Hurricane Melissa Unleashes Largest Resuspension of Ocean Sediments Ever Recorded
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NASA has confirmed that Hurricane Melissa, a Category 5 cyclone that impacted the Caribbean in late October 2025, triggered the most significant disturbance of carbonate sediments observed in the satellite era. The storm’s immense power not only caused widespread damage in Jamaica but also revealed a striking oceanographic phenomenon, staining the surrounding waters a deep blue as it churned up the seabed.
The unprecedented event was meticulously documented and analyzed by NASA, providing invaluable insights into the impact of major cyclones on marine sediment dynamics and the global carbon cycle. Satellite imagery and measurements captured details previously unseen, offering a new understanding of these powerful natural processes.
Unprecedented Sediment Plume Over Pedro Bank
Images from NASA’s Terra satellite revealed that Hurricane Melissa produced the largest resuspension of carbonate sediments ever recorded. This phenomenon occurs when the intense turbulence of a storm agitates the ocean floor, lifting particles of calcium carbonate – remnants of shells and coral – and redistributing them throughout the water column.
According to NASA, the most dramatic resuspension occurred over Pedro Bank, a shallow underwater platform south of Jamaica. Averaging just 25 meters in depth, Pedro Bank is a vital ecosystem teeming with coral reefs, seagrasses, and white sand beds composed of calcified organisms, making it a crucial geological feature in the Caribbean region.
“Tremendous Shaking Power”
A data support scientist at NASA’s Goddard Earth Sciences Data and Information Services Center explained that the hurricane generated “tremendous shaking power” within the water column. Comparing the event to previous storms, the expert noted, “Hurricane Beryl caused some brightness around Pedro Bank in July 2024, but nothing comparable to this.” Despite acknowledging the human cost of the disaster, the scientist emphasized the scientific value of the imagery, calling it “an extraordinary geophysical image.”
A Plume Spanning Over 37,500 Square Kilometers
Jude Wilber, a sedimentologist tracking the sediment plume via satellite sensors, estimated the affected area reached approximately 37,500 square kilometers – more than three times the land area of Jamaica. “It was extraordinary to see the sediment dispersed over such a large area,” Wilber stated, confirming that the Pedro Bank event represents the largest such observation made by satellites to date.
The suspended sediments acted as natural tracers, allowing scientists to observe surface currents, eddies, and the influence of Ekman transport – a physical phenomenon governing water mass movement under wind influence. The calcium carbonate particles, originating from marine organisms, imparted a distinctive deep blue hue to the affected waters.
Ecosystem Impact and Carbon Cycle Implications
Analysis, based on images from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite, showed that the normally faintly visible Pedro Bank was dramatically highlighted by the storm’s sediment plume. Historical sediment samples, collected during expeditions in 1987 and 1988 and archived at the Woods Hole Oceanographic Institution, provided valuable context for understanding the current event. These samples contained calcified algae and Halimeda macroalgae remains, whose finer fragments remain suspended longer during turbulent conditions.
The sediment plume branched into three distinct sections as it encountered smaller reefs, with ladder-like patterns observed in the eastern region, indicating sinking material. Satellite analysis tracked the phenomenon for a week, until the blue coloration dissipated and the sediment settled.
NASA experts underscored the importance of satellite observations for understanding these episodes and quantifying sediment transport following cyclones. As Wilber put it, “this event is a whole course in oceanography.”
The NASA study concluded that the sediment resuspension at Pedro Bank could have lasting consequences for the local marine ecosystem. Wilber suspects the hurricane’s intensity resulted in a “wipe” of the benthic ecosystem, potentially eliminating seagrasses, algae, and other organisms, with an uncertain timeline for repopulation.
Furthermore, the event highlights the connection between these occurrences and the global carbon cycle. Tropical cyclones facilitate the transport of carbon stored in shallow marine sediments to deeper waters, where it can remain sequestered for extended periods. Acker and Wilber have developed satellite analysis methods to estimate sediment volume transported after storms like Melissa.
Advancements in technology, such as NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission launched in February 2024, are expanding our ability to study these phenomena. The agency emphasized that the Pedro Bank episode following Hurricane Melissa presents a unique opportunity to investigate the physical, geochemical, and biological processes in marine environments impacted by large storms.
