What is geophony? Definition and examples

What is geophony? Definition and examples

what geophony means: non-biological ambient sounds generated by the natural world – for example, the sounds of wind, rain, thunder, and waves.

The term was originated by musician and soundscape ecologist Bernie Krause, and was constructed from the Greek “geo” (earth-related), and “phon” (sound). Geophony is seen by Krause as one of three categories of sound which make up the soundscapes – acoustic environments – perceived by humans. The other types are anthropophony and biophony

Geophony is caused by geophysical sounds which vary both daily and seasonally, and may be influenced by factors including climate, elevation, and topography. It can be divided into three sub-categories:

  • Continuous geophony: long-term sounds, such as from rivers or breaking waves
  • Ephemeral geophony: for example, wind, rainfall, and seasonal streams
  • Abrupt geophony: sudden and short-lived sounds like thunder, volcanic eruptions, and landslides.

A study intended to establish whether geophony interferes with animal communication, which took place in California’s Sequoia National Park, did show that animals communicate at different frequencies in different habitats in order to avoid competing with geophonic sounds. This adaptability may come to be beneficial to animal life in locations such as the Arctic, where ambient noise is likely to be steeply increased by geophonic (and anthropophonic) noise due to the climate change-driven acceleration of sea-ice melt. Such observations may allow the development of methods for mitigating such dramatic changes to soundscapes.

However, despite considerable evidence of the negative effects caused to animal communication and behavior by technological anthropophony (technophony), geophonies “are frequently dismissed or mischaracterized in acoustic studies as an outside factor of acoustic habitats rather than an integrated sonic component of ecological processes and species adaptations” (Farina et al., 2021). Similarly, as recently as 2021, geophonies’ relevance to soundscape ecology was still being portrayed as being ambiguous, with geophony also being contradictorily portrayed in both positive and negative ways: as “natural quiet”, but also as “environmental noise”.

In the present day, in all kinds of environments, the combination of the geophonies, biophonies, and anthropophonies which are present create unique ‘sonic signatures’. It is against this signature that soniferous organisms must compete, vocalizing on particular wavelengths – acoustic niches – which are not occupied by this background soundscape. Given that technological noise is producing tangible effects after less than 300 years, it stands to reason that sonic signatures – which have been present for billions of years – would have had fundamental and significant effects on the development of sound-producing (soniferous) organisms.

Verifiable contemporary effects of geophony on animal species include:

  • Juvenile reed frogs (Hyperolius nitidulus) fleeing recorded sounds of fire during aestivation (dormancy during a hot and/or dry period), in order to seek safety under protective cover 
  • Rock-kipper frogs (Staurois latopalmatus) giving higher frequency calls and possessing smaller bodies in the presence of geophony from waterfalls, compared to those in quieter habitats
  • The development of ultrasonic calls by concave-eared frogs (Odorrana tormota) in response to the sonic environment of their habitat, and of appropriately specialized ear structures in order to be able to hear them. 

These examples suggest the large part that geophony must have played historically in animals’ communication, physiology, adaptation, and evolution, and on their both instinctive and conscious criteria for the selection of habitats. As anthropogenic climate change affects the natural world, it is probable that geophonies are altering temporally and spatially, and therefore impacting animal communities and their distribution. This likelihood emphasizes geophony’s significance in the field of soundscape ecology, and its role in ecological processes more broadly.

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