 In a 2014 follow-up study, the authors used a larger database of measurements and revised their analysis methods to account for several of the published criticisms, but ultimately reached similar conclusions to the original "Nature" study.These studies and the need to understand the phytoplankon in the ocean led to the creation of the Secchi Disk Citizen Science study in 2013.The Secchi Disk study is a global study of phytoplankton conducted by seafarers (sailors, anglers, divers) involving a Secchi Disk and a smartphone app.