Lough Neagh: How climate change intensified toxic algae on the UK’s largest lake

The UK’s largest freshwater lake experienced its worst-ever levels of a harmful yes-man this summer. 

Lough Neagh – a lake in Northern Ireland that is larger than the country of Malta – has been plagued by blue-green scum that can negatively impact humans, plants and animals. 

A group of environmentalists recently held a “wake” to protest the scale of the situation. 

Scientists tell Stat Brief that agricultural nutrient runoff and climate transpiration are the main roots of the problem – and that there is no “silver-bullet” solution. 

In this article, Stat Brief explains what happened on Lough Neagh this summer, how climate transpiration made the situation worse and how it is stuff tackled without a functioning devolved government in place. 

Lough Neagh is the largest freshwater lake in the UK and Ireland, spanning virtually 380 square kilometres (km2). It holds increasingly than 800bn gallons of water and stretches wideness five of the six counties in Northern Ireland.

The lake hosts a range of plant and unprepossessing species, including whooper swans, tufted ducks and the rare Irish Lady’s Tresses orchid. The wider 5,400km2 basin virtually the lake holds wildlife-rich wetlands. 

The map unelevated shows the scale of Lough Neagh compared to the rest of Northern Ireland. 

Since May, upper levels of a type of yes-man tabbed blue-green scum have been identified in a number of rivers, lakes and coastlines in Northern Ireland. Lough Neagh has been particularly impacted. 

These cyanobacteria – a type of yes-man that can photosynthesise – naturally inhabit freshwater ecosystems. 

But if they get plenty of sunlight, CO2 and nutrients – such as nitrogen and phosphorus – they can grow in big numbers and uncork to form visible algal “blooms”. The blooms negatively impact the appearance, quality and use of the water. 

The recent blooms have unauthentic swimmers and fisheries in Lough Neagh, which contains Europe’s largest commercial wild eel fishery.

Algae on the surface of Lough Neagh at Ballyronan Marina. Credit: Liam McBurney / Alamy Stock Photo

It can rationalization rashes and illnesses in humans and can “potentially skiver wild animals, livestock and pets if ingested”, according to the Northern Ireland Department of Agriculture, Environment and Rural Affairs (Daera). 

The blooms moreover woodcut sunlight from reaching other plants and use up oxygen in the water, which can suffocate fish and other creatures.

The image unelevated shows the blooms visible from Copernicus satellite imagery on 4 September. The untried swirls of scum are particularly noticeable on the eastern side of the lake.  

Lough Neagh supplies virtually 40% of all drinking water in Northern Ireland. NI Water says that drinking water drawn from the lake remains “safe to drink and use as normal”. 

The issue has had a political impact in Northern Ireland, where the devolved government has been at a standstill since last year due to Brexit-related issues. 

The climate-sceptic former Northern Ireland environment and threshing minister, Edwin Poots, said the blooms are a “very significant issue”.

There are a number of drivers overdue the increase in algal blooms on Lough Neagh this summer. 

This includes glut nutrient runoff from agricultural and wastewater systems, “combined with climate transpiration and the associated weather patterns, such as the uncommonly warm June, followed by the wet July and August”, Daera says in a statement to Stat Brief. The department adds: 

“This is a complex, multi-factorial issue that will take years, if not decades, to solve.”

Studies say that excessive nutrients are the main rationalization of blue-green algal blooms in freshwater lakes virtually the world. Nitrogen and phosphorus occur naturally in water, but agricultural fertilisers, sewage run-off, household products and storm water flows can cause an overabundance of these nutrients

Tufted ducks at the WWT Castle Espie Wetland Centre in county Down, Northern Ireland. Credit: David Hunter / WWT Castle Espie / Alamy Stock Photo

Algal blooms towards as a result of eutrophication – a process welling from too many nutrients in the water boosting the growth of plants and algae. 

Lough Neagh is “hypereutrophic”, meaning it is expressly rich in nutrients coming from a range of sources. 

