Orbital Biosignature Survey: A Bright Blue Coccolithophore Bloom In The Barents Sea
When summer arrives at high northern latitudes, peripheral seas to the Arctic Ocean lose some of their ice cover and bask in long daylight hours. That’s when phytoplankton—microscopic plant-like organisms that often float near the ocean surface—can bloom across large swaths of these waters.
Summer conditions in the Barents Sea, a shallow shelf sea off the northern coasts of Norway and Russia, are conducive to these expansive, visually stunning blooms. In late July and early August 2024, communities of phytoplankton grew and drifted at the whims of winds and currents in the Barents Sea. The VIIRS (Visible Infrared Imaging Radiometer Suite) on the NOAA-21 satellite captured this cloud-free image of the bloom on August 9.
Many phytoplankton species live in these cool waters, but the milky blue color in this scene suggests that the bloom contains coccolithophores, a type of plankton plated with white calcium carbonate.
The coccolithophore species Emiliana huxleyi is a common constituent of Barents Sea blooms at this time of year, as it thrives when waters become warmer and more stratified. In the spring and early summer, when waters are better-mixed and higher in nutrients, blooms are typically composed of diatoms.
A scanning electron micrograph of a single G. huxleyi cell. (Wikipedia) This microscopic form of algae with silica shells and ample chlorophyll appears green in natural-color satellite images.
Tendrils of smoke from wildland fires in northern Russia also drift across the scene. Global Forest Watch reported 42 fire alerts in Murmansk Oblast based on detections by VIIRS sensors from August 5–12, 2024. Although fire is the main driver of tree cover loss in this region, the fire season has been quiet until this point.
NASA Earth Observatory image by Wanmei Liang, using VIIRS data from NASA EOSDIS LANCE, GIBS/Worldview, and the Joint Polar Satellite System (JPSS). Story by Lindsey Doermann.
Astrobiology, Remote Sensing,
