June 2025 | Oceanography
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INTRODUCTION
Events such as fish stock collapse, coastal flooding during severe
storms, and major oil and other toxic spills, along with the
need for the conservation of protected and endangered species
including many marine mammals, are making ocean users and
the broader public increasingly aware of the need for responsible
marine stewardship. Interest in responsible planning and man
agement of ocean resources has sparked international research
programs that are measuring baseline conditions that can be
used to assess current effects and future variations, trends, and
impacts. Through the National Oceanographic Partnership
Program (NOPP), the Bureau of Ocean Energy Management
(BOEM), Office of Naval Research (ONR), and National
Oceanic and Atmospheric Administration (NOAA) contracted
a team led by the University of New Hampshire to develop and
deploy the Atlantic Deepwater Ecosystem Observatory Network
(ADEON), whose objective was to improve the understand
ing of marine soundscapes and their relation to the ecosystem
of the US Atlantic deep waters. Marine ecosystem monitoring
supports the mandates of multiple federal agencies that seek to
understand and mitigate human impacts on the offshore envi
ronment. Long-term observations of living marine resources
and marine sound inform compliance with the US Endangered
Species Act, the Marine Mammal Protection Act, and the
Sustainable Fisheries Act, while physicochemical measurements
of water and air quality help inform agency compliance with the
Clean Water and Clean Air Acts.
Although there has been extensive hydrographic research
along the South Atlantic OCS (e.g., Lee et al., 1991; Atkinson
et al., 1983; Lee and Atkinson, 1983), knowledge of the ocean
soundscape and its relationship to regional OCS dynamics is rel
atively unexplored. Ocean sound is now an accepted Essential
Ocean Variable in the Global Ocean Observing System (Tyack
et al., 2023) due to its wide utility as an indicator of physical and
biological ocean processes. Sound travels efficiently underwater,
making it the dominant modality that marine life and humans
alike use to sense and respond to the changing environment;
information provided by underwater acoustic methodologies
has become critical to applications spanning national secu
rity, adaptive management of marine resources, monitoring of
climate change, tsunami warning, and search and rescue (Howe
et al., 2019). Thus, understanding the unique and complex rela
tionship between ocean sound and the environment at regional
scales is vital to assessing any projected impact of immediate or
forecasted change related to climate or human use.
A full contextual description of the relationship between
marine organisms and their environments, including acous
tics, is lacking (Hawkins and Popper, 2017). The effects of expo
sure of marine organisms to intense sounds is becoming bet
ter understood; however, the long-term cumulative effects from
noise-generating sources, including seismic surveys, offshore
wind energy, military and shipping vessels, and recreational
boating, is not well understood. Hence, there is a critical need
to work toward comprehensive knowledge of the interactions
between marine life and the ocean soundscape, defined as the
auditory scene in a region resulting from biologic (marine life),
geologic (non-biological natural sound such as wind, precipi
tation, and ice), and anthropogenic (human activity) contribu
tions to the soundscape, characterized by the ambient sound
in terms of its spatial, temporal, and frequency attributes, and
the types of sound sources (ISO 18405, 2017). ADEON was
designed to synoptically record ocean sound and ecosystem
indicators of biomass, conductivity, temperature, and dissolved
oxygen (CT-DO). Measurements from stationary, mobile, and
space-based platforms (Figure 1a) were combined to provide
context for understanding and modeling how environmental
variability manifests in the regional soundscape.
ADEON was structured into four major technical
phases: (1) Network Design, Equipment Procurement, and
Deployment; (2) Data Acquisition and Network Maintenance;
(3) Data Processing, and (4) Data Integration and Visualization.
During the proposal development stage, the ADEON team
recognized a lack of community-wide standardization for
ocean soundscape data and data products. Thus, standardiza
tion was an overarching effort elevated above the four techni
cal phases that generated products for soundscape terminol
ogy, data acquisition, processing, and reporting. In fulfillment
of the NOPP requirement to make all data and products pub
licly available, all raw data are publicly available through the
NOAA National Centers for Environmental Information
ABSTRACT. The Atlantic Deepwater Ecosystem Observatory Network (ADEON) along the US Mid- and South Atlantic Outer
Continental Shelf (OCS) collected multiple years of measurements that describe the ecology and soundscape of the OCS. Ocean pro
cesses, marine life dynamics, and human use of the ocean are each three dimensional and time dependent, and occur at many spatial
and temporal scales. Because no single measurement system (in situ or remote) is sufficient for describing dynamic ocean variables,
the approach taken by ADEON was to integrate ocean measurements and models. Acoustic information was combined with contex
tual data from space-based remote sensing, hydrographic sensors, and mobile platforms in order to fully comprehend how human,
biologic, and natural abiotic components create the OCS soundscape and influence its ecosystem dynamics. Standardized methodol
ogies were developed for comparing soundscapes across regions and for generating predictive models of the soundscape and overall
ecology of the OCS at 200–900 m water depths. These data provide a baseline for pattern and trend analyses of ambient sound and
the ecosystem components of the OCS soundscapes. They contribute to understanding of regional processes over multi-year time
scales and support ecosystem-based management of marine resources in an acoustically under-sampled ocean region.