Embedded in the sea ice of the arctic are creatures so small, you can't see them with the naked eye. These microalgae convert energy from sunlight into fuel.
The arctic ecosystem depends on them.
In springtime, the algae bloom brilliant shades of green and draw tiny crustaceans, fish, birds and more to Arctic waters.
But what happens in wintertime, when the sun goes down for months? Do the microalgae enter a state of dormancy and shut down their photosynthetic engines?
Many do.
For several months in winter, the Arctic is in perpetual darkness, or polar night. "It's really a black and white world, where you see some gray shades of things. And you see stars, and the moon," says Clara Hoppe, a biogeochemist at the Alfred Wegener Institute in Germany.
And yet, in late March 2020 when the sun briefly peaked over the horizon, Hoppe managed to capture something astonishing: Arctic microalgae with their photosynthetic machinery up and running. In the game of energy limbo, they could go low.
Hoppe gathered this data aboard the RV Polarstern, as a part of the MOSAiC Expedition. For months, her team gathered samples of sea ice and sea water. Combined with data on light levels beneath the ice, they were able to detect evidence of photosynthesis at extremely low levels of light -0.04 micromoles of photons per square meter per second. This finding was far lower than what had previously been observed in nature.
Hoppe isn't entirely sure how some microalgae are managing to do this, but the finding represents a paradigm shift in how biologists might view the Arctic ocean during the polar night.
"That means that there is a lot more productivity in parts of the oceans that we thought wouldn't be productive," Hoppe told NPR's Short Wave podcast.
Hoppe and her colleagues published these findings in the journal Nature Communications.
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Today's episode was produced by Hannah Chinn. It was edited by Rebecca Ramirez. Tyler Jones checked the facts. Robert Rodriguez was the audio engineer.
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