Muscat – A research project at Sultan Qaboos University (SQU) has shed new light on the environmental factors driving harmful algal blooms along Oman’s northern coast, providing valuable insights to help protect desalination plants, fisheries and aquaculture operations.

Titled ‘Formation, Characteristics and Advection of Harmful Algal Blooms (HABs) along Northern Omani Coast’, the project was funded by the Strategic Research Programme of the Research and Innovation Authority, in collaboration with the Ministry of Agriculture, Fisheries and Water Resources.

The project was led by Prof Sergey Dobretsov (in photograph above), UNESCO Chair in Marine Biotechnology at SQU’s College of Agricultural and Marine Sciences and Centre of Excellence in Marine Biotechnology.

Prof Dobretsov explained that harmful algal blooms occur frequently in the Sea of Oman, potentially disrupting desalination operations, affecting fisheries and aquaculture, interfering with marine activities and impacting tourism. The research investigated bloom ecology, identified environmental factors influencing development and examined how ocean currents transport and disperse blooms.

The team combined biological sampling with advanced oceanographic technologies, including sea gliders, to monitor water conditions, circulation patterns and marine ecosystem changes.

Findings revealed that bloom development is influenced by interconnected processes, including monsoon-driven winds, ocean currents, coastal upwelling, water outflow from the Arabian Gulf, internal tides and ocean eddies. Seasonal changes in water-column mixing and the thermocline, which separates warmer surface water from colder deeper water, also influence nutrient availability and phytoplankton biomass.

The researchers observed changes in phytoplankton communities, with diatoms dominating during 2018–2019. Noctiluca scintillans was identified as a major bloom-forming species in surface and subsurface waters. Nutrient-rich upwelled waters and low-oxygen conditions may contribute to bloom formation, while oxygenated water entering from the Arabian Gulf can modify oxygen minimum zones.

The project also examined bacteria associated with blooms. Bacillus species were the most abundant bacterial isolates, while bacterial communities differed between bloom and non-bloom periods. Potentially pathogenic bacterial strains were also detected, highlighting the need for continued monitoring and further research into microbial interactions.

Based on the findings, Prof Dobretsov recommended strengthening real-time monitoring at desalination plant intake points, focusing on chlorophyll-a, turbidity, dissolved oxygen and harmful algal species. Improved pretreatment systems and flexible contingency plans could help manage high algal biomass, reduce membrane fouling and limit operational costs during severe bloom events.

For fisheries and aquaculture, he emphasised careful site selection, continuous water-quality monitoring and emergency measures, including increased aeration, improved water exchange and relocating stock when necessary.

He also stressed stronger collaboration among research institutions, government agencies and industry to improve bloom forecasting, develop effective treatment technologies and strengthen mitigation strategies.

The project has produced four peer-reviewed journal publications, ten international conference presentations and three workshops covering harmful algal blooms, sea gliders and oceanography.

The research team included co-principal investigator Dr Gerd Bruss, Dr Khalid Al Hashmi, Dr Aisha Al Wahaibi, Dr Ahmed Sana and Dr Talal Etri.