Mysterious white clouds keep popping up near the Bahamas, and no one knows why: ScienceAlert

Mysterious white clouds keep popping up near the Bahamas, and no one knows why: ScienceAlert

The stretch of ocean sandwiched between Florida and the Bahamas is one of the most well-studied marine environments in the world, and yet it’s also the epicenter of an enduring geological mystery.

Ever since the 1930s, scientists in the region have noticed strange billowing white clouds appearing in the turquoise calm of the water’s surface.

The curious phenomenon has been dubbed a “whiting event,” and scientists still don’t understand why it occurs in the Bahamas.

For researchers at the nearby University of South Florida (USF), it has become something of a “white whale.”

Bahama Whiting Events
2015 satellite images of Bahamas whiting events. (NASA Earth Observatory/Joshua Stevens, using US Geological Survey data)

The mind-boggling stretches of light-colored ocean are sometimes spotted in other oceans and lakes around the world, but in the Bahamas they’re popping up more often than usual.

Direct sampling of the turbid water suggests that they contain high concentrations of carbonate-rich particles.

Much of the Bahama Archipelago sits on a submerged carbonate platform known as the Bahama Banks. Does this mean sediments are rising to the surface? Or could it be that the phytoplankton flowers actually produce the suspended material?

No one knows the answers to those questions, but USF scientists are determined to find out. They used satellite images from NASA to show how whiting events ebb and flow in the Bahamas.

The team doesn’t know if the trends they identified are natural or man-made, but what they do know is that from 2003 to 2020, the magnitude of these whiting events seemed to correlate with the seasons.

The largest spots occurred from March to May and from October to December. On average, the white spots were about 1.5 square miles each. On a clear-sky day, satellite images usually captured about 24, covering a total area of ​​32 square kilometers (12 sq mi).

However, between 2011 and 2015, the spot suddenly swelled in size, covering more than 200 square kilometers of the ocean at its peak (77 square miles). However, in 2019, the patches have shrunk again, although they never got as small as before.

The findings suggest that a 10-year cycle may be at play. But a cycle of what exactly?

“I wish I could tell you why we saw that spike in activity, but we’re not there yet,” said USF oceanographer Chuanmin Hu.

“We’re seeing some interesting connections between environmental conditions, such as pH, salinity of water and wind and current behavior, but we can’t yet say what exact mechanical, biological or chemical processes were responsible for that spike in activity.”

More direct field experiments are needed, and not just in the Bahamas. Comparing whiting events in other regions can help scientists figure out which features they have in common.

USF researchers have tested their model with preliminary success on whiting events in the Great Lakes, but now need to support those patterns on the ground, or rather, in the water.

For example, some studies have shown that whiting is more common in places with muddy sediments.

In addition, it could be that some ocean conditions favor the suspension of sediments and calcium carbonate in the water column. As mentioned earlier, recent satellite data suggests that white spots in the Bahamas are more common in spring and winter, and this is when Florida currents that run from north to south alternate.

Without more evidence, all of these theories will remain just that.

The study is published in Remote Sensing of the environment.

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