I first worked with protists at the University of Birmingham back in the 1990s. I began a PhD to look at protists which could behave in ways which we associate with plants and animals. The protists I studied are a golden-brown colour which comes from structures called chloroplasts. These are the same as the green that gives plants their colour, but these have different pigments which make them look golden-brown. In addition, they eat food such as bacteria. And the specific protists I was to become very familiar with have two whip-like flagella to swim with and a third coiling, hair-like structure called a haptonema. Flagella Awesome in Aggi and the Mystic Boots is based on one of these.
Starting a PhD is not easy. You can feel completely out of your depth most of the time. I remember it taking me a whole day to make some media to grow the protists in; later on it would take me 10 minutes. I was working on marine protists in Birmingham, almost as far from the sea as you can get in the UK. So I made quite a few trips to the Plymouth Marine Laboratory. They had (and may still have) a collection of marine protists and my first job was to select one to work on. I also had to collect large amounts of sea water.
The protists I worked on are oceanic species, very fussy about what they grow in and are happiest in real sea water. At the Plymouth Marine Lab they have a huge pipe which goes miles out to sea, away from the immediate coastal pollution and brings in clean sea water. I remember going down there in a van, carrying quite a few large containers to fill up with this sea water. Having taken several hours to drive down there, they were all filled from this pipe in a matter of minutes. I then had to drive back with over a ton of sea water in loosely tied containers. I was phenomenally naïve about this. I went round a roundabout in Plymouth and felt the whole lot shift from one side of the van to the other, pulling me out of the circle of the roundabout. I then drove up the motorway and at one point saw car lights braking ahead of me. I tried to brake and little happened. This huge weight in the back carried me forwards, and I moved out first to the middle lane and finally into the third lane and just managed to stop as I was within centimetres of the car in front. My heart was pounding, but as most students seem to do, I got away with something which could have been horrendous.
As I became more confident with the work I was doing, I took more trips to Plymouth to study protists in their culture collection. On one trip I was trying to photograph the protists feeding on fluorescently-labelled bacteria. This was not easy as there were no digital cameras. I had film in the camera and the exposure time was many seconds. I was filming flagellates which were swimming around and as the slide dried out they would burst so there was a finite amount of time when they would be still for long enough. I had been working on this for about four hours, using up many films which my PhD supervisor loaded into the camera for me. I was going slightly crazy, sitting in a darkened room trying to get a picture of these tiny, spinning, glowing circles. Early in the afternoon I finally got the perfect shot. It seemed odd though, because I had been winding on the film for more than the usual 24 pictures. I went to tell my supervisor that I had finally got the picture we needed, but when he came to get the film he discovered he had forgotten to load it into the camera. My feelings at this were beyond anything I could describe. Doing a PhD is full of highs and lows and this was a particular low point.
The protists I worked on appeared to have issues with their feeding behaviour. I took several trips to Southampton where there was video equipment to film the protists feeding. If I drove down in the morning to start work after lunch, nothing would make them eat. I learnt to drive down in the evening, let them settle for the night, and in the morning they behaved beautifully. My little oceanic flagellates seemed to suffer from travel sickness. I also found that around Lent they would stop eating. This happened in each year of my PhD. We know protists have circadian rhythms and here there seemed to be some sort of annual cycle of behaviour. There is so much we don’t know about these creatures. I learnt from other researchers that the vibrations of the incubators we kept them in could disrupt their feeding, and we had to be careful about the type of light bulbs we used as they had some sensitivity to the wavelengths of light. I also found that my particular species needed selenium in its culture medium to stay healthy. These seem such small details, but each took weeks, sometimes months, of dispiriting laboratory work trying to find out what would keep the protists happy.
Studying protists is fraught with difficulty. They can be so fussy; learning what makes them tick can be a long, slow process. But understanding them is crucial to understanding the whole massive food web, as they are at the base of it and so have a role supporting all other life on Earth.