'Blue tears' not toxic: Taiwan researcher

2019/06/16 20:56:07 fontsize-small fontsize-default fontsize-big
Photo courtesy of Lienchiang County Government

Photo courtesy of Lienchiang County Government

Taipei, June 16 (CNA) Fluorescent blue sparkles, dubbed "blue tears," that glow around Taiwan's offshore Matsu Islands are not caused by toxic algae and a sign of environmental deterioration, a Taiwanese researcher said Sunday in rebutting a recent study.

Chiang Kuo-ping (蔣國平), a distinguished professor at National Taiwan Ocean University (NTOU), said it cannot be established that the "blue tears" along beaches near Matsu are associated with toxic algae because they do not drain oxygen from the surrounding waters and kill marine life in the process as stated in the study.

He said the single-celled "noctiluca scintillans," also known as "dinoflagellates" or sea sparkles, that generate the bioluminescence described as "blue tears" when disturbed are non-toxic heterotrophs -- organisms that feed on other sources of nutrition to survive.

In coastal ecosystems, they replace copepods -- small crustaceans commonly found in aquatic communities -- as the main consumers of phytoplankton and play the role of a "terminator" of single-cell algae called diatoms, which Chiang described as a normal phenomenon in marine ecosystems.

The toxic algae argument does not hold water along the Matsu coastline because the sea sparkles have not caused the algae to starve the water of oxygen or led to the death of marine life, he contended.

Chiang also noted that the American study in the journal Geophysical Research Letters was conducted by people with expertise in studying satellite data and images rather than ecological experts.

The study by Chuanmin Hu, a professor of optical oceanography at the University of South Florida, that the Taiwanese professor was responding to was reported in local media.

It argued that bioluminescent sea sparkles have become more abundant in recent years based on satellite images that have tracked their movements.

The study observed that from 2000 to 2003 when the Three Gorges Dam was being built on the Yangtze River and there was little water flow, there was only a small distribution of the "blue tears."

But since construction has been completed and the water flow was restored to normal, the "blue tears" have steadily expanded.

While the reason for that cannot be determined for certain at present, it is likely related to the major release of pollution and agricultural runoff of nutrients from the Yangtze River into the East China Sea, the study argued.

In explaining the study to science news website Live Science, Hu said the sea sparkles are not toxic themselves, but when they eat, they usually choose toxic algae, and in the process release ammonia and other chemicals that poison the water around them.

They also breathe oxygen until there's none left in the surrounding waters, making their growing numbers particularly troublesome, Hu was cited as saying in the recent Live Science article.

"The oxygen in the water is so low that many animals can die," he was quoted as saying.

(By Feng Shao-fu and Evelyn Kao)
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