Abstract
In Antarctica’s coastal waters, the seafloor hosts a surprisingly rich diversity of life, shaped by intricate interactions between sea ice and flora and faunal communities. As sea ice forms and melts seasonally, it modulates the availability of light to both the microscopic algae living within and beneath the ice itself (sympagic algae), and, in turn, influences the productivity and biodiversity of the benthic ecosystems below. The complex pathways that connect sea ice dynamics with the benthos are particularly vulnerable to climate-driven changes in sea ice cover. Understanding responses to a rapidly changing icescape, shaped by warming air and ocean conditions, is essential for predicting the future of benthic biodiversity and its ecosystem functions and services, including biogeochemical cycling and carbon storage. Key to this understanding is coupling structural and biological observations across these mirrored ecosystems. We describe a proof-of-concept under-ice hyperspectral imaging platform, HIcyBot, that we deployed in the Ross Sea Marine Protected Area in 2023. HIcyBot is a remotely operated vehicle that leverages emerging sea ice bio-optical models to quantify ice algae biomass and classifies fine-scale seafloor features through integration of underwater hyperspectral imaging, stereophotogrammetry, and acoustic positioning. Through near simultaneous high-resolution characterization of these under-ice realms, the platform introduces a novel, spatially explicit approach to understanding how biodiversity and the ecosystem function beneath Antarctic sea ice and how they are responding to a changing icescape.