Transcript

Investigating small organisms

DR. DAVID ROBINSON

I'm David Robinson, and I'm a biologist at The Open University. And in this series of clips, we're going down into the world of the small organism, organisms that normally we're not aware of. So when you look out to sea, you see masses and masses of water, and you're just not conscious of the huge number of organisms that are in only a small volume of that water. One of the most interesting things you do when you start out in biology by the sea is just take a net and sweep it through that water. And then take your net out and wash off everything that you've got in your net. And you find you've got a whole world in your bottle of tiny organisms. And it's a completely different area of study. Because they're small, you require very different techniques to study them. And because they're so small, and they're completely immersed in their environment, the environment has great influences on them that you might not suspect until you study them.

INTERVIEWER

You just said that different methods are needed for working with small organisms. What type of instruments or methods are needed?

DR. DAVID ROBINSON

Well, firstly, of course, there's microscopes in order to magnify them and see them. But I think some of the other methods are ways of collecting them. The sea clearly is very deep. Although the plankton don't go down to enormous depths, but they do have quite a vertical distribution. And if you want to sample at a particular depth, you have to be able to send your bottle down there, collect water at that depth, and then bring it back up without it getting contaminated at other levels. In the film, there's a very high tech way of doing it where you have computer-controlled bottles. In earlier days, you had a bottle that went down on the end of a string, and you sent a little lead messenger down which opened the bottle to take a sample, and then a second messenger to close it again, and then you dragged it up. And you've got your sample from a known depth. And that's effectively what they're doing with the whole series of one litre bottles arranged in a circle and a computer deciding when to open and close the lids. And of course, it's very important to get the depth right because plankton do move up and down in the water. And this vertical migration of some plankton takes place on a daily basis. And then also, you get sudden increases in population at a particular point as a result of tidal movement. So for example, a population of phytoplankton might be swept past your equipment by the tide going one way and then swept back again going the other way. And this will produce, for example, a pulse in a detector that picks up phytoplankton, or it will produce a sudden surge in the number of individuals that were trapped in your bottle.

INTERVIEWER

We saw the painstaking work that was being done on the organism familiarly known as Tony by the research scientist. He said it had taken relentless hours of patience to come to some of the conclusions he's come to. Has it been groundbreaking, what he's produced, the research he's produced, about Tony?

DR. DAVID ROBINSON

I think the research that he's produced about Tony is extremely interesting, particularly because of where his sample comes from. And you can see in the clip the big drill bits and they're drilling down into the ground. What they're looking for is a lair of rock called an aquifer - that can be rock, sand, gravel - that is able to absorb a lot of water. And if that water becomes organically contaminated, then it will have bacteria in it. And Tony is living off the bacteria in that water. That is a very, very unusual place to look for life and to look for communities. Because, of course, Tony depends upon there being lots of bacteria there to feed on. And if the bacteria population declines, then populations of Tonys decline. And Tonys are able to form cysts, which can resist quite a bit of drying, as well as keeping the organism alive during a period when there aren't many bacteria about. And I think this is of course quite a common thing, of single-cell organisms forming cysts. But it's in this very strange environment, deep in water-bearing rock, I think makes it so special.