On Jan. 19, 2014, NASA’s Aqua satellite captured an image of a bloom of microscopic organisms off the southeastern coast of Brazil. Biologists working in the area have identified the bloom as a fast-swimming ciliate protist. Though it is not a true phytoplankter, it is an autotroph, i.e., it makes its own food.
Viewed up close, these blooms have a deep red color. But this bloom appears nearly black in the satellite image because of how the ocean scatters and absorbs sunlight. Myrionecta rubra blooms tend to float a meter or two below the water surface, so whatever photons of red light they reflect are likely to be absorbed or scattered on their way back to the surface.
Image courtesy of NASA.