The vast subtropical “gyres” – large systems of rotating currents in the middle of the oceans – cover 40 percent of the Earth’s surface and have long been considered biological deserts with stratified waters that contain very little nutrients to sustain life.
The vast subtropical “gyres” – large systems of rotating currents in the middle of the oceans – cover 40 percent of the Earth’s surface and have long been considered biological deserts with stratified waters that contain very little nutrients to sustain life.
These regions also are thought to be remarkably stable, yet scientists have documented one anomaly in the North Pacific Subtropical Gyre ecosystem that has puzzled oceanographers for years: The region’s chemistry changes periodically, especially levels of phosphorous and iron, affecting the overall nutrient composition and ultimately its biological productivity.
In a new study published this week in Proceedings of the National Academy of Sciences, researchers document what induces these variations: changes in the amount of iron that is deposited into the ocean via dust from Asia.
“We now know that these areas that were thought to be barren and stable are actually quite dynamic,” said Ricardo Letelier, an Oregon State University biogeochemist and ecologist, who in collaboration with David Karl at the University of Hawaii led this study. “Since these areas cover so much of the Earth’s surface, we need to know more about how they work in order to better predict how the system will respond to climate variations in the future.”
Read more at Oregon State University
Image: Asian dust. (Credit: NASA)
