![]() So we make sounds on purpose, and those sounds also can lead to a rising level of background noise. People have used sound to communicate underwater between different ships, we also bounce sounds off of the crust of the earth to get a better understanding of what's below including oil and gas deposits. ![]() That sound has a deep, low frequency – those lower tones below what humans hear well – that low tone made by all those ships moving all that stuff around, its leading to a rise in noise level. Those ships have propellers, when they spin produce bubbles, and when the bubbles burst (they) make an acoustic signature – they make a sound. Sometimes that sound is a bi-product of things that we are actually doing – we're moving all of the world's goods on large commercial ships, and that maritime traffic which is how we transport over 98% of the world's goods around the globe, we do that almost entirely on ships. People also do a great many things offshore, and many of them make sound. They listen for their predators, and they listen to each other. Those are all very predictable places for animals to find food, and they have an acoustic echo. They listen for food and the sounds made by their prey as it moves through the water, they listen to the echoes of environmental sounds – winds and waves – and the sounds they make against topographic features (underwater/undersea mountains) – which tells them about areas where fish may school, or where algae and zooplankton may cluster in upwelling. And beyond using sounds to talk to one another, animals hear – and marine animals have particularly evolved to use their hearing in a great diversity of ways. A wide variety of marine animals make sounds to communicate to one another. LEILA HATCH: Sound is an incredibly effective way for marine animals to communicate. I asked Leila to tell us a little bit about how the ocean noise produced by human activities affects marine animals. She's also the co-lead of the NOAA Ocean Noise Strategy. Her work focuses on acoustically-sensitive marine species and the impacts of underwater noise in the sanctuary, and she provides support on noise science and policy for other sanctuary sites. Leila Hatch - a marine ecologist based at the Stellwagen Bank National Marine Sanctuary in Massachusetts. To learn more about this issue, I spoke with Dr. NOAA and the Office of National Marine Sanctuaries are approaching this issue by aiming to reduce negative physical and behavioral impacts to species, as well as conserve the acoustic quality of their habitats. Rising noise levels can negatively impact ocean animals and ecosystems in complex ways, reducing an animal's ability to communicate and to hear environmental cues that are vital for survival. Noise from this activity travels long distances underwater, leading to increases and changes in ocean noise levels. In just the last 100 years, human activity has increased along the coasts, further offshore, and in deep ocean environments. Sound is a fundamental component of ocean life that many marine animals and ecosystems have relied on for millions of years. I'm Megan Forbes and today we'll be talking about Ocean Noise… when you think of the ocean, you might imagine a vast underwater world filled with strange and wondrous sights & creatures… but do you think about sound? It is a big part of marine life, as sound travels faster underwater and can be heard farther across the miles than above the surface, even by the human ear. HOST: Welcome to Making Waves – a podcast from the NOAA National Ocean Service.
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