Schmidt Fk231202 Cruise Report: Octopus Odyssey – Part 2

Report Prepared: 12 April 2024
Dates: 1 December 2023 to 15 December 2023
Ports: Balboa, Panama to Golfito, Costa Rica

Co-chief Scientists:
Dr. Beth N. Orcutt, Bigelow Laboratory for Ocean Sciences
Dr. Jorge Cortés-Núñez, Universidad de Costa Rica

Seamount ecosystems support highly diverse animal communities on the seafloor and the surrounding ocean, yet the diversity, connectivity and ecosystem services of these environments is poorly understood. This knowledge gap confounds efforts to delineate areas in need of conservation management and protection. The Pacific Ocean margin of Costa Rica contains a range of seamount habitats, from the rough terrain of the southwestern margin to the more sparse terrain of the northwest margin. While the southwestern terrain has previously been surveyed (including by RV Falkor classic) and some seamount areas here are already protected, far less is known about the ecosystems of the northwestern terrain. In 2013/2014 very unique animal behaviors and hydrothermal venting were discovered with ROV Jason and HOV Alvin on a small feature in the northwestern terrain. Namely, extensive aggregations of octopus were observed at a place called the Dorado Outcrop, located in areas of diffuse venting of slightly warmed hydrothermal fluids. At the time of discovery, it was unclear if these aggregations could be considered nurseries, since no viable eggs were observed with brooding mothers. Subsequently, similar behaviors were observed on the Davidson Seamount offshore California, and those aggregations were confirmed to be octopus nurseries. In June of 2023, an international team traveled to this region aboard RV Falkor (too) for the Octopus Odyssey expedition with a major goal 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 in June, the team witnessed baby octopus hatching. They also found the fifth known octopus nursery in the world on a different seafloor feature 30 nautical miles away. The team also explored four other seafloor features on Octopus Odyssey, revealing an incredibly rich biodiversity and biogeography of ancient volcanoes offshore Costa Rica. The team also documented additional evidence of the hydrogeology of the region – how water moves in, out, and through oceanic crust. Such data can inform why volcanoes and earthquakes in Costa Rica vary as different types of seamounts and oceanic crust subducts beneath overriding plates. As the final shakedown expedition of RV Falkor (too) in 2023, the Octopus Odyssey (too) team returned to this region to ask new questions about the connection of life, rocks, and fluids around these seafloor features. Are the octopus nurseries active at a different time of year? Do octopus brooding in hydrothermal springs have different microbiomes as compared to other octopus, and are those microbiomes connected to the microbes in the hydrothermal springs or surrounding rocks? Are the hydrothermal spring fluids from different sites unique, representing different trends in fluid-rock-life reactions, or do they represent a single altered fluid? Are there seasonal trends in biodiversity on the seafloor or in the water above? Sensors and experiments deployed by the team in June would be recovered on the December expedition to help address these questions, aided by interfacing new technology onto the ROV SuBastian. Equally as important to the science objectives, continuing the theme of capacity sharing, early career development, and raising awareness of deep-sea heritage in Latin American were major objectives of the expedition. The international Octopus Odyssey (too) team gathered anew for collaborative co-production of knowledge and training with Costa Ricans, honoring the work in Costa Rica’s waters. Spanish-speaking scientists were given priority for dive lead watches to enable live-stream narration in Spanish, and priority for leadership experience. Ship-to-shore engagements were also prioritized for Spanish-speaking audiences, particularly in Costa Rica. These efforts were intended to raise the profile of deep-sea heritage in Costa Rica ahead of the 2024 UN Ocean Conference meeting happening in Costa Rica in June 2024.