"Being able to use X-rays and see the element content of individual microscopic phytoplankton has completely altered our perspective on how these organisms use iron and how that could affect C02 levels," Ingall said.
In the paper "Role of biogenic silica in the removal of iron from the Antarctic seas" published June 10 in the journal Nature Communications, scientists conservatively estimate that 2.5 milligrams of iron annually is removed from every square meter of surface water in the Ross Sea and sequestered in silica skeletons on the ocean floor. This is roughly equivalent to the total amount of iron deposited annually into the Ross Sea surface through snow melt, dust and upwelling of seawater.
The same process may be occurring in the Southern Ocean and have a greater impact there, because this region dictates the nutrient mix for the rest of the world's oceans through migratory current patterns.
More study is needed to know just how much iron is used to make the silica skeletons and how much gets trapped on the ocean floor, the researchers said.
"This gap in our knowledge, combined with renewed interest in iron fertilization as an approach to the current climate crisis, makes it crucial that we have an improved understanding of iron cycling in marine systems," Ingall said.
Measurements of iron and silicon content in silica from living phytoplankton collected in the coastal seas of West Antarctica was derived through X-ray analysis on beamlines 2-ID-D and
|Contact: Tona Kunz|
DOE/Argonne National Laboratory