Climate Change: Welcome to Nigeria, Visitors from Brazil

Visitors come to Nigeria from different parts of the world. Climate change brings its own share of visitors. Here by are some of the recent visitors

Sargassum

On September 24, 1984, water hyacinths reportedly arrived Nigeria, accumulating very fast on the waterways at the Lekki and Epe lagoons. Experts said the water hyacinths originated from the Amazon forest and quickly spread to Latin America, Caribbean, and Africa.

Years later, Mrs. Abeni Balogun, who had been selling fish at the Epe market for the past 40 years, told Daily Trust Newspapers that the advent of water hyacinth had removed the excitement in the business, explaining, “I am an indigene of Epe and this is the only business I have done in the past 40 years. The joy is really no longer there. When you look at the sea, you can see water hyacinth everywhere. When you see that, there is nothing we can do. Our husbands can be stranded onshore for two, three days without catching any fish. They go to the neighbouring communities farther down onshore to fish and the boatmen will bring it to the market to give us. But have you seen anybody around? They have been onshore for days waiting for the hyacinth to clear.”

Experts blame climate change for the hyacinths.

Mr Isegbe , the Director General of Nigeria Agricultural Quarantine Service (NAQS) said in Premium Times in 2019, “Climate change alters landscapes and livelihoods without discrimination, imposing a new normal of aggravated drought and flooding as well as the ascendancy of a wave of strange pests.

Climate change effects threaten life on earth, especially economically poor areas, said Lucette Adet and others in ResearchGate in 2017. One of such threats is the shifting of the algae species Sargassum natans and Sargassum fluitanss seaweeds from the Brazilian coast to new areas along the West African coastline.

Sargassum washes ashore the beaches of Mexico,CREDIT: Stephen Rees/Flickr).

In addition, people in the coastal areas of Nigeria complain about the occurrence of a specie identified as Eichhornia crassipes, which disturbs fishery and causes boats displacements. In essence, climate change is an important emerging threat to every kind of life on earth, especially in the areas where populations are economically poor, a scholar wrote in a thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Federal University of Technology, Minna, Nigeria.

“Among those effects are the shifts of algae species from their native place to new areas more suitable. As a result of warming oceans, aquatic species shifted their distribution. This is the case for two algae species identified as Sargassum natans and Sargassum fluitans, which shifted from the Brazilian coast to West African coast,” scholars said in the thesis.

Seaweed distribution and diversity share the blame for this in the West African region, with the exception  of Ghana, wrote Solarin B. B. and others in IOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS). The reason for this, according to them was that ecological factors prevalent in Nigerian coastal waters and indeed in tropical West Africa such as low tidal amplitude, existence of a shallow, permanent thermocline, negligible upwelling phenomenon and lack of natural rocky shore may be reasons for poor seaweed diversity in Nigeria (Dublin-Green and Tobor 1992).

Fishermen removing Sargassum from their net, CREDIT:IOSR Journal of Agriculture and Veterinary Science

For  Richard Arghiris in Mongabay in 2020, the source of this seaweed is not the Sargasso Sea, but a massive, novel, transcontinental algal bloom, stretching 8,850 kilometers (5,500 miles) from West Africa to South America, north to the Caribbean and beyond to Mexico, the so-called Great Atlantic Sargassum Belt (GASB). It burst to life from April to October every year, though it can vary in mass, timing and distribution. In 2013, the GASB did not bloom at all, but in 2018, it grew to more than 20 million tons.

Variability in ocean climate and ocean circulation show  linkages with Sargassum cycles,  wrote  Dr. Kafayat Adetoun Fakoya, Department of Fisheries, Lagos State University, Ojo, Lagos State, Nigeria, in a paper titled  SARGASSUMIMPACTS IN WEST AFRICA: SENEGAL TO NIGERIA. He said maps of the sea Surface Temperature indicate that NERR and the Accumulation Region are the warmest regions in the Atlantic Ocean, affecting variability in the position and intensity of the Canary and Guinea Eastern Boundary Currents, causing associated equatorial upwelling and coastal upwelling off West Africa, a condition promoting the asexual reproduction by fragmentation for new growth of the species.

