Cyanobacteria: the Luxembourg Water Management Agency and the Luxembourg Institute of Science and Technology launch a mobile application

The Luxembourg Institute of Science and Technology (LIST), with the support of the Administration de la gestion de l'eau (Water Management Authority), has adapted the "Bloomin'Algae" mobile application so that users of Luxembourg's water bodies can now notify the authorities of blooms of cyanobacteria, commonly known as "blue-green algae".

©Police grand-ducale Lac de la Haute-Sûre - Photo d'archive 2021
Lac de la Haute-Sûre - Photo d'archive 2021

Cyanobacterial proliferation(ou 'blooms') in Luxembourg's waters* is not only a health risk for swimmers, domestic animals and livestock, but also undermines the ecological health of aquatic ecosystems.

In order to gain a better understanding of this phenomenon, which is becoming more and more frequent in Luxembourg, further field data is needed. To this end, the Bloomin'Algae application allows citizens to submit photos and the precise location of blue-green algae or suspected blue-green algae in just a few clicks. For the 2023 bathing season, the following sites will be targeted: The Upper-Sûre lake, the Weiswampach lakes and the Moselle.

How does it work?

Download the Bloomin' Algae application, which is available for free from GooglePlay or the App Store and then:

  1. Select "Luxembourg".
  2. Make your bloom observation in just 3 minutes:
  3. Confirm the GPS coordinates of your smartphone, the date of the observation and describe your observation using the options provided;
  4. Take one or more photos of your observation and then submit your report (immediately or later).
  5. After verification and validation by a LIST expert, your contribution will be visible on the interactive map of Luxembourg.

The interactive map and further information can be found on the website


*How do blue-green algae blooms develop?

Planktonic cyanobacteria need light, heat and nutrients to develop. In Luxembourg, cyanobacteria generally proliferate between August and October in calm, nutrient-rich waters such as lakes, ponds and the Moselle. In general, cyanobacterial blooms are observed with increasing frequency on all continents.

Planktonic cyanobacteria blooms mainly occur in stagnant waters (lakes and rivers with slow currents) where there is excessive nutrient input, leading to proliferation of plants and an imbalance in the ecosystem. To grow, cyanobacteria need high concentrations of nutrients, especially phosphorus, which can come from many sources: livestock effluent, compost, fertilisers applied to the soil, inadequately treated wastewater discharges, soil leaching during heavy rainfall. Reducing phosphorus and nitrogen inputs to surface waters remains the only sustainable way to protect and/or restore these ecosystems from planktonic cyanobacteria blooms. To that end, the measures set out in the third management plan for the Luxembourgish parts of the Rhine and Meuse international basin districts are being implemented. The modernisation of wastewater treatment plants, the reduction of fertiliser use in agriculture and the planting of riparian strips (Uferrandstreifen) along agricultural land are among the measures that contribute to reducing nutrient inputs into watercourses.

The factors and processes that regulate the proliferation of cyanobacteria are particularly complex, which means that these phenomena are often difficult to predict.

Press release by the Water Management Authority and the Luxembourg Institute of Science and Technology (LIST)

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