Advancing Autonomous eDNA Capacity with the McLane RoCSI

The Ocean Molecular Ecology (OME) group is expanding its technological capabilities to monitor long-term marine ecosystem dynamics across the Pacific Northwest and U.S. Arctic. Building on five years of deployments using the McLane Phytoplankton and Particle Sampler (PPS) in the Olympic Coast National Marine Sanctuary and Alaskan waters, OME is moving toward more frequent, automated observations over longer periods. To achieve this, OME and the Engineering Development Division (EDD) are evaluating the newly acquired McLane Robotic Cartridge Sampling Instrument (RoCSI) on stationary moorings under a Cooperative Research and Development Agreement (CRADA). While previously deployed on robotic platforms, such as remotely operated vehicles (ROVs), this testing focuses on its mooring performance. The 6,000-meter depth-rated RoCSI features a smaller footprint and holds up to 48 sample cartridges, offering expanded sampling capacity compared to current OME field units.

The RoCSI during its 2-week saltwater tank test at PMEL. Credit: Shannon Brown

Led by Shannon Brown (UW/CICOES - OME) in close collaboration with engineer Courtney Avioli (UW/CICOES - EDD), the team has been testing and adapting the instrument for moored operation:

• In-House Testing: Shannon put the new unit through its paces in the lab, running a series of creative stress tests, including using food coloring to trace water flow and to measure flushing volumes, and tilting the unit to see how the cartridge rotor handles rough sea motion. Her detailed feedback went back to McLane, driving key hardware and software upgrades.

• Mooring Adaptation: Courtney designed and constructed a temporary mooring cage and cartridge hopper tailored for the initial testing phase.

• Successful Field Test: In late May, the unit completed its initial pilot deployment in Puget Sound aboard the S.P. Hayes, successfully collecting eDNA across 34 of 38 planned sampling events. For direct comparison, it was deployed alongside a PPS unit, which completed all 24 of its planned sampling events.

Following the field test, the instrument was returned to McLane to repair an injector issue encountered during preparation for the May deployment. Up next, the team is preparing for a 3-month local deployment, scaling up closer to the unit's full 48-sample capacity while testing how it handles ocean biofouling (marine growth) over time. This winter, OME hopes to work with engineering to further upgrade the frame and cartridge capacity, paving the way for full deployments in Alaskan waters in upcoming field seasons.

Disclaimer: Mention of commercial products, processes, or trade names does not constitute or imply endorsement, recommendation, or favoring by the National Oceanic and Atmospheric Administration (NOAA) or the U.S. Department of Commerce.

RoCSI mooring on the deck of the S.P. Hayes before deployment.