• The twice-a-year algal bloom phenomenon that extends from the Gulf of Oman to India is attributed to climate change.

• The Irish call it the sea ghost, the Taiwanese refer to it the blue tears.

• Algal blooms are a global phenomenon.

• They resemble a toxic spill and often looked at with caution, for they wreck the local ecosystem.

More Details on Algal Bloom:

• Algal bloom is a population explosion of algae in freshwater or marine water system.

• They are identified by the change in colour of the water.

• They turn the water green in places like the Great Lakes of North America, Thailand and the Seychelles, red in Florida, chalky white in North Atlantic and orange in Puget Sound.

• Blooms can be harmful: they can lead to fish die-offs and affect water supply to the cities.

• At the Gulf of Oman, people are greeted by smelly green waters twice a year.

• The bloom extends up to India across the Arabian Sea.

Study Findings:

• Scientists have attributed this phenomenon to climate change. 30 years ago, algal bloom were unknown to the Gulf of Oman, as algae stayed put beneath the surface like invisible commoner just going about with usual routines.

• But now they surface twice a year, putting up a great show, displacing zooplankton and destroying the whole marine ecosystem.

• Many factors contribute to the harmful algal bloom (also called HABs).

• They also spread when the wind and water currents are favourable.

• It may also result from overfeeding, when the water gets new nutrients.

• Blooms have often been noticed after extreme weather events or during high water temperature.

• Scientists based at the Lamont-Doherty Earth Observatory at Columbia University link the Arabian Sea condition to the melting of the Himalayan ice due to global warming and climate change.

• Less ice has raised temperatures in South Asia and strengthened the Indian Ocean’s southwest monsoon.

• As the weather pattern moves across the Arabian Sea, the oxygen-poor water become nutrient rich, leading to the rise of algae called noctiluca scintillans.

• Marine ecologists, who have been studying the waters for the past four decades, say that the blooms are growing bigger and lasting longer, affected the local food chain.

Source: The Hindu