Dr. Amy Baco-Taylor : Collecting Coral Samples
In this clip, you see Peter Etnoyer and myself looking at the bathymetry of the seamount that we are about to dive on. This map was put together by Randy Keller and his group. We are trying to decide where the best place would be to dive, and where we think we might find corals, or some of the other invertebrates that we are interested in.
During this expedition, I did five dives in the Alvin. Altogether, I've done 51 dives in submersibles including Alvin, Pisces IV and V, the Johnson Sea Link, and the Turtle. The average dive lasts about 8 hours. We go down right after breakfast and then come up just before dinner. Diving in Alvin is a really unique experience. You get to go down to places where most people will never get to see, and get to see things that few other people will ever get to see. It's very cramped quarters though, in the Alvin. The whole sphere of where the people are is only about 7 feet in diameter, and there is three people in that space with a lot of electrical equipment that keeps the submersible running.
This video shows me getting out of the Alvin after one of our dives on the seamounts. I got to go down and see how the animals are, see how there is different interactions between different species in their natural environment, things that you can't really get a sense with from using trawls. A difference between using submersibles and ROV's is that ROV's aren't really designed for exploration. They are really designed, for example, if you have an experiment on the seafloor, in one place. You can go down with the ROV, and spend a lot of time in that place, longer than you can in a submersible, and collect a lot of samples. Whereas it's not always as easy using an ROV, to go along the seafloor and stop to look at something, and with the submersible, you can go forward, you can stop, you can move along a little ways and say 'I want to go back and check that out again'. It's a lot easier to manipulate. Other ways to sample things in the deep sea include using deep sea trawls which are very non-selective. It's basically just a big net that goes down and scrapes everything off of the bottom. And when you bring it up, you try to sort out all the animals and put them all back together. This method is very destructive, and you can't really get a sense of how these animals were distributed on the seafloor. You know that they all came from that seamount, but you don't know where or necessarily what depth they came from.
This is the sample basket from the Alvin. When the Alvin goes down, we use it to collect pieces of each of the corals that we are looking at in the video, so that we can go back and identify them. And so what it does is it takes either the whole coral colony or a piece of the coral colony and puts it in the basket, in the boxes or the jars on the basket. In this particular image, you can see the particular types of jars inside of one of the boxes. The idea with those is to keep each individual coral sample separate, so we can know where that particular specimen came from, what depth, what exact site. When we go back and describe the species, we would like to know where they came from. So the samples are brought up, and we take all of these sample jars and all of the corals, and we put them into the cold rooms to try to keep them at the temperature at which they lived, to try to keep them alive longer, so that we can process them longer.
Here, I have a sheet of paper in my hand, and while we are in the submersible, we write down what we're collecting and where it was collected from, to correlate to each jar. When we first bring the samples up, you can't always tell looking at a video or looking through the window of the submersible, what family or species a coral is. So when you first bring it up, to make sure you label everything correctly, we look at the corals again, to make sure that we have the identifications right from what we were able to see through the window.
So when we collect the corals from the deep sea, its really hard to get the crews to go and do this kind of research. And so the specimens are very valuable. You never know, down the line, what other types of experiments you might think of to do with them. So we try to preserve the corals. Every single specimen we get, we try to preserve as many different ways as we can. So that's what you see here, is us going through and taking different pieces from each coral, and putting them into different types of tubes, and each of those types of tubes has a different type of preservative, for the different types of experiments we might want to do down the line. The two most important samples are, we put a large piece in Ethanol, which we give to the Smithsonian, which they use to identify what species the coral is, and the next most important sample is we take a small piece and we put it into a freezer that is at -80 degrees Celsius. And that's the reason that we're wearing gloves. This is because we are going to use those samples to look at the DNA of the coral, and we don't want to contaminate the coral with our own DNA.
In this image, you see the mucus coming off of the corals. The bamboo corals in particular, like to produce a lot of snot. We had a group with us on the cruise who looks at the microbial community associated with each of the corals, so they were collecting this slimy mess to take back to their labs and look at the DNA, to figure out which species of microbes were living on the corals.