The West Antarctic Peninsula has been identified as highly vulnerable due to rising temperatures and increased anthropogenic carbon emissions impacting its biodiversity. Glacier retreat is one of the identified responses of the ecosystem, opening up new ice-free areas available for colonization but also changing the environment due to meltwater input, sediment runoff, and ice impact. A habitat is characterized by the combination of environmental parameters that support carbon cycling within a specific blue carbon ecosystem, such as macroalgae forest/assemblages. Species Distribution Models (SDMs) are an efficient tool to link environmental parameters with species presence/absence to identify their habitat suitability and distribution. What if the tool allows us more? We aim to estimate potential carbon standing stock expansion in the recently ice-free areas of a fjord ecosystem under glacial retreat from the determination of habitat suitability of macroalgae species. This study focuses on the SDMs of Chlorophytes, Rhodophytes, and five Phaeophytes species, projecting macroalgae habitat suitability by ensemble modeling applying biomod2 in the Potter Cove fjord. Further estimations of macroalgal expansion and colonization, as well as potential carbon stocks, were conducted through SDMs results, binary transformation, data from published in-situ abundance quadrat surveys, and conversion factors. From 1956 to 2020 Fourcade Glacier opened up ~1,6 km2 free of ice. Our estimation of macroalgal colonization during this time period at Potter Cove shows an expansion of ~0.42 km2 with a total carbon standing stock of 9.73 ± 6.32 tons of C. Through the integration of SDMs and field data, this research provides valuable insights into the dynamic relationship between Antarctic macroalgae, environmental changes, and carbon stocks, contributing to the broader understanding of ecosystem dynamics in the face of global climate change.