Study of FreshWater Watch water quality data from 150 streams in North and South America find nutrient levels exceeding threshold for eutrophication in 86%. These were associated to catchment and local scale conditions observed and recorded by citizen scientists in the FreshWater Watch.
Eutrophication occurs when there are excessive nutrients, such as nitrate and phosphates used in fertilisers or released by poor wastewater management, in a water environment. This can lead to the growth of algal blooms, which can be harmful to human health but also deplete oxygen in the water leading to an overall decline in biodiversity as birds, fish and aquatic plants.
The new research analysed the relationships between nutrient concentrations in 150 streams in 57 water basins in Buenos Aires, Curitiba, São Paulo, Rio de Janeiro, Mexico City and Vancouver.
The phosphate nutrient concentrations exceed the threshold for eutrophic conditions in waterbasins where residential and industrial waste discharge points and road run-off pollution sources were identified.
The study showed that FreshWater Watch data is uniquely useful in that the citizen scientists record nearby vegetation, pollution sources and land use which can have important influences on freshwater ecosystems as well as measure nutrient levels. Local authorities can use this microscale information to improve their management of streams and rivers ecosystems. For example preserving and expanding bank vegetation provides a buffer-zone to absorb excessive nutrients.
FreshWater Watchers also collect water quality data in small tributary rivers, which are often overlooked by agencies and researchers.
The study Micro and macroscale drivers of nutrient concentrations in streams in South, Central and North America is open source and online at