Last update: August 23rd, 2019 at 9:00 am
Springtime brings increased sunlight, bursts of nutrients, and changing water conditions to the Gulf of Alaska. The combination promotes massive blooms of phytoplankton—microscopic, plant-like organisms that turn sunlight into food and then become fodder for some of the richest fisheries on the planet.
This image shows the southern Alaska coast and the Gulf of Alaska on May 2, 2014. It is a composite knitted together from several orbits of the Aqua satellite and its Moderate Resolution Imaging Spectroradiometer (MODIS). Two comma-shaped cloud formations (image center and far left) dominate the skies over the North Pacific Ocean. These clouds were likely moving around and ahead of a low-pressure system, showing some cyclonic circulation. Dark green traces of a phytoplankton bloom are just visible off of the Alaska coast at top center.
The waters around Alaska are among the most biologically productive in the world. Ash from the many volcanoes and wind-blown glacial powder occasionally seed the seas with the nutrients necessary for phytoplankton growth. The rivers carry their share of rich sediments, and the stormy, turbulent waters offshore sweep up a fair bit from the seafloor. So when spring and summer bring more sunlight, the waters are primed for explosive blooms of aquatic plants and phytoplankton—and then the many crabs, fish, and whales that feed on them.
Credit: NASA images by Norman Kuring, NASA’s Ocean Color web. Caption by Mike Carlowicz.