MELBOURNE, Jan. 27 (Xinhua) -- Narrow bands of ocean covering just over a third of global seas absorb nearly three-quarters of the carbon dioxide (CO2) that oceans pull from the atmosphere, a study shows.
The study, published in Nature Climate Change, reveals that ocean fronts play a far larger role in regulating Earth's carbon cycle than previously understood, said a statement from Australia's University of Tasmania (UTAS) on Tuesday.
The study, led by the UTAS Institute for Marine and Antarctic Studies (IMAS), found that these dynamic regions, where water masses meet and mix, creating turbulent zones rich in marine life, cover about 36 percent of the global ocean but take up 72 percent of total oceanic CO2, roughly 1.8 billion tons of carbon a year, it said.
"This is the first time we've been able to quantify the disproportionate role that ocean fronts play in absorbing atmospheric CO2 on a global scale, and it has major implications for climate modelling," said lead author Yang Kai, who completed the research during his PhD at the IMAS.
Using more than 2 decades of satellite data, researchers linked changes in ocean front activity to both phytoplankton biomass and CO2 uptake.
Ocean fronts are most common in mid-to-high latitudes where colliding water masses drive downwelling and upwelling that bring nutrient-rich deep water to the surface, fueling massive phytoplankton blooms, the study said, adding these plants absorb CO2 during photosynthesis and, upon dying, sink it to the deep ocean for centuries-long storage.
The study showed that fronts are shifting toward the poles, with intensified regions absorbing carbon at twice the global average rate.
"Current climate models struggle to represent the fine-scale dynamics of ocean fronts because their resolution is often too coarse to capture these relatively narrow zones," Yang said. ■