“Fact is Sargassum proliferation is a consequence of warming and changing of ocean temperature due to global climate change. Critical knowledge gaps exist on the ecological impacts of invasive Sargassum on the ecosystem in general. Understanding what environmental factors are controlling recent variability is difficult, however, without understanding drivers of variability in Sargassum distribution on seasonal time scales. Discontinuous and unreliable supply coupled with presence of pollutants present a challenge to utilization,” he wrote.

Invasion of Sargassum in Côte d’Ivoire,CREDIT: Credit: Grass-Sessay

According to Y A Fidai and others in ResearchGate in December 2020, the socio-economic impacts of Sargassum blooms and beach landings are notable on the aquaculture and tourist industries.  It clogs fishing gear and limits fishing ground, resulting in a reduction in revenue and income and an increase in maintenance costs. Scholars estimated that in China, seaweed damage cost the aquaculture industry 73 million USD.

 “Additionally, surface blooms restrict light penetration through the water column which affects communities (McGlathery 2001). Despite the negative impacts on communities, Sargassum influxes also present opportunities for economic benefit as it has a variety of potential uses including for biofuel energy, soil fertiliser and animal feed, construction blocks, bioplastics and pharmaceutical products,” Fidai and others wrote.

“For nearly a decade, vast quantities of Sargassum seaweed have been washing ashore on either side of the Atlantic,” wrote Richard Arghiris in Mongabay. According to Richard, the seaweed hampers the activities of coastal communities and damages ecosystems. Researchers are working to better understand the phenomenon, which may be linked to wind and ocean currents shifted by climate change, to nutrient-rich discharge from the Amazon and Congo rivers, or iron-laden dust from the Sahara. The seaweed comes from a new perennial bloom that may be a permanent feature of the Atlantic Ocean.

Fishing gear such as gillnets, beach seine, stownet, and trawlnets used by artisanal fishermen and industrial trawl net were observed to have being clogged by the floating mass of seaweed, wrote  Solarin B. B.  and others in a paper titled  Impacts of an invasive seaweed Sargassum hystrix var. fluitans (Børgesen 1914) on the fisheries and other economic implications for the Nigerian coastal waters. As a result of clogging by seaweed, cleaning of fishing nets and preparations for fishing trips took longer hours.

“Sargassum hystrix var fluitans had invaded both brackish and marine coastal waters in Nigeria with patches on the beach and also impeded navigation and fishing activities by artisanal and the industrial fishermen respectively. The clogging of the fishing nets mainly monofilament and multifilament resulted in loss of man hours spent in removing the weed from the net in preparation for the next fishing trip. Although gillnets were sighted mainly during this survey, several other fishing gears used were also impacted by clogging based on their operational methods including beach seine, purse seine, stownet and trawl nets,” Solarin and his team of researchers wrote.

Indeed, Sargassum deposits in decomposition attract large number of flies. It releases an awful smell and the poisonous hydrogen sulphide gas, which is harmful to most marine animals. The hydrogen sulphide gas can lead to several human health issues as the skin rash, nausea, headaches,  Lucette Adet and her team wrote in a paper titled Mapping Sargassum fluorescence distribution on Nigerian sea.

Sargassum mass found at Ajegunle Erun-Ama beach, Ondo State, Nigeria,CREDIT: ResearchGate

“The hydrogen sulphide gas can lead to several human health issues as the skin rash, nausea, headaches when population is exposed to high concentrations in prolonged way. And even breathing difficulties if there is a prolonged exposure, and can tarnish metals. Oxidation attacks fishing boats, affects populations’ coastal activities. The masses along the shoreline limit water-sports activities, boat moorings and harbours to reach the coast. In addition, decaying Sargassum trapped along the coasts creates brown plumes in the water, which threatens the health of ecosystems that depend on low oxygen content affecting marine life. According to past studies, Sargassum upcoming covered certain seasons over years. Stranded Sargassum diminish considerably beaches attraction, mostly in the case where Sargassum rafts entrapped plastics and medical wastes,” Lucette and her team wrote.

