The squit and the whale: can artificial faeces revive the ocean ecosystem?

The world’s whale population is only 5% of what it was estimated to be 400 years ago. Photograph: Design Pics Inc/Alamy

In a few weeks an international group of scientists will launch an unusual marine research project. They will dust the surface of the Indian Ocean with artificial whale faeces.

The aim of this excremental experiment is straightforward. It is to determine if it is possible to reboot marine ecosystems that have been starved of nutrients and in the process restore dwindling fish populations. It is also hoped the project will help in the battle against the climate crisis.

“Whales eat tiny crustaceans called krill, typically about 300 metres below sea level,” said Sir David King, a former chief scientific adviser to the UK government and one of the project’s leaders.

“At that depth, the pressure of their backsides is so high they cannot poo. So they come to surface – to get air but also to relieve themselves. They then create a floating bed of excrement and, as sunlight falls on it, phytoplankton grows there and this provides food for fish,” added King who now heads the Centre for Climate Repair at Cambridge University.

The problem is the planet’s population of whales is now only 5% of its estimated level 400 years ago, whaling having taken a terrible toll on the world’s largest marine mammals. As a result, the ocean has been starved of excreted nutrients that have provided sustenance for fish. “We need to find a way of restoring stocks,” said King.

The marine biomass regeneration project – as it is delicately named – aims to put this right. Backed by a group of large marine laboratories, including the Woods Hole Oceanographic Institution in Massachusetts and the Institute of Maritime Studies in Goa, scientists are about to launch a key experiment to determine the project’s feasibility.“In Goa, there is a massive rice production factory whose main waste product is rice husks,” said King. “This will form the basis of our artificial whale poo experiment, which will take place in the Arabian Sea. Baked and then mixed with nutrients, the husks will float on the ocean surface and we can then study [them] to see if phytoplankton will grow there and replace what whales used to provide.”

King stressed that the initial experiment, which is set to be carried out next month, will be limited in size and will last only a few weeks, although he also stressed the potential benefits. “Apart from the fact that phytoplankton will provide food for fish, it will also absorb carbon dioxide, so there is a second potential gain that the project might provide for the planet.”