WWF-Pakistan solves Karachi stench mystery

KARACHI: According to the World Wide Fund-Pakistan on Friday, the source of the stench that has engulfed Karachi for the last few days was the decay of Noctiluca scintillas—a small planktonic dinoflagellate.

Mass bloom of this small free floating organism was reported from the Arabian Sea including the Pakistan coast. The bloom was more prominent along the Pakistan and Oman coasts, it was learnt.

Noctiluca scintillas blooms have been reported from Pakistan’s coast on many occasions.

The WWF-Pakistan, on Friday, said the green bloom along Pakistan’s coast started appearing back in February 2017 and continued till late May, which has turned the sea water into a green soup at some places.

The water has been discoloured during the last five months, according to fishermen reports. A reversal of current and wind patterns under the influence of the south-west monsoon in late May has resulted in the decay of the bloom, which caused the atypical stench in the coastal areas of Karachi.

The mass scale green bloom of the current year have not affected fish or shellfish so far, according to the reports; while in Oman, mass scale mortality of pelagic shrimp and associated fishes was reported.

According to WWF-Pakistan official, this unusual phenomenon like the blooms of Noctiluca scintillas, also known as sea sparkle, occurs at least twice a year.

However, over the recent few years, the intensity of such bloom increases substantially and have also resulted in fish mortality in some cases. He also said that the onset of the monsoon results in a change in current pattern and due to this Noctilucastarts dying and results in an atypical odour.

He further said that the smell is not generally harmful.

While senior director programmes of the WWF-Pakistan such increase in the frequency of the blooms may be a result of climate change. However, other factors cannot be ruled out either.

People of Karachi have taken to social media to complain and speculate about the strange smell that had enveloped the different parts of the city for the past few days.