Trophic and Microbial Patterns in the Ross Sea Area (Antarctica): Spatial Variability during the Summer Season

In open regions of the Ross Sea, role microbial community in turnover organic matter has scarcely been investigated; indeed, very little is known on how distribution and functional diversity respond to environmental conditions hydrographic structures. During austral summer 2017, two pelagic areas Sea [the Drygalski Ice Tongue nearby Terra Nova Bay polynya (A area), continental Shelf Break area near Cape Adare (C area)] were studied at selected depths [surface, Deep Chlorophyll Maximum (DCM), Circumpolar Water (CDW), deep waters]. Trophic properties [nutrient concentrations, particulate (POC), dissolved carbon (DOC) its optically significant fraction (CDOM) measured, together with main hydrological variables. Microbial abundance [total prokaryotes, living, dead, actively respiring fraction, high- low nucleic acid cells (HNA LNA), pico- nano-eukaryotes, culturable heterotrophic bacteria], composition, metabolism (as whole as isolated bacteria) also assessed. Through a multidisciplinary dataset, this study highlighted variable response abundance, diversity, changing local Sea. Different forces, such inputs (mostly detrital nature) released from glacier A area, coastal-to-offshore gradient C coexisted within extreme ecosystem. This resulted spatial segregation edaphic parameters, metabolic activity patterns.