IPSO₂₅ and a combination of phytoplankton biomarkers and IPSO₂₅ (termed PIPSO₂₅) have been proposed as qualitative sea ice proxies in Antarctica. Exploring the effects of hydrodynamic conditions on the proxies might prompt the development of quantitative sea ice reconstruction. We investigated the variabilities of IPSO₂₅, brassicasterol, P_BIPSO₂₅ (B indicates using brassicasterol as the phytoplankton biomarker) in a sediment trap, and the distributions of these proxies, and mean grain size and sorting (σ), which are indicators of hydrodynamic conditions in surface sediments from Prydz Bay. The proxy signals in sediments decoupled with the information from the upper layer reveal that the export of biomarkers to sediments would be affected by the hydrodynamic conditions. Accordingly, we normalized IPSO₂₅ and P_BIPSO₂₅ to the sorting to compensate for different deposit environments. The accuracy of summer sea ice reconstruction increased from ca. 23% (based on IPSO₂₅ or P_BIPSO₂₅ alone) to 63% (based on P_BIPSO₂₅ ×σ²).