Late Holocene benthic foraminiferal turnover events and sea-ice dynamics in Edisto Inlet, Ross Sea

Identifying marine environmental changes is crucial to understand Earth’s climate system and its components. Foraminiferal assemblages are widely used as environmental tracers, linking shifts in their community composition to environmental changes. However, less attention has been given to the properties of the foraminiferal community, which can offer a comprehensive environmental view. This study examines laminated marine sediment core TR17-08 from Edisto Inlet (Ross Sea, Antarctica), focusing on turnover events in benthic foraminifera over the last 3.6 kyrs BP. By using the Rate-of-change (RoC) analysis, three major turnover events at 2.7–2.5, 1.2–1.0, and 0.7 kyrs BP were characterized. Changes in dominant species, such as a shift from Miliammina arenacea to Epistominella exigua, Nonionella iridea, and Stainforthia feylingi, aligned with XRF ratios (Zr/Rb, Ca/Ti, Br/Ti) . At 2.7–2.5 kyrs BP, a transition from multi-year landfast sea ice (3.6–2.7 kyrs BP) to seasonal sea ice (2.5–1.5 kyrs BP) occurred, linked to increased modified Circumpolar Deep Water inflow with longer summer ice-free periods. High RoC values marked unstable benthic communities under more persistent landfast sea-ice conditions, while low values between 2–1.5 kyrs BP indicated greater community stability during seasonal sea-ice phases, aligning with the benthic macrofaunal records. Continental archives (penguin and seal remains) along the Victoria Land support this Late Holocene sea-ice shift. Our findings suggest increased mCDW presence in the fjord and Ross Sea after 2.7–2.5 kyrs BP, associated with a persistent positive Southern Annular Mode, and highlight the utility of foraminiferal community properties in paleoenvironmental reconstructions.