Red tide planktons in Oman are not toxic

Muscat: Most of the phytoplanktons triggering red tide in the Sultanate’s waters are not harmful, according to a new report published by Lynx, the monthly bulletin issued by the National Field Research Centre for Environmental Conservation of Diwan of Royal Court.

According to the report, red tides were recorded 138 times in Omani waters between 1976 and 2019, but it has not caused direct problems to marine life.

As for the recorded deaths of the marine organisms, they were either due to a lack of dissolved oxygen levels, an increase in ammonia, or clogging of the fish gills.

The red tide occurs after the sudden multiplying of one or more species of phytoplanktons that live in water whether in sea, oceans, rivers, and lakes. They are organisms that cannot be seen with the naked eye. These planktons are the source of food for marine life and contribute to the production of oxygen in the water.

Nevertheless, the impact of this natural incident can be reduced. The Center of Marine and Fisheries Sciences continues to conduct studies and research on the understanding of the factors that cause the recurrence of the red tide. The Ministry of Agriculture and Fisheries is also currently implementing a strategic programme for the phenomenon of harmful algae flourishing (2020-2024) along with government agencies and institutions, to develop a mechanism for managing the phenomenon and its environmental, economic, and health impacts.

A study prepared by Ahlam al Kharusiya, a marine environment specialist, revealed that winter is the most productive season for phytoplankton, while the spring and summer seasons recorded the lowest growth.

Taking Majis Desalination Plant located in the Sohar Industrial Zone as a sample location in her study, Al Kharusiya said continuous monitoring programmes for the physical, chemical, and biological changes of sea water using the latest technologies will help in the study of the species.

The report said that the number of marine phytoplankton recorded globally is about 5,000 species, 60 to 80 species of which cause harmful plankton bloom, while another 90 species are proved to be toxic to the marine environment and human health around the world.

Noctiluca scintillans cause 50 per cent of red tide occurrences in the Sultanate’s waters. It belongs to the group of flagellates. This is non-toxic, but it leads to a lack of oxygen and an increase in ammonia in the water. Light southerly winds following the storm are responsible for concentrating the red tide on the beaches.

Another type known as Margalefidinium polykrikoides was first detected in Omani waters in 2008. Like the first one, it is also not toxic, but it leads to the death of fish and coral reefs. It affects traditional fisheries and affects coastal tourism and leads to the closure of many desalination plants and refineries bordering the coasts.