FreshWater Watch scientists have published a study that demonstrates how citizen scientists can play a key role in monitoring algal blooms and their causes.
Aided by citizen science water quality data, from 250 urban FreshWater Watch locations, covering over 1,600 streams, rivers, lakes and ponds, scientists have discovered important links between urbanisation and algal blooms and confirmed the reliability and scientific standards of FreshWater Watch citizen science data.
The scientists’ initial research objectives were to test the reliability of the citizen science data for observing and measuring algal blooms, measuring the occurrence of algal blooms in urban areas and finding out how phosphates and nitrates interact to create conditions for algal blooms.
Algae is a naturally occurring organism in waterbodies. When excess nutrients are available, algae populations spike causing visible green blooms and possibly producing harmful toxins. They also use the available oxygen in the water which can choke other aquatic life leading fish kills.
The study shows that citizen scientists’ turbidity measurements and water colour observations are accurate predictors for algal blooms. A big challenge for water management agencies is the identification of algal blooms.
FreshWater Watch is proving that citizen scientist data can provide fundamental info for scientist and agencies. Earthwatch Research Manager, Global Freshwater Research scientist, Professor Steven Loiselle said: “Our citizen scientists are seriously committed ambassadors for their local waterbodies and our analysis shows that their observations have the potential to be key elements of a sustainable water management strategy. In fact they’ve already been instrumental in a South East Asian FreshWater Watch location.”
Land use and algal blooms
The scientists found that the urban land use surrounding waterbodies favour algal blooms. In particular ponds and lakes surrounded by impermeable land cover allows pollutants to run straight in to the water creating a significantly higher occurrence of algal blooms. Therefore urban planning decision makers need to take great care when planning land use around waterbodies. Removing vegetation around a waterbody removes a natural pollution buffer as well as areas of natural beauty.
Professor Loiselle said, “FreshWater Watch training equips citizen scientists with the skills to take accurate scientific measurements on a scale that is simply impossible for environmental monitoring organisations and professional scientists. FreshWater Watch is sharing this data with agencies, leading institutes and scientists across the globe.”
Nutrients and eutrophication
FreshWater Watch data shows that in flowing water, high phosphate levels have a positive correlation with high algae population, however nitrate levels appear not to be related to algae presence. Whereas in still water, high nitrate and high phosphate levels both have a significant relationship with algae presence.
In urban areas phosphates are most likely to come from waste water treatment and this study highlights the importance of managing our waste water well.
The Earthwatch scientists are analysing the FreshWater Watch data and preparing to publish more papers in the next two years. FreshWater Watch is entering its fourth year with over 5,000 citizen scientists trained, over 10,000 water quality datasets added to the online database and hundreds more being added each week.
This study was possible thanks to collaboration between FreshWater Watch, Universidade de São Paulo and The Open University of Hong Kong making it the first collaborative publication of the project. We’re expecting and hoping for many more.
The publication is open access and free to download here.