Despite being a staggering 140 million miles away from our planet, Mars exerts a profound influence on Earth’s deep oceans by driving the formation of massive whirlpools, a groundbreaking study reveals. This discovery emerged from an extensive analysis of sediments extracted from the depths of the sea across numerous sites over the last fifty years, offering a glimpse into Earth’s climatic history spanning tens of millions of years. The aim was to unravel the mysteries of the deep ocean currents’ strength.
The findings, which took the scientific community by surprise, indicated that the deep-sea currents have experienced phases of weakening and strengthening in sync with 2.4 million-year climatic cycles. This pattern, as detailed in the research published in the journal Nature Communications, was unexpected. Adriana Dutkiewicz, a sedimentologist at the University of Sydney and co-author of the study, attributed these cycles to the gravitational interplay between Mars and Earth as they orbit the Sun, marking the first time such a connection has been established.
This gravitational dance, known as “resonance,” involves the mutual gravitational forces exerted by two orbiting bodies on each other. This interaction not only alters the shape of their orbits but also impacts their proximity to the Sun. For Earth, this means periods of increased solar energy, leading to a warmer climate and, consequently, more vigorous ocean currents.
However, it’s crucial to note that these natural climatic cycles, spanning 2.4 million years, are distinct from the rapid global warming currently observed due to human activities, such as the burning of fossil fuels. Dietmar Müller, a professor of geophysics at the University of Sydney and another co-author of the study, emphasized this distinction.
The study describes these ocean currents, or eddies, as colossal whirlpools capable of reaching the ocean floor, eroding it, and causing significant sediment accumulation. The researchers were able to trace these powerful eddies through disruptions in the sediment layers they examined. While satellite data has only recently allowed us to observe changes in ocean circulation directly, sediment cores serve as a vital tool for understanding past climate conditions.
Müller warned that if the current trajectory of human-induced warming persists, its impact will overshadow all other processes for the foreseeable future. Yet, the geological record still offers valuable insights into ocean behavior in a warmer world.
The research also suggests that these eddies could potentially mitigate some effects of a potential collapse of the Atlantic Meridional Overturning Circulation (AMOC), a crucial oceanic conveyor belt. Scientists have raised concerns about the health of this system, with some fearing early signs of collapse due to global warming.
A collapse of the AMOC would lead to dramatic climate shifts, including rapid temperature changes in various regions. However, Müller clarified that the study does not predict the AMOC’s fate but rather highlights other ocean mixing processes that could occur, albeit with different effects.
The possibility that intensified deep-ocean eddies in a warmer world could prevent ocean stagnation is a significant finding. Joel Hirschi, a marine systems modeling expert at the National Oceanography Centre in the UK, not involved in the research, acknowledged the discovery of a 2.4 million-year cycle in sea sediments as noteworthy. However, he cautioned that the link to ocean circulation and the assertion that deep ocean circulation strengthens in warmer climates requires further evidence.
As satellite observations reveal more active eddies in recent decades, it’s clear that not all currents reach the ocean floor, potentially limiting their ability to prevent sediment buildup. The study’s authors hope their findings will contribute to more accurate climate modeling in the future, despite uncertainties about how various processes will affect deep-ocean currents and marine life.