Cataloguing the depths of Monterey Bay National Marine Sanctuary

By Megan McDaniels

November 2017

What inhabits the depths of the ocean? Even the most popular sanctuaries like Monterey Bay hold mysteries offshore. Twenty-eight miles beyond the California coast lies Sur Ridge, an underwater feature that is home to a wide variety of marine life. Explorations of this remote rocky structure have shed light on some of its secrets, which have been captured in a new field guide.

Between 2013 and 2017, scientists from Monterey Bay National Marine Sanctuary and Monterey Bay Aquarium Research Institute conducted 29 dives with a remotely operated vehicle (ROV) to scout the seafloor and water above Sur Ridge. The expeditions were led by chief scientist Dr. Jim Barry of Monterey Bay Aquarium Research Institute. While the main objective of the expeditions has been to understand the ecology of this deep-sea area, an important subcomponent has been developing the Sur Ridge Field Guide.

This guide documents more than 260 deep-sea corals, sponges, sea stars, fishes, and other organisms that were encountered. “During our first visit to Sur Ridge we were hoping to find something, but were overwhelmed by the underwater oasis we found right off our coast,” says Erica Burton, a Monterey Bay National Marine Sanctuary research specialist on the Sur Ridge exploration team. “The diversity, abundance, density, and large sizes of corals and sponges took all of us by surprise.”

This inventory of deep-sea and midwater organisms provides a baseline measurement for scientists of what organisms live at Sur Ridge. It will be useful for future expeditions as well as for students and deep-sea enthusiasts.

The Sur Ridge study is also important in the broader context of ecosystem-based management and will provide scientists with information to better understand the distribution, age, growth, productivity, and predation of deep-sea corals. “We will continue to conduct research at Sur Ridge to better understand the distribution and growth of deep-sea corals and sponges, and the habitat they provide for other living organisms,” Burton says. “Sur Ridge is absolutely stunning!”

Learn more about the exploration of Sur Ridge at the project website.

Click the images below to see the full version.

heterochone calyx
Fingered goblet vase sponge, Heterochone calyx
This is a benthic sponge that can build reefs, similar to how corals create habitat for other species. Like all sponges, Heterochone calyx is a filter feeder that sifts nutrients from the deep water.
asbestopluma monticola
Asbestopluma monticola
A white, branched predatory horny sponge. Their velcro-like structures (spicules) help to capture small prey that float by.
sclerothamnopsis compressa
Sclerothamnopsis compressa
A species of glass sponge. The spicules that make up their main structure are made of silica. A clear acrylic suction sampler attached to the ROV (shown in image) aids in the collection of specimens.
isidella tentaculum
Bamboo coral, Isidella tentaculum
A deep-sea bamboo coral with long stinging tentacles (“sweepers”) near the bottom to keep predators away.
Photo ©MBARI
keratoisis sp.
Keratoisis sp.
A deep-sea bamboo coral which is bioluminescent. Other species are often found living on the coral, including sea stars, sea slugs, and crabs.
Photo ©MBARI
paragorgia arborea
Paragorgia arborea
This deep-sea octocoral is also known as “bubblegum coral” for its dark pink hue and round knobby structures. Scale worms are often found living on the coral.
Photo ©MBARI
acanthogorgia sp.
Acanthogorgia sp.
A deep-sea octocoral (a group of corals with eight pinnate tentacles surrounding a mouth).
Photo ©MBARI
hippasteria californica
Hippasteria californica
A widely distributed deep-sea sea star that feeds on deep-sea corals.
Photo ©MBARI
asthenactis fisheri
Asthenactis fisheri
A large deep-sea sea star.
Photo ©MBARI
A deep-sea brittle star.
Photo ©MBARI
apristurus kampae
Longnose cat shark, Apristurus kampae
A little-known species of deep-water cat shark.
Photo ©MBARI
neolithodes diomedeae
Neolithodes diomedeae
An especially spiny species of deep-sea crab. They are in the family Lithodidae, otherwise known as king crabs.
Photo ©MBARI
rov doc ricketts
ROV Doc Ricketts
The ROV Doc Ricketts before launch from the R/V Western Flyer.
Photo: Chad King/NOAA

Megan McDaniels is a volunteer social media intern for the NOAA Office of National Marine Sanctuaries.