Baseline assessment of underwater noise in the Ria Formosa

Area of Science:

• Marine Biology
• Acoustics
• Environmental Science

Background:

• The Ria Formosa lagoon in Portugal is a protected natural park with rich biodiversity.
• Intense vessel traffic generates significant underwater noise, posing a threat to marine ecosystems.
• The Faro-Olhão Inlet is proposed for tidal stream turbine deployment, adding a new noise source.

Purpose of the Study:

• To establish baseline underwater noise levels in the Ria Formosa lagoon.
• To assess the impact of existing anthropogenic noise sources, primarily boat traffic.
• To inform future noise mitigation strategies for renewable energy developments.

Main Methods:

• Acoustic data collection during winter and summer 2017.
• Monitoring conducted over several days on each occasion.
• Analysis focused on sound levels, diurnal patterns, and seasonal variability.

Main Results:

• Boat traffic is a major contributor to underwater noise in the lagoon.
• A wide range of sound levels were recorded, indicating significant acoustic energy introduction.
• High diurnal and seasonal variability in noise levels were observed.

Conclusions:

• Baseline noise monitoring is crucial for understanding and managing anthropogenic impacts.
• Existing boat traffic noise levels provide a critical reference for future tidal energy noise assessments.
• Further research is needed to fully understand the ecological consequences of underwater noise in Ria Formosa.