Green Crab Experiment Part 6

Treatment Days 1 and 2

Day 1

Sara and Mikayla helped me set up the rest of the experiment! This is what we did:

  • Measured, labelled, and weighed all the crabs
  • Set up the cold room with lights, timers, aerators, and aquarium filters
  • Randomly distributed crabs from each acclimation tank into a treatment tank
    • This actually took a while because the labelling on some crabs had rubbed off (paint pen didn’t dry or the crabs climbing on eachother led to some of the label being scratched off), but we figured out the giant tetris
  • Added heaters to all 30ºC tanks (T3 and T6)
  • Moved cold tanks into cold room (T2 and T5)

It doesn’t seem like a lot, but it took us all day to do with 85 crabs (technically 84 for the experiment as we have one extra crab)! Since it took us all day, I decided to move our first sampling day to Day 3 instead of Day 2 to give the crabs more time to adjust to their new conditions.

Day 2

  • Systems check: air line power strip on, aquarium filter power strip on
  • CRABS ESCAPED! The crabs in the warmer tanks (T3 and T6) decided it was too hot and played American Ninja Warrior by climbing cords and yeeting themselves out of the tanks and into the 15ºC water bath. I put those crabs back in their tanks.

    Figures 1-2. Crabs escaping from tanks by climbing cords

    Screen Shot 2022-07-06 at 10 43 42 AM

    Screen Shot 2022-07-06 at 10 43 45 AM

    • T3: 5, 44, and 75 escaped
    • T6: 11, 14, 28, 43, and 52 escaped
    • Secured mesh netting on the tops of the tanks so crabs couldn’t leave anymore

    Figure 3. Mesh netting on top of tank secured by duct tape acting as velcro

    Screen Shot 2022-07-06 at 10 43 50 AM

  • Mortality check
    • T1: 15 alive (one extra placed in tank)
    • T2: 14 alive
    • T3: 14 alive
    • T4: 14 alive
    • T5: 14 alive
    • T6: 14 alive
  • Vacuumed debris from tanks and topped off with water. Used 15ºC for warm and ambient tanks and 10ºC for cold tanks. Can probably chill water ahead of time to add to cold tanks for less of a shock
  • Fed all crabs
    • Warm: 1 tsp food
    • Ambient: 1/2 tsp food
    • Cold: 1/4 tsp food
    • I returned to ESL in the afternoon to check on the crabs and there was quite a bit of food still left in the 30ºC tanks. I will feed them 3/4 tsp of food tomorrow instead.
  • Learned how to dissect a live crab
    • Sever neuroganglia (right above tip on the underside)
    • Flip crab over and pop the top off
    • Obtain heart tissue
    • Will need to snap-freeze heart tissue for metabolomics (RNALater or ethanol would alter the metabolite profile). Carolyn ordered some dry ice for Friday, so I’ll sample the initial time point then and run respiration trials on the crabs to follow throughout the experiment on Thursday
  • Sara and Mikayla added the clamps to the respirometry chambers, covered the chambers and lids with black plastic, prepped dissection materials, and got the refractometer! I obtained the FireSting and labelled tubes for Friday sampling.
  • Practiced time-to-right assay

Going forward

  1. Complete first day of respirometry
  2. Continue with scheduled animal care
  3. Organize project repository and datasheets
Written on July 6, 2022