Life beneath the Arctic ice: New findings on extreme photosynthesis

Scientists have long been trying to determine whether life exists beyond Earth and, if so, under what conditions it might develop. It turns out, however, that there is still much to discover on our planet. The journal "Nature Communications" discusses one breakthrough in this field. In its pages, researchers elaborate on their discovery beneath the Arctic ice.

Conditions can be so extreme deep in the oceans and seas around the world that many species are unable to survive. However, this does not mean that such inhospitable areas lack life. Researchers have repeatedly demonstrated that even at depths of several miles, some creatures have adapted to these harsh conditions.

According to research by Clara J. M. Hoppe and her team from the German Alfred-Wegener-Institut, life can develop even deep beneath the Arctic ice. "Photosynthesis in the ocean is possible under much lower light conditions and can, therefore, take place at much greater depths than previously assumed," they reveal.

The researchers studied, among others, microalgae living beneath the snow and ice cover of the Arctic Ocean. They provided evidence that life can indeed thrive under the ice at the North Pole, despite exceptional low light levels. Even when the sun barely rises above the horizon, and in near-total darkness where the algae are located, plants still perform photosynthesis – even in very low light conditions.

Experts explain that photosynthesis converts sunlight into biologically functional energy, thus creating the foundation for life on Earth. Until now, it was assumed that the light levels under the Arctic Ocean ice were well below the critical minimum required for photosynthesis. However, it turns out that plants can accumulate biomass even with light levels close to this minimum.

"It is very impressive to see how efficiently the algae can utilise such low amounts of light. This shows once again how well organisms are adapted to their environment," Hoppe explains. She emphasizes that the snow-covered ice in the Arctic allows only a few photons of incoming light to pass through.

Scientists report that they needed to freeze special, newly developed measuring instruments to study such minimal light levels during the Arctic winter. It was challenging to account for irregularities under the ice due to changes in the thickness of the ice and snow. Still, ultimately, they determined with high precision how many photons appeared beneath the ice.

Hoppe's team's research is essential for the entire planet because it illustrates what plants are capable of – not just in the Arctic but globally. This insight allows scientists to speculate that many organisms in other regions may have developed the ability to perform photosynthesis under challenging conditions.