Acoustic Research in Cordell Bank
A mooring containing a hydrophone was deployed in the sanctuary in October 2015.
My name is Danielle Lipski, I'm the Research Coordinator at Cordell Bank National Marine Sanctuary. We're here on NOAA's research vessel, Fulmar, to deploy an acoustic mooring out at Cordell Bank. Our goal is to record ambient sound in the ocean for two years. And with this information we'll be able to create a soundscape of the sanctuary which gives us information about what types of sounds and how loud the sounds are in the ocean.
This mooring is going to be listening to low frequency sounds, so it will give us sounds like noise from commercial ships, and from large whales that vocalize. This project is a collaboration with NOAA's Pacific Marine Environmental Lab and Cordell Bank National Marine Sanctuary. And the Lab at PMEL, our experts in bioacoustics have built the instruments and we're deploying them here in Cordell Bank National Marine Sanctuary today. The mooring is made up of several components.
At the top of the mooring is a large buoy that is made of hard syntactic foam. And then there is a length of line. Below that is the hydrophone itself which is the instrument that records sound in the water. Then there's some more line. Down near the bottom of the mooring there is an acoustic release. And then some other line and chain and below that is a very heavy anchor that weights it to the bottom. The mooring is heavy and sturdy, it remains in the ocean for two years and records all that data to a hard drive.
At the end of two years we'll come back and we'll use a transponder to send a signal to the acoustic release which then releases the entire mooring, except for the anchor, to the surface, so that we'll be able to recover it.
We're concerned about noise in the ocean because the oceans have gotten noisier, much noisier, within the past several decades, and it's largely due to commercial shipping. Animals in the ocean use sound to communicate, to forage, to communicate with members of their species for reproductive behavior and things of that nature. So when the ocean is very noisy it can interfere with the animal's behavior and ultimately perhaps their health and condition. So our goal is to understand what types of noise are in the ocean, both noise from humans such as shipping – other types of noise that are in the ocean include military activities, construction activities, seismic activities, and even wind and weather.
So, we'll be recoding all of these sounds, as well as sounds from animals that are vocalizing. And with that information we hope to understand how these animals might be affected, what types of noise they're experiencing in the ocean, and how much of that noise they're experiencing to understand how that could be affecting their habitat. This project is part of NOAA's effort to establish an ocean noise reference station network. So, PMEL as well as NOAA Fisheries and the Office of National Marine Sanctuaries have been engaged in an effort to deploy a series of buoys around the country to understand types and amount of noise in different locations. So, all of these buoys are made the same way and calibrated so that the recordings can be compared to each other and also compared over time to see if the oceans are getting noisier.
This project is made possible partially from a grant from the International Fund for Animal Welfare which has been supportive of our effort to understand and protect whales in sanctuaries and has helped us with the funds to acquire the equipment to deploy this mooring. As well as the partnership and collaboration between both PMEL and Cordell Bank National Marine Sanctuary.