Light Pollution Is Probably Messing With Ocean Life

Illustration for article titled Light Pollution Is Probably Messing With Ocean Life

The bright lights of cities have a clear and well-documented effect on urban wildlife. Less clear, though, is if lights from ports, ships, and offshore oil rigs affect marine creatures underwater. A recent study off the coast of Wales says yup, it’s probably happening.


Ocean water is full of tiny larvae from a diverse set of sea creatures. And light is an important cue for guiding where the larvae settle to become adult sea squirts, worms, and sea bristles. In a study published in Biology Letters, scientists left 36 plastic panels in the ocean and exposed to them no light or streetlight-level illumination. Here’s what happened, explains Science:

The artificial lights reduced colonization of the panels by the sea squirt, Botrylloides leachi, and the sea bristle, Plumaluria setacea, filter feeders that dine on nutrients and plankton from the water column and keep coastal ecosystems healthy...But the marine worm Spirobranchus lamarcki was much more abundant on artificially lit panels than on control panels. Overall, the study found that the lights either encouraged or discouraged settlement in 39% of the taxa, or groups of species, living on the panels by the end of the experiment period.

This initial small study hints at something larger: Artificial light is probably not a bad thing for every animal. It may harm some creatures, and it may help others. In any case, it likely disrupts the ecosystem that would naturally emerge without it. And that is a complicated tale we’re only just beginning to understand.

[Biology Letters via Science]

Top image: Dudarev Mikhail/shutterstock

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I read an article a few years ago about how sound pollution was affecting songbirds, basically making them shift to singing at nighttime when the city is much quieter, instead of during the day. At the time I thought it was BS. But that was after almost all commercial construction had stopped in the center city area where I live back in 2008. I was not hearing songbirds at night. Over the last 2 years, construction has picked up full steam, with 16 cranes being installed over the last 18 months, and sure enough, there are songbirds singing like crazy at night now. There are birds I have never heard at night in my entire life. I grew up in the country, and literally would sleep outside nearly the entire summer and fall, so I am well aware of what birds should sing at night (which is very few around here). It is amazing that we can have such an impact on animals with such simple things like light and noise. We are changing behaviors that have been around since before our species evolved. When you realize it is happening around you at this very moment, it can be a bit shocking. Of course, most people never even notice, or if they do, they fail to see the importance of it. My wife did complain about the birds making so much noise at night in the tree outside of our 4th floor balcony this spring, but her eyes glazed over when I tried to explain the significance of it.