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.