AMU

With the consensus that human activities are leading to dangerous interference in Earth’s climate, there has been growing policy pressure for clear quantification and attribution of the resulting biological impacts. For this reason, there is an urgent need to understand the effect of ecological and evolutionary processes caused by past climate change on range dynamics. In fact, adaptation of plant populations in fitness-related traits to different local climate condition might enable species to take on future climate change. In general, species performance (genetics, physiology, morphology and demography) is predicted to decline gradually from population growing in the climatic optimum (central population) to population growing in harsh climate conditions (peripheral populations). However, studies aimed to analyse differences between central and peripheral populations relate this differences with only one or two possible causal factors (i.e., historical, ecological or biogeographic factor), without distinguishing between geographical, environmental and historical isolation. For this reason, the goal of our project is to evaluate whether the environmental (ecological niche), historical (biogeographical processes) and geographical barriers may explain difference in both gene diversity and fitness-related floral traits between central and peripheral populations in Lilium pomponium, a species potentially prone to extinction risk because of range loss induced by climate change and spanning across Mediterranean to Alpine climate. The originality and interdisciplinarity of this research programme lies into integrate ecological niche characteristics together with current and past range structure to investigate evolutionary processes that have affected spatial patterns of genetic and demographic variation across species ranges combining different research fields in evolutionary biology as reproductive biology, ecology, phylogeography and population genetics.

About 98% of the ocean’s biomass is composed of microorganisms like the tiny algae, phytoplankton. Tiny but mighty when it comes at capturing carbon dioxide (CO2). Phytoplankton acts for half of the Earth’s photosynthesis, allowing ocean’s to supply major living resources and dioxygen (O2). Microbial respiration is the other fundamental biological process that counterbalances photosynthesis and returns organic carbon back as CO2. Yet, despite ocean’s pivotal role in global climate, microbial respiration remains one of the least explored metabolic processes; so that, whether oligotrophic ocean is a net sink or source of CO2, is highly debated for the last 20 years. The BULLE project aims to evaluate the ocean’s metabolic balance between photosynthesis and respiration by looking at the production of CO2 evolved to that O2 consumed by marine bacteria, the so-called “respiratory quotient” (RQ). Limits of detection of biological CO2 production have left RQ measurements far behind the multitude of investigations of photosynthesis. BULLE will face these challenges using the most recent technologies. The project strongly relies on the multidisciplinary expertise I will share with my host lab to tackle this issue at both cellular and community level. Specifically, BULLE aims to (1) investigate how the chemical characteristics of nutrients (Fe and C) regulate the RQ in bacterial cells and (2) study the links between the RQ, net primary production and bacterial activities. An innovative aspect of BULLE is the implementation of continuous measurements of O2/N2 and pCO2 concentrations respiration, and the deployment of In Situ Oxygen Dynamic Autosampler (IODA) instrumentation in the coastal NW Mediterranean Sea. The training I will receive with BULLE will help me give my career a new direction from a lab expertise towards high resolution in situ observations. In return, I will transfer my experience in microbial metabolisms and radioisotopes tracking methods to the host team.