Paleocene

The Paleocene is the deep-time setting for a proposed chain linking a meteor impact to marine extinctions and, possibly, mutations in marine parasites. The novel uses this geological period not as background alone, but as the starting point of an ecological argument: a parasite shaped by its hosts and environment can become dangerous when those limits change.

The Impact Hypothesis

The argument begins with Luis Alvarez’s theory, based on an unusually high concentration of iridium in clay layers at Gubbio in the northern Apennines and at Stevn’s Klint in Denmark. Alvarez proposed that a meteor struck Earth about 65 million years ago. Between four and nine miles in diameter, it would have released energy comparable to 100 million megatons of TNT when it exploded.

The impact’s ash cloud, according to the article Smilla reads, blocked sunlight for at least several days. Food chains collapsed; many marine and submarine microorganisms were annihilated, with further consequences for larger herbivores and carnivores. The text presents these claims as the basis of a theory, rather than as a complete explanation of every extinction.

A Proposed Marine Afterlife

Drawing on discoveries in the Barents Sea and Davis Strait, the article considers whether radiation from the explosion might explain mutations among marine parasites in the early Paleocene. It also raises the possibility that such mutations contributed to the extinction of large sea animals. The connection is explicitly speculative: the geological catastrophe is offered as a possible cause of biological change, not as proof of a single, settled chain of events.

This hypothesis gives the Paleocene a continuing relevance in the novel. The period becomes the remote point at which an altered relationship between parasite, host, and marine environment might have begun. The present-day danger is not simply that an ancient organism has survived, but that its capacities and constraints may have changed.

From Geological Time to the Arctic Worm

In the final confrontation, Tørk identifies a water flea, Cyclops marinus, under a microscope and explains the Arctic worm’s ordinary life cycle. The worm, Dracunculus borealis, is a nematode known since at least the Middle Ages and found in whales, seals, and dolphins. It enters through the intestine, penetrates muscle, and eventually reaches the subcutis, where the female forms a large nodule. When it senses Cyclops in nearby water, it releases millions of larvae; the fleas carry them through a developmental stage before being eaten by a larger mammal.

Tørk describes the familiar parasite as well adapted to its hosts, but ordinarily restrained by the conditions of transmission. He compares it with the Guinea worm, which depends on heat and stagnant water: rainfall and flowing, cooler water make its environment less favorable. In his account, a parasite that develops alongside its host tends toward compatibility rather than killing that host. This ecological balance provides the contrast against which the novel’s altered Arctic worm becomes alarming.

Tørk says that, after twenty-five years of work, Loyen discovered the larva had adapted to the human immune system. It could pass through the mouth’s open mucous membranes and acquire a protein-made covering that made it appear to the body’s defenses as part of the body itself. In humans, growth, mating, and movement through the body could take days rather than the months required in marine mammals. Verlaine’s experiments, Tørk adds, showed that the parasite could be grafted onto many kinds of fish, in salt water and fresh, across different temperatures. The host range that would normally restrict its spread was therefore missing.

Deep Time and Changed Conditions

The Paleocene hypothesis and the contemporary parasite explanation operate at different levels of certainty. The impact’s proposed biological legacy is presented as a possibility, while Tørk’s account of the worm’s development and adaptation is part of the immediate scientific explanation he gives Smilla. Together, they make deep time consequential without collapsing speculation into fact: a catastrophe millions of years past may have altered marine life, while later adaptation and human intervention make an old parasite newly capable of crossing ecological boundaries.