The lab recently attended the 45th annual Benthic Ecology Meeting located in Portland, Maine. This meeting occurs yearly allowing scientists to exchange information on benthic ecosystems and to encourage the next generation of benthic biologists.
Stacy presented an oral presentation on her newly published paper Unconscious uncoupling: invasion of novel habitats disrupts haploid-diploid life cycles.
Paige and Sarah presented their research at the poster session.
Paige's poster was titled Are introduced populations of the seaweed Gracilaria vermiculophylla more resistant to herbivores than native populations? A test of post invasion adaptation.
Sarah presented The Role of Heat Tolerance in the Invasive Success of the Red Seaweed Gracilaria vermiculophylla
The Science Spotlight team stopped by the Sotka lab today and found Sarah and Paige who had just finished cleaning up in the wetlab. It turns out, sometimes things in science don't always go as planned- and a lot of times there isn't a plan, because you just don't know. In this case, raising and growing Gracilaria in a lab meant that at some point, some of these specimens might "kick the bucket", quite literally. Much of the Gracilaria residing in the wetlab had died off and as of yesterday, the Sotka lab was down from 48 buckets housing algae to 22. This is neither a positive or a negative necessarily, just the natural flow of events in a lab over time as experiments and research goes on. Despite the death of some specimens, Sarah is wrapping up one last experiment with the Gracilaria collected in Japan.
Follow up with our blog this week as we discuss a potential theory for the wetlab Gracilaria mortality!
"This week I've been busy with finals, but yesterday I had my last one! Stacy worked out a great picture-taking method that reduces the glare on photos of temperature assay samples, here's an example of what one looks like..."
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.
I've been playing around with exposing Gracilaria samples from our mudflat to hot and cold temperatures to find out the limits of what they can survive. I'm trying to figure out the best set of methods for doing this. So far, I've done 3 heat assays and 2 cold assays. For the heat assays, I've exposed samples to temperatures between 30-50 degrees Celsius (or 86-122 degrees Fahrenheit) for time periods of either fifteen or thirty minutes. From these experiments, we've found that samples exposed to temperatures of ~44 degrees C and above will die, samples exposed to temperatures of 30-34 degrees C are mostly okay, and samples exposed to temperatures in between these showed some variability. I attached a couple of graphs-the x axis has the temperatures and the y-axis shows the bleach index, which is basically a ranking of how bleached the samples are (5 means they're totally bleached and 0 means no bleaching).
For the cold assays, I've put samples in the freezer at -20 degrees C for varying periods of time, ranging from 5 minutes all the way up to 1 hour. I found during this experiment that the water that the samples were sitting in froze after just 10 minutes. I checked the samples a week after exposing them to the freezer and found that even the samples that had spent an entire hour in the freezer looked perfectly healthy-so this is a pretty tough seaweed! Next week, I'll keep some samples in the freezer for up to four hours to see if I can figure out how long it takes to freeze them to death!
This past week I exposed some Gracilaria samples to a range of temperatures between 30-50 degrees Celsius by putting them in the Thermal Cycler that we use for PCRs. One set of samples was exposed to the temperatures for 15 minutes and the other set for 30 minutes. We then cultured the samples in the wet lab for a week and checked them every other day. The samples exposed to the highest temperature (50) were completely bleached after a week, so it looks like this is the upper range of temperatures they can tolerate. We are still playing around with culturing methods and different ways of exposing samples to different temperatures.
The Scientists Tell all!
Stay updated with what the Sotka Lab scientists have been up to with their blog posts.
Patriots Point Naval and Maritime Museum
40 Patriots Point Rd.
Mt. Pleasant, SC 29464
40 Patriots Point Rd.
Mt. Pleasant, SC 29464