Even though I’m not in the field right now (I postponed my return to Africa until later in the spring to get some much needed lab work done here in Gainesville, FL) the African manatee project still has alot of different things going on. I’ve spent quite alot of time over the past couple months working with partners on a proposal to the Convention on International Trade in Endangered Species (CITES) that would hopefully increase regulation and protection of African manatees (more about this in my next post), as well as setting up collaborations with colleagues in 4 African countries, working on the usual grant applications and reports to keep the project funded (always my greatest challenge!), writing a proposal for a national manatee management plan for Senegal that was requested by their Ministry of the Environment, and shipping equipment to Africa.
Yesterday I sent off several barrels full of project t-shirts (that we give out during educational outreach programs), books and other field equipment by ship to Senegal. It will only take 3 weeks to get there, and this method will save the project thousands of dollars over shipping via the airlines.
In the lab I’m focusing on the stable isotope work these days, which is the analysis that’s going to help me determine what types of food African manatees eat, to see if there are seasonal differences in their diet, and if their diet varies by age. Right now I’m processing reference samples- the food resources that manatees eat (which have either been confirmed by observing manatees eating in the wild or found in stomach samples from dead manatees, and even a few sources I’m not sure of, but that I suspect they might eat). As readers of the blog will remember, I collected many species of plants, fish and mollusks in Senegal last summer, so that’s what I’m working with now.
First we sample different parts of each specimen… I’ve learned quite a bit about freshwater mussel anatomy! For plants I sample leaves, roots, stems, and seeds.
Samples go into these tiny glass vials, and once I have alot of them they are dried in a special oven for 24 hours.
After they’re dried, all the samples are crushed into powder. Which turns out to be harder than it looks, because the samples are minute yet somehow the powder goes flying everywhere. One of the best methods I’ve learned so far is to chop the samples inside the vials using very fine scissors. After a couple hours your hands cramp up, but at least it preserves most of the sample!
Every single thing about this process is tiny and delicate, which is challenging for a fairly non-graceful person like myself! After the powder is crushed, a minute amount has to be placed in individual tin capsules. First the empty capsule is weighed on a very sensitive balance, then the powder is added with a miniture spatula. This is my biggest nightmare- a couple grains of powder too much and I’m over the limit, and getting excess powder back out means I always take too much. It literally took me 15 minutes to get the correct amount of powder in my first capsule. I started calculating 15 minutes x 200+ samples and almost had a nervous breakdown, but they tell me I’m getting better at it!
Thankfully Michelle, an undergraduate in the lab, is a very patient teacher! Once the powder is in the capsule, the tin is gently closed up and smashed into a tiny ball. This is good for getting some aggression out after dealing with the balance!
After that each ball goes in a separate well in a mini tray. We also put in “standards” that have known values, to make sure the machine that reads the carbon and nitrogen content of each sample is working correctly. Once the tray is full, it goes off to another lab to have the sample values read. And then I’ll hopefully get some interesting results!
I’m really enjoying learning the technique, as well as the great discussions I’m having with stable isotope researchers about all the possible ways we can study manatees with this tool. There has been very little of this kind of research done for manatees so far, and all of it was with the Florida manatee, so everything we’re learning about African manatees is completely new… which makes it all worth it!
