The Hakon-Mosby mud volcano is a deep-sea feature near the Norwegian continental slope, 1,250 metres below the surface. Its vents release gas, water, and sediment from within the Earth onto the seabed. In the novel, the volcano matters not only as a geological landmark but as a possible source of warmth that a Yrr collective could harness to alter conditions around the slope and, in turn, affect the wider ocean system.

Location and geological setting

The volcano lies close to the Norwegian continental slope at a depth of 1,250 metres. Gas, water, and sediment rise from inside the Earth and emerge at the seabed. The surrounding water is not hot, but it is warmer than the water elsewhere—an unremarkable difference until the novel treats warmth as a resource that an immense biological collective might gather and redirect.

The setting belongs to the little-known depths beyond the continental shelf. The sea floor is not simply an extension of familiar land: its relief and depth shape what can happen there, while the water above it obscures the processes underway. The Hakon-Mosby mud volcano gives that hidden terrain a specific point of reference and a measurable physical feature around which the proposed mechanism can be imagined.

A source of warmth in the Yrr model

During a discussion of what the Yrr might be capable of, Karen Weaver outlines a computer model in which the organisms aggregate into an enormous collective and form a long, narrow funnel. Its walls would be only several cells thick, but the structure would extend over several kilometres and require billions of cells. The funnel’s circumference would match the volcano’s main crater, roughly 500 metres across.

In the model, the collective uses the funnel to draw comparatively warm water from the volcano and transport it to the area where worms and bacteria have been burrowing. The volcano is thus not described as causing a collapse by itself; it supplies heat within a proposed sequence in which the Yrr redirect local conditions and the slope then gives way. The distinction matters: the explanation presents an imagined biological intervention built around real features of the seabed, not a confirmed account of an observed event.

Wider implications

Weaver extends the same hypothetical method beyond the Norwegian continental slope. A Yrr collective, she suggests, could use it to warm waters near Greenland and around the poles, melting ice caps and disabling the Gulf Stream. The mud volcano consequently serves as a local demonstration of a much larger possibility: collective life might manipulate environmental processes at a scale that connects a seabed slope to polar ice and ocean circulation.

That possibility also sharpens the novel’s contrast between human instruments and the Yrr’s proposed form of agency. The volcano’s depth, crater, vents, and temperature difference can be measured, but the model imagines those physical particulars reorganized into a living structure spanning kilometres. A geological feature that might otherwise remain remote becomes a point where deep-sea geology, biological coordination, and planetary consequences meet.