Drexel University

Postdoctoral fellow Position in Omics and Soil Microbiome Research (2 years) The Mohammed VI Polytechnic University (UM6P) invites applications for a Postdoctoral fellow position to join an interdisciplinary research project focused on metaproteomic analysis of soil microbial communities. This project aims to identify key genes and enzymes involved in mitigating salinity stress and improving soil health and crop productivity. These positions are part of a broader initiative to develop biofertilizers and sustainable agricultural strategies to combat soil degradation and salinization. Research will involve state-of-the-art metaproteomics, bioinformatics, and functional microbiome studies conducted in field trials, greenhouse experiments, and laboratory settings. This role will focus on the interactions between rhizosphere microbiota and plant roots, investigating how microbial enzymes enhance plant stress tolerance under salinity conditions. The successful candidate will: Conduct metaproteomic and genomic sequencing of microbial communities associated with plant roots. Identify microbial enzymes and functional pathways involved in nutrient acquisition and stress adaptation. Analyze plant-microbe interactions in response to salinity stress. Collaborate on biofertilizer development incorporating beneficial microbial enzymes. Required Qualifications: Ph.D. in Microbiology, Bioinformatics, Soil Science, Plant Science, Environmental Science, or a related field. Expertise in microbiome data analysis, metagenomics, or metaproteomics. Proficiency in bioinformatics tools for multi-omics data processing Strong publication record in relevant fields. Ability to work in a multidisciplinary team and collaborate across research groups. Preferred Qualifications: Experience in functional characterization of microbial enzymes. Familiarity with microbial ecology and soil biochemistry in stress adaptation. Background in field and greenhouse experimental design. Application Process: Applicants should submit the following documents: Cover letter detailing research interests and relevant experience. Curriculum Vitae (CV) with a full list of publications. Contact information for three references. For inquiries, please contact achraf.elalali@um6p.ma

Area of specialization: Critical Zone is the “heterogeneous, near-surface environment in which complex interactions involving rock, soil, water, air, and living organisms regulate the natural habitat and determine availability of life-sustaining resources”. Its limits range from the top of the canopy down to the bottom of the aquifer. The successful applicant to this position will join the Global Critical Zone Science Chair to develop and conduct a research program to better understand forest nutrition and nutritional stress in Eucalyptus forest stands in Brazil. Research context: Forests cover 1/3 of the continental surfaces and play a crucial environmental role both at local and global scales. Forests sequester 25% of the carbon injected each year to the atmosphere by human activities and thus regulate the Earth’s global climate at short time scales. In its 2022 report for policymakers, the Word Resource Institute (Seymour et al., 2022) draws attention to the fact that forests do not only play a role by absorbing carbon from the atmosphere but also influence global and local temperature, rainfall patterns through albedo, evapotranspiration (forest ecosystems provide 2/3 of the continent precipitation), surface roughness and aerosols emission. At longer timescales, forests, via the formation of soil organic matter, erosion and deposition in the ocean, play an essential role in the regulation of climate at the geological time scale. As a consequence, protection and better management of forests is crucial for climate warming mitigation through carbon sequestration, as well as for other ecosystem services such as wood production or recreation. However, forests are “not just carbon”. For forests to play their role on the planet, not only do they need carbon withdrawn from the atmosphere and water from the soil, but they also require a number of major and minor nutrients. Among the factors that limit the energetic yield of photosynthesis to 0.1%, and thus the productivity of forest ecosystems, the availability of soil nutrients is probably one of the most important. With the exception of nitrogen (N) that can be fixed from the atmosphere, major nutrients such as potassium (K), silicon (Si), phosphorus (P) or minor nutrients such as metals (zinc, Zn; magnesium, Mg; calcium, Ca; boron, B; molybdenum, Mo,…) are ultimately derived from the transformation of soil minerals into secondary phases such as cation-poor clays and oxides, a process known as chemical weathering and taking place in soils or affecting atmospheric mineral aerosols. There is now ample evidence that forests are under increasing nutritional stress (Penuelas et al., 2020). The limitation of forest productivity by nutrients like N and P has been extensively studied (Du et al., 2020; Hou et al, 2020), while the role of other mineral-derived nutrients has attracted less studies. This situation is all the more critical now that we know that the pure “liebigian” limitation (one factor limits the growth) is not true for most ecosystems (Wurzburger et al., 2012), implying that the effect of other nutrients and micronutrients must be studied in detail. Hence a prerequisite for our ability to assess forest ecosystem evolution and maintenance of biomass productivity of agroforests, in the face of environmental change, is a better understanding of how plant nutrient requirements are met beyond C, N, and P. K is one of those mineral nutrients that has been investigated. Fertilization experiments have confirmed that K deficiency limits tree growth and forest productivity and mechanistic models have been developed that confirm the strong response of GPP (gross