Dr. Richard Kirby takes a reading as part of his global Secchi Disk Project.
Dr. Richard Kirby takes a reading as part of his global Secchi Disk Project.
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Citizen Plankton Science! Join the Secchi Disk Project (and be Extremely Awesome)

Categories: Guest Posters

So, you want to be a marine biologist but you have no training? No problem, as long as you’ve been to the eye doctor lately. Don’t have all that expensive equipment? All you’ll need is little more than your smart phone. Forget the endless hours of studying and the late nights analyzing data… Dr. Richard Kirby is giving you an easy and fun chance to contribute, and on a really important project.

Dr. Kirby is a scientist across the pond at Plymouth University’s Marine Institute and he studies plankton. We’ve taken a close look at plankton recently, both the plant and the animal variety. These sea-drifters are responsible for at least half of the oxygen we breathe, and they lie at the base of a food chain that produces hundreds of millions of tons of food for us. Their importance cannot be overstated.

But how do you study a group of organisms that are so small in size and so large in number? Well, it’s not easy, especially when you’re trying to determine the amount of phytoplankton on a global scale. Some have tried, and a widely publicized report from Nature found that phytoplankton numbers have been declining over the past century, an alarming finding given their importance. But the study has been hotly contested, and the only certain fact coming from the debate is that we need more information.

And that’s where you come in. Dr. Kirby figures the best way to get more information is to enlist the help of the roughly 7 billion amateur-scientists that may already be out at sea, whether it be working, sport fishing, or just pleasure cruising. He has developed a free mobile phone app that allows you to easily record a measure of plankton abundance from anywhere in the ocean.


The system is based around a simple little device that marine scientists have been using since 1865: the Secchi disk. Named after its inventor, Father Pietro Angelo Secchi, a Secchi disk is basically just a weighted white disk attached to a tape measure (instructions on how to make one can be found here). You lower the disk into the water and record the depth at which it disappears from sight. That is called the Secchi depth and it gives scientists a measure of how much plankton is in the water. If the water has a lot of plankton, it’ll be tougher to see the disk, and it will disappear from sight at a shallower depth.

After you determine a Secchi depth you enter it into the free Secchi App, which records your location along with the measurements that you made. All of this information is stored on your phone and passed along to Dr. Kirby once you get an internet connection. Voilà! You’re part of a major study to help figure out the changes that our world’s oceans are going through. You can even check out the data coming in from all over the world!

Our technological advances and changing climate have intersected to make this the perfect time for such an ambitious study. Dr. Kirby notes “This app enables seafarers around the world to take part in a science project and if we can just get a small percentage of the global population of sailors involved, we can generate a database that will help us understand how life in the oceans is changing. It would help us learn much more about these important organisms at a crucial time when their habitat is altering due to climate change.”

So next time you’re heading out to sea, make sure to bring your Secchi disk and your phone, and help us to understand what’s happening to our global ocean. While you’re at it, put a picture of you doing your citizen science on our Facebook page so everyone knows how awesome you are!

Casey Diederich is a 5th year PhD candidate in Tuft’s University’s Biology Department, and is conducting his research on slipper-shell snails. We are thrilled to have Casey guest blogging for us about some of the more fascinating plants and animals in our ocean. – Ed.

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