Along 120,000 miles of Asia’s shoreline, land and sea struggle against each other in a rivalry which creates one of Asia’s greatest resources.

Kingdoms of the Coast explores the huge variety of the coasts by focusing on two themes: their wealth, in sheer volume and in diversity, and their wide range of influence, which stretches far beyond the thin line on the map which marks the shoreline.

In India, torrential rains are part of the great cycle of exchange between land and sea. The rains tear at the land, sometimes producing huge floods. But as rivers laden with sediment rush towards the sea, they pass through mangrove forests, which steal the earth back again.

Indonesia has the greatest area of mangroves on earth. Over 4 million hectares of trees provide shelter and food for creatures of land and sea, and for some animals which live between both worlds.

Mangrove forests act as vast natural machines which help drive the richness of inshore waters. Here, the coast’s fertility is founded on sediments washed from far inland. The mangrove forest transforms the silt into a rich food supply for the vibrant community it supports, and the forest itself slowly colonises and reinforces the soft, muddy edge of the land.

The hard coasts of Indonesia are built by more traumatic forces — volcanic eruptions and tectonic forces constantly wrack the land and seabed, raising new shorelines.

Here we find the most spectacular examples of coral reef ecosystems on earth. The boundless energy of tropical sun powers the rapid growth of coral communities and allows countless sea creatures to take on a kaleidoscope of diversity, adopting extraordinary disguises and lifestyles to earn their living on the reef.

The cold coastal waters of Northern Asia freeze during winter, forcing coastal dwellers to seek refuge at the edge of the ice. But as the spring sun warms the northern shores, they burst into life.

Salmon arrive in their millions along the shores of the north-west Pacific and the Sea of Okhotsk, and feed a host of predators which have journeyed to the coasts from far afield.

To cross the coast and pass from one world to another — from saltwater to freshwater — in order to spawn and die, the salmon must first undergo an amazing physiological change and then complete an arduous journey, overcoming powerful river currents and evading determined predators.

The death of the salmon confers a gift on the land, and reminds us of the endless bargain between these two great realms, uniting our vision of the wealth and huge influence of Asia’s coasts.