Huge algal blooms in the Indian Ocean dance to their own rhythm. In other places, such blooms occur every spring, when masses of tiny plants multiply in surface waters. But off the coast of Madagascar, the greenery erupts in late summer, and only every few years. Now, one researcher attributes this unusual pattern to typhoons that boost the amount of iron in the ocean.
Springtime blooms occur as surface-temperatures rise, warming nutrient-rich water that has risen from the cold ocean depths all winter. This creates the perfect environment for single-celled plants to thrive. But the erratic summer timing of the Indian Ocean bloom has puzzled scientists.