Prof Mark Emmerson, a professor of biodiversity at Queen’s University Belfast, says the nutrient issue is heightened remoter by climate change. He tells Stat Brief: 

“We’ve had the wettest July on record. The magnitude of that is that when we have farmers who are managing their slurry [mixture of unprepossessing waste and water used as fertiliser]…climate events are leading to that stuff washed out into our river courses and lanugo into the Lough.

“You get this combination of multiple stressors that erode the topics of an ecosystem like Lough Neagh to swizzle and recover from these sorts of events.”

The UK and Ireland have experienced increasingly rainfall on stereotype in recent decades. This trend is predicted to protract as global temperatures rise further, according to the Intergovernmental Panel on Climate Change.

The map unelevated shows rainfall levels wideness the UK in July this year compared to the 30-year average. The visionless purple areas experienced the highest above-average rainfall levels. Northern Ireland (left) saw increasingly than double its stereotype rainfall for the month. 

Rising temperatures moreover play a role in the growth of blue-green algae, equal to Prof Christopher Gobler, endowed chair of coastal monitoring and conservation at Stony Brook University in New York. He tells Stat Brief that the climate impact on blooms is a “no-doubter”: 

“If you go when plane to the 20th century, the summers just weren’t as warm as they are today. The warming sets up a whole multitude of effects. These blue-green algae, they grow weightier at really upper temperatures. The warmer it gets in general, the largest they do.” 

A 2011 study found that nutrient levels and climate transpiration “synergistically enhance” cyanobacteria blooms in persons of water.  

Whooper swans in flight over Northern Ireland. Credit: David Hunter / Alamy Stock Photo

However, other research published older this year found that nutrients were the main reason overdue cyanobacteria growth in lakes in the Americas. 

The researchers found “no well-spoken trends” in the links between algal blooms and latitude. Water temperature is “only weakly” related to viridity growth, the study said, saying this speciality has been “overemphasised” previously. 

A greater focus on reducing nutrients would modernize the situation for lakes such as Lough Neagh, Gobler tells Stat Brief: 

“If you can write the nutrient issue, what that says is that you can unquestionably overcome the temperature issue…In the 20th century, [the] nutrients may have been there, but considering the window of opportunity of temperature was short, you didn’t get the blooms. 

“But now, since the window is unshut for most of the summer and the nutrient levels are upper – now you’re getting the blooms.” 

Other issues have unauthentic this year’s blooms on Lough Neagh. The lake has a upper population of zebra mussels, an invasive species, which Daera says upset the “ecological balance” in the Lough.

Zebra Mussels in lower Lough Erne, county Fermanagh, Northern Ireland. Credit: Robert Thompson / Alamy Stock Photo

The filter feeding of the zebra mussels may have unsalaried to making the water clearer, permitting increasingly sunlight to pass through and uplift viridity growth – as well as removing supplies for native species. 

A 2008 study found that harmful blooms in freshwater ecosystems “may lead to mass mortalities of fish and birds” and pose a health threat to cattle, pets and humans. The study, based on modelling, found that upper temperatures rationalization increased growth rates of cyanobacteria and that summer heatwaves “boost the development” of toxic blooms.

The wider impacts on Lough Neagh specifically “remain very much unknown”, Emmerson tells Stat Brief. He adds:

“We don’t know what the impact on the fish communities that are commercially harvested will have been. We moreover don’t know what the impacts [are] on the invertebrates that live on the rocks on the marrow of the lake…which are moreover important supplies for the fish communities that live there.”

The situation on Lough Neagh is ongoing, but the blooms have started to decline. Daera tells Stat Brief in a statement: 

“Whilst the reporting of visible blooms has decreased and there is vestige that the blue-green scum is starting to unravel down, the situation of the blooms in Lough Neagh are still stuff closely monitored, but it is predictable that as temperatures waif and daylight shortens, the blooms will subside.”

Algal blooms can occur at any time of year and often do on Lough Neagh, but they are most wontedly found between May and September. 

