Ocean Noise: The Human Footprint on Underwater Soundscapes

The growing human footprint on coastal and open-ocean biogeochemistry.

Climate change, rising atmospheric carbon dioxide, excess nutrient inputs, and pollution in its many forms are fundamentally altering the chemistry of the ocean, often on a global scale and, in some cases, at rates greatly exceeding those in the historical and recent geological record. Major observed trends include a shift in the acid-base chemistry of seawater, reduced subsurface oxygen both i...

Ocean Variability Effects on Underwater Acoustic Communications

Several studies have been conducted in recent years that show correlation between high frequency acoustic fluctuations and environmental parameters. For example, effects of tidally driven temperature fluctuations on underwater coherent acoustic communications were studied for a carrier frequency of 18 kHz [1]. However, the relationship between environmental fluctuations and the performance of c...

Visualizing Underwater Ocean Optics

Simulating the in-water ocean light field is a daunting task. Ocean waters are one of the richest participating media, where light interacts not only with water molecules, but with suspended particles and organic matter as well. The concentration of each constituent greatly affects these interactions, resulting in very different hues. Inelastic scattering events such as fluorescence or Raman sc...

Underwater radiated noise levels of a research icebreaker in the central Arctic Ocean.

U.S. Coast Guard Cutter Healy's underwater radiated noise signature was characterized in the central Arctic Ocean during different types of ice-breaking operations. Propulsion modes included transit in variable ice cover, breaking heavy ice with backing-and-ramming maneuvers, and dynamic positioning with the bow thruster in operation. Compared to open-water transit, Healy's noise signature incr...

Underwater Ambient Noise