The Sound of Science: towards robust monitoring of the optic and acoustic environments

There is a companion article at TopOc which takes a more detailed look at the science of environmental sound and light

If you look up at the sky, and it seems to glow orange and drown out the stars, you're looking at light pollution.


This is a satellite composite map, showing the light released by humans, color coded by activity. Urbanization in particular has brightened the surface of the Earth over the last century or so. Light has lways been our friend, so it may sound odd to speak of it as a pollutant, but remember: pollutants are things that jam the workings of an ecosystem. And light is an important environmental regulator. A recent review highlights 'well known', 'catastrophic consequences' of light pollution:

"the deaths of migratory birds around tall lighted structures, and those of hatchling sea turtles disoriented by lights on their natal beaches. The more subtle influences of artificial night lighting on the behavior and community ecology of species are less well recognized, and constitute a new focus for research in ecology and a pressing conservation challenge."

If you've dealt with a headache while Atlanta traffic squonked outside, you know what a nuisance urban noise pollution can be. It's also a recognized occupational hazard. Moreover, the impact of human sounds on the environment are just now being recognized: robins and frogs are shifting their calls to communicate around or through traffic noise, and songbirds have begun to rebroadcast human sounds, chirping in ringtones.

Considering the scale and significance of human influence on the sonic and optic environments, there is a great deal we could learn from widespread ecological monitoring of sound and light. The review cited earlier reccomends: "measurements of light disturbance should be included routinely as part of enviromental monitoring protocols". Monitoring of sonic ecology has thusfar been fairly transient and concentrated on localized and/or urban settings (eg, here and here)

At ArkFab, we've been thinking about how to develop and deploy an inexpensive infrastructure to monitor these environmental variables. The proposed system would involve a number of sensors placed in a wide variety of settings (urban, suburban, rural, etc) in geographically diverse regions. The sensors would consist of a small microphone and photodetector (and perhaps other inexpensive detectors, such as a thermometer for temperature measurements) in a weatherproof housing. Data would be stored, via a microcontroller circuit board, on USB sticks for easy retrieval and large data storage. The familiarity and small size and cost of a USB stick would mean that the disk drive could be easily replaced when full and mailed through the post office to a central site for data retrieval and processing. These low-power units would also be equipped with a solar panel for longer battery life.

Retrieving information from a geographically dispersed sensor array will require a nonlocal approach, and citizen science seems to be the best solution. Citizen science is the involvement of people outside of the mainstream scientific community in participatory research. A canonical example is that of SETI@Home, a distributed computing project which used spare computational power (ie, screensaver time) to analyze radiotelescope data. The success of the SETI@Home project has led to an explosion of distributed computation projects, such as running malaria and climate predictions, protein folding and artificial intelligence simulations, and numerical explorations of famous unsolved mathematical problems. Protein folding further involved citizen science with the success of FoldIt, a puzzle game in which players add the finishing touches to protein-folding simulations (the last few steps are apparently more economical to do with a human brain than with a computer.) Citizen science has also been successfully used to monitor populations of insects, mammals, plants, and birds. In fact, this sort of distributed measurement philosophy has been explored, implemented, and advocated in studying urban noise pollution:

"...involvement of citizens is key. [...] In geography and urban planning there is a trend towards support for such participation. Under the flag of participatory GIS and participatory mapping new methodologies are being researched to better support the participation and involvement of citizens in projects that are typically tackled using geographical information systems (GIS), such as the mapping of spatial phenomena or land use and urban planning."

Interested volunteers and science hobbyists already keep home weather stations; this enthusiasm could be tapped for sound and light monitoring. Indeed, there already exists a program which uses volunteers' cell phones to record data about urban sound levels. Another group of potential citizen scientists are schoolchildren- the sensors could be given to schools as low cost educational kits, and possibly even designed to be assembled at the schools themselves, providing education in electronics and computer science as well as in ecology. There is already a strong precedent of student participation in citizen science. Remote areas are could be monitored by hikers and sight-seers, who often have an interest in the condition of the natural areas they visit. One place to start might be the Appalachian Trail, which is seasonally visited by hikers with a pre-established community which could be tapped into. Indeed, this community participates in monitoring mammal populations; participant and David Helms, participant and Natural Bridge Appalachian Trail Club president remarks:

"The Appalachian Trail was built and is still maintained by volunteers. Using volunteers is the way the world works on the trail."