Swirls of iridescent green decorated the South Pacific Ocean east of New Zealand’s South Island on January 5, 2008 (local time; January 4, 2008, in UTC). The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite took this picture the same day. In this image, a large, intense phytoplankton bloom appears directly east of Banks Peninsula while a smaller, fainter bloom appears northeast of the peninsula. A very faint, wispy plume appears to the east. The blue-green water along the coastline south of the peninsula is probably sediment re-suspended from the ocean floor by waves and tides, or else washed into the ocean through rivers. Another perspective of this image is available from the Goddard Space Flight Center Ocean Color Team.
Phytoplankton—tiny surface-dwelling ocean plants—thrive in cool waters that are rich in nutrients. Turbulent waters often provide the best environment for producing phytoplankton blooms by supplying a mix waters with differing temperatures and salinities. East of New Zealand, the Indian Ocean and the Pacific Ocean meet at the Southern Hemisphere Subtropical Front. As currents from each ocean brush past each other, they stir up cool, nutrient-rich waters from the ocean depths. When there is sufficient sunlight—January is summer in the Southern Hemisphere—these nutrients fuel blooms of phytoplankton. These plants are the base of the marine food web, and they remove about as much carbon dioxide from the atmosphere on a yearly basis as plants on land.
Clear skies provide a view not just of the ocean but also of New Zealand’s South Island. Snowcaps linger on the island’s mountainous terrain in the west. East of the mountains, which are alternately snow-covered or bare, the landscape is largely green and snow-free, where the island generally sees less precipitation. Banks Peninsula is the remnant of extinct volcanoes that were active between 6 and 11 million years ago.
NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Text by Michon Scott.
