Nasca Ridge: messages from the bottom of the sea

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The sea was not calm, but at 2 hours and 30 minutes on the afternoon of March 22, 2020, Captain Rafael Benavente felt another shock.

He was in the cockpit of the Peruvian Armed Ship (BAP) Carrasco, an oceanographic vessel built in 2014 by the Freire Shipyard company from the port of Vigo, when he heard a message with the air of Eureka!

- Here it is, it's the mountain range!

- Some crew members warned him from the lower part of the ship.

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Benavente immediately went down to the area where the ship's scientific equipment is located and saw the surprising profile of the seabed on a screen.

It rose and fell from more than 3,000 meters deep and rose up to more than 1,800 meters in the water, as if it were a portion of the Andes Mountains stuck in the darkest depths of the sea.

The submerged mountains

"We were satisfied and there were hugs," says this officer of the Peruvian Navy commanded by Carrasco with emotion.

They came from a mission in Antarctica with several other officers and scientists, and they had organized to, when they arrived off the southern coast of Paracas (about 260 kilometers south of Lima), to drop an echo sounder and explore the seabed.

Not that this deep mountain range was absolutely unknown.

Its existence has been known for some years, to the point that in 2010, Chile created at the opposite end of it, near Easter Island and where the seamounts do come out of the sea, a protected area of ​​150,000 square kilometers, called Motu Motiro Hiva Marine Park or PM Salas y Gómez.

The point is that, from those remote places located 3,500 kilometers from the Chilean coast, to the area located in front of Paracas, which is rather called the Nasca Dorsal, there are 2,900 kilometers of submerged mountains that have barely revealed their secrets.

"There may be the origin of life," says Héctor Soldi, former director of the Peruvian Sea Institute (IMARPE).

This extensive chain of mountains and underwater plains, called Cordillera de Salas, Gómez and Nasca, includes apparently volcanic cones, whose activity is unknown, as well as underwater canyons, where there could be unregistered abyssal fish or species associated with sulfur gas emanations. .

"We do not know what is in those depths," adds Soldi.

What is known is that there are millions of bacteria that process what falls from the distant surface downwards (a dead fish, for example) and allow nutrients to flow into the waters above, where 12 edible species circulate.

Among them, horse mackerel (

Trachurus murphyi

), mackerel (

Scomber japonicus

) or bonito (

Sarda chilensis chilensis

).

Three species of tuna (yellow-tailed, big-eyed, skipjack) also navigate these parts;

three shark (blue, diamond, hammer);

14 species of cetaceans, including the blue whale (

Balaenoptera musculus

), the killer whale (

Orcinus orca

) and the bottlenose dolphin (

Tursiops truncatus

);

as well as two types of reptiles, including the loggerhead turtle (

Caretta caretta

).

In the Nasca Ridge there is a record of 1,116 species of marine fauna, which makes it a hot spot due to its high biodiversity

At the moment, according to a report from the National Service of Natural Protected Areas by the State (SERNANP), in the Nasca Ridge there is a record of 1,116 species of marine fauna, which makes it a hot spot due to its high biodiversity.

What's more: it has one of the highest level of biological endemism on the planet, especially in fish and invertebrates.

Life emerging from the oceans

All that which is above, within the reach of human activity and in the

photic

part

(where the sunlight arrives), has to do with the mysterious submerged mountains.

“There, among the mountains and underwater canyons, there are micro-habitats,” explains Patricia Majluf, a marine biologist and vice president of Oceana Peru, an international organization dedicated precisely to conserving the oceans.

The exchange between deep waters, medium waters and surface waters is key for the profuse biodiversity of this marine region to be maintained.

It is not even known what exactly is below, because according to the SERNANP document only between 0.4 and 4% of the species that live in seamounts around the world "have been sampled for scientific purposes."

Hence, it has become essential to create the Nasca Dorsal National Reserve, the first exclusively marine protected area in Peru, where the exploitation of resources in a sustainable way would be allowed.

It would have an area of ​​almost 63,400 square kilometers, located under the sea and on seamounts, and 105.5 kilometers from the coast, in front of the town of Paracas.

