Ice sheets are crucial to the climate system, contributing 0.7 mm annually to global sea-level rise. Submarine landforms from past ice sheets remain well-preserved on high-latitude continental margins, enabling reconstructions of ice sheet extent, flow, and stability—essential for accurate climate and sea-level projections. These formations also harbor unexplored ecosystems that will be impacted by future changes.
Submarine canyons facilitate the transport of organic matter (OM) from the shelf to the deep sea, influenced by oceanographic conditions and extreme events. Understanding ecosystem functions within canyons exposed to polar temperature patterns and nutrient cycling is essential for predicting climate change impacts on deep-sea environments.
Holothurians are key deep-sea megafauna influencing sedimentary OM cycling. They rapidly deplete OM in abyssal sediments by consuming phytoplankton-derived OM and reworking sediments, affecting food availability for other benthic organisms. Changes in holothurian populations have been linked to variations in phytoplankton at the surface and the quantity and quality of particulate organic carbon (POC) fluxes to the seafloor. These shifts can impact deep-sea ecosystem structure and function, serving as indicators of climate change and carbon remineralization.
This study aims to understand the role of deep-sea holothurians in OM cycling in the Bellingshausen Sea (Antarctica). We will analyze sedimentary OM quality and quantity and estimate holothurian utilization. The key hypotheses are: (a) do holothurians selectively feed on specific OM components? (b) are they significant contributors to deep-sea OM cycling? Findings will enhance knowledge of OM cycling and improve our understanding of abyssal Antarctic ecosystem functioning.
