It's World Rivers Day on Sunday and there's plenty of riparian news out today:

New study finds that sewage release is worse for rivers than agriculture - University of Oxford

Ahead of World Rivers Day (24 September), new research by the University of Oxford reveals that sewage discharge into rivers has a greater impact on water quality, and the animals and plants that live in rivers, than surrounding land use. This has strong implications for the state of UK rivers in light of the recent threats to weaken nutrient neutrality regulations for new housing developments. The findings have been published today in the journals Global Change Biology and Ecological Solutions and Evidence.

Researchers from the University of Oxford’s Department of Biology investigated the effects of three different pollution sources (treated sewage discharge, agriculture, and urban run-off) on different aspects of river systems. The group tested four rivers in England, both up- and downstream of sewage discharge, over three different months.

The results demonstrated that treated sewage discharge was the best predictor of high nutrient levels, bottom-dwelling algae, and sewage fungus abundance, regardless of the type of land use (agriculture or urban) in the surrounding area.

Dr Michelle Jackson (Department of Biology, University of Oxford), senior author of the study, said: 'There is ongoing debate about the cause of the poor ecological state of many rivers in the UK because it is difficult to disentangle different pollution sources. Here, we show that even treated sewage appears to have a stronger influence on river communities than pollution from the surrounding land. This important information should be used to prioritise the management and conservation of our rivers moving forward.'

An early-detection system for spotting dangerous outbreaks The researchers also developed a new method to allow early detection of potentially dangerous outbreaks of "sewage fungus." This is a complex mix of fungus, algae, and bacteria which forms large masses when there are high organic nutrient levels. They not only cause unpleasant smells, but severely reduce oxygen levels in water which can adversely affect all river species, and cause mass fish mortality.

Dr Michelle Jackson said: 'Rapid identification of sewage fungus pollution events will allow early intervention which would help prevent any potential negative consequences for local wildlife.'

• The paper ‘The combined effects of treated sewage discharge and land use on rivers’ has been published in Global Change Biology.
• The paper ‘Early detection and environmental drivers of sewage fungus outbreaks in rivers’ has been published in Ecological Solutions and Evidence.