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A toxic plant lurks in Norfolk's waterways, threatening to cause serious harm to wildlife living in the Broads. But work to tackle the risks of harmful algae is spurring breakthroughs that will help combat the growing problem in the rivers and lakes of the protected wetland. Pyrmnesium algal blooms can devastate fish populations and other aquatic species, with have huge ramifications for the health of the Broads environment.
Thousands of fish were killed following an algal bloom in 2015 at Martham on the Thurne (Image: Newsquest) It can create 'dead zones' due to the plants starving habitats of oxygen and by releasing harmful toxins. Experts at the University of East Anglia (UEA) who have studied the effect of the plant on the waterways say higher temperatures can cause blooms to increase. With a warming climate bringing more extreme and hotter weather to the region, the danger is growing.
Views across Hickling Broad (Image: Newsquest) Nutrients in our rivers from human and agricultural waste, notably nitrogen and phosphorus, have also been blamed on increasing algae growth. Eco-laws have been introduced to limit excess nutrients, which has halted thousands of new developments in the county. Efforts to tackle the amount of sewage being released into the Broads is also ongoing, with the number of spills rising in 2024.
Last year, there were 1,162 releases, lasting a total of 8,913 hours in the Broads from Anglian Water storm overflows. Agricultural run-off from farms is also a big source of excess nutrients entering the waterways. An algal bloom in a river - blooms can be harmful to aquatic life (Image: PA) To help combat the toxic plant, a collaborative study has been investigating ways of combating the golden-coloured algae Prymnesium parvum .
The long-term research project is led by the University of East Anglia in collaboration with the Environment Agency, Broads Authority and the Norfolk pike angling community. It has recently gained momentum after receiving a £4,000 funding boost from the angling community which has helped with water sampling across the Broads. Fishing contributes £100m to the local economy, with algal blooms risking the growth of this industry.
Professor Rob Field, vice chancellor for UEA's faculty of science (Image: Newsquest) Rob Field, vice chancellor for UEA's faculty of science, said: “This research is crucial for the future of the Broads’ ecosystem and economy. “With the support of local anglers and environmental agencies, we are making significant strides in understanding and heading off harmful algal blooms.” Recent breakthroughs from the UEA and John Innes Centre have revealed crucial insights into how and when these algae produce toxins, and how the toxins are released into the environment.
They have found that a common disinfectant, hydrogen peroxide, can be used to decontaminate the water to allow fish to be rescued from bodies of water suffering blooms. Tests to detect the presence of the algae have also been developed. A man fishes on Whitlingham Broad (Image: Newsquest) John Currie, chairman of the Norwich and District Pike Club, said: “Local anglers well know the devastating effects caused by a toxic prymnesium bloom and the negative effects on the whole ecosystem.
"It is great we have world leaders on this research on our doorstep." Algal blooms are one of many threats to the fragile ecosystems in the Broads. Fewer than 4pc of Broadland waterbodies are in good ecological condition.
Another factor affecting the health of the wetlands is insecticides, which can flow into rivers, causing pollution. The wherry Hathor sailing on the River Thurne (Image: Newsquest) Matt Shardlow, a conservationist who specialises in insects and a BA member, has warned the use of neonics - a type of seed treatment - risks poisoning our waterways. The chemicals were banned except for being used on sugar beet crops until the Department for Environment and Rural Affairs (Defra) blocked its use this January.
However, some of these chemicals continue to be used for flea treatments despite the serious harm to aquatic life due to legal loopholes. Mr Shardlow, in a recent Broads Society publication, said: "The chemicals banned in agriculture are now polluting freshwater habitats because regulation of veterinary products is almost non-existent. "We cannot expect life in its glorious variety to continue to spring from the Broads waterways if they are still being polluted by toxic veterinary products.
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