Wave-driven shoreline retreat in Potter Cove, Western Antarctic Peninsula

Abstract

Coastal erosion is a dynamic process driven by multiple environmental factors. In Antarctic regions, the interaction between wind, waves, sea ice, sediment transport and precipitation creates a complex setting for understanding shoreline change. This study focuses on Potter Cove, a small fjord in Maxwell Bay, south-west of King George Island (South Shetland Islands), where winter waves are investigated as a key erosive driver. Shoreline changes were assessed through satellite imagery, in situ beach profiling and sediment sampling. Additionally, a numerical wave modelling system was implemented to simulate wave dynamics within the cove. The results indicate a coastal retreat of up to 20 m along the southern shore of Potter Cove since 2020. Simulations for winter 2021 reveal two high-energy wave events with significant wave heights (Hs) of ~2 m, along with eight moderate events (Hs ≈ 1 m) occurring within the cove. The most energetic events (Hs = 2.11 m) originated offshore and entered directly through the cove’s mouth from the west-south-west. Conversely, moderate waves could be generated both internally and externally. Reduced sea-ice cover probably diminished the natural wave-buffering effect, enhancing the erosive impact of wave action on the coast. However, the absence of quantitative assessments of other relevant processes (e.g. permafrost thaw, glacial meltwater discharge, sea-level variability and sediment supply) limits our ability to gain a comprehensive understanding of the ongoing erosion. These findings highlight the role of wave dynamics in Antarctic coastal change and the need for integrated monitoring approaches.