Why is it important to measure flluorescence?
As well as water colour and transparency, fluorescence of a natural water sample changes over time, depending on the material in the sample. Yet, whereas colour and transparency evolve from the combined effects of different water components, such as sediment, microscopic algal cells or dissolved organic matter, fluorescence is highly specific. As an example, blue light activates red fluorescence of the algal pigment chlorophyll a, whereas UV light induces fluorescence in humic substances or oil.
The fluorescence signal also gives information about the concentration of microscopic algae, CDOM or oil. When observing such components over time, changes in their concentration can be related to processes of high societal concern, such as eutrophication. To determine if the measured value is natural, or caused by an extreme event, such as an algal bloom, it is necessary to collect long-term data of an area.
To measure fluorescence with a smartphone, an App is being developed within the Citclops project. Learn more about the principle of fluorescence and on how to measure fluorescence.
Figure 1. Red fluorescence of the algal pigment chlorophyll a is excited by blue light in a cuvette. The Citclops fluorescence App is being developed by our experts at the ICBM Oldenburg, Germany. (image: courtsey of Julia A. Busch and Anna Friedrichs)