Last updated: March 2025
Coastal erosion is a well-known consequence of climate change, driven by rising sea levels, extreme storms, and powerful coastal surges. Dollymount Strand, a popular spot for bathing and water sports in Dublin, is particularly vulnerable. Located on North Bull Island and managed by Dublin City Council, the area is part of several protected zones, including a Special Area of Amenity, a Special Area of Conservation, a Special Protection Area, a Ramsar Wetland, a Natura 2000 site, and the UNESCO Dublin Bay Biosphere. To help mitigate this issue, Dublin City Council has implemented a solution that works with, rather than against, natural processes. During late summer and autumn—particularly following high tides, warm weather, and storms—a type of seaweed called Ectocarpus siliculosis naturally accumulates along Dublin Bay’s beaches. Instead of removing it, the council allows the seaweed to remain, recognizing its essential role in maintaining the beach’s rich biodiversity. Ectocarpus contributes to the health of the coastal ecosystem, supporting marine life and enhancing the natural resilience of Dublin Bay. (1.2)
Ectocarpus carpeting South Side Dublin Bay, Niamh Ni Cholmain September 2016
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Overview
Nature-based solution
- Blue infrastructure
- Coastlines
Key challenges
- Climate action for adaptation, resilience and mitigation (SDG 13)
- Climate change adaptation
- Environmental quality
- Waste management
- Green space, habitats and biodiversity (SDG 15)
- Habitat and biodiversity conservation
- Health and well-being (SDG 3)
- Creation of opportunities for recreation
Principal problems in Functional Urban Area (FUA)
- Climate-Related Hazards
- Coastal hazards (e.g. erosion, flooding)
- Extreme weather events (e.g. storms, hurricanes)
- Environmental Degradation
- Biodiversity loss
Key priorities
Climate action (adaptation and/or mitigation), Biodiversity (conservation and/or restoration)
Focus
Coastal landscape management or protection, Coastal ecosystems restoration and maintenance (mangroves, dunes, saltplains, underwater meadows), Improving coastal resilience, Ecological restoration of ecosystems, Restoration and protection of ecosystems (including water ecosystems), Protection of natural ecosystems, Habitat conservation, Marine and coastal conservation initiatives, Monitoring and maintenance of habitats and/or biodiversity, Species-specific monitoring and conservation programs
Project objectives
To mitigate coastal erosion.
To reduce the impact of waves and water surges.
To preserve biodiversity.
To protect sensitive habitats.
To maintain the recreational value of the beach
To enhance public awareness and engagement about coastal erosion
To maintain the ecological health of the beach.
To prevent pollution and promote environmental cleanliness (1, 4, 7)
Implementation activities
The primary approach to managing Ectocarpus siliculosis, a type of seaweed that accumulates on Dublin Bay beaches, focuses on preserving its natural role within the beach ecosystem. In late summer and autumn—especially during high tides, warm weather, and post-storm conditions—a type of seaweed called Ectocarpus siliculosis often accumulates along Dublin Bay beaches. Ectocarpus siliculosis is considered to be a naturally occurring nuisance species. Typically growing on the seabed from early springtime until the end of its lifecycle in the autumn when it dies out. At this time of year the seaweed is decaying and becoming uprooted from the sea bed and washing ashore at various locations along Dublin Bay. When large amounts of Ectocarpus gather on Dollymount Strand, the seaweed is raked into mounds up to two meters high and positioned in front of the sand dunes. These mounds act as natural, soft-engineering coastal defenses, creating a barrier that absorbs and reduces the force of water, thus protecting the dune structures from erosion. To prevent pollution, major litter is removed from the mounds before they are set in place. Staff have observed that this is helping to slow down dune erosion in this part of the beach and research has been carried out to determine the effectiveness of this technique. (1,2).
