Our Submerged Past: Exploring Inundated Late Pleistocene (10,600 - 17,000 years ago) Caves in Southeast Alaska with Sunfish

May 15-June 4, 2022 / May 24-June 10, 2023

Our Submerged Past 2023 Field Summary

From May 25 through June 10, our team of Indigenous Alaskans, local community members, and scientists explored and sampled the continental shelf west of Prince of Wales Island in southeast Alaska. The SUNFISH® autonomous underwater vehicle completed 33 dives, surveying, 3D mapping, sampling sediment, and guiding our dive team to retrieve sample cores, which are currently undergoing analysis.

We struggled with some of the worst weather Captain Roby Medina has seen in years, including small craft advisories for 10 of the 15 days of the deployment. As a result, we were unable to return all of the targets identified in the 2022 survey. However, field operations manager Vickie Siegel and field and robotics technician Mimi Alexander wrangled SUNFISH in all conditions, so that despite the limitations, it was able to complete full, high-resolution, 3D surveys at 22 different locations, covering 640,00 square meters (0.25 miles).

Robotics principal investigator Kristof Richmond and robotic software engineer Tyler Haden guided SUNFISH to explore Sea Lion Cave, bringing back high-resolution 3D sonar maps and a sediment sample. In addition, SUNFISH-generated maps of two other rockshelters or overhangs were used to physically lead our divers, Jason Gulley and Tamara Adame, to locations selected by science principal investigator Kelly Monteleone to retrieve larger sample cores using a two-inch PVC pipe. All of these sediment samples were processed in the field with the help of intern Taylor Heaton and have been sent out for pollen, dinoflagellete cyst, microdebitage, and radiocarbon analysis.

We are now reviewing and comparing the side-scan sonar data from 2022 and the multibeam sonar data collected by SUNFISH this year. The combined sonar data set will further our understanding of the locations identified in the 2022 data and, combined with the diver samples and SUNFISH’s camera, give us a clear picture of these seafloor features.

Our Submerged Past project field team.
The Our Submerged Past 2023 project field team. Image courtesy of Jason Gulley.
Marine archeologist Dr. Kelly Monteleone, rear, manages hundreds of meters of green fiber optic cable from the aft deck of the Showtime fishing vessel while Sunfish chief technology officer Dr. Kristof Richmond finishes pre-dive testing on autonomous underwater vehicle SUNFISH during 2023 field work for the Our Submerged Past project. While SUNFISH can operate autonomously, the team uses the thin tether to connect the robot to a station on the boat where operators can remotely supervise missions and redirect it as necessary.
Marine archeologist Dr. Kelly Monteleone, rear, manages hundreds of meters of green fiber optic cable from the aft deck of the Showtime fishing vessel while Sunfish chief technology officer Dr. Kristof Richmond finishes pre-dive testing on autonomous underwater vehicle SUNFISH during 2023 field work for the Our Submerged Past project. While SUNFISH can operate autonomously, the team uses the thin tether to connect the robot to a station on the boat where operators can remotely supervise missions and redirect it as necessary. Image courtesy of Jason Gulley.
Cave diver Tamara Adame collects sediment samples beneath an overhang in southeast Alaska during 2023 field work for the Our Submerged Past project while autonomous underwater vehicle SUNFISH documents the sampling process and creates a 3D map of the sample site.
Cave diver Tamara Adame collects sediment samples beneath an overhang in southeast Alaska during 2023 field work for the Our Submerged Past project while autonomous underwater vehicle SUNFISH documents the sampling process and creates a 3D map of the sample site. Image courtesy of Jason Gulley.
Robotics technician Mimi Alexander, left, and captain Roby Medina haul autonomous underwater vehicle SUNFISH back onto the boat after a 2023 Our Submerged Past survey mission while project co-investigator Kristof Richmond, center, minds the fiber optic cable connecting SUNFISH to mission control on the boat.
Robotics technician Mimi Alexander, left, and captain Roby Medina haul autonomous underwater vehicle SUNFISH back onto the boat after a 2023 Our Submerged Past survey mission while project co-investigator Kristof Richmond, center, minds the fiber optic cable connecting SUNFISH to mission control on the boat. Image courtesy of Jason Gulley.
Taylor Heaton, a 2023 Our Submerged Past project intern, Native Alaskan (Tlingit), and Cornell University undergraduate, samples sediment from a core collected from an underwater cavern. The cores will be examined for microdebitage (tiny flakes of rocks chipped off by toolmakers), pollens, and dinoflagellate cysts to see if anyone might have lived in the cave and to learn more about the past environment.
Taylor Heaton, a 2023 Our Submerged Past project intern, Native Alaskan (Tlingit), and Cornell University undergraduate, samples sediment from a core collected from an underwater cavern. The cores will be examined for microdebitage (tiny flakes of rocks chipped off by toolmakers), pollens, and dinoflagellate cysts to see if anyone might have lived in the cave and to learn more about the past environment. Image courtesy of Jason Gulley.
Initial 3D sonar map views of front (left) and cross-section (right) of a cave entered, explored and mapped by SUNFISH. The cave entrance is approximately 9 m from floor to ceiling. Post-processing of the 3D sonar and camera data from SUNFISH and the lower-resolution surface survey from 2022 is underway.
Initial 3D sonar map views of front (left) and cross-section (right) of a cave entered, explored and mapped by SUNFISH. The cave entrance is approximately 9 m from floor to ceiling. Post-processing of the 3D sonar and camera data from SUNFISH and the lower-resolution surface survey from 2022 is underway.
Initial 3D sonar map views of front (left) and cross-section (right) of a cave entered, explored and mapped by SUNFISH. The cave entrance is approximately 9 m from floor to ceiling. Post-processing of the 3D sonar and camera data from SUNFISH and the lower-resolution surface survey from 2022 is underway. Images courtesy of Sunfish, Inc.

By Kristof Richmond, Our Submerged Past Principal Investigator; CTO, Sunfish, Inc.
Published July 26, 2023