The image to the right was captured by NASA’s Aqua satellite at 1:30 p.m. that afternoon.

Swirls of light green and blue clearly visible south of Galveston and Lake Charles were caused when turbulence from Ida dredged up sediment on the Gulf floor.

The textured swirls near the surface rapidly give way to darker blue to the south, indicating areas of deep water not obscured by the sediment.

Secondary and different-looking patches of sediment are also clearly visible along the Louisiana coast.

Areas of swirling tan and brown are where runoff from the Mississippi and its tributaries were flowing into the Gulf.

A small plume of dark brown at the Texas-Louisiana border is from the outflow of the Sabine River.

These waterways carry nutrients like iron from the soil and nitrogen compounds from fertilizers. These substances often provide the food to fuel blooms of tiny plants known as phytoplankton along the Gulf Coast.

Since the color of such blooms is often ocean blue and green, NASA observers say that they might have been a contributing factor to the colorful swirls.

October 2009 was the wettest on record in the south-central U.S., causing rivers to run high and carry more sediment than usual to the Gulf.

The brightness and contrast of the photo-like image were adjusted by Earthweek to compensate for the waning midday sunshine of autumn and to provide a clearer view of the sediment swirls.

Full story and image: NASA