Quick Facts
Where? Winyah Bay, South Carolina. [33.19619564, -79.18145235].
What’s in the photo? The tea-like “black water” that flows into the ocean after Hurricane Sally.
Which satellite took this photo? Landsat 8.
When was this filmed? October 1, 2020.
This 2020 satellite image was taken about two weeks after tea-like “black water” flowed into the ocean from Winyah Bay in South Carolina. Hurricane Sally makes landfall and caused widespread flooding.
Winyah Bay is a coastal estuary near Georgetown, South Carolina, that empties into the Atlantic Ocean. The bay is fed by four blackwater rivers in eastern South Carolina: the Waccamaw, Pee Dee, Black, and Sampit Rivers.
The Blackwater River flows through swamps, marshes, forests, and other ecosystems rich in decaying vegetation. As it decomposes, this decaying vegetation releases chemicals like tannins, phenols, and humic acids that stain the water brown, similar to brewing tea. NASA’s Earth Observation Satellite.
The substance causing this pollution is known as colored dissolved organic matter (CDOM). After heavy rains, floodwaters pick up more CDOM and wash it into nearby rivers, which then drain into Winyah Bay and into the ocean.
Related: 12 Amazing Images of Earth from Space
Hurricane Sally made landfall in Alabama on September 16, 2020, with maximum sustained winds of approximately 110 mph (177 km/h). The Category 2 storm dumped up to 30 inches (76 centimeters) of rain on Florida, Alabama, Georgia, South Carolina, and Louisiana, causing flooding in most of those states, according to the National Weather Service. National Weather Service report.
On October 1 (the day this photo was taken), a monitoring station at Winyah Bay revealed that levels of CDOM in the estuary were more than 50% higher than average for that day. Most of the CDOM has ended up in the ocean. National Aeronautics and Space Administration (NASA)Earth Observatory.
As CDOM levels in the ocean increase, less blue light penetrates deeper into the water column. Deep below the surface, only red light is absorbed, giving the water a rusty color when viewed from above.
Changes in light availability also affect some photosynthetic algae.
“If phytoplankton did not have pigments that could absorb red light, they would not be able to photosynthesize.” Tammy Richardson“This could have huge knock-on effects up the food chain throughout coastal ecosystems,” the University of South Carolina oceanographer told NASA’s Earth Observation satellite at the time, she added.
But some plankton, such as cryptid plants and diatoms, can absorb red light and therefore thrive in dark water, according to NASA’s Earth Observatory.
