Scientists at Ohio State University have developed a device to conserve coral reefs by using light to attract zooplankton and turbocharge their feeding.
The Underwater Zooplankton Enhancement Light Array (UZELA) is a system of programmable lighting that can run for six months on a single battery. If operated for no more than an hour after nightfall it can optimise the feeding time of the corals, reports the research team that developed it.
Limited operation times are considered not only economical but prudent, because artificial lighting could disrupt the behaviour of other marine life. However, the study emphasises that UZELA does not appear to harm the environment, nor interrupt the flow of other zooplankton in the surrounding area.
Testing the tool on two species of coral native to Hawaii over a period of six months, the scientists found that it could “greatly enhance” zooplankton density, boosting feeding rates of both healthy and bleached corals.
As a result the corals grew stronger and apparently more resilient in the face of threats such as heat stress or ocean acidification.
“If you imagine zooplankton in a column floating above coral, instead of being naturally dispersed UZELA is just pulling them down – but it’s not taking away from the coral beside it,” explains earth sciences professor Andrea Grottoli, lead author of the study.
“We show that if you put the corals close to the light, they benefit from that concentrated zooplankton, and feeding rates go up 10- to 50-fold.”
This is equivalent to an 18-68% increase in the amount of metabolic demand that can be met by zooplankton alone, helping to supplement much of the corals’ diet and boosting their survival rates. UZELA is said to be widely adaptable to different marine environments and, once suitably located, it can be serviced easily by scuba divers.
The Ohio team hand-built their current UZELAs but are now working with an engineering company to make the devices readily manufacturable within the next three years, if not sooner.
At Earth’s current rate of warming, coral reefs and the ecosystems they sustain could be devastated as early as 2050. Grottoli says of UZELA: “Think of it as a Band-Aid for about a couple of decades. It can protect some corals in some places, sometimes.”
“The real intent of this project is to inject new technology and energy into coral-restoration success. It’s something that can be deployed strategically for high-value reefs, or projects that have already had a lot of investment in them.”
“We are not mitigating climate change fast enough to save coral, and UZELA is not going to instantly save coral reefs, but it is an exciting solution that will buy us time as we work toward a more sustainable environment.”
The Ohio State University-led study, supported by the University of Hawaii Foundation, National Science Foundation and Defence Advanced Research Projects Agency, has just been published in the journal Limnology & Oceanography: Methods
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