A hidden ‘living oasis’ has been discovered at the bottom of the ocean in the Maldives: ScienceAlert

A team of aquanauts has discovered that the Maldives is an oasis for underwater life in a vast aquatic desert.

A recent underwater mission around a deep-sea seamount in the archipelago revealed a thriving new type of ecosystem, which researchers say has never been described before.

They call it “The Trapping Zone”: a 500-meter-deep (1,640-foot) world where big fish congregate to feast on microscopic nekton.

Micronekton are similar to zooplankton, although slightly larger, between 2 and 20 centimeters (up to 7 inches) in size (krill is among the smallest).

These tiny organisms actively swim between the ocean surface and mile-deep waters, creating a vertical wave of migration every day and night as larger fish follow them to feed.

The Nekton Maldives mission is the first study to systematically map the deep waters of the Maldives, a chain of 26 coral atolls southwest of Sri Lanka and India.

The mission is a venture between a nonprofit research institute of the same name, the government of the Maldives, and researchers at the University of Oxford.

Already, the international team has come across a new ecosystem surrounding the “Satho Rahaa” underwater mountain, based on the movement of micronekton.

As the sun rises each day, these tiny organisms begin to swim downward from the surface. Near the sunken seamount, however, submerged volcanic ridges and fossilized carbonate reefs formed 60 million years ago prevent micronekton from diving deeper than about 500 meters.

Trapped by the topography, the animals become “sitting ducks” for larger predators, such as schools of tuna, hungry sharks, and other deep-sea fish like spiny oreos, alfonsinos, and dogs of sea, who reside in the area.

In a glass bubble submarine, known as the Omega Seamaster II, the mission’s aquanauts observed a teeming ecosystem of predators and prey battling it out in the depths.

Not only did the team count a large number of fish, but they also observed a great diversity. Their submarine has shined its spotlight on tiger sharks, gill sharks, gulper sharks, scalloped hammerhead sharks, silky sharks, sand tiger sharks, or even bramble sharks, which are relatively rare.

“Why is this happening? Is it something specific at 500 meters, does this life go even further, what is this transition, what is it and why?” wonders marine scientist Lucy Woodall of the University of Oxford.

“This will allow us to better understand the deep ocean.”

frameborder=”0″ allow=”accelerometer; automatic reading; clipboard-write; encrypted media; gyroscope; picture in picture” allow full screen >

If such an ecosystem exists in the Maldives, it is likely to be found on other oceanic islands with similar underwater structures.

Perhaps seamounts and submerged volcanoes are hotspots for deep-sea life because of the way they trap micronekton.

The daily back-and-forth vertical movement of fish through the water column is, by some estimates, the greatest mass migration on the planet.

Zooplankton and micronekton seem to be the leaders of the pack. Yet, despite the fact that micronekton constitute a large part of the biomass in pelagic environments, our understanding of their migratory behavior pales in comparison to zooplankton.

By actively swimming in the water column, micronekton weave an overlooked food web for ocean ecosystems around the world. By some estimates, all the micronekton in the world weighs over 10 billion metric tons, 45 times heavier than all of us humans.

However, most of what we know about these creatures dates back to the 1960s and 1970s. It’s only recently that they’ve started to receive more attention from scientists.

Micronekton can easily slip through fishing nets and therefore are not hunted commercially. That said, many species important to the fishing industry, such as tuna, are highly dependent on micronekton.

A bramble shark seen in the Maldives ‘trapping area’. (Maldives Nekton Mission)

The newly discovered trapping area in the Maldives could allow scientists to learn about these overlooked organisms in a whole new way, possibly enabling better ocean conservation practices.

“It has all the characteristics of a distinct new ecosystem,” says marine biologist Alex Rogers of the University of Oxford.

“The trapping area creates an oasis of life in the Maldives and it is highly likely to exist in other oceanic islands and also on the slopes of continents.”

Unfortunately, recent climate reports suggest that some micronektons in some parts of the world, such as krill in Antarctica, are not weathering the global warming crisis well.

If they disappear, other fish, mammals and birds will likely follow.

You can read more about the Nekton Maldives mission here.

Comments are closed.