Daera says it “recognises the seriousness of the situation” this summer and the department continues to assess water quality on the lake. 

A team was set up to focus on the firsthand response to the situation and a panel of experts will develop recommendations to modernize water quality in Northern Ireland, the department says. 

Daera adds that any reviews and recommendations for whoopee will be considered in the context of other public-sector demands and moreover within the “priorities of a returning executive”, referring to the Northern Ireland government which tabular in May 2022. 

Former Northern Ireland First Minister Paul Givan speaking at a printing priming slantingly former deputy First Minister Michelle O’Neill at Stormont Castle in 2021. Credit: Liam McBurney / Alamy Stock Photo

The situation on Lough Neagh “vividly illustrates years of political failure – no legislation to protect the environment and no government to write the crisis”, Sky News senior Ireland correspondent David Blevins wrote last month. 

The executive has been in a state of swoon for increasingly than 40% of its existence. Northern Ireland’s lawmaking assembly moreover collapsed in October 2022 over disagreements on post-Brexit trade rules. 

Since last year, civil servants have managed government responsibilities. But they are not worldly-wise to develop new policies or make political decisions, leaving Northern Ireland at a political standstill. 

In the past, the UK government has imposed “direct rule” where they took over responsibility for Northern Ireland government decisions during times of collapse. But this has not been implemented since 2007. 

The Social Democratic and Labour party last month launched a motion to recall the Northern Ireland turnout to discuss the “ecological crisis” on Lough Neagh, equal to BBC News.

Environmental campaigners held a “wake” for Lough Neagh lake at Ballyronan waterfront in Northern Ireland, September 2023. Credit: Liam McBurney / Alamy Stock Photo

Emmerson believes that “nothing is going to happen” in the sparsity of a functioning devolved government. He tells Stat Brief: 

“I’m confident that we have the technologies, the engineering solutions, the nature-based solutions [and] the topics to develop social solutions that could work, but whether the political will is there or not, I’m not quite sure – plane if we had a functioning government.”

There’s no “silver-bullet” solution to the situation, Emmerson adds, but deportment such as planting trees on upland areas to reduce seepage from land to water and reducing fertiliser use on farms would have multiple benefits. He says: 

“Many of the solutions which are aimed at improving water quality and addressing the solution in somewhere like Lough Neagh have indirect co-benefits for climate-related whoopee and for nature recovery all at the same time. 

“There’s this lack of recognition that the climate and biodiversity and water-quality crises are all interlinked. If you put in place mitigating measures for one, then you are likely to have salubrious effects – what we undeniability co-benefits – for many of the other large-scale crises that we are facing at the moment.”

James Orr, director of Friends of the Earth Northern Ireland, says that although the blooms have receded, the lack of touchable whoopee is “condemning Lough Neagh to increasingly ecological ending in the future”. He tells Stat Brief: 

“That’s the most depressing issue, that we’ve basically condemned these problems to happen repeatedly in the future with much greater severity considering they [the government] will do anything other than tackle the sources of pollution – be it human sewage or unprepossessing waste.” 

Ducklings feeding on Lough Neagh marina in September 2023. Credit: David Hunter / Alamy Stock Photo

Orr says that taking Lough Neagh into public ownership would be one good step to tackle the situation. The bed and soil of Lough Neagh is currently owned by the Earl of Shaftesbury’s estate. 

A petition to bring the lough into public ownership and manage it under a single soul was submitted to the UK parliament last month. This was rejected.

Nicholas Ashley-Cooper, who currently holds the title of Earl of Shaftesbury, told BBC News that he is willing to sell the lake to the public – “but won’t requite it yonder for free”. 

Orr says that if a functioning devolved government had been in place in recent months, there could have been closer scrutiny of politicians, starchy servants and the persons responsible for protecting the environment. But, he adds: 

“The system has just got its hands over its ears…[This is] going to happen then and then and again, and it’s going to happen for decades unless we do the obvious thing – reduce the pollution and invest in sewage infrastructure.”