Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Beginning in June of 2014, a short-term effort was initiated to record ambient underwater sound at high temporal resolution, within the Middle Marsh portion of the Rachel Carson Estuarine Research Reserve. This was accomplished using a low-power SoundTrap recorder and hydrophone (Ocean Instruments New Zealand).

The instrument was strapped vertically to a metal post and positioned ~0.15m above the seafloor, and in water of sufficient depth so that it remained submerged during spring low tides. At low tide, the SoundTraps were submerged at least 0.15 m, and at high tide, the SoundTraps were submerged in approximately 1 m of water, depending on the magnitude of the tide.

Three individual deployments were carried out using eight SoundTraps between 12 June 2014 and 31 August 2014. Deployment start and end dates for each site are listed in Table 1. The instrument was programmed to record for 130 seconds every 20 minutes at a 96 kHz sample rate. The SoundTrap analog signal is digitized at a fixed rate of 288 kHz. A digital anti-alias filter, with a cutoff frequency of 0.45 times the desired sample rate, is then applied before decimation. Consequently, at our sample rate of 96 kHz, the useable (-3 dB) bandwidth of these recordings is 0.020-43.0 kHz. In total, 36,870 separate 2-minute recordings were made as part of this monitoring initiative.

The data may be read into MATLAB using functions included in MATLAB.

Example:
% Set calibration
cal=10^(STcalibration/20);

[y,fs]=audioread(‘filename.wav’); %read in audiofile
y=y(fs*5:end) %remove first 5 seconds that have calibration sound
y=(y-mean(y))*cal; %demeaned and response correct to uPa

Additional information about this dataset can be found in Ricci et al (2016 and 2017).

No processing. These are the raw data files in .wav format.

BCO-DMO Processing:

- added conventional header with dataset name, PI name, version date
- created flat file with submitted metadata including lat and lon, date/time, recording parameters, and links to download the data files.
- converted datetimes to ISO_TimeDate_Local_start and _end

The overall goal of this study is to advance our general understanding of the role of underwater sound in biological oceanography by characterizing spatiotemporal variation in an estuarine soundscape, and determine if this variation affects the settlement of larval invertebrates. The investigators will use larval bivalves and subtidal oyster reefs in Pamlico Sound, North Carolina as a study system. A combination of field and laboratory experiments will be used to test the effects of sound on larval behaviors and settlement. The underwater sonic environment has the potential to provide meaningful sensory information to all aquatic animals. Acoustic signals are transmitted relatively large distances, are present at all depths, and reflect biological and physical characteristics of the environment, while other cues (e.g. light, chemicals) are rapidly attenuated from the source. Sound is well established as an orientation and habitat selection cue for marine mammals and fishes, and has recently emerged as a potentially important contributor to larval settlement. Building capacity (knowledge, expertise, equipment) for integrating geophysical aspects of underwater sound propagation with ecological and oceanographic processes is central to bio-physical studies of larval connectivity and recruitment in marine systems. It also informs our understanding of the potential adverse effects of noise pollution in the ocean and may elucidate untested benefits of marine reserves - ultimately leading to healthier and better managed oceans and estuaries. The project supports graduate, postdoctoral and undergraduate student training, as well as educational outreach programs that span local, regional and national levels