Hey there sailor...

... want to be a scientist? All you need is a bucket lid, a length of rope, and a smart phone app.

Scientist Richard Kirby at Plymouth investigates how climate change affects phytoplankton in the oceans. One of the oldest and yet simplest methods to measure the density of phytoplankton in surface waters is to use a device called the Secchi disk, invented by the Jesuit Pietro Angelo Secchi in 1865. This is simply a plain white disk, usually made of plastic, that's lowered into the water until it can no longer be seen; this depth is read off from the line. The denser the plankton, the more turbid the water and the faster the disk disappears from view.

Kirby's team has developed an app to gather data from "citizen-scientists". Because of its simplicity, the Secchi method is well-suited for crowd-sourcing, and can be made quickly from easily-available materials. The group's aim is to get data on plankton density from throughout the world's oceans, far more than any single scientific group would be able to accomplish on its own.

Download the app for iPhone or Android from the Secchi App website.