Experts say green waters along coasts of Balochistan and Karachi pose no toxic threat
Gwadar coast glows green as Noctiluca bloom paints the sea. Photo: Express
KARACHI:
The waters along Gwadar coast have turned green, replacing the usual blue with a greenish hue, caused by a natural marine phenomenon known as Noctiluca bloom, officials confirmed on Saturday. First widely observed in 2017, the phenomenon affects not only Pakistan’s coasts but also large parts of the Arabian Sea, including Iran, India, Oman, and the Persian Gulf.
Muhammad Muzammil Khan, Technical Advisor at DWLF Pakistan, assured that the green waters along the coasts of Balochistan and Karachi pose no toxic threat. The bloom was reported on Friday by Abdul Rahim of the Gwadar Development Authority, who noted that large sections of the western and eastern bays of Gwadar had turned green.
DWLF Pakistan, a joint venture between National Logistics Corporation (NLC) and DP World Logistics FZE (DWLF), clarified that such seasonal changes in water colour are normal and have been monitored in Pakistan since 2012. The green waters typically appear during the winter months from November to February. The most intense bloom occurred in 2017, spreading across the Arabian Sea and affecting neighbouring countries.
This year, the bloom began in November along Pakistan’s waters, extending from Balochistan’s coastal areas to Karachi. While some observers mistakenly linked the green colour to eutrophication and the growth of cyanobacteria, scientific studies – including reports from Iranian researchers — confirm it is a natural seasonal process. The phenomenon has also been observed in Pasni, Jiwani, and as far as Sistan in Iran.
Noctiluca is a small, free-floating organism that can appear in red, orange, green, or colourless forms. Along Pakistan’s coasts, it is mostly green or orange. The organism itself is not inherently green; the color comes from an internal pigment, Protogelina noctiluca, which allows it to multiply rapidly. Naturally bioluminescent, Noctiluca often glows at night.
Khan stressed that the current green waters do not pose any health or environmental risk and have not been linked to fish or marine life deaths. Observations since 2012 show that nearly all Noctiluca blooms along Sindh and Balochistan are non-toxic. Misinterpretations often associate the bloom with pollution, but DWLF Pakistan stressed that this is a natural marine occurrence, not a result of contamination.
