scientists have found cycles of 2.4 million years between the strength of deep-sea currents

The strength of deep-sea currents varies in cycles of 2.4 million years

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Using geological data from the deep sea, scientists have discovered a connection between the orbits of the Earth and Mars, and also found the reason for the acceleration of circulation in the depths of the ocean.

Scientists from the universities of Sydney and the Sorbonne have established that there is a cycle of 2.4 million years during which deep currents grow and weaken. The results of their research published in Nature Communications.

Scientists used deep-sea sediment records to test for connections between sediment shifts and changes in Earth’s orbit.

“A hiatus in deposition indicates intense deep-sea currents, while continuous sediment accumulation indicates calmer conditions.

Combining these data with extended spectral analysis allowed us to determine the frequency of breaks in deposition over a period of 65 million years.” – said geologist Adriana Dutkevych from the University of Sydney.

Scientists have been trying to determine how currents on the ocean floor change as the climate warms: do they become more energetic or slow down.

Sediment disruption indicates faster eddies on the seafloor, while persistent sediment accumulation indicates calmer conditions.

The scientists based their analysis on 293 scientific deep-sea wells around the world. In them, they found evidence of 387 cracks in sedimentary rocks that appeared over the past 70 million years.

Tracking the timing of these ruptures, they noticed an interesting clustering — a 2.4-million-year cycle that coincided with the major astronomical cycles of Earth and Mars.

“We were surprised to find these 2.4 million cycles in our deep-sea sedimentary data. There is only one way to explain them: they are related to the interaction cycles of Mars and the Earth revolving around the Sun“, the scientist added.

Geophysicist Dietmar Müller from the University of Sydney explained that the gravitational fields of the planets of the solar system interact with each other. When they get too close to each other, a resonance occurs, which causes increased circulation of water in the oceans.

“Freezing and melting of sea ice is not the only mechanism that affects the circulation in the depths of the ocean. Deep-sea eddies are predicted to intensify in a warmer, more energetic climate system as strong storms become more frequent”, explained Professor Müller.

On the other hand, severe storms become more frequent in much warmer climates. They create eddies that stir the sediment and can reach the deepest parts of the ocean. This could mean that the oceans are somewhat more resilient to climate change than previously thought.

“Our deep-sea data for 65 million years suggests that warmer oceans have more intense deep circulation. This would potentially avoid stagnation in the ocean even if the Atlantic meridional circulation slows down or ceases altogether.”– added Dr. Dutkevich.