I have been hard at work the past few weeks trying to complete the character trait assays on the new seaweeds from Fiji and California. So far I have finished determining the protein concentrations, ash-free dry mass (which relates to organic content), and percent calcium carbonate in the seaweeds. We are seeing some latitudinal patterns (with the polar seaweeds being more nutritious)! We are also seeing differences between red (Rhodophyta) and brown (Phaeophyta) seaweeds, although I am still working through the analysis for confirmation on everything. Hopefully, I will be able to get you some figures (graphs and tables) soon!
I have also been continuing on with my feeding assays and am more than halfway through. We just got some more emerald crabs (Mithraculus sculptus) into the lab so we can do multiple feeding assays at once which should speed things up quite a bit. Moving forward, I am still going to be doing the feeding assays and am getting back into the molecular side of things trying to extract DNA from all my new seaweeds this week.
I am starting to write up my results from my Gracilaria genetic manipulations this summer, so I am meeting with everyone involved this week to talk about them! It is always good to have other eyes look at the same data to make sure there are no mistakes. It looks like we have some differences between monocultures (1 genotype) and polycultures (6-8 genotypes), but you will have to stay tuned to see what they are!
Dr. Sotka and I have begun analyzing a massive data set to trace the invasive history of Gracilaria vermiculophylla, meaning we are trying to follow the trail of this species from its native range in the Northwest Pacific (Japan, Russia, Korea and China) as it has spread along all major coastlines in North America and Europe. There are roughly 2500 specimens from over 65 sites! And, we have genotyped all these samples at 12 different markers. 2500 multiplied by 12 is a lot!! But, it is very exciting to finally get to play with data after over a year of generating this … this, does, however, mean that I will be spending days anchored to my desk. Luckily my computer screen is quite large so it helps when playing with huge Excel spreadsheets!
I am currently running a feeding assay with the decorator worm, Diopatra cuprea, to see how they respond to the chemistry of Gracilaria. Diopatra live in tubes that they build and "decorate" with what is in their environments. Usually bits of shell, Gracilaria, and Ulva are found attached to Diopatra tubes. Many seaweeds will produce chemicals that make them taste bad to herbivores and act as a defense. The worms love to eat Ulva, but they do not seem to like eating Gracilaria and we want to know why. To determine if Gracilaria has chemicals that keep Diopatra from wanting to eat it, we first extracted the chemicals from Gracilaria using Ethyl Acetate. Then, we set up a feeding assay to compare how much Ulva the worms will eat when it is coated with just Ethyl Acetate and how much Ulva the worms will eat when it is coated with Ethyl Acetate and Gracilaria chemicals. This method allows us to find out if the chemicals of Gracilaria deter feeding by Diopatra. Since we know that the worms like to eat Ulva, if they eat less of the Ulva when it has chemicals from Gracilaria, this will indicate that the chemistry produced by Gracilaria is protecting it from herbivores such as Diopatra. Stay tuned for the results of the feeding assay!
This past week I broke down the Gracilaria growth experiment! After two weeks of growing Gracilaria attached to different structures we found that the Gracilaria that grew in the hollow tubes with mesh on each end grew the best. Next, I will be researching how other scientists have grown Gracilaria in the lab before setting up another experiment to look at how salinity influences algae growth.
The past couple of weeks I have continued working on feeding assays with the crabs and urchins. We received some more Fijian seaweeds courtesy of our collaborator Mark Hay and we also received a few more temperate seaweeds thanks to Nicole who is now in CA. Our total number of seaweeds is now at 50 which is pretty exciting! I am about halfway through the feeding assays on the crabs and urchins and will begin working with the amphipods soon. I also will be starting trait assays on the new seaweeds sometime in the next week so stayed tuned for more on that!
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Patriots Point Naval and Maritime Museum
40 Patriots Point Rd.
Mt. Pleasant, SC 29464
40 Patriots Point Rd.
Mt. Pleasant, SC 29464