Aono Raina High Sea

At roughly ten degrees south, the central Pacific lies near a transition in its surface waters. Along the 150th meridian west, nitrate becomes scarce in the upper mixed layer south of this latitude, while a deeper band of phytoplankton lies below the thermocline. The westward South Equatorial Current varies with the seasons here; farther north it is stronger, while an eastward countercurrent may appear in the warmer part of the year.