The Marine Environment The marine environment is full of noise. Some of the noise is natural. Some of the noise is man made. Can you think of any noises you might hear?

Sound and Water Sound can travel 5 times faster in water than air. Sound can travel great distances underwater. A whale’s song can travel up to 3,000 km. Sound can be bounced off objects underwater (an echo).

Marine Mammals have developed their hearing for many reasons Hunting Navigation Communication …they depend on sound to sense the ocean around them, find food and travel. Image Source – wikimedia commons http://commons.wikimedia.org/wiki/File:Sperm_whale_and_squid.JPG I, the copyright holder of this work, release this work into the public domain. This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

Dolphins and Echolocation Some animals use echolocation to determine the distance from objects including food and predators. Dolphins use sonar clicks. Clicks bounce back when they contact an object (echo). If the object is close the sound returns fast. If the object is far away it will take longer to return.

A dolphin can detect a golf ball sized object which is placed over a football field away. A dolphin’s sense of hearing is much more developed than it’s sense of sight. Why do you think that is? Image Source – Golf ball – Author – Paolo Neo. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Communication Marine animals use sound to communicate. As sound travels well in water, some animals can communicate over great distances. - Blue whales can hear each other up to 1,000 miles apart. Image Source – Blue Whale – Author: Mike Baird. This file is licensed under the Creative Commons Attribution 2.0 Generic license. http://commons.wikimedia.org/wiki/File:Blue_whale_tail.JPG.

Where do sounds come from? Man made examples: Wind farms Ships Drilling Sonar Natural examples: Waves and rocks Wind Marine mammals Birds Image: Ashley Dace Image Sources - Offshore Wind Image: Author - Ashley Dace. This work is licensed under the Creative Commons Attribution-Share Alike 2.0 Generic Licence. To view a copy of this licence, visit http://creativecommons.org/licenses/by-sa/2.0/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA. Super Tanker – http://commons.wikimedia.org/wiki/File:Supertanker_AbQaiq.jpg. This file is a work of a sailor or employee of the U.S. Navy, taken or made during the course of the person's official duties. As a work of the U.S. federal government, the image is in the public domain. Fin Whale - http://commons.wikimedia.org/wiki/File:Fin_whale_from_air.jpg. This image is in the public domain because it contains materials that originally came from the U.S. National Oceanic and Atmospheric Administration, taken or made during the course of an employee's official duties.

Noises from Wind Farms Construction: Hydraulic hammers Offshore pilling Operation Ships that service the wind farms. Image: Thom Gordon Image source – Monopile – Author - Thom Gordon. Boat - This image was taken from the Geograph project collection. See this photograph's page on the Geograph website for the photographer's contact details. The copyright on this image is owned by gary faux and is licensed for reuse under the Creative Commons Attribution-ShareAlike 2.0 license. Image: Gary Faux Image: Gary Faux

Impacts of noise on marine mammals Unnatural background noise can interfere with the sense of hearing of marine mammals. This can make it harder for them to hunt, navigate and communicate. This is called masking.

Different frequencies have different effects… Noise trauma - damages hearing and long exposure can cause permanent loss of hearing. Mammals may avoid noisy areas. This can be a problem if these are important feeding or breeding grounds.

Reducing Damage The offshore wind industry can try to reduce the damage caused by noise pollution in the sea: Drilling monopiles instead of hammering them Slow start pile driving Using floating turbines or other alternatives to monopiles Using sound barriers such as air bubbles and foam wrapping Using pingers to scare off mammals.

What have we learned? Sound travels very well in water. Marine mammals have an excellent sense of hearing and use sounds for many things. Background noise and noise pollution affect the hearing of marine mammals. A lot of this noise can come from human activities including wind farms. It is possible to reduce human noise pollution in the sea.

Life around the turbines is funded by COWRIE (Collaborative Offshore Wind Research Into the Environment). Workshop materials are available for hire or can be delivered in schools by MBA experts. Please contact Jack Sewell at the Marine Biological Association for more information: Email: jase@mba.ac.uk Tel: 01752 633336