Multiproxy sediment record in Collins Harbour (South Shetland Islands) and controls on marine productivity over the last ∼2200 years

Tudurí A.; Perez L.; Lopes Figueira R.C.; Ng-Cutipa W.L.; Cerpa L.; de Lima Ferreira P.A.; Cifuentes E.; Herrera J.; Venturini N. · Palaeogeography, Palaeoclimatology, Palaeoecology (2026) · DOI: 10.1016/j.palaeo.2026.114110

Resumen

The Antarctic Peninsula has experienced substantial warming since the mid-20th century, yet its late-Holocene climate was marked by high natural variability driven by interactions between atmospheric modes, oceanic currents, and ice dynamics. Understanding past marine productivity provides insights into how coastal ecosystems responded to climate forcing. Here, we investigate the last ∼2200 years of environmental variability at Collins Harbour (Maxwell Bay, South Shetland Islands, Antarctic Peninsula) using multiproxy analyses of one sediment core, including diatom assemblages, geochemical ratios (Fe/Al, K/Al, Ti/Al, Br/Ti, Zr/Rb), geochronological analysis (210Pb and 14C) and sedimentological data. The record reveals alternating phases of enhanced glaciomarine influence and relatively stable pelagic conditions throughout the late Holocene. Glacial meltwater supplied terrigenous iron to the coastal system, which was associated with enhanced paleoproductivity when stratification and light availability allowed an effective biological response. In contrast, periods characterized by stronger glaciomarine influence, including increased sediment delivery, turbidity, and expanded sea-ice cover, show a muted biological signal, underscoring the conditional and non-linear nature of iron fertilization in Collins Harbour. Climatic events such as the Medieval Warm Period and the Little Ice Age are expressed subtly and superimposed on a broader Neoglacial cooling trend. Since the mid-19th century, the sedimentary record documents intensified meltwater influence, seasonally open-water conditions, and increased productivity, consistent with regional warming trends documented for the Antarctic Peninsula. Variations in sedimentary and biogeochemical proxies broadly align with regional temperature changes and phases of the Southern Annular Mode, indicating coupling between atmospheric forcing, glacier dynamics, and coastal biogeochemical responses in Collins Harbour.