It begins in the land of lakes, around 2.5 billion years ago. Once one of the largest freshwater bodies on Earth, Lake Chad extended across much of northern Africa. With its floating islands, the lake functioned as an oasis of life, sustaining a wide range of species—from large mammals to vast communities of migratory birds.

Beneath the surface, plants, algae, and microorganisms thrived, supporting fish and other aquatic life forms. These organisms coexisted as a dynamic assemblage, collectively shaping and sustaining their environment as a living system.

In a remote and arid region of the Sahara Desert—once part of Lake Chad—lies the Bodélé Depression. Rivers, wetlands, and shallow lakes once expanded across this landscape during the period known as the Green Sahara, creating warm, fertile conditions in which grasses, trees, algae, and microorganisms flourished. Among them were diatoms, microscopic organisms ubiquitous to aquatic systems.

As the Sahara gradually dried, the former lakebed became rich in siliceous remains. During the winter months, strong winds generated by differences in atmospheric pressure funnel through surrounding mountain ranges, lifting vast quantities of fine dust into the air.

The Amazon rainforest, despite its apparent abundance, exists in a state of permanent nutrient deficit. Heavy tropical rainfall continually washes minerals from the soil, leaving ecosystems dependent on external sources of replenishment. This nourishment arrives through the long-distance aerial transport of silica-rich dust from the Sahara, carried thousands of kilometres across the Atlantic.

Two landscapes—one marked by fertility and coexistence, the other by aridity and desolation—remain separated by an ocean, yet connected through atmospheric circulation. In this exchange, the Sahara appears to whisper to the Amazon, recalling a shared geological past that once united continents within Pangea.

In the Amazon, communities of termites play a vital role in maintaining soil stability during the rainy season. As leaf litter and organic debris accumulate on the forest floor, termites act as decomposers, processing surface material and redistributing nutrients.

Through burrowing, termites create networks of micropores that allow rainwater to penetrate deep into the soil, reducing evaporation and erosion while improving nutrient retention. Their mounds—some reaching up to ten metres in height—are among the largest structures built by non-human species.

While termite colonies may persist for decades, their mounds often outlast them by centuries. As wind and rain erode these structures, clay-rich remnants remain embedded in the landscape. These remnants become sites of renewed ecological activity, offering shelter and resources to a range of species.

Among these relationships, the bond between termites and elephants is particularly striking. Elephants are drawn to abandoned termite mounds for their mineral-rich clay. During rainfall, the clay transforms into mud, which elephants use to regulate body temperature and protect their skin. Over time, repeated wallowing forms depressions that evolve into water-filled basins, supporting new habitats for other species.

Ecological communities often give the impression of stability, yet they persist only as long as the conditions that sustain them remain intact. Changes in temperature, rainfall, acidity, or seasonality can destabilise these systems, prompting migration, adaptation, or disappearance. Some environments shift across landscapes; others vanish entirely.

Such transformations do not always result in ecological collapse. Instead, they may give rise to new assemblages of species and landscapes. Along its passage, the jet stream grinds diatom remains into fine dust—an estimated 180 million tons annually—lifting these particles into the atmosphere and depositing them in the Amazon rainforest, where they once again enable life to flourish.