Every human endeavour in the ocean generates some amount of noise and the environmental impact of noise on marine life can only be investigated thoroughly if noise levels are known. Today, however, little is known about the ambient ocean noise, its spatial variability and the impact of anthropogenic noise pollution. Studying recordings of existing ocean bottom seismometer (OBS) deployments or arrays will nurture our understanding of ocean noise. Natural sources are forced by ocean waves, wind, lightning, ice noise, earthquakes, and submarine volcanic activity. Marine seismologists have collected over the years a unique dataset of hydro-acoustic data. Using the availability and the global distribution of data from all oceans, we will investigate records covering the frequency range ~0.01 Hz – 100 Hz, where anthropogenic changes are most prominent. Measurements suggest that since the 1960ies, anthropogenic and hence artificial sound in the ocean has risen by over 40 dB. While most natural sources are generally reasonably short-lived (e.g. earthquakes, submarine landslides), anthropogenic noise such as shipping activities produce continuously sound at low frequencies, reverberating through the oceans. We will compare levels of anthropogenic noise to natural sources, such as from submarine landslides. We need to learn more about the ocean-wide noise distribution and how it changes with water depth, season, weather conditions or locations.
To date, we know little about the noise level and soundscape in the ocean or at major seaways. By harvesting existing data sources, we will gain insights into the ambient noise and the impact of anthropogenic sources on the noise field. This information will have fundamental consequences on the assessment of noise and acoustic pollution in the oceans.
Keywords: ocean noise, anthropogenic noise pollution, submarine landslides, soundscape, marine life.
Host institute: GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany
Supervisors: Heidrun Kopp, Ingo Grevemeyer, Dietrich Lange (GEOMAR, Germany)
Co-supervisor: Reginald Hermanns (NTNU Norway)
Collaborations: Collaborations are expected with the NTNU (Norway) on rockslide monitoring and with WSL (Switzerland) on landslide processes.