Thick Saharan dust which blanketed T&T last weekend has caused hardship for scores of people suffering from asthma and sinus but for agriculturalists, the dust has been welcomed as free natural fertilizer.
Agricultural economist Omardath Maharaj said much of T&T's lush soil has to do with the Saharan dust which blows across the Atlantic from November to March. He said the dust is rich in soluble iron and other minerals which are good for plant root and development.
"The seasonal dust deposit is likely to affect both bacteria and fungi within the topsoil and on canopy surfaces, and especially benefits highly bioabsorbent epiphytes," Maharaj said.
An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water or from debris accumulating around it.
While the plumes of dust cause many people to suffer from cracked lips and dry skin, Maharaj said Saharan dust can provide essential macronutrients and micronutrients to plant roots and leaves.
He noted that international research shows that the dust results in substantial iron bioavailability across the rainforest canopy especially in the Amazon Basin which provides 20 per cent of the world's oxygen. More than half of the world's estimated 10 million species of plants, animals and insects live in the tropical rainforests of the Amazon and one-fifth of the world's fresh water is in the Amazon Basin.
"Our entire planet benefits from the Saharan dust deposits. The dust which spreads across the oceans is also a likely contributor of iron to marine life," he added.
He noted however that depending on the soil type, the dust can be beneficial.
"One study showed iron was helpful to corn farmers in northern Nigeria while a 2013 study showed that it was a threat to rice grown in several tropical savannah areas. Large amounts of Saharan dust on soils can improve more acidic soils whose pH is too low for plant growth, whereas more alkaline soils should benefit from the addition of iron," he added.
Maharaj noted that the distribution of iron in the oceans is likely to be a way of trapping excess atmospheric carbon dioxide.
" On the one hand, global warming could increase winds and therefore dust production, but then more dust could enter the ocean, potentially providing a natural mitigator to those effects," he added.
Apart from the iron deposits, the Saharan dust can actually block sunlight sufficiently to make temperatures drop.
It has been estimated that 400 million to 700 million tonnes of dust are transported from the Sahara every year. As much as 20 per cent of it reaches the Amazon – and satellite data has been used to calculate that some 27.7 million tons of dust are deposited over the Amazon basin, which plays a crucial role in fertilising the soil.
Meanwhile, Director of Health Dr Albert Persaud said there has been no unusual influx of people coming into the hospital with respiratory ailments over the past few weeks.
"We have seen nothing unusual. Up to a month after Carnival we usually see people with varying levels of lung illness. This year was no different," Persaud said.
- by Radhica De Silva