Jeff Berardelli is WFLA’s Chief Meteorologist and Climate Specialist
TAMPA, Fla. (WFLA) — Right now, Florida is under a dense blob of Saharan dust, making for hazy skies and itchy throats.
This dust – and the associated dry air in the cloud layer – pretty much shut down our rainy pattern and dried things out today.
The dust will linger through the weekend, but it will start to dissipate by Sunday. Consequently, rain levels are expected to remain lower than usual over the weekend. Reduced rainfall is just one effect of these dust outbreaks.
This outbreak is not unusual. Plumes of Saharan Dust are common during the early part of hurricane season, kicked up by thunderstorm systems over Africa.
It is then transported westward by the Trade Winds.
And the Bermuda High gives it a boost westward.
Throughout the year, about 200 million tons of it is transported across the Atlantic – that’s the weight of 33 million African elephants!
Since it occurs every summer, the immediate effects are familiar to most Floridians. The dry, dusty air deters tropical development and afternoon thunderstorms. It results in hazy skies, but can also lead to vibrant sunrises and sunsets. However, it may cause respiratory problems for those who are susceptible.
But what is less well known is that African dust is vital for our coral reefs. In fact, it would not be a stretch to say that the reefs as we know them, which surround Florida & the Bahamas, would not exist without thousands of years of dust plumes.
That’s because, without the dust from Africa, Florida waters are very nutrient-poor. Thus, the coral reefs and the creatures that live there can not flourish.
Over tens of thousands of years, dust has helped build the foundation of the coral reef tract. It is not just a background player, but a key architect. Today, Florida’s reef tract is the 3rd largest in the world!
The dust that comes over from Africa is dense with minerals like iron and phosphorus. This helps feed phytoplankton and other living creatures who live a co-dependent relationship with the coral reef.
The reefs have also used the dust itself as part of its foundation, a building block which can be found inside coral cores taken by scientists, suggesting it has been a consistent part of the reef-building process. In fact, some of the calcium carbonate base material that forms the reefs contains dust-derived elements.
But too much dust can also be bad. Not only can it aid in algae blooms and red tides, but it can also degrade a reef by blocking out sunlight and bringing pathogens with it.
Scientists believe that climate change will change the steering and also amount of dust that is transported across the Atlantic in the coming decades. While the jury is still out, some climate models project a long-term decline in Saharan dust transport across the Atlantic of 30% to 60% by the end of the 21st century. This is due to weakening temperature gradients and thus winds acorss the Sahara.
It remains to be seen what this potential decrease in dust will mean in the longer term.
