Green algae in Brittany: A challenge for Integrated Coastal Zone Management

Introduction:

Green algae, also known as ulvae, have become a symbol of a significant environmental issue along Brittany's coasts. Since the 1970s, these massive algal blooms have developed on Brittany's beaches every summer, impacting local ecosystems, the regional economy, and public health. This phenomenon is mainly caused by excess nitrates in coastal waters, which are linked to intensive farming practices.

Addressing this issue is complex, as it requires coordination among various stakeholders---farmers, local authorities, fishers, and national policymakers. Integrated Coastal Zone Management (ICZM) provides a relevant framework for tackling such issues. The ICZM approach aims to reconcile economic development goals, environmental preservation, and local participation. This article explores the causes and impacts of green algae in Brittany, reviews the solutions already implemented, and proposes possible improvements within the ICZM framework.

Case Study: Green Algae in Brittany:

• Description of the Affected Area

Brittany, located in northwest France, has one of Europe's richest and most diverse coastlines, spanning over 2,700 kilometers. This natural heritage is vital for the local economy, particularly in sectors such as fishing, tourism, and agriculture. However, certain bays in Brittany---such as Saint-Brieuc, Douarnenez, and Lannion---are regularly affected by green algae blooms.

Localisation of Brittany (https://id.m.wikipedia.org/wiki/Berkas:Localisation_Duch%C3%A9_de_Bretagne.svg)

• Origin of the Phenomenon

Green algae blooms are caused by high concentrations of nitrates in coastal waters. These nitrates mainly come from chemical fertilizers and slurry used in intensive farming, which eventually enter rivers and flow into the sea. Brittany's high concentration of livestock farming (pigs, cattle, poultry) exacerbates the issue. The region's temperate climate, combined with shallow, well-lit waters, creates ideal conditions for algae proliferation.

                           

• Environmental, Economic, and Health Impacts

Environmental      Impacts:        Green algae reduces marine biodiversity by consuming oxygen during decomposition, creating dead zones where marine life cannot survive.

Economic Impacts:       Algal blooms damage Brittany's tourism image, with degraded beaches leading to financial losses for local businesses. Additionally, local authorities bear the high costs of cleaning operations, which are estimated to exceed 1.5 million annually in some areas.

Health Impacts:        As algae decompose, they release hydrogen sulfide (HS), a toxic gas. Severe cases of intoxication, and even animal deaths, have been reported, raising increasing public health concerns.

Solutions Implemented and Their Results:

1. Agricultural Regulations: Reducing Nitrate Inputs

Since the 1990s, France has implemented several plans to reduce nitrate inputs into Brittany's rivers:

• The EU Nitrates Directive (1991): This directive imposes strict limits on the use of nitrogen-based fertilizers. Vulnerable zones in Brittany are subject to strict rules to prevent nitrate runoff into rivers.

• The Green Algae Action Plans (PLAV): Launched in 2010, these plans include specific measures such as reducing livestock density, creating vegetative buffer zones along rivers, and managing livestock effluents.

Results:      
According to a report by the Loire-Brittany Water Agency (2022), average nitrate concentrations in Brittany's rivers decreased by 20% between 2000 and 2020, dropping from around 50 mg/L to 40 mg/L in critical areas. However, these levels remain above the EU threshold of 25 mg/L needed to prevent eutrophication.

Limits:

• Farmers face high costs to adapt their practices, which slows compliance.

• The effects of these measures, while visible, remain insufficient to completely eradicate green algae blooms.

2. Collecting and Treating Green Algae

Every year, cleanup operations are conducted to collect green algae before they decompose. Local authorities, such as those in Saint-Brieuc Bay, use mechanical equipment to remove stranded algae.

Results:      
In 2021, approximately 50,000 tons of algae were collected along Brittany's coasts, according to the regional prefecture of Brittany. These collections help limit health hazards, but they are expensive, costing up to 1.5 million annually for some municipalities.

Limits:

• These operations address symptoms rather than root causes.

• Storage and treatment of collected algae remains challenging.

3. Farmer Awareness and Education

Campaigns have been launched to train farmers in more sustainable practices. For instances:

• Nitrogen Balances: Farmers are taught to calculate crop needs to limit unnecessary fertilizer use.

• Sustainable Agriculture Contracts (CADs): Funded by European aid, these contracts encourage crop rotation, organic farming, and the use of cover crops.

Results:      
Approximately 30% of Brittany's farms have adopted agroecological practices, according to a report by the Brittany Chamber of Agriculture (2020). These farms have reduced nitrate leaks by 15% to 30% while maintaining competitive yields.

Limits:

• The transition to sustainable practices is slow due to economic constraints.

• Small farms, often the most vulnerable, lack resources to invest in these changes.

4. Scientific Research and Algae Valorization

Research focuses on the potential valorization of green algae:

• Energy Production: Projects like Green Algae Energy, funded by the French ecological transition agency (ADEME), test transforming collected algae into biogas or organic fertilizers.

• Biomaterials: Other studies explore their use in biodegradable plastics.

Results:      
These initiatives remain experimental, but they could provide sustainable solutions to reduce treatment costs while creating economic opportunities.

Proposed Solutions in the ICZM Framework

ICZM encourages holistic, integrated solutions combining ecological, economic, and social dimensions. Potential improvements include:

1. Strengthening Agricultural Regulations with Economic Incentives

• Targeted Subsidies: Provide additional aid for farmers adopting zero-nitrate practices or transitioning to organic farming. According to an OECD report (2021), such subsidies could reduce nitrate inputs by an additional 30%.

• Ecological Taxation: Introduce taxes on excessive nitrogen fertilizer use to encourage rationalization.

2. Improving Integrated Watershed Management

• Watershed Committees: Establish local committees of farmers, scientists, and policymakers to develop tailored plans for each watershed.

• Ecosystem Restoration: Wetlands act as natural filters for nitrates. According to the IUCN (2022), wetland restoration in Europe has reduced diffuse pollution by 20% on average.

3. Developing Algae Valorization Industries

• Green Energy: Invest in local biogas plants to transform algae into energy. A pilot facility in Brittany produced 1 GWh of electricity in 2022, according to ADEME.

• Local Markets: Promote algae use in short supply chains, such as organic fertilizers for local farms.

4. Strengthening Public Awareness and Engagement

• Environmental Education: Organize school workshops on the impact of intensive farming on marine environments.

• Community Participation: Encourage citizen-led initiatives, such as beach cleanups or participatory audits to identify local pollution sources.

5. Investing in Research and Innovation

• Develop technologies to capture nitrates directly from rivers, such as biological filters.

• Support interdisciplinary projects to understand the interactions between farming practices, climate, and coastal ecosystems.

Conclusion

Green algae blooms in Brittany exemplify the challenges facing coastal areas, where human pressures on ecosystems demand coordinated, sustainable responses. Current solutions, while partially effective, demonstrate that ICZM is a vital lever for reconciling economic development and environmental conservation.

By strengthening regulations, valorizing collected resources, and mobilizing local actors through participatory governance, Brittany can transform this issue into an opportunity. With appropriate measures, the region could become a model of innovation and resilience for coastal areas facing similar challenges.