SCIENCE

Why listen to anything?

Well, the sounds of nature are a treat! Bird song, water, insects, wind, dogs, cats, even humans. These are all beautiful things to get into your ears, and can tell us something about nature, the workings of the natural world. Also, you don’t know what you’re going to hear…

Ecoacoustics is a scientific venture that uses environmental sounds to study specific habitats. Ponds are a great example of this. The apparent calm peacefulness of a pond is shattered, in a nice way, when you put a microphone through its filmy boundary. The sounds heard can come from loads of sources: animals living in the pond (biophony); the ground, water movement and weather (geophony); and the humble human (anthrophony). They can be a massive surprise and not for everyone…

The ocularcentric ways of the humble human mean sounds are often unnoticed or given less importance in general when just getting about. But it turns out they provide a huge part of the landscape.

These sounds have been used as a way of understanding how healthy and diverse soil and ponds are. When there are lots of different kinds of sounds these habitats are thought to be healthier. The more things that live in there generally being considered a good thing!

The excellent researcher, and luckily our scientific collaborator, Jack Greenhalgh has used ecoacoustics to show that pond restoration leads to richness and abundance of sounds, making these sounds a potential marker for monitoring how well things are doing. Using sounds can be less invasive than other measures, meaning less damage to the habitat being studied.

The diel (daily) soundscape

The daily rhythm of sounds shows a pattern in ponds, with louder sounds really early in the morning, around 4am, and also at lunch time. In soil they tend to get louder as the day goes on and quieten down at night.

Plants and sounds

The roots of plants use moisture levels to hone in on a water source in the soil, but they have to get close enough to the water source first. To get to the right location they use the sound (vibrations) of water, which is ridiculous. The movement of water creates specific vibrations in the soil which are picked up by the roots and they head towards it. Plants are also thought to use vibrations to detect an attack by herbivores.

Sounds as a marketing tool

Scientists have started to use the sounds of nature to create more diverse habitats. By playing the sound of a healthy environment in struggling coral reefs oysters and fish were found to return to and stay in the area. This increases the health of the whole habitat.

Fungi live under the ground, and some are really good at helping other plants to grow, like the plant growth-promoting fungus Trichoderma harzianum Rifai. People have found that playing it a specific sound increases the rate of growth of the fungi and it produces more spores (like baby fungi) as well. These fungi are great at helping some types of plants that we eat grow, so it’s useful for the fungus and us.