Turquoise swirls colored the waters off of northern Canada’s ice-covered Victoria Island in mid-October 2021. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of the scene on October 14.
The gorgeous colors are created by a bloom of phytoplankton in the cool Arctic waters. Phytoplankton are tiny, plant-like organisms that often float near the ocean surface and turn sunlight and carbon dioxide into sugars and oxygen. In turn, they become food for the grazing zooplankton, shellfish, and finfish of the sea. The also play an important but not fully understood role in the global carbon cycle, taking carbon dioxide out of the atmosphere and sinking it to the bottom of the ocean.
While it is impossible to know for sure which species of phytoplankton float in any bloom without taking samples, the milky tones of this milky blue bloom suggest the presence of a type of phytoplankton known as coccolithophores. These organisms possess calcium carbonate plates that appear chalky white when amassed in great numbers, and large colonies typically appear milky blue from space.