Continuous Plankton recorder being lowered into the sea from the Esperanza(C) Greenpeace/Dave Walsh
I woke up thinking about plankton today, largely on account of having promised Dave W (our web guru) some info on the Continuous Plankton Recorder (CPR) which we brought on board in Falmouth. He seems, truth to tell, a little obsessed with it all... Delay and excuses were no longer good enough, so to keep him quiet here goes!
First we'll deal with the rumours put about the ship by some scurrilous person who shall remain nameless. They should note that the CPR is not a device for recording noises made by small plants and animals that make up the plankton, as they drift on the ocean surface. It is, however, no less remarkable for that - so here is a little explanation of why we towed one behind the ship as we sailed out from the west of Ireland.
The first CPR was designed and built in 1926 by Alister Hardy, and the design has remained largely unchanged since then. Today, the Sir Alister Hardy Foundation (SAHFOS), based in Plymouth UK, continues the work that he started. Since 1931, some 210 vessels have surveyed over 4.7 million miles of ocean over regular routes and at regular intervals. As it is towed behind the ship, the device collects plankton from the ocean, which is preserved for later examination in the Foundation laboratories. Over the last seventy years, an immensely powerful long-term data set has been built up.
These data can be put to various uses. At a relatively simple level, they have allowed scientists to establish what and where various animals live in the ocean and how it changes with time. This baseline information can then be used in more complex ways. It can be used to trace the spread of alien species (alien as in introduced from other parts of the world - not extraterrestrial!) around the oceans even before they create a biological "nuisance". Changes in the way that planktonic species are distributed can also be used to gauge the impacts of climate change. This may be the reason for changes in the type and quantity of microscopic plant species observed in the North Atlantic over the last few decades. The CPR has also provided evidence of how whole food webs can be influenced by weather patterns.
Above all, the CPR demonstrates the value of long term scientific vision applied to understanding the natural world, and the ways in which we can change that world (deliberately or otherwise). Without the CPR, we would not have known that humans can potentially influence the whole ecology of huge ocean ecosystems. It's definitely worth having a look at the SAHFOS website at www.sahfos.org. And if the little bit of work that we have done on this trip helps contribute a little more to this understanding, then that's a very positive thing!
