Citizen Science, Secchi Disks & Ocean Optics

Tomorrow I’m off to the Ocean Optics conference, which has taken place every two years since 1965 and brings together specialists united by light in the ocean; this year the conference has topics as varied as environmental management, fluorescence, remote sensing, phytoplankton, sediments and underwater imaging.

Secchi disk measurements, as of mid October 2014

Secchi disk measurements, as of mid October 2014

I first came to Ocean Optics in 2006, when it was held in Montreal, Canada. I enjoyed it so much I’ve attend every one since, which have been in Castelvecchio (Italy), Anchorage (USA) and Glasgow (Scotland), and this time we are in Portland, in Maine USA. One of the things I really like it is, unlike large conferences, there are no parallel sessions, and so I don’t have to make any difficult decisions on which speakers I can, and those I can’t, see. Conferences can reinforce the silo approach, with the Ocean Colour group meeting in one room and the land remote sensors meeting in another. I think the Ocean Optics format promotes a more collaborative atmosphere, where you see a more diverse range of presentations and people. The collaborative approach to research and innovation is at the centre of my philosophy of working, and so Pixalytics is also one of the conference sponsors.

Next Tuesday, I’m giving a keynote presentation on Crowdsourcing Ocean Optics. My presentation will bring together the topics of Citizen Science, collaborative research that includes members of the public in any one of a variety of way, and Earth observation (EO) data acquired via ocean colour satellites; one example of this is the Secchi Disk project.

A Secchi disk, originally created in 1865 by Father Pietro Angelo Secchi – who was the
Pope’s astronomer, is a flat white disk 30cm in diameter, attached to a tape measure or a rope and also weighted from below. The Secchi Disk is lowered vertically into the water from the side of a boat, and the point at which the disk just disappears from sight is recorded. This depth measures the turbidity of the water, which is influenced by the amount of phytoplankton in the water column.

The Secchi Disk project developed smartphone Apps to allow participants to use a homemade Secchi disk and their smartphone / tablet to record and upload depth data alongside positional information. Through everyone uploading their measurements we are building up a global map of Secchi depths.

The project is a collaboration between Dr Richard Kirby who leads the project and publicity, with Dr Nicholas Outram and Dr Nigel Barlow (Plymouth University) as the App developers, and myself for the online database and EO linkages. The Apps were released at the end of February 2013, and since then 481 Secchi disk measurements have been collected globally; see the figure at the top that shows the global distribution of the uploaded data with the coloured Secchi disks indicating the values recorded.

The Secchi Disk project data is being compared to ocean colour satellite measurements as a cross-validation exercise and, in the longer term, to contribute to our understanding of phytoplankton dynamics. Why don’t you become part of the growing citizen science movement, go on take a measurement and upload it!