Italy’s Adriatic Coast was fringed in jewel-toned color in mid-September 2019. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of the colorful scene on September 13 as it passed over the region.
The large Po River Delta sits along the northeastern edge of the Italian coastline, surrounded by green-tinted water. The Po pours large amounts sediment-laden water into the Adriatic Sea. These sediments often appear tan when they are near the surface and, as they sink, reflectivity changes to make sediment appear green from space. Along with sediment, the Po River contributes large amounts of fresh water to the salty Adriatic and also creates currents, especially along the Italian coastline. Fresh water influx, mixing currents, and nutrients carried by the river set up conditions ripe for the growth of phytoplankton (microscopic plant-like organisms). When phytoplankton reproduce vigorously, they often created large, colorful blooms that can be seen from space. The bright color along Italy’s Adriatic Coast may be created by a phytoplankton bloom, from sediment stirred by the currents, or by a combination of both.