Deep ocean currents surrounding Antarctica play a crucial role in sustaining marine life. However, a new study reveals that these currents have slowed significantly and may soon cease due to rising global temperatures.
Vital ocean currents around Antarctica, providing 40% of the world’s deep ocean with fresh nutrients and oxygen, have slowed by 30% since the 1990s due to global warming. This reduction has triggered concerns about stagnating deep-sea currents and subsequent impacts on marine life. The ongoing influx of fresh meltwater from the Antarctic ice shelves threatens to grind these currents to a halt, causing profound changes to ocean circulation.
The Silent Engines of Marine Life
Antarctic bottom waters, driven by dense, cold water from the Antarctic continental shelf, sink deep below 10,000 feet. From these depths, they spread into the Pacific and eastern Indian oceans, forming a network of currents essential to global marine life. They are, as Professor Matthew England describes, the “lungs” of the oceans.
However, these silent engines are beginning to falter as warming temperatures unlock vast quantities of less-dense fresh water from Antarctic ice shelves. The influx of fresh water slows down the circulation of these currents, raising concerns for the marine ecosystem.
Abyssal Currents: At The Brink Of Stagnation
A new study led by England confirms predictions of slowing Antarctic bottom waters. By studying changes in bottom water entering the Australian Antarctic Basin from 1994 to 2017, the team recorded a 30% reduction in velocity. This decrease suggests that these abyssal currents, critical to the circulation of nutrients and oxygen, are beginning to stagnate.
If these currents slow down, marine life that dies off and sinks to the ocean depths may no longer be brought back to the surface. This stagnation may sever a vital nutrient cycle, crippling marine productivity.
This study opens avenues for more research into the impact of warming temperatures on ocean currents. Further studies could investigate how these changes affect the broader marine ecosystem and their potential effects on global climate. Additionally, the results offer an imperative for research into strategies to mitigate the effects of global warming on these vital ocean currents.