The algal blooms that are dominating parts of China’s waters are the results of Noctiluca scintillans, a single-celled microorganism that produces the bioluminescent blue glow known locally as “blue tears” or “sea sparkle”. Algal blooms can be green or blue, depending on the type of microorganism. These organisms are a species of dinoflagellate (which are marine plankton). Algae can be used as indicator organisms to monitor pollution in various aquatic systems.
Harmful algal blooms are the consequence of the human impact on aquatic ecosystems, particularly through a process called eutrophication, which refers to an excessive richness of nutrients in a body of water, frequently the result of run-off from the land. This build up of algae causes a variety of deleterious effects, including the poisoning of fish, habitat disruptions for many organisms, water discoloration, beach fouling, and sometimes toxic effects for humans. Through these effects, excessive algae can starve water of its oxygen, creating noxious dead zones.
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According to new research, the extent of algal blooms in China is increasing. Published in the journal Geophysical Review Letters (“In Search of Red Noctiluca scintillans Blooms in the East China Sea”), researchers from the College of Marine Science, University of South Florida, note an increasing algal bloom trend. Concerning algae have been found farther from shore than ever before—in some cases as far as 300 kilometers offshore.
With the specific region of focus, the researchers indicate that this algal bloom is being driven by a combination of hydrographical and biological factors, most probably linked to the construction of the Three Gorges Dam. The dam is one of the largest power stations in the world, spanning the Yangtze River by the town of Sandouping, in Yiling District, Yichang, Hubei province, China.
The bioluminescence is generated throughout the cytoplasm (material enclosed by the cell membrane) of the organism, the product of a luciferin-luciferase reaction in thousands of spherically shaped organelles, called scintillons (individual cytoplasmic bodies located in certain regions of the cell). Luciferin is a chlorophyll-derived tetrapyrrole ring that acts as the substrate to the light-producing reaction, which is triggered by the enzyme dinoflagellate luciferase.
The new research is not only significant in terms of highlighting pollution in China, it is also the first to use satellites and digital images to track algal blooms, tracking how plankton absorb and scatter light.
