The ocean is vital to all of humanity. Besides generating revenue through industries like fishing and shipping, it also plays a crucial role in regulating climate and weather patterns. Now, experts have discovered a concerning change in the ocean that could potentially cause significant problems.
A recent study conducted by researchers at MIT and published in Nature Communications has revealed that ocean currents are slowing and these experts are now concerned about its potential impact on climate change (via BGR).
This study focuses on a particular phenomenon called the Meridional Overturning Circulation (MOC). The MOC is a system of ocean currents regulating Earth's climate by moving deep, nutrient-rich water to the ocean's surface.
A Humpback whale swims in the surface of the Pacific ocean at the Uramba Bahia Malaga natural park in Colombia, on September 1, 2022.JOAQUIN SARMIENTO/AFP via Getty Images
What Is Changing in the Ocean?
According to the study, MOC, including the Atlantic (AMOC) and Southern Ocean (SMOC) components, is essential for bringing old, nutrient-loaded waters back to the surface.
This process supports the growth of phytoplankton, tiny ocean plants that require sunlight, carbon, macronutrients (like nitrate and phosphate), and micronutrients (like iron) to thrive.
Phytoplankton not only form the base of the marine food web but also play a vital role in the global carbon cycle. They absorb carbon dioxide (CO2) during photosynthesis, some of which sinks to the ocean floor when they die, helping to regulate atmospheric CO2 levels.
In some regions of the ocean, however, phytoplankton growth is limited by the availability of iron and sunlight. The Southern Ocean, for example, is particularly low in iron because it does not receive much from external sources.
This incomplete use of nutrients results in higher CO2 release into the atmosphere. As the study points out, "Changes in MOC strength affect CO2 levels in the atmosphere, influencing climate cycles."
The research team, headed by MIT scientists, explains that a reduction in nutrient upwelling, due to slower ocean currents, leads to less biological activity, even less iron, incomplete nutrient use, and consequently, more CO2 release.
The slowing down of ocean currents has significant implications for climate change. Weaker circulation could mean less carbon dioxide is pulled down from the atmosphere by the ocean, but it might also release more of the stored deep ocean carbon.
The study suggests this could accelerate the accumulation of CO2 in the atmosphere, exacerbating global warming and hastening the planet's decline.
Increased atmospheric CO2 levels contribute to the greenhouse effect, trapping more heat in the Earth's atmosphere. This can lead to rising global temperatures, potential thawing of ancient ice shelves, and rising sea levels, posing a threat to coastlines around the world.
The researchers emphasize the urgency of addressing this issue by finding ways to cut emissions now to buy more time to mitigate the climate change problem.
