In addition to the growing challenge of bleaching, many of the world’s coral reefs are being eaten by crown-of-thorn starfish,media New Atlas reported. However, scientists have recently developed a simple new portable test tool that can detect their presence faster than ever before.
Aquatic organisms constantly shed their DNA into the water as they shed old biological tissue, excrete waste, and perform other body functions. The genetic material in this water is called environmental DNA — or eDNA — which can be detected in water samples, even at very low concentrations. So by identifying the obvious eDNA signals found in these samples, scientists can determine which organisms exist in a particular area. In recent years, this process has been used to track fish migrations, warn nearby great white sharks and even look for loch Ness monsters.
Now, under the leadership of biochemist Jason Doyle, scientists at the Australian Institute of Marine Science have developed a field-deployable kit to detect eDNA from crown starfish in seawater samples. The kit uses the inexpensive lateral flow detection technique currently used in home pregnancy testing, which is characterized by a colored band on the target DNA if it is present.
The kit is very sensitive and reacts to eDNA substances as small as 0.1 pikes. This means it can detect intrusions when starfish are still young, small and hidden by corals — at which point they are unlikely to be detected by divers who see coral reefs.
Still, Doyle doesn’t think the equipment can replace divers. Instead, he believes it can be used to mark certain areas of the reef, where divers can concentrate on finding and removing starfish so they don’t cause much damage.
A paper on the study was recently published in the journal Environmental DNA.
And this isn’t the first time we’ve heard that eDNA analysis is being used to help protect coral reefs. Last year, scientists from the University of Hawaii at Manua described a way to monitor the abundance and species of corals on coral reefs by testing DNA in the water.