The Atlantic Ocean is more than a backdrop to the novel’s crises: its continental margins and hidden depths define the limits of human knowledge, even as the sea carries the infrastructure on which human society depends.

The Continental Margin

The ocean’s geography begins at the continental shelf, the relatively shallow underwater continuation of the continental plate that borders every major landmass. In many places the shelf extends only a short distance offshore; elsewhere it runs for hundreds of kilometres before descending, steeply or in terraces, toward the ocean floor. The shelf is comparatively familiar territory, but the depths beyond it remain an obscure world, less explored than outer space. That contrast makes the Atlantic’s edge a threshold between waters people have learned to use and a vast environment they cannot readily survey.

The scale of human settlement reinforces this dependence on the margin: two-thirds of the world’s population lives within sixty kilometres of a coast. The North Sea illustrates how shelf waters can become central to human activity. Formed in its present shape less than ten thousand years ago, it is shallow, with depths averaging between twenty and 150 metres, yet it lies amid industrial nations and some of the world’s busiest maritime routes. Against that crowded, worked seascape, the open ocean offers few reliable bearings. At sea, water and sky can merge into a horizon without landmarks; rain and low cloud can erase light and shape, leaving even hardened sailors surrounded by monotony. The change from inhabited shelf to open water is therefore not simply a change in depth, but a loss of the visual assurances by which people orient themselves.

The Seabed as a Fault Line in Human Systems

The continental margin is not merely a boundary between shallow, familiar water and the deep ocean: it can move with enough force to remake the surface above it. When the shelf and slope slid downward, the displaced mass lowered sea levels across a vast area and drove water outward in a wave. Near the slide, the tsunami spread over thousands of square kilometres but rose scarcely a metre above the sea, concealed by the storm until it reached the shallows. The submerged disturbance became catastrophic not through visibility but through its arrival at a coast where the seafloor rose toward land.

The same collapse tore into the Atlantic’s less visible connective tissue. TAT 14, a major transatlantic fibre-optic cable, was severed beneath tonnes of mud and rock; its reinforced casing and glass fibres broke, and the torn ends were left hundreds of kilometres apart. The cable formed part of a global web carrying calls, images, email, and other data, so the undersea break travelled outward as a communications crisis. A week after the northern European disaster, transatlantic Internet traffic had stopped, while phone calls depended on satellite links that were not reliably available. The message sent from Kiel could cross the ocean in milliseconds under normal conditions; after the landslide, it ended in the seabed. The novel thus makes the Atlantic both a medium of connection and a force capable of severing it, exposing how much of the apparently seamless human world rests on infrastructure laid across an unstable ocean floor.

Oceanic Highways and Their Failure

The Atlantic Ocean is also a corridor through which the world’s material economy moves. Merchant shipping connects the east coast of North America with northern Europe, while European waters tie the Atlantic to the North Sea, the Baltic and the Mediterranean routes leading toward the Suez Canal and South Asia. These connections make a shipwreck more than a local accident: a lost container vessel can interrupt production chains elsewhere, threaten livelihoods, and endanger communities dependent on goods arriving by sea. The novel’s crisis briefings therefore treat maritime routes as an interlocking system whose distant consequences are difficult to see from any single port.

That dependence becomes newly alarming when fish shoals begin sinking boats in the Atlantic. At the same time, fishing fleets elsewhere report sharply reduced catches, while fish in the Pacific appear to evade nets. Sal Peak presents these events as a possible sign of coordinated learning rather than coincidence: the animals may be responding to vessels and fishing gear in ways that imply an unexpected capacity to perceive and adapt. The effect reaches beyond individual crews. As catches fall, the fishing industry and the wider food economy are placed under pressure, adding a biological threat to the disruption of shipping.

The ocean floor carries a second, less visible network: the fibre-optic cables through which international communications travel. After the underwater slide severed major transatlantic connections, further outages made the damage harder to explain as a single geological accident. Jack Vanderbilt reports that FLAG Atlantic-1, linking New York City with Brittany, has also gone dead, while another cable between California and Hawaii has failed. He argues that something is cutting through the cables and that the loss of these routes is disconnecting societies from the communications systems on which they rely. His explanation is presented as a claim at a crisis meeting, not as a confirmed identification of the cause; its force lies in the pattern of failures and the growing uncertainty about what is happening below the surface.

Together, the failing shipping lanes, fishing grounds and communications cables reveal an ocean that is not an empty interval between continents. It is the working medium of trade and communication, but also a space in which human instruments and assumptions can be defeated: marine growth can interfere with a ship’s speed log, misleading the radar system that depends on its readings, while damage to the seabed can interrupt cables that appear effortless to users on land. The Atlantic’s importance is thus inseparable from its opacity. The networks crossing it sustain ordinary life, yet their vulnerability becomes visible only when the ocean disrupts them.

The Ocean as an Inner Space

The novel’s account of underwater descent makes the ocean’s depth a limit on perception as well as a geographical measure. In polar waters, sparse chlorophyll leaves the sea blue rather than green; as Karen Weaver descends in the Deepflight, that blue darkens and familiar visual cues fall away. A thousand metres below the surface, the body cannot tell whether it is rising or falling: neither sight nor the inner ear can substitute for the depth gauge. Even at sixty metres, the sensors register only four per cent of the surface light. The floodlights offer a fragile human answer to that darkness, illuminating only a small patch of an immense, unfamiliar world.

This vertical perspective complements the Atlantic’s shifting margin and the disruptions to its seabed networks. The ocean is not simply distance to be crossed or infrastructure to be laid across; it is an environment that resists the senses and exceeds the instruments used to navigate it. By setting human dependence on the sea against the difficulty of seeing and interpreting what lies beneath, the novel makes the Atlantic’s hidden depths part of the crisis itself.