An innovation of two established methods for monitoring water colour and clarity: participatory science using the mini- and midi- secchi disks

Measurements of water colour and clarity are used to track the environmental status of lakes, estuaries and oceans. The oldest standardised methods for measuring water clarity and colour are the Secchi disk and Forel-Ule colour scale. Both techniques were developed in the 19th century and require use of the human eye. Despite the advent of optoelectronic-based sensing, these visual methods are still used today, owing to their sensitivity, affordability, simplicity and long history of use. Recently, a hand-held device was developed for measuring the Secchi depth and Forel-Ule colour (presented in two formats, named the mini- and midi-Secchi disk). Designed to be small, light and convenient-to-use, it is well suited for participatory science projects that involve monitoring water colour and clarity. To date, over 900 mini- and midi-Secchi disks have been distributed to citizens and scientists, primarily through six projects, with data mostly transferred via mobile phone applications to data servers and dashboards. In this paper, we describe the methods used in the projects and show some characteristics of the datasets collected so far. We showcase how the device can be used for scientific applications, such as verifying satellite data products, gaining new scientific insights, and supporting public engagement and education. Finally, we provide suggestions for methodological improvements and future developments.

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Publication Details

Journal
Frontiers in Environmental Science
Published
2025-07-01
DOI
https://doi.org/10.3389/fenvs.2025.1610130
Primary Topic
Water Quality Monitoring Technologies
Type
article
Field-Weighted Citation Impact
0.00

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article

An innovation of two established methods for monitoring water colour and clarity: participatory science using the mini- and midi- secchi disks

Yasmin Ghadyani, Stella Patricia Betancur-Turizo, Maurício Almeida Noernberg, C. Jasmin et al.
Frontiers in Environmental Science
Water Quality Monitoring Technologies
article

An innovation of two established methods for monitoring water colour and clarity: participatory science using the mini- and midi- secchi disks

Yasmin Ghadyani, Stella Patricia Betancur-Turizo, Maurício Almeida Noernberg, C. Jasmin, Thomas G. Brewin, Lamona Irmudyawati Bernawis, Daniel Odermatt, Sebastian Mäder, Essowè Panassa, B. Troy Frensley, Philip J. Bresnahan, Adriana González-Silvera, Natacha Pasche, Shubha Sathyendranath, Lilian Anne Krug, Abdulaziz Anas, A. Pochelon, Xuerong Sun, Grinson George, Edem Mahu, Stefan Simis, Samina Kidwai, Robert J. W. Brewin, Happiness Anold Moshi, Awaz Mohamed, Joanne L. Wood, Waqar Ahmed, Subrata Sarker, Nandini Menon, Noir P. Purba, Norbert Schmidt, Nabanita Das, David McBride, Ancy C. Stoy, Laurence Haller, Alexandre Camus, Adrien Bonny, Akintoye Edward Akinnigbagbe, Ousmane Diankha, Rodrigo Hernandez-Moresino, Houssem Smeti
article en

Abstract

Measurements of water colour and clarity are used to track the environmental status of lakes, estuaries and oceans. The oldest standardised methods for measuring water clarity and colour are the Secchi disk and Forel-Ule colour scale. Both techniques were developed in the 19th century and require use of the human eye. Despite the advent of optoelectronic-based sensing, these visual methods are still used today, owing to their sensitivity, affordability, simplicity and long history of use. Recently, a hand-held device was developed for measuring the Secchi depth and Forel-Ule colour (presented in two formats, named the mini- and midi-Secchi disk). Designed to be small, light and convenient-to-use, it is well suited for participatory science projects that involve monitoring water colour and clarity. To date, over 900 mini- and midi-Secchi disks have been distributed to citizens and scientists, primarily through six projects, with data mostly transferred via mobile phone applications to data servers and dashboards. In this paper, we describe the methods used in the projects and show some characteristics of the datasets collected so far. We showcase how the device can be used for scientific applications, such as verifying satellite data products, gaining new scientific insights, and supporting public engagement and education. Finally, we provide suggestions for methodological improvements and future developments.

Frontiers in Environmental ScienceVol. 13
Shahjalal University of Science and Technology (BD), Bandung Institute of Technology (ID), University of Ghana (GH), University of North Carolina Wilmington (US), University of Monastir (TN), Universidad Autónoma de Baja California (MX), University of Dar es Salaam (TZ), Zuyd University of Applied Sciences (NL), University of Zurich (CH), Cochin University of Science and Technology (IN), University of Victoria (CA), University of Exeter (GB), Edinburgh Napier University (GB), Partnership for Observation of the Global Ocean (GB), Plymouth Marine Laboratory (GB), North Kent College (GB), University of Kara (TG), Nigerian Institute for Oceanography and Marine Research (NG), Science and Technology Corporation for Naval, Maritime and Riverine Industry Development (CO), Département de la Santé et de l'Action Sociale (CH), The Geneva Association (CH), Aga Khan University (TZ), Nansen Environmental Research Centre India (IN), Centro Científico Tecnológico Patagónico (AR), Dirección General Marítima, École Polytechnique Fédérale de Lausanne (CH), Universidade Federal do Paraná (BR), Bahria University (PK), Swiss Federal Institute of Aquatic Science and Technology (CH), Council of Scientific and Industrial Research (IN), University of Algarve (PT), National Institute of Oceanography (IN), Université de Thiès (SN), Central Marine Fisheries Research Institute (IN), Padjadjaran University (ID)
UK Research and Innovation
Openalex Percentile: Top 84%
Water Quality Monitoring Technologies
DOIOpen Access PDFOpenAlex
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