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Reports from the Field: Citizen Science

An important part of our work at DANUBE4all focuses on citizen science. The Citizen Science Toolbox is a resource we aim to develop and share with our project demonstration sites, the Danube Water Museum Network and any other interested parties or individuals that would like to contribute via citizen science to a healthy Danube.

As part of the development of this toolbox and under the mentorship of our citizen science lead Sandra de Vries of Pulsaqua, undergraduate student Alice Demolder was invited to research the experience of participating citizens in a number of existing citizen science methodologies used to examine (biological) water quality. Thanks to her, we have been able to learn a lot that we will use to improve the usefulness of the toolbox.

Read her field report below!

Images courtesy of Pulsaqua/Alice Demoulder


My name is Alice Demolder. I am an undergraduate student in Marine Biology at the University of Aberdeen. In September 2023, I undertook field work in conjunction with DANUBE4all as part of my honours project at Persina Nature Park, Bulgaria. The park is an impressive area of wetland and a dedicated nature reserve along the Danube, where many different restoration projects are underway.

My project objective was to test and examine the impact that the use of technology has on the improvement of participant awareness in citizen science projects. In conducting my field research, I aimed to work with citizens of all ages, however I found that I ended up working with younger people aged around 12 to 26.

During my work, I worked with volunteers from the community of the Persina Nature Park who kindly agreed to help. Participants were asked to experiment with two types of citizen science methodologies aimed at measuring water quality in different ways.

Methodologies were categorized into processes that use a mobile application and processes that don’t. The analogue approach used a Secchi disc and the MiniSASS approach, with the digital approach using the smartphone apps Eyeonwater and iNaturalist

The aim of my research was to find out how the usage of mobile apps impacted the volunteers’ experience in the field, and to what extent impacts were positive or negative.

Images courtesy of Pulsaqua/Alice Demoulder


The Experiments

The experiments conducted were aimed at understanding the surrounding nature and measuring water quality in the test area. Biodiversity and the presence of species are important indicators for understanding the health of an ecosystem. In general, an ecosystem is healthier when its biodiversity is high. To assess the biodiversity of a specific area, we need to record and identify the species we encounter in the field. To do this, we use various types of identification tools.

Among the methodologies used for species identification, I employed iNaturalist (a mobile app) and miniSASS (dichotomous key).

miniSASS is a citizen science methodology that aims to evaluate the health of a river stream by identifying species of invertebrates found within the area. This identification is done using a dichotomous key, which consists of a series of paired questions, each with two alternative answers, "yes" or "no." Volunteers follow the key by selecting the answer that best describes the species they are trying to identify. By making a series of choices and eliminating options, users eventually arrive at a specific identification.

iNaturalist is a mobile app that allows users to take photos or make observations of various organisms. By uploading these observations or pictures to the iNaturalist platform, users receive recommendations of species that could represent the one in their pictures. If users don't believe they are the same species, they can upload it and ask for help from the community to the observation. Eventually, the species in the picture will be identified and made available on the platform.

Images courtesy of Pulsaqua/Alice Demoulder


Turbidity is one strong indicator of water quality that was tested. To explain, turbidity essentially relates to the clarity and cleanliness of water. When the water is clear, there is low turbidity. When the water is cloudy, there is high turbidity. High turbidity allows less light to penetrate through the water, which therefore has negative impacts on the health of the ecosystem and aquatic plant and animal life. High turbidity is caused by excessive amounts of pollutants, agricultural run-off and poor wastewater and sewage treatment among other factors. 

Among the methodologies used were Secchi disk (analogue device) and EyeOnWater (mobile app device).

A Secchi disk is a device used to measure water turbidity. The device comprises an 8-inch diameter disk with 4 quarters, alternating between black and white. The disk is lowered into the water until it can no longer be seen from the surface. The point at which the disk is no longer visible provides a measurement for the water clarity. Data is recorded and collected in a spreadsheet for further analysis.

EyeOnWater is a citizen science mobile app developed to help measure the health of rivers, lakes, coastal waters, and oceans by their colour and clarity. So, it has a similar purpose to the Secci Disk but is based on the use of a mobile app.

In conducting these experiments, I worked with a group of 9 children and teens (aged 10-16 yrs.) and a group of 4 young adults (25-26 yrs.) through the full range of approaches, with some others engaged in certain elements in the process. All in all, I collected data from 20 volunteers. This data was used to test the impact that the use of technology has on the improvement of participants awareness by contrasting participant knowledge before and after the use of methodologies, as well as comparing the improvement that resulted from processes using apps and methodologies that didn’t use technology. We are still finalizing the results in a paper, that we hope to publish.


Personal reflections

Alice Demoulder

Overall, my fieldwork has been a very enriching experience. I have learned greatly from it and from the team that was looking after me and helping me. Particular mention to Sandra De Vries of Pulsaqua, who is heading up the Citizen Science programme within DANUBE4all, and who has helped me all the way from finding a location for my fieldwork to writing up my paper.

Working with DANUBE4all and the Persina Nature Park has opened doors to me that I thought (and was told) would be too ambitious for an undergraduate student! It was a great experience to have to work with volunteers. I had to learn how to lead fieldwork within a group setting, keeping in mind that everyone is not a scientist! It was great to reach out to people from all backgrounds and see them motivated to learn about our project. I was given all the support I needed to realise this project and create a comfortable environment for me to learn and enjoy this experience. While I was independent through the project, I never felt left alone. This experience has been challenging but not overwhelming and has been a fantastic learning experience!

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