Salas y Gómez and Nazca ridges
Imagine a mountain range the length of the southern Andes –110 volcanic peaks, stretching nearly 3,000 km end to end. Imagine these mountains are filled with rare, spectacular wildlife, that nearly half the species they shelter live nowhere else on Earth, and that scientists are discovering new life forms with every expedition.
Now stop imagining, because these mountains are real: they’re called the Salas y Gómez and Nazca ridges, and are deep in the waters of the South East Pacific.
These two unique chains of submarine slopes and summits areseparated from South America by the rich, cold waters of the Humboldt Currentand the yawning abyss of the Atacama Trench. Numerous studies have concluded they’reamong the most ecologically significant areas in the high seas – those areas ofthe ocean that lie beyond the jurisdiction of any country. Far below the waves intricategardens of slow-growing corals and gorgonians adorn the rocky slopes in some ofthe clearest waters on the planet, and in the plankton-abundant upwellings overthe ridges sharks, turtles, whales and seabirds gather to forage. This uniqueregion is a vital habitat for commercial species too, from swordfish to jackmackerel, underpinning sustainable food security for millions – but only if welook after it.
Threats and the future
The Salas y Gómez and Nazca ridges are still largely ecologically intact, but biodiversity and ecosystem resilience are never the less under threat. Deep-water trawling has destroyed coral and seabed habitats down to depths of 2,000 m, and has taken a heavy toll in bycatch of animals and plant life alike. Floating plastic debris drives the risk of ingestion and entanglement for nearly 100 species. Meanwhile climate change is making the seas warmer, less oxygenated and more acidic, all of which pose an existential threat to marine biodiversity .
Ominously, there’s cobalt in the crusts of the Salas y Gómezand Nazca ridges, which the deep-sea mining lobby may one day step up effortsto exploit – but doing so would be an ecological disaster.
We’ve got a time-sensitive window of opportunity. By permanently closing the area to fishing and mining and establishing a high seas MPA, we can save the Salas y Gómez and Nazca ridges for ourselves and for future generations. And with 80% of the mountains still unexplored, there’s surely so much more for them to discover…
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Back to the surface
Salas y Gómez and Nazca ridges
The new High Seas Treaty sets up a global process for the establishment and effective management of networks of representative and well-connected marine protected areas in the High Seas, including highly and fully protected areas where no harmful industrial activities are allowed.
Every year in the Eastern Pacific something remarkable happens. Strong seasonal winds blow warm waters out from the coast into the high seas, where they meet cooler water carried by ocean currents. The collision causes a unique dome-shaped upwelling system, which forces cold, nutrient-rich waters up from the depths to the surface of the sea.
Within this upwelling, sunlight and cold water create ideal conditions for the growth of certain microscopic blue green algae – in fact, the so-called ‘The Thermal Dome’ contains the highest concentration of this particular blue-green algae anywhere on the planet. Enormous volumes of zooplankton gather to feed on the phytoplankton, forming the base of one of the richest marine food webs known to science, and incidentally, traps more carbon than is emitted by all the vehicles in Central America. The biomass of krill in the Dome is the largest in all the Tropical Eastern Pacific, supporting innumerable animals higher on the food chain, including whales.
Many, and much larger species benefit from these nutrient rich waters. The Dome provides a year-round habitat to blue whales (some 1,400 of them) from the Northeastern and Southeastern Pacific. At the Dome, the blue whales mate, feed, and raise their calves. It’s an important feeding and migration corridor for other species as well, including dolphins, whale sharks, hammerheads, thresher sharks, rays, sailfish, marlins and several kinds of sea turtle.
This is an area of open ocean that directly benefits the land, providing vital connectivity between the two. For example, Critically Endangered leatherback hatchlings travel from Central American beaches through the Dome on their way to the mating and feeding grounds in the Southeastern Pacific. As well as being part of one of the world’s most important tuna capture areas, the plentiful food supplies of the Dome sustain commercial species which pass through to the coast and are caught in Central American fisheries. And this marine life provides people with more than just food: many species thriving at the Dome migrate to the coastlines of Central America where this biodiversity sustains nature tourism, with sea turtle nesting, whale and dolphin watching, and sport fishing - all supporting industries which make big contributions to local communities and national economies.
When researchers explored two of the Dome’s deep-water seamounts they found a spectacular benthic community with octocorals several metres long, and metre-high glass sponges, and there are undoubtedly other wonders in the depths of the Dome just waiting to be discovered.
Threats and the future
For UNESCO and the IUCN, the Dome is one of five priority areas of the global ocean that should be given immediate World Heritage status – but actually listing it is a more complex proposition than it may sound. The Dome is never quite the same two years in a row: it moves around, and its width can vary between 300 km and 1,500 km. While the phenomenon itself is clear for all to see, the international community faces a new challenge when it comes to regulating this movable feast across a High Seas area of more than half a million square kilometers.
Nevertheless, nothing could be more worth protecting, and urgent, intelligent action is needed to combat the growing threats to the Dome’s natural riches. Overfishing – both ‘legal’ and illegal – is depleting stocks and causing high bycatch of vulnerable species. A significant volume of the world's global shipping traffic steams through the area on the way to the Panama Canal, and despite some attempts to introduce re-routing schemes, noise pollution and ship strikes on marine mammals are a growing cause for concern. Plastic pollution is equally serious: the winds that help create the Dome by driving warm water away from the shore bring with them the waste from the continent. In this respect, marine protection desperately needs to be strengthened with land-based solutions.
This amazing, unique marine phenomenon is part of our shared world heritage - and one to be protected. We need to make an immediate, concerted international effort to ensure the High Seas Treaty enters into force swiftly to secure the creation of a High Seas marine protected area within the Thermal Dome.
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Photos courtesy of NOAA, Getty Images, NGS & Studio Smart