Octopus Odyssey (too)

Expedition dates: December 2nd- December 15th, 2023

In June of 2023, Co-chief Scientists Dr. Beth Orcutt of the Bigelow Laboratory for Ocean Sciences (USA) and Dr. Jorge Cortés of the Universidad de Costa Rica and an international team traveled to the Dorado Outcrop– Earth’s first-ever-discovered octopus nursery. One of their goals was to determine if the eggs at the nursery were viable, as past expeditions to the outcrop had never seen evidence of developing embryos. On their first ROV dive at the nursery, they witnessed baby octopus hatching. They also found the fifth known octopus nursery in the world on a seamount 30 nautical miles away. The team returns to continue their research, collect experiments they placed earlier in the year, and examine new regions never-before-seen by humans. The science team’s ultimate goal is to better understand the hydrogeology, microbiology, ecology, and geochemistry that may facilitate octopus nurseries while characterizing life-supporting services provided by the ecosystems on these seamounts. 

Half of the expedition’s science party participants come from Costa Rica and other Latin American and Caribbean countries: an important step for knowledge and deep-sea research capacity sharing. The expedition’s science party also has gender parity.

Octopus Nurseries in the Deep 
In December 2013, scientists witnessed an astonishing octopus behavior at the Dorado Outcrop: an estimated 100 female octopuses were brooding their eggs together at low-temperature hydrothermal vents. The behavior shocked cephalopod experts because octopuses were considered solitary creatures at the time. In the past, octopuses were observed fighting over territory or mating toward the end of their life. Female octopuses are known to brood their eggs alone in rocky crevices, passing away after their eggs hatch. 

The science team who first discovered the nursery were puzzled as the octopuses’ eggs did not appear to be viable. When the octopuses were gently nudged aside, no embryos were seen developing in the egg sacs. On a return trip in December 2014, scientists observed octopuses at the same location with undeveloped eggs. The scientists hypothesized that the water coming from the low-temperature hydrothermal vents was too low in oxygen to support embryonic development, though a question loomed: why were the octopus laying their eggs in a hostile environment?

In June 2023, the Octopus Odyssey  team traveled to the Dorado Outcrop to determine if the gathering of octopus were really laying non-viable eggs. In the first hour of arriving at the octopus gathering, they witnessed babies  hatching, immediately disproving the hypothesis. The discovery resulted in a ship of elated scientists, all shouting with glee as they watched the babies emerge. After a few moments celebrating, they got to work laying down experiments, collecting samples, and examining the fluid being emitted from the low-temperature hydrothermal vents. In addition to determining that Dorado Outcrop is an active nursery, the team also found a new octopus nursery at a neighboring seamount– the fifth known nursery in the world. 

Alongside documenting the octopus, the team is examining the microbial communities at these sites and determining if they have symbiotic relationships with the octopuses and their young. Scientists know little about the microbial communities hosted within deep-sea octopuses. The team are curious if the microbes emitted from low-temperature vents are essential to the health of the octopus and any eggs that hatch. 

Off-Axis Seamounts
The Dorado Outcrop is one of Costa Rica’s “Off-Axis” seamounts on the complex Cocos Plate. It is part of a group of seamounts formed on the East Pacific Rise, as compared to more southerly seamounts offshore Costa Rica that were formed from the Cocos-Nazca Spreading Center.  Several of the southern seamounts near Cocos Island National Park and the spreading Nazca spreading center are partially protected within the Montes Submarinos Marine Management Area. However, the Dorado Outcrop and its surrounding seamounts sit outside the national park and away from the axis of the spreading centers, making them “off-axis.” The volcanic activity that fuels hydrothermal vents diminishes as seamounts are pushed further away from the spreading center, rendering them inactive. 

The low-temperature fluid that emerges on these seamounts is not the result of volcanic activity but comes from the natural cooling of the Earth’s crust. Scientists hypothesize that seawater is drawn down through larger inactive seamounts into the warmer crust, and in turn, is vented out a through nearby smaller seamounts. The term “low-temperature venting” does not mean the water emitted from the earth is cold, rather it is a lower-temperature than the superheated fluids that come from volcanic vents. The water at low-temperature vents is on average between 12-15 degrees Celsius, which is still much warmer than the deep sea’s ambient temperature of two degrees Celsius.  Low-temperature vents formed through the natural cooling of the crust are likely the most common form of hydrothermal venting across our planet. Still, they are poorly studied as these vents have been historically harder to locate. 

The Octopus Odyssey (too) objective is to search for more low-temperature hydrothermal vents on Costa Rica’s northwestern seamounts, documenting microbial and observable communities, and the relationships between them, on these lesser-explored geologic features. They will also be recovering experiments placed in June 2023. Through this work, they hope to capture a complete picture of the ecosystem services provided by the seamounts.

Ecosystem Services and Deep Sea Management 
Ecosystem services is a term that describes the science of quantifying life-sustaining resources our planet provides, like nutrient cycling and food production. Microbes, for example, are the base of the food web for hydrothermal vents, and these systems would not exist without them. Human activities, like mining and overfishing, threaten many of these environments. To better understand how humans may impact seamounts and their services, Orcutt and her team will work to quantify the role of microbes and animals in providing ecosystem services in these habitats. They hypothesize that  microbes may be involved in the formation of ferromanganese crusts on rocks exposed at these seamounts. Globally, these crusts are potentially an economically valuable mineral resource in the deep sea currently targeted for deep-sea mining. By quantifying the baseline ecosystem services provided in seamount ecosystems with ferromanganese crust , the scientists hope to establish what the world may lose should deep-sea mining occur.

Mother octopus brooding their eggs at the Dorado Outcrop.
The Octopus Odyssey group photo.
A rare image of a gulper eel with a full stomach recorded during the June Octopus Odyssey expediiton.
The first octopus of the cruise is spotted, much to the excitement of the team.
Brooding Octopus research sketch/ watercolor by Michel Droge
In the Dirty Wet Lab, the team work on removing sediment push cores from their container. These contain hugely valuable stratigraphic information about the seafloor and give the team access to a wealth of microbial information.
These tripod fish (possibly genus bathypterois) were spotted at a depth of 3026 meters on an unnamed outcrop southwest of Fuente Seamount in Costa Rican waters as the research team was exploring the area for the first time.
Bigelow SecondaryLogo
Universidad De Costa Rica Firma Vertical

Data & Publications

ADCP data, curated by University of Hawaii, can be accessed here.

Live ROV Footage

In the News

Scientists find four new octopus species off Costa Rica

Washington Post • January 21, 2024

Four new species of deep-sea octopus swim in Costa Rica

The Independent • January 16, 2024

New Species of Octopus Thrives in Deep Sea Nurseries

Atlas Obscura • January 16, 2024

Four New Octopus Species Discovered in the Deep Sea

Scientific American • January 16, 2024