Continuous Plankton Recorder Project Leader, Dr Graham Hosie:
The continuous plankton recorder is a means of mapping the distribution and abundance of plankton. Very quickly and very consistently and very repeatedly over very large areas.
Plankton are the basis of the food web. They are important not only for the food web. They are important for the rest of us in terms of oxygen production, CO2 absorption and we need to map their distribution and abundance to see if it’s changing. If it changes there are consequences for the food web, there are consequences for us.
The CPR is a very simple device, its 1931 technology, it takes in water through a very small aperture at the front as it’s towed behind a ship and traps plankton between two sheets of silk. We then unravel that silk in the laboratory and we have actually got a continuous record of what the plankton existed in the water column over about 450 nautical miles or about 830 kilometres. And at the same time we are recording environmental data so we can match the two, the distribution of the plankton and distribution of oceanography.
The coverage we have got to date is roughly about 70 % around the Antarctic, and to date we have something like about 230 zooplankton species, and probably I think about this stage 70–80 phytoplankton species that we are also looking at.
We are just starting to see indications that we are not seeing as many krill in the sea ice zone as we used to get. We don’t know why, whether it is a change in numbers, a change in distribution or a change in behaviour.
In the sea ice zone, where most of the predators are found during the summer months, the whales, penguins, flying seabirds, it’s a keystone species. These animals have evolved to feed on an organism like krill which are about 50–60 millimetres in size. Now if they disappear or the animals can’t find them to feed on them, they’ll have to either shift their diet to something else, some of the smaller zooplankton, or maybe fish which feed on smaller zooplankton. So there’s consequences higher up, if you start removing keystone species.
We have also been mapping the biogeography of the species, so we have actually now produced a new Atlas on the distribution of what we call our top 50 species. That’s useful for researchers and other monitoring programs they can look in the Atlas and see what species they can expect to see in a certain area.
We need to continue the project, we’ve just set the foundation and we need to continue to look at the potential changes and the consequences. We can use plankton as a bit of an early warning indicating system of what may be coming and what’s happening. It’s the foundation of the whole Antarctic system, if we are not monitoring that part it’s very hard to explain what’s happening elsewhere.