ENVIRONMENT DAY-CARIBBEAN:
Sea, Sunshine...and Sahara Sand
Orlando Matos

HAVANA,  (IPS) - A beautiful, bright-red sunset seen from Caribbean beaches could be a cause for alarm rather than for delighted contemplation, because it signals the annual arrival of dust from the Sahara desert, which could be harmful.

Millions of tons of dust reach the Caribbean, the Gulf of Mexico and the south of the United States, brought across the Atlantic by the winds. The dust is suspected of containing pollutants, and has been studied more closely by the scientific community in the last few decades.

The theme of World Environment Day 2006, celebrated on Jun. 5, is Don't Desert Drylands! The slogan was chosen to highlight the risks faced by these ecosystems, which cover more than 40 percent of the planet's land surface.

In Cuba, research is in progress to evaluate the impact of the dust which is scattered all over the islands every year, mainly from June to August.

The study of the airborne particles began in the 1970s, when the Cuban Institute of Meteorology started using satellites, Paulo Ortiz, an expert at the Institute, told IPS.

However, only now, thanks to technological progress and the growing knowledge about the dust in the atmosphere, is the research gaining respect and recognition, Ortiz said.

He explained that the Cuban project analyses "anomalies of climate variability" by different scientific methods, as well as "how illnesses respond to climate change and variations."

Eugenio Mojena, another expert at the Institute, told IPS that "in the last 30 years, ten times more dust has been flung into the atmosphere," because there have been more sandstorms in the Sahara.

Ever since a continuing severe drought hit North Africa in 1970, there has been a dramatic increase in the dust clouds in that region, with especially high concentrations in 1973, 1983, 1987 and 2000.

It has been calculated that the atmosphere has accumulated between two and three billion tons of dust, mostly from deserts. Scientists consider this to pose a serious threat to the environment and to human health.

The airborne dust is monitored by "an international network of satellites," as well as "surface observations," which detect the "presence, distribution and movement of the particles, and the areas where they are deposited" on the island, Mojena explained.

This natural phenomenon has been occurring for millions of years, but according to Ortiz, "it is still not receiving as much attention as it should be" from the international scientific community - an opinion shared by academics in other parts of the world.

According to Andrew Goudie, a geography professor at the University of Oxford, dust is one of the least understood components of the atmosphere, and could have a greater influence on climate change than has been realised up until now.

Mojena predicted that the drought in Africa would continue, and so would "the transport of large quantities of dust to the Caribbean," which meant that the current drought plaguing the Caribbean region was likely to drag on.

Researchers warn that the dust's chemical and biological composition has a number of effects on human and animal health, oceans and their biodiversity, and the weather.

Ortiz said that in Cuba, "studies to determine the relation between the dust and patterns of rainfall, hurricanes, droughts and other signs of climate change, have only just begun."

The expert said research is also being done to establish the "possible effects (of the dust) on certain enterically transmitted diseases and respiratory disorders, among others."

Studies in the southern United States, Puerto Rico and other parts of the Caribbean suggest that there is a rise in illnesses such as asthma when the dust clouds arrive in the region.

The phenomenon has also been linked to the decline of coral reefs in the West Indies, which are suffering from several fungal diseases, and even to the occurrence of "red tides" or algal blooms, the rainfall cycle, and the frequency and intensity of tropical cyclones.

Ortiz said that "although such correlations are reported in the scientific literature, here in Cuba we have not found results that corroborate the hypotheses of other authors."

The deputy minister of Science, Technology and the Environment, José Díaz, told IPS that the damage to Cuban coral reefs is not due to the dust, but to "the global increase in water temperature," according to "preliminary findings."

Díaz ruled out atmospheric dust as a contributing factor to the persistence of drought and the soil degradation in the country, which he said were due to "a centuries-long process of deforestation and inappropriate agricultural management," respectively. In a bioclimatic forecast for the month of June 2005, the Cuban Institute for Tropical Medicine mentioned Saharan dust as one of a number of factors that could trigger enterically transmitted diseases, such as diarrhoea.

When the Institute was asked for follow-up information, its directors declined to comment, saying only that they "are not studying that phenomenon."

The world's most active dust source is the Bodele depression in Chad, in Africa. Although other deserts, such as the Gobi desert in Asia, also contribute dust particles to the atmosphere, it is the Sahara desert that has direct impact on the Western hemisphere.

The dust cloud takes approximately six days to cross the Atlantic, and reaches the Caribbean region between June and October, bearing an amazing variety of microorganisms.

In a study headed by U.S. Geological Survey scientist Gene Shinn, no less than 120 different live fungi and bacteria were found in dust samples. The number of viruses, meanwhile, has not yet been determined.

A significant finding of his research was that 25 percent of the organisms were pathogenic. The proportion of disease-producing agents will probably increase because, according to the researchers, the airborne particles may carry more viruses than bacteria.

Another study by a research team in the United States, made up of marine biologist Ginger Garrison and microbiologists Dale Griffin and Christina Kellogg, found 130 different bacteria and fungi in 2000.

Ortiz said that research into Sahara dust would continue for the next five years in Cuba, "with the possible collaboration of other countries in the area," with the aim of "preventing harmful impacts."

Preventive measures would become possible "as dangers and potential risks and outcomes are determined for our study region," and "applied in other fields of knowledge."

Deputy Minister Díaz said: "It's early days for research on Sahara dust in Cuba, and environmental processes are long-term." However, "action is being taken," based on the research findings, to limit its possible effects on the island.