When scientists say that we know less about our oceans than about outer space, they’re not exaggerating. Around 14,500 of Earth’s seamounts—ancient mountains that have formed on the ocean floor—have been mapped out so far. But these are assumed to make up less than 1% of the actual number.
Only a handful have been closely studied, with Davidson Seamount possibly being one of the most explored. This underwater inactive volcano was discovered off the coast of California in 1933 and is massive, spanning 25 miles. It hasn’t erupted in the last 9.8 million years.
Its summit is a mile beneath the ocean surface, and yet this dead volcano teems with life. Davidson boasts coral reefs and deep-sea octopus gardens, where tens of thousands of marine animals breed and feed, including whales.
Last year, an ancient, still-active volcano was found off the Canadian coast, covered in millions of giant eggs laid by Pacific white skates (a hauntingly beautiful cartilaginous fish that looks like a stingray). In comparison, the last nursery of this species was found in the Galapagos, with a mere dozen or so eggs, according to one marine biologist at Fisheries and Oceans Canada.
The most recent discovery involved a crew from Schmidt Ocean Institute finding a 1.5-mile-high seamount along with three others in the southern Pacific. One seamount along Nazca ridge off the coast of Chile sent chills down the spines of the explorers, who witnessed hundreds of never-before-seen species. They reported that the journey felt like one “through the cosmos.”
Never-Before-Seen Marine Life Include Ancient Coral Forests, Flying Spaghetti Monsters And More
The month-long expedition paid out huge dividends. Ethereal white sponge gardens that were thousands of feet long, flying spaghetti monsters (a type of colonial hydrozoan), casper octopuses, thousand-year-old glass sponges and towering forests of bamboo corals made up just a few of the life forms found here.
Glass sponges are some of the longest-living sea creatures that build intricate, cylindrical structures using needle-like “spicules” as bricks. Some sponges have trapped crustaceans living inside them until death. They feed on bacteria and plankton, and produce excreta that feed the crustaceans until they grow too large to exit the sponge. In a display of mutualism underwater, the crustaceans in return clean the sponges and even breed inside them.
Much of the animals at the unnamed Chilean seamount were bright red in color, like glowing red lobsters and red fish that “walked” on the sea floor. This hue lends the animals a cloak of invisibility as at these depths, red light is absorbed first. The crew also found cactus-like sea urchins and marine sponges that were as tall as humans.
Scientists from Ocean Census, one of the organizations that planned the expedition, said that these seamounts in the southern Pacific had a high level of endemism, meaning the species here are seen nowhere else on the planet.
Seamounts Are A Much-Needed Climate Refuge
At a time when climate change is rapidly boiling our oceans, seamounts clearly offer a unique refuge for marine life, according to the National Oceanic and Atmospheric Administration. Their steep surfaces provide an ideal hard substrate that are preferred by cold-water corals, sponges and other creatures that grow on surfaces.
The currents around seamounts also stir up nutrients from the ocean floor, which help phytoplankton grow explosively and attract entire food chains within the marine world. Additionally, these currents also bring with them stray larvae of countless species that finally find a safe place to latch onto and grow.
Seamounts have a role to play in ocean circulation and can influence how the high seas store carbon. They accelerate ocean currents and act as a waste management system while removing sediment build-up.
Pristine, ancient coral reefs are often discovered on seamounts, whose skeletons store valuable information that can add to climate records. These also act as nurseries for a wide variety of marine animals, often those that are rarely seen anywhere else.
We know so little about the seamounts of the world, let alone offer any protection from deep sea trawlers or mining. Chile banned deep sea trawling in 2016—a decision that may possibly have played a role in helping conserve the explosion of creatures found on its seamounts. Scientists are eager to conduct further research to understand how the ban may be benefitting Chilean seamounts.
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