Unveiling the Blue Mystery: Hurricane Melissa's Impact on Jamaica's Waters
A stunning natural phenomenon, captured by NASA, reveals the power of nature and its impact on our planet's oceans.
On October 28, 2025, Hurricane Melissa, a category 5 storm, made landfall in Jamaica, leaving a trail of destruction in its wake. With winds reaching an astonishing 295 kilometers per hour, the hurricane not only caused widespread damage to infrastructure and agriculture but also had a profound effect on the island's forests, leaving them battered and brown.
However, the story doesn't end there. Before Melissa reached land, it created an extraordinary natural experiment in the waters south of Jamaica. As the monster storm crawled over the Caribbean Sea, it churned up the water, leading to a unique and rare event that scientists believe is a once-in-a-century occurrence.
The Blue Plume Phenomenon
On October 30, 2025, NASA's Terra satellite, equipped with the MODIS instrument, captured an image of the waters south of Jamaica. The image revealed vast areas colored in a brilliant blue, a sight that left researchers in awe.
This vibrant blue was caused by sediment stirred up from a carbonate platform known as Pedro Bank. Submerged under approximately 25 meters of water, Pedro Bank is slightly larger than the state of Delaware. Normally, this plateau is only faintly visible in natural color satellite images, but when disrupted by powerful storms or cold fronts, its presence becomes more evident.
The suspended calcium carbonate (CaCO3) mud, primarily composed of remnants of marine organisms living on the plateau, turned the water into a captivating Maya blue color. This unique coloration contrasted with the greenish-brown sediment carried out to sea by the swollen rivers on Jamaica's southern coast.
An Extraordinary Geophysical Image
James Acker, a data support scientist at NASA Goddard Earth Sciences Data and Information Services Center, described Hurricane Melissa as having "tremendous stirring power" in the water column. He compared it to Hurricane Beryl, which caused some brightening around Pedro Bank in 2024, but emphasized that Melissa's impact was on a whole new level.
Sedimentologist Jude Wilber, who tracked the plume's progression using multiple satellite sensors, estimated that Melissa affected an area of approximately 37,500 square kilometers on October 30. This area is more than three times the size of Jamaica itself! Wilber, with his decades of experience studying carbonate sediment transport, believes this event was the largest observed during the satellite era.
The sediment acted as a tracer, illuminating currents and eddies near the surface. Some of these currents extended into the flow field of the Caribbean Current heading west and north, while others suggested the influence of Ekman transport. The scientists also observed complexities in the south-flowing plume, which divided into three parts after encountering small reefs. The sinking sediment in the easternmost arm exhibited a cascading stair-step pattern.
A Temporary Coloration with Long-Lasting Effects
While the temporary coloration of the water faded after about seven days as the sediment settled, the changes to Pedro Bank itself may have more lasting consequences. Wilber suspects that the hurricane's strength resulted in a "wipe" of the benthic ecosystem, decimating seagrasses, algae, and other organisms living on and around the bank. The repopulation of this area remains unknown.
Perhaps the most significant consequence for Earth's oceans is the effect of the sediment suspension event on the planet's carbon cycle. Tropical cyclones play a crucial role in transporting carbon from shallow-water marine sediments to deeper waters, where it can remain sequestered for extended periods. Additionally, carbonate sediments dissolve at depth, contributing to another important process in the oceanic carbon system.
Advancing Our Understanding with Satellite Observations
Continuous ocean observations by satellites have greatly enhanced our understanding of these events and their impact on the carbon cycle. Acker and Wilber have been working on remote-sensing methods to quantify the amount of sediment reaching the deep ocean following the turbulence of tropical cyclones. Their recent work with Hurricane Ian over the West Florida Shelf has provided valuable insights.
Now, with the launch of NASA's PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) mission in February 2024, hyperspectral observations are poised to further advance our knowledge in this area. The phenomenon at Pedro Bank following Hurricane Melissa presents a unique opportunity to study complex ocean processes, offering a large natural experiment that cannot be replicated any other way.
Researchers will continue to investigate a range of physical, geochemical, and biological aspects illuminated by this occurrence. As Wilber aptly put it, "This event is a whole course in oceanography." It serves as a reminder of the intricate connections and processes that shape our planet's oceans.
Stay tuned for more updates from NASA as we continue to explore and uncover the mysteries of our home planet.
