"It naturally raises the question as to whether and how much plastic we're inhaling," researcher Melanie Bergmann said.
Scientists found the ice contained up to 12,000 microplastic particles per liter.
The video shows what's happening both outdoors and inside the submarine, too.
The Sibir weighs 33,500 tons, is more than 576 feet long and is fueled by two nuclear reactors, giving it the power to plow through icy Arctic terrain.
The Arctic is a priority zone for the Russian Navy's current expansion and modernization strategy.
The project would, for the first time, enable researchers to study what exactly goes on in the Arctic ocean during wintertime.
Most of the Arctic isn't up for dispute. But the little that is will take years, even decades, to resolve.
"The Arctic is a unique treasure," Clinton tweeted. "Given what we know, it's not worth the risk of drilling."
The final permit came after the company repaired a ship essential to its exploration in the region this season.