Ecological role and modelling of long term (1987- 2017) spatial-temporal dynamics of the pteropods and copepods in the Ross Sea (Southern Ocean)

This thesis investigates the distribution and ecological dynamics of copepod and pteropod species in the Southern Ocean, with a particular focus on Terra Nova Bay and the Ross Sea Region Marine Protected Area. Drawing from legacy datasets, newly collected field samples, and predictive species distribution models, the study applies machine learning techniques to examine how environmental descriptors, and biological interactions influence Antarctic planktonic communities across spatial and temporal scales. The first chapter explores the response of zooplankton and sympagic biota to sea ice dynamics, documenting species turnover during a slow-melting season. The second chapter contributes a novel dataset based on copepods collected through the desalination unit of the Mario Zucchelli Station, highlighting new occurrence records for the region. The third chapter analyses mesozooplankton diversity and density in relation to water mass distribution, revealing distinct spatial assemblages and phylogenetic patterns. The fourth chapter presents the first-ever 3D predictive maps of copepod distributions in the Ross Sea, generated using FAIR-aligned legacy data and open-access GIS platforms. The fifth chapter emphasizes the importance of biological interactions in understanding ecological processes, modeling co-occurrences of phytoplankton and zooplankton using environmental predictors and machine learning to generate 3D SDMs. Final chapter investigates the fundamental and realized niches of the pteropods Limacina rangii and Clione limacina, including larval stages and egg masses, identifying spatial hotspots and the influence of both abiotic and biotic drivers. Overall, this thesis demonstrates that integrating open-access data, species interactions, and advanced modeling techniques provides a powerful, replicable approach to understanding and managing one of the world’s most pristine ecosystems. The findings offer valuable insights for future research, monitoring, and conservation efforts in the face of accelerating ...