Abstract: The lithosphere of Antarctica reacts to both the stress variations due to the dynamics of the mantle and the variation of the glacial load due to changes in climate. These two factors act on the dynamics of the glacial mass, on the evolution of the continent's topography and on the plate seismicity. This means that the knowledge of spatial variations in lithospheric thickness is needed to comprehend of the processes that involve interactions between climate and the geosphere. The main aim of this work is to produce a tomographic model of the continent. The classic data source for tomographic studies is a set of seismic signals produced by earthquakes. In this work I use a different technique: information is extracted by correlating the ambient seismic noise recorded in different locations. Instead of a the classic cross-correlation, this work uses the phase cross correlation technique, which appears to be more robust in our use case. Signal phases are used even to improve the correlogram stacks, by weighting the stack samples according to the correlograms' coherence. In Antarctica, the 30s Rayleigh wave group velocity map shows lower velocities in East Antarctica, and higher velocities in West Antarctica, coherently with expectations related to a thicker cratonic crust in the East, and thinner extending crust in the West. Deeper sensitivity of longer periods make the color pattern switch for the 80s map, sensing the upper mantle and consequently higher velocity at the cold roots of cratonic East Antarctica and lower velocity in the tectonically active West. I also contributed to the maintenance and development of the seismic observational infrastructure in Antarctica. This thesis recaps the activities I carried out during my participation to the 31st campaign of the Italian National Antarctic Research Program, to which I participated during the PhD course.

Abstract: In the Southern Hemisphere the species attributed to Corella eumyota , Traustedt, 1882 are likely more varied than previously expected. This ascidian species was described from specimens collected at Valparaiso (Chile). Until now it was considered as a widely distributed species in the southern hemisphere. New collections from Chile and the Antarctic area have allowed to separate two species and re-establish Corella antarctica Sluiter, 1905 as a valid species (Alurralde 2013).A morphological re-examination of many specimens from the MNHN collections and especially recent surveys as CEAMARC and REVOLTA confirms that Antarctic specimens from the Antarctic Peninsula and Terre Adélie obviously differ from sub-Antarctic material more varied than previously estimated. On the other hand, C. eumyota invasive in Europe (Lambert 2004) has been shown to be the same as specimens from Chile, New Zealand and other sub-Antarctic regions. The present morphological study compares Corella from different regions and describes a new species Corella brewinae n. sp that is found living mixed with C. eumyota populations.

Abstract: A new species of freshwater amphipod, Pseudingolfiella possessionis n. sp. (Senticaudata, Pseudingolfiellidae), is described from the submerged moss vegetation of small brooklets at sub-Antarctic Île de La Possession, Crozet archipelago. It constitutes the second freshwater amphipod species known for the sub-Antarctic and Antarctic region, and the fourth member of the genus. The main characters distinguishing it from all congeners are: the spine on the posterior margin of the dactylus, incisor and lamina mobilis of mandible each with 5 teeth, the setation of the maxilliped, the vestigial second article of pleopod 3 in the female, the undulate and laterally notched posterolateral margin of the external ramus of uropods 1 and 2 in the male, the spinulate dorsomedian projection of the telson.