps! Stay tuned for an Update on Lab Work!