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Sargassum can reduce the cost of building by 40 percent

22 June 2022
Sargassum blooms on a coast

The use of Sargassum, an aquatic invasive weed, which is negatively impacting the activities of fishermen along the coast can reduce the cost of building by 40 percent.

Amidst the rising cost of cement, blocks made with aquatic weed can build a house 60 percent cheaper than the use of traditional cement.

Dr. Thierry Tonon, a Lecturer in Algal Biology, at York University, UK, said this at a stakeholder workshop in Accra to disseminate findings on Sargassum locally known as brown algae or seaweeds. 

In recent times, the shores of Ghana and other West African countries have been experiencing an invasion of Sargassum at shorelines.  Reports indicate that coastal dwellers and the hospitality industry manage the influx in several ways. Players in the hospitality industry dig and bury landed sargassum whiles coastal inhabitants leave them to dry and decompose at the beach.  

Dr Tonon said one of the key findings of the joint study, conducted by the University of Ghana, Legon, the University of Southampton, University of York and other partners, was that blocks made with sargassum could last for 120 years. “Already, a construction company that makes building blocks from sargassum has designed a machine to make adobe bricks adjusted to process a mix of 40  percent sargassum and 60 percent of other organic materials for blocks,” he said. The machine can produce 1,000 blocks a day, and after four hours of baking in the sun, the blocks are dried and ready to be used. 

He said there was a window of opportunity to process the weeds into liquid fertiliser to improve the quality of soil with nutrients, including nitrogen, phosphorus and potassium. Several companies in the Caribbean, he said, were commercialising liquid plant tonics and fertilisers based on pelagic sargassum.

He said Ghana could explore the opportunity of using the weeds to restore its mangroves, protect shorelines, ensure water quality improvement, biodiversity support through the provision of a range and of habitats, and carbon sequestration.

Professor Emma Tompkins, a Professor of Environment and Development at University of Southampton, said sargassum across the tropical Atlantic appeared to be a 'new normal' associated with eutrophication, climate change and natural variability of the climate. 

Prof. Kwasi Appeaning, the Director of the Institute for Environment and Sanitation Studies, University of Ghana, said the capacity for sargassum research was being developed to grow innovation in its utilization. The seaweed, he said, was only viewed as a menace and complete waste by coastal dwellers and those along the fisheries value chain who were directly impacted by the influx.  

Those along the fisheries value chain have reported financial losses due to damage to nets and outboard motors and other fishing gear.  They also complain about reduction in fish catch due to reduced fishing periods. Fish processors have reported shorter shelf-life of fish caught during sargassum influx. 

Mr Ebenezer Appah -Sampong, the Deputy Executive Director of Environmental Protection Agency – Ghana/Technical Services, said his outfit was ready to collaborate with others to find a lasting solution to the menace. 

Madam Joana Akrofi, an official of the United Nations Environment Programme, stated that sargassum invasion was one of the ocean pollution issues that affected the well-being of coastal dwellers.

Ghana has no specific policy on the management of sargassum and that seaweed had been reported in the maritime waters of the country since the early 1960s. 

They are usually attached to sub-tidal rocks.


Source: GNA/Albert Oppong-Ansah