For several weeks in May and early June, daily satellite images of the North Atlantic Ocean west of Ireland have captured partial glimpses of luxuriant blooms of microscopic marine plants between patches of clouds. On June 4, 2007, the skies over the ocean cleared, displaying the sea’s spring bloom in brilliant color. A bright blue bloom stretches north from the Mouth of the River Shannon and tapers off like a plume of blue smoke north of Clare Island.
Those who live in the mid- to high-latitudes of the planet are familiar with the flush of green that comes with early summer as plants mature in the long, warm days. The ocean, too, comes alive during the spring and summer at those latitudes. During the darkness of winter, when the growth of plant-like marine life slows, nutrients accumulate in the surface waters of the cold northern (or southern) oceans. When light returns in the spring and summer, these plant-like organisms—phytoplankton—proliferate in the surface waters. Spring and early summer phytoplankton blooms can cover a broad swath of the ocean, providing an abundance of food to marine life.