Harbor lights can adversely affect marine life

Chuck Bednar for redOrbit.com – @BednarChuck

The artificial lights used in harbors during the nighttime is changing the behavior of animals that attach themselves to the hulls of sailing vessels, causing some creatures to be lured and others to be scared off by the illumination, according to a new study.

In research published Wednesday in the journal Biology Letters, University of Exeter ecologist Dr. Thomas Davies explained that the artificial lighting is attracting types of marine life that could damage ships and boats, and that light pollution from coastal development and other sources could be altering the composition of marine epifaunal communities.

“The presence of lighting at night can change the composition of these marine communities,” Dr. Davies told BBC News. “There is also what we call an ‘ecosystem disservice’. The presence of artificial lighting might actually increase ‘fouling’ species that can damage boats.”

Measuring the impact of light pollution

According to the British news agency, researchers have estimated that nearly 25 percent of the world’s coastal regions (not including Antarctica) are subject to some form of artificial lighting at night. Harbors, marinas, fisheries, and oil rigs all contribute to this phenomenon.

In order to measure the impact of this synthetic glow, Dr. Davies and his colleagues looked at a group of small creatures that live in sediment or attach to hard surfaces. These creatures, known as sessile creatures, include mussels, barnacles, sponges, and sea squirts, BBC News explained.

During the larval stage of their life cycles, sessile creatures use light to find good places that they can become attached to, and they will remain in those locations throughout their adult lives. This process is often guided by the intensity and spectral quality of that light.

To investigate the impact of light pollution around harbors, they created artificial rafts, exposed them to different lighting conditions, and observed what happened. They found that the light in some way affected 39 percent of the analyzed creatures, and they were either inhibited or encouraged by the sight of the light.

Dr. Davies said that the team now plans to expand the research to find out how lighting impacts a wider range of marine organisms, as well as to determine the degree of disruption it is causing. If it turns out to be a significant problem, he explained, it may mean that different types of artificial lighting will need to be used – perhaps ones that use different wavelengths.

—–

Follow redOrbit on Twitter, Facebook, Google+, Instagram and Pinterest.