Expansion of macroalgae forests and gains in Blue Carbon at Caleta Potter, Antarctica

Abstract

In the western Antarctic Peninsula, glacier systems have retreated as a result of a temperature increase of approximately 2°C over the past 50 years. This process has led to the formation of “new ice-free areas” (NALH) which are suitable for the colonization of benthic marine algae, as observed in the case of Caleta Potter in response to the significant retreat of the Fourcade Glacier. Studies were conducted to estimate the expansion of macroalgae and gains in Blue Carbon in recently ice-free areas, focusing on the spatial and vertical distribution of macroalgal communities, colonization processes, and the succession in the NALH of Caleta Potter. The Fourcade Glacier has retreated ~1.5 km^2 since 1956 and our estimates indicate colonization and expansion of macroalgae in NALH of ~0.005-0.012 km^2 with a carbon storage of ~0.2-0.4 tons C per year. Beneath the Antarctic Sea lies a unique life adapted to extreme temperature and light conditions. Antarctic macroalgae are true ecosystem engineers, creating and modifying habitats whilst also providing shelter and protection to a variety of marine organisms. In the context of climate change, continued colonization and expansion of macroalgae is expected, leading to significant changes in primary productivity and trophic chains in Antarctic coastal systems.