Report reveals vulnerabilities of Lough Carra

A study of Lough Carra has raised concerns about elevated ammonia and phosphorous levels in certain areas.

Ann Marie Meane, who is the Surface Water Officer for the Lough Carra LIFE project, delivered an indepth report at the Lough Carra Catchment Association’s public meeting last month. The meeting attracted an impressive audience of over 40 people to the Carnacon Community Centre. The event kicked off with updates from association director Chris Huxley, followed by a detailed progress report from Kieran Flynn, manager of the Lough Carra LIFE Project.

In her report, Ms Meaney noted that water testing was conducted at 37 sites across the catchment. She highlighted Lough Carra’s sensitivity to nutrient levels and stressed the importance of achieving ‘high-status environmental quality standards’ to protect the lake. Noting the elevated ammonia and phosphorus levels in certain areas, she revealed that the catchment’s water quality is highly reactive to rainfall. To address these issues, she emphasised the need for tree and hedge planting around the lake and inflowing streams to help naturally filter out excess nutrients before they enter the watercourses.

The association, in partnership with the LIFE Project, has also been closely monitoring the lake’s unique marl crust as part of baseline assessments to evaluate the ecosystem’s health. Samples have been collected from strategic locations, including sites participating in the Lough Carra LIFE agri-environmental scheme and at the mouths of watercourses feeding into the lake. 

Phillip Doddy provided a compelling presentation on this work, stressing the importance of preserving the marl, which serves as a key indicator of the lake’s overall health. He also noted that rising nutrient levels are driving an increase in green algae and higher chlorophyll concentrations, further underscoring the need for urgent action.

Additional speakers included Cillian Roden, a specialist in underwater ecology, who presented concerning findings from his monitoring of Lough Carra’s underwater vegetation. Mr Roden reported a troubling increase in pondweed species, which pose a threat to the lake’s native charophytes by out-competing them. He also highlighted that the lake’s water is becoming progressively darker, and its marl crust continues to degrade, both signs of a deteriorating ecosystem. 

Chris Huxley also gave an insightful presentation, focusing on the increased growth of bulrush and water milfoil, further emphasising the shifts in the lake’s vegetation.