Graduate School in Physics and Astrophysics ------------------------------------------- ANNUAL REPORT ------------------------------------------- Fill with a text editor (without TAB or formatting) Repeat fields for each course as necessary. ------------------------------------------- name: Baudena Alberto email: alberto.baudena@hotmail.it ciclo: 31 year completed (1,2 or 3): 3 supervisor: Guido Boffetta (Unito) and Francesco d'Ovidio (UPMC, Paris) ------------------------------------------- GRADUATE SCHOOL COURSES (only completed courses, with examination passed in the year) code: title: teacher: hours: ------------------------------------------- COURSES FROM OTHER GRADUATE SCHOOLS (only completed courses, with examination passed in the year) school: IMAS, UTAS (Australia) title: Fisheries Science teacher: Klaas Hartmann hours: 35 ------------------------------------------- UNDERGRADUATE COURSES (Laurea Magistrale) (only completed courses, with examination passed in the year) title: teacher: hours: ------------------------------------------- CONFERENCES, WORKSHOP (only those attended in the current year) title: Journées jeunes chercheurs place: CNES, Toulouse webpage: https://cnes.fr/fr/web/CNES-fr/10591-st-journees-cnes-jeunes-chercheurs-jc2.php days: 3 talk (Y/N): Y poster (Y/N): Y title: CNES meeting place: LOCEAN, UPMC, Paris webpage: https://cnes.fr/ days: 1 talk (Y/N): Y poster (Y/N): N title: Journée spatiale place: Sorbonne Université, Paris webpage: // days: 1 talk (Y/N): N poster (Y/N): Y ------------------------------------------- VISITS AND STAGES (only those done in the current year) institution: IMAS, UTAS, Australia place: Hobart, Tasmania (AU) starting date: 16 January days: 40 institution: CNR-ISMAR place: Lerici (La Spezia) starting date: 21 June 2018 days: 2 institution: Marbec place: Séte (Montpellier) starting date: 27 June 2018 days: 2 institution: SCRIPPS place: Paris starting date: 20 October 2017 days: 1 (NB: SCRIPPS Students visited in Paris) --------------------------------------------------- Research activity/Publications in the current year (max characters 2500) Submission of “Crossroads of the mesoscale circulation” at Journal of Marine Systems. The paper is actually under review. 2 papers in which I am the first author are in preparation, one is close to submission, and the other is expected to be submitted in the first part of 2019. 5 paper in which are I am co-author are in preparation too. 3 of them are close to submission. Research activity. The framework of my research activity concerns the comprehension of the coupling between physical and biological dynamics. This is a pivotal step to assess the health of the oceans, in order to protect the ecosystems therein from the effects of global change, human exploitation and pollution as well as for understanding the role of the ocean in the climate system. Indeed, in the oceans, physical phenomena and biological processes are intimately linked, since marine organisms live in a fluid environment, continuously under the effect of the currents. Thus, contrary to what happens on land, where the landscape topography changes over evolutionary timescales (periods in the order of hundreds to millions of year) in the ocean the landscape (“seascape”) evolves on the same timescales of ecological processes. In my thesis I analysed in particular the role of the fine scales, which present a peak in the ocean energy spectrum, and whose time scales (of days to weeks) overlap important marine ecological processes like the development of planktonic blooms and the duration of foraging trips for top predators. The fine scale features have been already shown to play a central role into conditioning primary production, lower trophic levels abundance and composition, and apex predators behaviors. However, less is known on their influence on intermediate trophic levels, i.e. swimming organisms (such as fish), which however constitute an essential part of the trophic chain, and which are under unprecedented pressure by human activities. This is mainly due to the scarce availability of data on them at large scales, and to problems of ship-based measurements. Two knowledge gaps were addressed in my work. The first is the fact that intermediate trophic levels distributions cannot be detected by remote sensing, and thus require the development of novel, ad hoc sampling strategies. The second open challenge addressed by this thesis was how the swimming ability of the nekton can interact with the fine scale physical dynamics. In order to address the aforementioned questions, in my PhD I adopted a Lagrangian approach, therefore focusing on water parcel trajectories, and I integrated it with novel methodologies applied to acoustic data, complex system analysis and network theory. I focused on the Kerguelen region, because of its ecological importance and the large availability of informations, which permitted to characterize its relatively simple ecological dynamics, mainly based on iron limitation which is furnished by the plateau. I considered the myctophids as reference fish of the study, for their worldwide abundance and for their importance for the ecology of the area, and because they may constitute a future target by commercial fishing. In the first part of my work I analyzed the relationship between satellite-derived fine scale processes and acoustic data of fish concentration, finding that high biomass levels are observed in correspondence of frontal systems identified through Lagrangian structures. I then proposed a possible mathematical mechanism of fish aggregation on frontal features based on gradient climbing strategy and reduction of fish hotspots by horizontal currents, finding that frontal features can couple with swimming behavior and enhance fish aggregation. I assessed also that frontal system presence is a necessary but not sufficient condition to assure large fish concentrations, a result which is confirmed also by the analysis of the acoustic data. In the second part of the thesis I analyzed flow circulation properties through Lagrangian Flow Network methods in order to develop an efficient monitoring strategy of waters coming from, or going to, a target region. This methodology could be used to design an optimal sampling network to assess fish or larval abundance. I validated the method proposed with 43 real drifters released in Kerguelen region, and I found that the monitoring network built in this way has a performance two times greater than a regular grid, assessing furthermore its robustness even when sampling high turbulent regions. The results provided open interesting perspectives, concerning applications in marine spatial planning, conservation issues and design and protection of marine protected areas. BE AWARE: research activity and Pubs are not evaluated as didactic credits, but are requested to trace the PhD students' career