Director of studies: Dr. Daniele Iudicone
Department of Integrative Marine Ecology
This project will address the overarching question of how geophysical variability in time and space affects ecosystem diversity, focusing on oceanic plankton as a model system. A long-standing, as yet unresolved challenge - the "plankton paradox"- is to understand how phytoplankton maintain their observed rich biodiversity while inhabiting a relatively unstructured environment and competing for only a few resources. In fact, the local structure and function of their communities is organized by ocean circulation and resource delivery, together with organismal acclimation and adaptation. How these factors interplay to maintain ocean biomes is a key question of phytoplankton ecology, with important implications for the structure of marine food webs and climate. Specifically, we will bring together expertise in theoretical ecology, genomics and oceanography to explore how spatial-temporal variability in the environment may allow for the stable coexistence of many species in competition while favoring the establishment of new species. We will pay particular attention to the novel hypothesis that plankton do not always respond to high frequency environmental signals in order to competitively exploit environmental variability.
Marine biology is under-going a rapid and significant transition due to the availability of new, cost-effective molecular and bioinformatics tools. The recent Tara Oceans global survey provides one of the first, and certainly the most comprehensive survey of detailed molecular information and oceanographic context. Using an holistic approach, the work will focus on examining the environmental seasonality vs ocean circulation as factors shaping the diversity in real data (Tara Oceans) and in a hierarchy of models describing climate-plankton interaction at increasing levels of detail and realism. The combined expertise will allow to make informed, innovative modelling choices at each level of complexity and test the results against the observed distribution of species and associated traits. The simulations will inform future models of global scale organization of phytoplankton populations and their response to climate change. Specifically, by combining curated transcriptome datasets from key selected, evolutionarily distant organism groups with diversity analyses and tracking their dispersal across the oceans, we will develop models to test hypotheses on plasticity, adaptation, microevolution, speciation and collective processes in globally relevant unicellular communities.
As main intellectual merit, the interdisciplinary team of oceanographers, modelers and biologists will allow an innovative end-to-end (molecular mechanisms - organisms - communities) analysis of phytoplankton dynamics and the validation of hypotheses in well contextualized water masses. In turn this will inform conceptual models directly from data in addition to building up upon previous modelling exercises. Finally, the study of the impact of seasonality upon plankton will allow to bridge terrestrial and marine ecology to a point rarely reached before, with broad impact on the marine community. In addition, the evolutionary significance of overlooked traits and the dynamical balance with oceanic dispersal will inform new directions of theoretical and applied research.
