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The secret, he said, is to measure the rate of photosynthesis in the algae, meaning the plant’s ability to transform light into energy. During photosynthesis, plants also release oxygen into the air.
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A prototype tester, that occupies about one square meter of a laboratory desktop, shoots a laser beam at water samples to stimulate photosynthesis in the algae. But not all of the laser’s heat is used.
Depending on the condition of the algae and the rate of photosynthesis, some of the heat is shot back into the water, creating sound waves, Dubinsky said.
With a special underwater microphone, researchers are able to analyze the strength of the sound waves and determine the health of the algae and the condition of the surrounding water.
“Algae suffering from lead poisoning, like waste discharged from battery and paint manufacturing plants, will produce a different sound than those suffering from lack of iron or exposure to other toxins,” said researcher Yulia Pinchasov.
. . . [ read more Scientists ‘listen’ to plants to find water pollution]