The seas around Antarctica can, at times, resemble a garden. Large-scale experiments where scientists spray iron into the waters, literally fertilizing phytoplankton, have created huge man-made algal blooms. Such geoengineering experiments produce diatoms, which pull carbon dioxide out of the air. Experts argue that this practice can help offset Earth’s rising carbon dioxide levels. However, the experiments are controversial and, according to a new study at the Georgia Institute of Technology, perhaps not as effective as expected.
Georgia Tech research published online Monday in Nature Communicationsindicates that diatoms stuff more iron into their silica shells than they actually need. As a result, there’s not enough iron to go around, and the added iron may stimulate less productivity than expected. The study also says that the removal of iron through incorporation into diatom silica may be a profound factor controlling the Southern Ocean’s bioavailable pool of iron, adversely affecting the ecosystem.
“Just like someone walking through a buffet line who takes the last two pieces of cake, even though they know they’ll only eat one, they’re hogging the food,” said Ellery Ingall, a professor in Georgia Tech’s College of Sciences. “Everyone else in line gets nothing; the person’s decision affects these other people.”
Ingall says, similarly, these “hogging” diatoms negatively affect the number of carbon-trapping plankton produced. They also outcompete other organisms for the iron.
Read more at: Phys.org