Global warming reverses water cycle in the Pacific Ocean
Scientists have determined that global warming slows down vertical currents in the Pacific, reversing the age cycle of water and threatening ecosystems.
A new oceanography study conducted at the University of California, San Diego, revealed that global warming has caused a fracture in the water cycle of the Pacific Ocean, reversing vertical currents and affecting oxygen levels.
Surprising fracture in the water cycle
An oceanography study conducted within the University of California, San Diego determined that global warming has led to a surprising fracture in the water cycle of the Pacific Ocean. With the slowing of ocean currents, a picture has emerged where young and oxygenated waters age, while deep, oxygen-depleted older waters remain locally younger.
Definitions of young and old water
In ocean science, waters that lose contact with the surface and consume their dissolved oxygen are defined as old, while surface waters that have direct contact with the atmosphere and contain fresh oxygen are defined as young. This classification forms the basis for understanding the state of ocean layers.
100-year simulation and thermocline
Researchers developed a 100-year current simulation to predict the effects of the climate crisis on water layers in the Pacific. During the examinations, a major circulation anomaly was detected in the upper thermocline layer, which is located at a depth of 200 to 1000 meters and forms the transition between surface waters and the cold deep sea.
Slowing of vertical mixing in layers
It was determined that vertical mixing between ocean layers slowed down due to the decrease in the density of warming surface waters. As a result of fresh and young water coming from above being unable to mix downwards in the Subtropical North Pacific, the water in the thermocline layer ages rapidly and remains oxygen-free.
Opposing movements in the tropical zone
In contrast, it was revealed that in the Tropical Pacific, the upward velocity of oxygen-free older water seeping from the deeps has been cut. This situation leads to the water in the relevant tropical layer remaining relatively younger.
Connection with the Southern Ocean
The research team noted that this opposing movement experienced in the tropical belt is directly linked to the warming of the Southern Ocean surrounding Antarctica. It was emphasized that the temperature increase at one end of the ocean locks vertical currents thousands of kilometers away.
Oxygen loss and dead zones
Attention was drawn to the fact that the North Pacific will be the region to suffer the harshest oxygen loss in terms of marine life in the coming century. Experts warned that the halting of vertical water circulation could lay the groundwork for large-scale dead zones in ocean ecosystems.