Water hyacinth, wrote Daniel Ovarr Ezama in a paper titled Impact of Water hyacinth  Infestation  in Nigerian Inland Waters: Utilization and Management  in World Maritime University Dissertation, was discovered in South America in 1816 and spread to New Orleans, Louisiana, the United States in 1884. It spread into Australia, Asia, the Middle East and Africa through the influence of human activities.

“The proliferation of water hyacinth in Nigeria freshwater ecosystem clogs waterways and prevents navigation; it alters the ecology of water, thereby disrupting fishing activities and prevents hydroelectric power generation,” Ezama wrote. 

A trader, Mrs Yetunde Bello, told Daily Trust that most of the traders had been incurring huge losses because they could not get fish supply to sell, restating that the fishermen had been onshore for days without catching enough fish.

Mrs Bello said, “The hyacinth is like poison to us. It destroys our canoes and the nets. This has worsened our economic woes.” She said, “Maybe during the rainy season we can have some respite, but as at today, the water hyacinth remains a major problem to us.”

The Chairman of Epe Local Government Area, Mr Adedoyin  Adesanya told  Daily Trust, the water hyacinth was a natural occurrence which was too expensive to control.

Mr Adesanya said, “It is not only affecting the fish traders alone; all the water transporters are affected. Water hyacinth is natural. I believe the wind will soon blow it away. We don’t have the wherewithal to clear it by ourselves. It requires machines which will cost us a lot. We have written to the authorities in charge – the Waterfront Ministry and the Ministry of Environment – and I believe they will do something.”

The shores of many fishing villages surrounding Ghana's Jubilee Oil Field are now covered with decomposing sargassum, which, in addition to releasing offensive smells, clogs the fishing nets and boat engines of local fishermen, in turn, disrupting livelihoods considerably, wrote Abigail Ackah-Baidoo in Community Development Journal in 2013. Fishermen from villages such as Cape Three Points have linked the ‘blackened’ colour of rotting sargassum to the recent commencement of oil production, calling on the government to discipline Tullow, the main company operating in the Jubilee Oil Field, and to compensate them accordingly.

Although Sargassum has considerable potential as a source of biochemicals, feed, food, fertiliser, and fuel,  wrote John Milledge and Paticia Harvey in Journal of Marine Science Engineering, “variable and undefined composition together with the possible presence of marine pollutants may make golden tides unsuitable for food, nutraceuticals, and pharmaceuticals and limit their use in feed and fertilisers.”  

Still, all is not lost in the fight against the visitors from Brazil. Affected nations can improve  satellite data quality by using check-up system and algorithms for radiometric correction.  Ocean color survey could be implemented to improve and enhance satellite capacity to resolve gaps and errors contained in imagery. A Sargassum early advisory system based on satellite imagery in correlation with current and wind data to validate Sargassum transport patterns could be established, Lucette and her team wrote. 

According to Clifford Louime and others in a paper titled Sargassum invasion of coastal environments: a growing concern, there is yet no scientific consensus on the origins of this problem and how to address the specific causes with the goal of redressing this natural catastrophe. “In the meantime, the accumulation of these algae on beaches continues to have a tremendous impact on tourism in the region, as well as on the balance of the marine ecosystems and even on the health of affected local populations. However, this unprecedented invasion seems to offer several economic opportunities in the energy and agricultural sector. This macroalgae can in fact be transformed into biogas and biocoal as an energy source or organic fertilizer for plant health and soil amendment,” Clifford and his team wrote. Ultimately, these newly discovered characteristics of Sargassum will partly help us redress some of the environmental issues brought about by global climate change. Now it is the time to turn this problem into opportunities.