Sea Sparkles, Noctiluca scintillans (credit: Wiki-commons)
When is the color blue a symptom of pollution? When algae glow-in-the-dark along beaches and in harbor.
Small bio-luminescent algae (dinoflagellates), commonly known as Sea Sparkles (Noctiluca scintillans), can produce massive blooms in polluted. Such a bloom happened when a red tide developed in polluted ocean waters and slow moving currents. One such situation occurs in Hong Kong which is situated at the mouth of the Pearl River delta.
Agricultural run-off from farms upstream in mainland China allows excess nitrogen and phosphorous fertilizers and untreated wastes to flow into the river. These organic materials are basic nutrients for all plants, including algae. In small amounts, they increase production but plants are inefficient users of dissolved nutrients. Any un-absorbed chemistry simply runs off the land into waterways and encourages aquatic species to flourish. Algal blooms and dead zones result when oxygen in the water is depleted (hypoxia), the plants die, and rot.
Guangdong Province, Pearl River Delta, and Hong Kong (credit: NASA)
Biologists have noted that: Hong Kong and the entire Pearl River Delta has a big problem with wastewater pollution. A video illustrates the City's blue pollution along the harbor and coastline. It would not be wise to take a midnight swim in the toxic algae. WHB