West Coast Green Crab Experiment Part 4
Finalized facility set-up
With Lauren and Julia’s help, I set up ESL before C-Day! Here’s what we did:
- Set up 12 tanks in the main room. Six in the upper tier, six in the lower tier. I set up a naming scheme for the tanks. Bottom tier has tanks 1-6, going from left to right, with the top tier having tanks 7-12, left to right. I’ll place crabs in these tanks and then randomly assign which tanks get moved to each temperature treatment, so I won’t have to shuffle crabs between tanks after they’re placed in a tank.
- Added aerators, air lines, and air stones to all tanks. Air lines and cords for the aerators were labelled with tank ID.
- Added filters to each tank, but did not add a cartridge. I’ll add the cartridges once we have crabs.
- Added mesh to the top of each tank and adhered velcro so the mesh will stay put underneath the tank lid.
- Added one HOBO logger to each tank. I’ll add a second logger with a weight once the crabs arrive.
- Labelled all cords, extension cords, and power strips. Bunched wires with zipties and covered with plastic bags to prevent water damage.
- Added remaining LED lights using bungee cords.
- Covered the bottom tier with a black trash bag curtain
All of this took about ~1.5 days, spread out over a few half days due to our schedules or me needing to run and get more materials!
The temperature saga
It’s not an experimental set up if there isn’t constant fingagling with temperature control. While Lauren and Julia did a lot of the set up, I checked HOBO loggers in all the tanks.
Bottom tier tanks:
The ambient tanks weren’t reaching the 14-15ºC average I thought they would.
Figures 1-2. Temperature of 14ºC tanks on June 8.
Dave said I was the only one using the 14ºC line, so I could crank up the flow. Which is exactly what I did.
Figures 3-8. Temperature of 14ºC tanks on June 9.
When I checked the tanks after the weekend, I noticed that there were some temperature spikes close to 18ºC happening overnight.
Figures 9-14. Temperature of 14ºC tanks on June 12.
These spikes were only occurring for a few tanks. To help stabilize temperature, I added a second 14ºC line to the bottom tier tanks.
Top tier tanks:
I used the top tier to experiment with the heater. The goal is to have the heater and connected pump circulate 25ºC water to heat the tanks. After starting the heater, I came back to ESL to find a lot of the water in the bath had evaporated! Thankfully the pump was off and wasn’t running dry. I checked the HOBO loggers in the tanks and saw that the temperature was quite variable, likely due to all the evaporation.
Figures 15-16. Temperature of 25ºC tanks on June 9.
I set up a 20ºC line to deal with the evaporation.
Figures 17-22. Temperature of 25ºC tanks on June 9.
The tanks weren’t quite reaching the desired temperature, and I think it’s because I had the flow rate too high on the 20ºC line. I adjusted the flow and checked the temperatures after a few hours.
Figures 23-25. Temperature of 25ºC tanks on June 9 after 20ºC line adjustment.
It looked like it helped, so I adjusted the flow a bit more and checked again after the weekend.
Figures 23-27. Temperature of 25ºC tanks on June 12. I forgot to screenshot the plot for one HOBO logger.
Things looked good after the weekend! I turned off the heat pump and set up two 14ºC lines in the top tier tanks. I will need to maintain both of the tiered tanks at 14ºC for the acclimation period, and I wanted to give the water bath some time to reach the proper temperature before the crabs arrive.
Cold room tanks:
The 10ºC tank was perfect without any modification. This makes sense because the walk-in is set to 10ºC, and the door isn’t held open for any extended amount of time.
Figure 1. 10ºC tank on June 8.
The real struggle was the 5ºC tank. The first two times I checked the 5ºC tank, it was hovering around 8ºC instead.
Figure. Temperature of 5ºC tank on June 8 (top) and June 9 (bottom).
I then moved a HOBO logger from inside the 5ºC tank to the water bath to see what that temperature was. The chiller itself was at the correct set point.
Figure. Temperature of 5ºC water bath on June 9.
So the water bath was at the correct temperature! I noticed that the water level in bath wasn’t reaching where the water level (and the HOBO logger) was inside the tank. I added more water and let it sit over the weekend. This helped cool down the inside tank, but it wasn’t quite there.
Figures. Outside (top) and inside (bottom) HOBO loggers for 5ºC water bath and tank on June 12
Before I left ESL, I set the chiller to 37ºF to see if I could reduce the temperature in the water bath and tank.
Figures. Outside (top) and inside (bottom) HOBO loggers for 5ºC water bath and tank on June 13
Looks like adjusting the water level and the chiller worked! The tank is a little colder than the target, but I figured I’d keep the chiller at this temperature since I need to connect two more large tubs for the remaining two crab tanks. Since I don’t know how well the water will circulate between the tanks at this point, keeping the lower chiller setpoint for now seems like a good idea.
- Set up connected cold room tanks
- Add remaining HOBO loggers to tanks
- Create data sheets for crab measurements
- Label and measure all crabs
- Obtain leg joints for genotyping
- Test formatting and analysis for one set of respirometry data
- Respirometry analysis
- Update methods
- Update results
- Cover respirometry chambers with black trash bags and duct tape, and add the probe holders with silicone glue