A green wave measures thousands of miles across the ocean and is responsible for drawing nutrient-rich water from the ocean depths to the surface, according to Nature. Once the nutrients are near the surface, plankton that require photosynthesis to generate energy may make use of them.
The upper 50 to 150 meters of the ocean is where sufficient sunlight is able to penetrate and sustain photosynthetic plankton. Since these creatures cannot travel against ocean currents, they are at the mercy of oceanic forces, such as green waves, to pump nutrients to this surface layer. In areas of the ocean's surface where green waves are present, satellite imagery detects increased levels of chlorophyll. This is a result of the increased number of plankton taking advantage of the added nutrients to grow in number. This increase is more prevalent along the front edge of the green wave. This detectable increase in chlorophyll levels is the reason why these types of oceanic movements have been colloquially termed "green waves," making reference to the green pigment found in chlorophyll. Rosby waves, one of the most common forms of green waves, measure only a few centimeters in depth and travel approximately 10 centimeters per second.