Get all your news in one place.
100’s of premium titles.
One app.
Start reading
LiveScience
LiveScience
Harry Baker

Earth from space: 'River of tea' bleeds into sea after Hurricane Sally smashes into US coast

A satellite photo of dark water flowing into the ocean from an estaury.
quick facts

Where is it? Winyah Bay, South Carolina. [33.19619564, -79.18145235].

What's in the photo? Tea-like "blackwater" flowing into the sea after Hurricane Sally.

Which satellite took the photo? Landsat 8.

When was it taken? October 1, 2020.

This 2020 satellite image shows tea-like "blackwater" bleeding into the sea from South Carolina's Winyah Bay around two weeks after Hurricane Sally made landfall and triggered widespread flash flooding.

Winyah Bay is a coastal estuary that's located near Georgetown, South Carolina, and flows into the Atlantic Ocean. It is fed by four blackwater rivers: the Waccamaw River, the Pee Dee River, the Black River and the Sampit River, all of which run through eastern South Carolina.

Blackwater rivers flow through swamps, wetlands, forests and other ecosystems that are rich with decaying vegetation. As it breaks down, this rotting vegetation releases chemicals such as tannin, phenol and humic acid, which stain the water brown — similar to brewing tea, according to NASA's Earth Observatory.

The staining material is known as colored dissolved organic matter (CDOM). After heavy rains, the floodwater gathers more CDOM and feeds into nearby rivers, before being washed into Winyah Bay and then flushed into the ocean.

Related: 12 amazing images of Earth from space

Winyah Bay and the four blackwater rivers that feed it all flow through heavily vegetated ecosystems like swamps and forests. (Image credit: NOAA)

On Sept. 16, 2020, Hurricane Sally made landfall in Alabama with max winds of around 110 mph (177 km/h). The Category 2 storm dumped up to 30 inches (76 centimeters) of rain across Florida, Alabama, Georgia, South Carolina and Louisiana, triggering flash flooding in most of those states, according to a National Weather Service report.

On Oct. 1 (the day this photo was taken), monitoring stations in Winyah Bay revealed that the levels of CDOM in the estuary were more than 50% higher than average for that date. Most of the CDOM ended up in the ocean, according to NASA's Earth Observatory.

Increased CDOM levels in the ocean mean that less blue light can penetrate deep into the water column. Only red light can be absorbed deep below the surface, giving the water a rusty color when viewed from above.

The change in available light also affects some photosynthetic algae.

"If phytoplankton do not have pigments that can absorb red light, then they will not be able to photosynthesize," Tammi Richardson, an oceanographer at the University of South Carolina, told NASA's Earth Observatory at the time. This can have big knock-on effects on the food webs across the coastal ecosystems, she added.

However, some plankton, such as cryptophytes and diatoms, can still absorb red light, which lets them thrive in blackwater, according to NASA's Earth Observatory.

Sign up to read this article
Read news from 100’s of titles, curated specifically for you.
Already a member? Sign in here
Related Stories
Top stories on inkl right now
One subscription that gives you access to news from hundreds of sites
Already a member? Sign in here
Our Picks
Fourteen days free
Download the app
One app. One membership.
100+ trusted global sources.