The structure and function of microbial communities in sea-ice have been studied in Terra Nova Bay, Ross Sea, Antarctica during several campaigns since 1997. During the austral spring sea ice in Antarctic coastal areas represents a major reserve of autrotrophic biomass and a hot spot of biological activities, however, the role of sea-ice covered coastal regions (in terms of production, consumption, degradation and carbon export) on the availability of biological resources is still poorly known. Major changes in sea ice coverage around the Antarctic continent has been reported in the last decades. This opens a number of questions as to the impact of such changes on the biota and specifically on the primary producers dwelling inside the ice or directly affected by the waxing and waning of sea ice. We analysed the variability in nutrient dynamics and physiological parameters of sympagic algae, phytoplankton biomass, photosynthetic pigment spectra, sea-ice meiofauna, micro- and mesozooplankton biodiversity as well as the quantity, composition and degradation rates of particulate organic matter (POM) and bacterial secondary production. Our aim is a contribution to a better understanding of the functioning of sympagic communities as well as on the impact of changing sea ice conditions on these communities and in particular on the enhancement or reduction of carbon drawdown and release.