This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Almost every marine ecosystem on Earth carries some human fingerprint: a fishery worked down from its historical abundance, a shipping lane, a warming trend already reshaping which species can live where. The Ross Sea, an Antarctic marginal sea of the Southern Ocean, is the exception scientists point to when they want to describe what an intact ocean food web actually looks like, from the phytoplankton at the base up through krill, fish, penguins, seals and whales, largely undisturbed by the industrial fishing that reshaped almost every other productive ocean region across the twentieth century. That is the basis for calling it, as many researchers have, the most pristine marine ecosystem left on the planet.
In 2016, twenty four countries and the European Union agreed under the Convention for the Conservation of Antarctic Marine Living Resources to protect it: a marine protected area of more than 1.5 million square kilometers, about 1.1 million of it a general protection zone closed to all commercial fishing, the largest marine protected area on Earth at the time it was created. The protection took effect on 1 December 2017 and runs for 35 years, a deliberately time limited agreement rather than an indefinite one, which is itself part of what the negotiation required to bring every party to agreement.
The sea is home to roughly 38 percent of the world's Adelie penguins and about a quarter of its Emperor penguins, along with Weddell seals, Ross seals, minke whales and killer whales, all part of a food web that industrial fishing never reorganized the way it reorganized food webs elsewhere. It sits within the Marine biome alongside every other ocean ecosystem this atlas records, from coral reefs to kelp forests, but as the one entry in that biome that comes closest to a baseline: not a place recovering from disturbance, but one that was mostly never disturbed at all.