If approved ―the Peruvian government has announced it for this year―, the marine protected areas of Peru would jump from 0.48% to 7.6% of the national territory.

It would not be much (Brazil has 26.6% and Chile 42%), although it would be close to the 10% agreed in goal 11 of the Convention on Biological Diversity (CBD), which should have been achieved in 2020.

This is also connected with the Sustainable Development Goal (SDG) 14, which calls for “conserving and sustainably using the oceans, seas and marine resources for sustainable development”.

The latter should occur in 2030, so that we would be at the beginning of a crucial decade for the conservation of the Peruvian sea and other seas of the world.

The Nasca Ridge is the extreme northeast of the Cordillera de Salas, Gómez and Nasca.

According to the technical file that supports the creation of the reserve, it is 45 million years old and its seamounts are found from 1,500 to 4,000 meters deep.

Normally, we visualize that on the earth's surface, not on the bottom of the sea.

However, it exists.

According to the marine biologist Susana Cárdenas, from the Universidad Peruana Cayetano Heredia, it is estimated that in all the oceans there are “around a million mountains greater than 100 meters”.

They have the particularity of inducing currents, which favors upwelling and biodiversity, and they are also a source of signals for the migration of fish, birds, cetaceans, cephalopods, turtles.

Eyes down

Strictly speaking, the oceans are mysterious, still unexplored, but they can be partially seen from boats such as the BAP Carrasco or from a submarine.

This ship, as Captain Benavente explains in detail, has equipment to do so, including a multi-beam echo sounder, which allows the bottom to be explored in various sectors of the seabed, not just at one point.

"This allows us to report the depth of the sea in a larger area," says Soldi, who has vast experience in the application of bathymetry, which is the method that makes it possible to know those depths, even though they cannot literally be touched.

That was what BAP Carrasco released when it was planted about 100 kilometers off the Peruvian coast, off Paracas.

The Peruvian sea is one of the most productive in the world, despite the fact that it only represents 0.1% of the planet's marine surface

Such an incursion allowed us to see the magical bottom of the underwater mountain range.

And it also made it possible that, at a peak of the incursion, an oceanographic rosette was released, consisting of several special plastic bottles that collect what is in the different water levels.

They measure conductivity, salinity, and other important parameters.

The samples have been sent to the Peruvian Sea Institute (IMARPE), so that it can carry out a rigorous analysis and after that it is determined from what depth the underwater protected area will begin, an unusual and unprecedented matter in Peru, where the majority of protected areas are terrestrial.

Hence, the decision is key to conserving this portion of the ocean.

It can be done from 800 meters downwards, but as Soldi explains there are some species that live in a wider range and even lower.

One case is that of the toothfish (

Dissostichus eleginoides

), which can circulate from 800 to 2,500 meters deep.

What happens if this species breaks the biological cycle?

The Peruvian sea, according to Oceana, is one of the most productive in the world, despite the fact that it only represents 0.1% of the planet's marine surface.

If the fishing fleet that works in the area intensifies its activity, it could affect the new protected area and all that wasteful oceanic ecosystem, where currents, fish or plankton flow incessantly.

In addition, part of the existing fauna in the Nasca Ridge is threatened, according to the categories established by the International Union for the Conservation of Nature (IUCN).

The blue whale and the antipodean albatross (

Diomedea antipodensis

) are "endangered", which means that they face a "very high" risk of extinction.

Life and oceans

Eight other animals -among them the sperm whale, the wandering albatross, the loggerhead turtle- are in a “vulnerable” situation, that is to say, facing a “high” danger of extinction.

There are a total of 30 species in this area that must be protected, because they are in those categories or in others ("near threatened", "insufficient data", "least concern") and cannot disappear.

Does all this matter to the human species?

In the midst of an ongoing pandemic, or financial worries and political crises, it might be thought of as secondary.

But not creating this new protected area in Peru, and others that protect other sea beds, would be like giving up on encouraging the flow of life itself, which precisely began down there.

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