how cold is too cold for gracilaria?!

Updates from Sarah:

I'm still doing a lot of temperature assays. Because the seaweed that was frozen for up to 1 hour survived, I ran another cold assay experiment the next week. I put samples in the freezer for each of the following time periods: 1 hour, 2 hours, 3 hours, and 4 hours. All samples that were frozen for 2 or more hours were dead a week after the experiment. This week, I'll be running another cold assay to try and figure out the time point between 1 and 2 hours at which the seaweed reaches its limit. I'll be putting samples in the freezer for the following time periods: 45 minutes, 1 hour, 1 hr 15 min, 1 hr 30 min, 1 hr 45 min, and 2 hours. I'll also use a control group that won't go in the freezer at all.

I've also been playing with an image analysis software called Image J. This software can help me measure the length of the seaweed tips that I use in the temperature assay experiments-the tips are so small that they are difficult to measure with a ruler. Image J can also help quantify color-I've been classifying the samples as dead/bleached, dying/partially bleached, or alive/no bleaching based on qualitative observations of color. However, this is a pretty subjective way to measure color- if a sample looks a bit lighter 1 week after the experiment to me, someone else could look at it and think it looks exactly the same. The blue and black vs. white and gold dress controversy is a good example of how color can be subjective! http://www.nytimes.com/interactive/2015/02/28/science/white-or-blue-dress.html?_r=0 

Image J quantitatively measures the amount of red, green, and blue (RGB) in a selected piece of seaweed, so I'll be using this from now on in addition to my own observations.