Ocean sound refers to the collection of acoustic energy present in marine environments, encompassing a variety of sources, including sounds from marine animals, geophysical noise from waves, wind, rain, and human generated noise from shipping, sonar, and offshore construction. This collection of sound at a given place and time is often called a soundscape. Monitoring ocean soundscapes provides key insight to understanding ecosystem dynamics, detecting environmental changes, and managing the impacts of noise pollution on marine organisms. Learn more about ocean sounds at Discovery of Sound in the Sea.
Why do we care? Ocean sound is critical for the survival of many marine animals because it is a primary means of communication, orientation and navigation, finding food, avoiding predators, and choosing mates. As such, human activities that produce underwater sounds have the potential to negatively impact animals by reducing their ability to hear prey, predators, and each other. US National marine sanctuaries are home to many acoustically active marine animals and understanding the presence and impacts of noise is a conservation priority. Further, the occurrence and types of sounds present offer key insights on animal presence, species behaviors, human-use patterns, and changing ocean conditions
When, where, & why are we listening?
NOAA's Office of National Marine Sanctuaries (ONMS) maintains a nationally coordinated underwater sound monitoring network across the National Marine Sanctuary System, known as ONMS Sound. ONMS sound works with partners to monitor off the US East Coast, in the Gulf of Mexico, off the West Coast and in the Pacific Islands region. Ocean Sound monitoring sites are located in strategic locations within sanctuary boundaries and records continuously. Audio recordings and standardized sound measurements are available through the NOAA National Centers for Environmental Information's Passive Acoustic Archive. Explore the acoustic monitoring sites here.
The Stellwagen Bank National Marine Sanctuary is a wild ocean
place near an urban world, sits east of Boston, Massachusetts between Cape Ann and Cape Cod.
Historically important as a fishing ground, New England’s only national marine sanctuary now reigns as
a premier whale watching destination and continues to support commercial and recreational fishing.
Ocean sound monitoring within SBNMS has a long history of underwater acoustic monitoring with
a focus on monitoring of
marine mammal, including the endangered North Atlantic Right Whale presence. As well as
noise reduction during
vessel speed reduction programs.
Current ocean sound monitoring and analysis is maintained at four sites within SBNMS. Two sites
(SB01, SB02, SB03) are located more inshore, capturing more local vessel activity and sounds from nearshore
species. The one offshore sites (NRS09) capture patterns in migrating whales and transiting commercial vessel
traffic and is part of the
US Ocean Noise Reference Station Network.
Summary of ocean sound monitoring sites:
Site
Primary.monitoring.purpose
Oceanographic.Setting
Depth
Seasonality
Known.biological.sounds
Vessel.Traffic.Setting
Latitude
Longitude
TotalDays
StartDate
Information
SB01
To monitor a site that supports seasonally high abundances of Atlantic cod and is located near a region of elevated commercial vessel activity.
Continental shelf (<200m)
50 m
Seasonal winds and baleen whales presence
nan
near inbound TSS lane to Boston, within existing Off Race Point SMA slowing large traffic in March-April
Soundscapes are complex -- representing all the types of sounds present at a given time and location and influenced by the weather. How do we visualize this information? Let's start with the main contributions to a soundscape: the colored lines represent seasonal differences, vertical lines indicate different sound sources of interest and what frequency(s) represents the source, and the black lines bound the soundscape to expected range based on when only wind noise is present. We can track these different contributions over time to understand how soundscape are changing. We can also compare across locations.
What are the latest conditions in ocean sound?
Soundscapes are dynamic, changing with season and annual differences in sources (wind, biologics, and human-activity). Comparing annual ocean sound levels provides insights on trends in ocean noise: Are levels lower in the most recent year of monitoring? Efforts to reduce noise are underway on global to local scales though vessel speed reduction strategies and engineering solutions, and these efforts may be be reflected in the annual data. Typically, a more focused analysis is necessary to tease apart the multiple drivers of ocean sound levels.
How often is ship noise above threshold?
In many nearshore marine environments, vessels are transiting the region for a variety of reasons and adding noise to the soundscape. Using 100 Hz as an indicator of vessel noise, we measured how often vessel noise is above sound levels at the known wind conditions. This method helps to control for the influence of wind on a soundscape. Specifically, when wind is high, vessel noise exceedance will be lower, compared to lower wind speed conditions.
How much noise do nearby ships contribute to the soundscape?
Sound levels increase when ships are transiting nearby a monitoring locations because of noise produced by the ship. Ocean sound data can be segmented into time periods when a ship is transiting nearby to understand how much noise is added when a ship is nearby. Ships are considered nearby if transiting within 10 km of the monitoring location. In some cases, multiple ships are transiting nearby to further segment the ocean sound data into categories of high, medium, low vessel presence. Nearby ship presence is tracked using Automatic Identification System (AIS) data which most ships are required to transmit.
How much noise do nearby ships contribute to the soundscape?
Sound levels increase when ships are transiting nearby a monitoring locations because of noise produced by the ship. Ocean sound data can be segmented into time periods when a ship is transiting nearby to understand how much noise is added when a ship is nearby. Ships are considered nearby if transiting within 10 km of the monitoring location. In some cases, multiple ships are transiting nearby to further segment the ocean sound data into categories of high, medium, low vessel presence. Nearby ship presence is tracked using Automatic Identification System (AIS) data which most ships are required to transmit.
What are we learning?
We continue to discover even more from these ONMS ocean sound data. Collaborative partnerships help us gain key insights on sanctuary resources and conditions from ocean sound data by leveraging ecological and technological expertise.