Climate-focused activities
Climate change adaptation:
- Implement measures that prevent/manage desertification, soil erosion and landslides
- Restore sediment supply to coastal zone
- Reducing socio-economic vulnerability to climate impacts (e.g. awareness raising)
Biodiversity conservation or restoration-focused activities
Biodiversity conservation:
- Protect and enhance urban habitats
- Preserve and strengthen existing habitats and ecosystems
- Reduce negative impacts and avoid the alteration/damage of ecosystem
- Means for conservation governance
- Raise public awareness
Biodiversity restoration:
- Rehabilitate and restore damaged or destroyed ecosystems
Main beneficiaries
- Local government/Municipality
- Researchers/University
- Citizens or community groups
Governance
Management set-up
- Government-led
Type of initiating organisation
- Local government/municipality
Participatory approaches/ community involvement
- Dissemination of information and education
- Co-management/Joint management
Details on the roles of the organisations involved in the project
Dublin City Council manages the project, which oversees the maintenance and management of Dollymount Strand on North Bull Island and addresses public complaints, often clarifying the misconception that decaying seaweed is sewage. Climate Action Regional Office (CARO) conducted research to evaluate the effectiveness of using Ectocarpus mounds as coastal defence, assessing how this natural process influences dune erosion and contributes to the overall efficacy of the intervention (1).
Project implemented in response to ...
... an EU policy or strategy?
Yes
(Natura 2000 and Dublin Bay Biosphere (UNESCO) (1))
... a national policy or strategy?
Unknown
... a local policy or strategy?
Yes
( Special Area of Amenity by Order and a Special Area of Conservation, Special Protection Area, a Ramsar Wetland, An Taisce Blue flag status (1))
Type of enablers
Unknown
Financing
Total cost
Unknown
Source(s) of funding
- Public local authority budget
Type of funding
- Earmarked public budget
Non-financial contribution
Unknown
Impacts and Monitoring
Environmental impacts
- Climate change
- Strengthened capacity to address climate hazards/natural disasters
- Expected strengthened capacity to address climate hazards/natural disasters
- Enhanced protection against extreme weather events (e.g. storms, cyclones, tidal surges, coastal erosion)
- Expected enhanced protection against extreme weather events (e.g. storms, cyclones, tidal surges, coastal erosion)
- Water management and blue areas
- Enhanced protection and restoration of coastal and marine ecosystems
- Expected enhanced protection and restoration of coastal and marine ecosystems
- Green space and habitat
- Reduced biodiversity loss
- Expected reduced biodiversity loss
Economic impacts
- Unknown
Socio-cultural impacts
- Unknown
Type of reported impacts
Presence of formal monitoring system
Yes
Presence of indicators used in reporting
Yes
Presence of monitoring/ evaluation reports
Yes
Availability of a web-based monitoring tool
Yes
Potential risks of implementation and trade-offs
Social justice and conflicts, Lack of social acceptance
References
1.
CARO (n.d.). Case Study: Mitigation Coastal Erosion using Algae (Ectocarpus). CARO, Accessed on August 30, 2024, [Source link];
2.
O'Sullivan, K. (2020). Swimming ban at three beaches following overflow at Ringsend wastewater treatment plant. The Irish Times, Accessed on August 30, 2024, [Source link];
3.
Dublin Bay Biosphere (n.d.). About Dublin Bay Biosphere. Dublin Bay Biosphere, Accessed on August 30, 2024, [Source link];
4.
Haro, S., Bermejo, R., Wilkes, R., Bull, L., Morrison, L. (2023). Monitoring intertidal golden tides dominated by Ectocarpus siliculosus using Sentinel-2 imagery. International Journal of Applied Earth Observation and Geoinformation 122, Accessed on August 30, 2024, [Source link];
5.
Dublin City Council (n.d.). Beaches and Bathing Water Quality. Dublin City Council, Accessed on August 30, 2024, [Source link];
6.
Dublin City Council (n.d.). Research at North Bull Island UNESCO Biosphere 1995-2014. Dublin City Council, Accessed on August 30, 2024, [Source link];
7.
Bathing Water Task Force (2023). Dublin Bay Bathing Waters Report by the Bathing Water Task Force . Bathing Water Task Force , Accessed on September 12, 2024, [Source link];
Ectocarpus mounds near fore dunes Dollymount Strand, North Bull Island. Dublin CARO August 2020
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Ectocarpus carpeting at Dollymount Strand, Dublin CARO August 2020
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Information about this nature-based solution was collected as part of the Naturescapes project funded by the European Union under Grant Agreement No 101084341.