SuMOS, a submerged microscope for observing substrates: Studying benthic activity in aquatic environments

Described here is the construction of a low-cost, standalone underwater camera system designed for recording processes occurring on aquatic substrates. The Submerged Microscope for Observing Substrates (SuMOS) utilizes a Raspberry Pi Zero 2 W paired with a Raspberry Pi Camera Module v3 NoIR, with IR illumination for low-light situations. It features a waterproof housing inspired by the open-source PipeCam project, with enhancements for sealing and substrate mounting. The SuMOS system operates autonomously, capturing high-resolution images at fixed intervals under various lighting conditions. Tests in the Choptank River of Maryland demonstrated the system's robustness in capturing patterns of amphipod activity under challenging optical conditions. This versatile tool offers a scalable solution for highly time-resolved, <i>in situ</i> studies of processes occurring at the interface of the aquatic/solid surface boundaries. The SuMOS provides significant advantages in cost, ease of deployment, and data collection.