Spatial and temporal variability of the soundscape in a Southwestern Atlantic coastal lagoon

Coastal lagoons are valuable sources of ecosystem services and important for regional development plans. Human pressure threats these areas, so increasing knowledge about coastal lagoons is essential to enhance their protection. Here we investigated the temporal and spatial patterns of the soundscape in the Mar Chiquita coastal lagoon (Buenos Aires, Argentina), the unique coastal lagoon of Argentina. The study was conducted during May-June and November months. Four recorders were deployed along the lagoon and one was located close to invasive polychaete aggregates to investigate their effects on the soundscape. The analysis of acoustic energy revealed a strong circadian rhythm involving the lagoon and a spatial differentiation driven by low frequency (< 100 Hz) noise. The biophonic component of the soundscape was dominated by black drum and crustaceans sounds with higher activity during November and in the mouth of the lagoon. This area was also the most affected by human noise. The polychaete aggregates determined changes on the biophonical and geophonical components of the soundscape. This study highlights the importance of soundscape analysis to assess ecosystem changes along space and time, particularly in coastal lagoons systems, where their dynamic and high productivity make them key ecosystems.