Scientists find exotic life in ocean depths off Sonoma Coast
Thirteen years ago, he made history by filming the sunken RMS Titanic where it lay broken on the Atlantic seabed.
Since then, he’s dived in nearly every ocean on the planet. On a good day, he can swim for 24 hours — but at 2 tons, he needs help getting out of the water.
His associates call him Hercules.
And this month, the bright yellow, remotely operated diving vehicle was in the Pacific off Sonoma County to explore, for the first time, the deep-water life in the Cordell Bank National Marine Sanctuary, 6 miles west of Bodega Bay.
For ROV Hercules, that meant commuting an hour-and-a-half to work, driving nearly 6,000 feet beneath the rolling ocean swells. With two flexible arms, dazzling lights, video cameras and a long, long tether, Hercules was designed to go where humans cannot — to peer into the unknown.
On a clear day when the fog lifts, you can see the Cordell Bank Marine Sanctuary from shore, from either Bodega Head or Point Reyes. On the surface, it’s an unremarkable patch of blue ocean. But go 115 feet down, and you’ll find a submerged rocky island, 9 miles long and 4 miles wide, teeming with fish and a riot of colorful marine life.
The shallow bank is actually the peak of an underwater mountain sitting in what scientists call a biological hotspot. Surrounded by deep, steep walled canyons, the rocky seamount perches on the very edge of the continental shelf, which falls away in a vertical cliff another 2 miles down. No sunlight can penetrate that deep, so the walls and bottom are in permanent blackness, the water is nearly as cold as ice, and the sheer weight of the ocean above creates crushing pressure, nearly 5,000 pounds per square inch. That’s equivalent to two fully loaded 747 jumbo jets sitting on your chest.
So what’s special about Cordell Bank? Jennifer Stock, the enthusiastic Outreach Coordinator for the Marine Sanctuary, answers that question a lot from her headquarters at Point Reyes. Jennifer was also one of the lucky few pulling watch on board the Nautilus during Hercules’ dives.
Cordell is unique, Stock says, because of its position on the lip of the continental shelf, and the dynamics of the Pacific Ocean there. The undersea mountain sits in the flow of the California current. Every spring, up on the surface, the prevailing winds blow strong, and drive the surface water away from the shore. That draws in water from far deep below, pulling it up and over the bank.
“That seawater, upwelling from the depths, is loaded with organic nutrients,” she explains. “Currents spread it like fertilizer in the water creating a bloom of life, particularly small marine planktons, and teeming numbers of tiny shrimp called krill.”
The clouds of krill are the favorite dining choice for a wide diversity of life, including ocean-going salmon, and blue whales. Along Cordell Bank, the bloom supports more than 240 species of fish — 40 species of rockfish alone. All that sea life attracts predators, including seabirds, sharks and dolphins, and even the giant sunfish called Mola.
Leatherback turtles and black-footed albatross make their way here from thousands of miles across the Pacific for the annual feast. More than 25 species of marine mammal frequent the bank.