reef walls

‘We are rewriting the textbooks’: first dives to Amazon coral reef stun scientists

There is a flickering, bright glimmer of sky as the two-person submarine descends beneath the muddy equatorial waters to a place no human has ever seen – a vast, complex coral reef at the mouth of the world’s greatest river.

Thirty metres under the murky plume of the sediment-heavy Amazon, the sub enters a darker, richer world. A school of curious remora fish approaches the two-tonne machine. Crabs and starfish loom in its eerie lights. A metre-long amberjack swims past, then a two-metre ray.

At a depth of 80 metres, the pilot pauses to record large mounds of coral covered in rainbow-coloured pygmy angelfish, wrasses and parrotfish. There are sponges 30ft long.                     

At 120 metres the sub settles on the nearly level ocean floor in a field of soft coral, sea whips and fans. The pilot manoeuvres its remote cameras to within inches of the reef wall. It consists mainly of sponges and colourful rhodolith beds – masses of coral-like red algae – which are formed by chemical synthesis and thrive in the low light.

Most of the world’s shallow reefs are in trouble due to bleaching, climate change and fishing, but this one is pristine. Its wall is full of minute grooves and cracks, each hole and fissure home to something alive. Small, brave crabs approach the sub and raise their claws as if to defend themselves against this alien monster.

There are four Brazilian oceanographers, ecologists and marine scientists taking turns to dive in the sub from the Greenpeace boat Esperanza. For them, the chance to observe the reef, which they and others discovered three years ago after dredging brought up corals, is as thrilling as winning the World Cup.

Last year, based on chemical analysis of the plume and measurements of oxygen levels, they estimated the reef to be about 600 miles long, to cover 3,600 square miles, and be about 30 to 120 metres deep. They thought it was biologically relatively impoverished compared to other equatorial reefs, but nevertheless they recorded more than 60 species of sponge, 73 species of fish, spiny lobsters, stars and other reef life.

The Amazon reef: ‘a mega biome, a major ecological community of plants and animals with its own endemic species’. Photograph: Greenpeace

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Stick urchin up! A sea urchin’s mouth is home to Aristotle’s lantern, a wonderful feeding apparatus complete with a complex set of jaws and five self-sharpening teeth. Food is brought to the urchin’s mouth and manipulated into position by rows of flexible tube feet. The teeth then chop food into manageable bits, while frilly gills provide extra oxygen to power the feeding frenzy. 

Sea urchin jaws are a force to be reckoned with. Not only can they strip a kelp forest bare if left unchecked, but these constantly replenishing Exacto blades can carve away custom-fitted nooks into rocky reefs—and our exhibit walls! When paired with a longevity of over 100 years, urchin density in dentistry puts perpetual pressure on delicate diversity.

But with a host of predators ready to tackle a spiny supper—from sea otters to wolf eels and spiny lobsters—urchins and their voracious appetites are part and parcel of the politics of kelp forest productivity.

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Tomas Hermes, Joan Duru, Pat & Tanner Gudauskas on killing it in the Reef Hawaiian Pro the past few days. Congrats boys!

photos: ASP/Cestari & Ed Sloane