Cold Acclimation Green Crab Experiment

Starting the 2024 experiments

It’s May, which means that it’s time to start preparing for this summer’s experiment!

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Figure 1. The super rough, very idealized schedule.

My plan is to run one-week acclimation experiments for crabs in MA and WA. During the week, I’ll measure plastic responses to 5ºC and ~0ºC. Once I get the crabs, I’ll quickly label and grab leg joints for genotyping. The hope is that I can design a restriction band digest so instead of sending samples out for sequencing, I can run a digest in the lab! This way, I can distribute the different genotypes across treatments.

After acclimating crabs for at least a week, I’ll expose them to either ~0ºC or 5ºC for another week. I’ll measure time-to-right on all crabs, heart rate on a subset, and take molecular samples from a subset day 0, after 12 hrs, after 24 hours, after 48 hours, and day 5. If needed.

I will have four tanks per treatment, with 18 crabs per tank. This will allow for two crabs per tank to be sampled at each time point (eight per treatment, which is above the minimum for metabolomics), in addition to three HR crabs per tank and a few spares.

In addition to metabolomics, transcriptomics, and genotype, it would be great to get students involved in citrate synthase or total lipid assays. My hope is that the students can pick a phenotype or sub-question they are interested and analyze data from this experiment. Alternatively, it would be nice to rerun the marine heat wave experiment. In any case, I’m trying to minimize the number of additional experiments I run this year.

Temperature tests

Of course, the first step is to actually ensure I can have a space that allows for chilling down to ~0ºC! After some back and forth, I will not have space in the ESL cold box. HOWEVER, I got a cold box in Redfield instead which is WAY more convenient! Over the weekend, I reduced the temperature in the cold box to 0.5ºC (swoon) and placed a couple of HOBO loggers in there.

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Figures 2-3. Temperatures from HOBO loggers in cold box.

It looks like the logger in the front of the room stayed around 1ºC, while the logger in the back of the room stayed around 0.7ºC. I decided to add four tanks in the room: 5ºC tanks in the front where it was already warmer, and 0ºC tanks in the back. Sarah helped me set up the tanks with seawater, air stones, aerators, lids, and two HOBO loggers each. For the 5ºC tanks, we added in one immersion heater per tank. I’ll let these sit a few days to monitor the temperature!

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Figure 4. Temperature testing setup in the Redfield cold box

Going forward

  1. Check temperature of tanks
  2. Design new SMC primers
  3. Develop restriction band digest for genotyping
  4. Develop heart rate protocol
Written on May 20, 2024