primary production) to a nutritional stress for K (Cornut et al., 2022) The overall objective of this postdoc project is to improve our knowledge of nutritional dynamics in forest ecosystems based on the balance between organic (dead biomass recycling) and mineral (chemical weathering or added sources by fertilization) sources. To achieve this goal the project aims at make use of isotopes, in particular boron isotopes, and potentially K isotopes. Recently, the analytical and conceptual development of so-called non-traditional stable isotopes opened up a new avenue for the study of nutrient cycling in forest ecosystems, the main idea being that biogeochemical processes will generate measurable discriminations between metal isotopes that can be used to trace their routes through living individuals, ecosystems, or the critical zone (e.g. Cividini et al. 2010, Dessert et al., 2015). In this respect, the trace element boron (B) appears as a powerful tool as it is a micronutrient involved in a wide variety of physiological processes where it undergoes significant isotopic fractionation of the two stable isotopes: 10B and 11B (Gaillardet et Lemarchand, 2018, Roux et al., 2021, Chetelat et al., 2021). In the Eucalypus stands, Boron is frequently added to the soil as it has been observed that boron fertilization improves the resistance of the trees to drought. The aim of the project is to focus on forest plantations as a “model forest” to better understand the behavior of boron and other major nutrients (and in particular potassium) and how their cycles is linked to the ecosystem services. It is coupling experimentation, isotopic measurements and modeling aspects taking advantage of a network of international collaboration and collaborations with the private sector. Importantly, this project is associated to a broader project funded by the French National Research Agency (Nutribor project, PI Pr. Jérôme Gaillardet) which aims at applying boron isotopes to a range of critical zone observatories covering environmental and geological gradients. The successful postdoc will integrate the scientific community of the Nutribor project.  Briefly, the Nutribor project consists of different workpackages. 1/in-situ experimentation at the Ile de France Ecotron near Paris. 2/ boron isotope measurements in the critical zone of three natural catchments from the OZCAR network (French Critical Zone Observatory network) in Northern France, Southern France and the French Lesser Antilles. 2/ecophysiological and reactive transport modelling. The postdoctoral work will particularly be interesting for the comparison with the controlled experiments at the Ecotron facility near Paris. It will benefit for a pluridisciplinary research environment.  Eucalyptus plantations in Brazil and methodology: Brazil has one of the world’s largest surface areas of planted forest (9.9 million ha), of which more than 70 % is covered by eucalyptus (Pena-Vergara et al. 2022). These fast-growing forest plantations have high wood productivity, coming from the intensive management practices including short rotation, fertilization and genotype selection. These plantations are providing an increasing share of wood biomass for producing pulp and paper, charcoal, firewood, and panels. The rapid growth rates of eucalyptus with large wood exports at harvest make this ecosystem particularly interesting for studying and modeling biogeochemical cycles (Cornut et al. 2021), and poses important challenges in finding the right levels of fertilization to limit their environmental impact. Boron-poor soils are commonly found in the ‘Cerrados’ region of Brazil, where there is the greatest expansion of eucalyptus spp plantations on degraded pastures (José et al. 2009, da Silva Damasceno et al. 2023). Boron is one of the most limiting nutrients to eucalyptus seedling growth in these soils (Sgarbi et al. 1999, Sakya et al. 2002). Fertilization in boron is therefore necessary in the more depleted soils, but is also important in other areas where chemical weathering is no longer sufficient for sustaining the high exportations. The primary field site in Brazil, EucFlux, is a 200 Ha Eucalyptus instrumented plantation that has been highly monitored since 2008 with an eddy-covariance flux tower together with numerous ancillary data related to water, carbon and nutrient cycles (Christina et al. 2017). The soils at this site are deep Ferrasols (FAO classification) developed on Cretaceous sandstone, with approximately 80 % sand content down to the water table at 17 m. The mean annual rainfall is 1430 mm year-1. Harvest is planned for September 2025, following which a nutrient omission design for boron and potassium will be included for the next plantation cycle (of 6-7 years). The primary objectives of the postodoctoral work at this site will be to use existing infrastructure and additional experimental equipment to establish a partial boron mass balance at two developmental stages of Eucalyptus spp subject to different fertilization regimes: in a mature fertilized Eucalyptus spp stand after canopy closure in the final months leading to harvest, from January to September 2025, as well as post-harvest over the early developmental stages of the same clone of a Eucalyptus spp plantation subject to a fertilization design with boron and potassium omissions (Figure 1). Figure 1. Schematic design of nutrient omission in the Eucflux experiment made in collaboration with the private companies of forest exploitation. Various critical zone compartments will be analysed for B content and isotopic signature, as well as for the various macro- and micronutrient contents of these compartments (soil, soil water, different parts of the vegetation, rivers). More specifically, soils will be collected at four depths to 150 cm and multiple belowground and aboveground tree compartments at these different development stages (roots at three depths, branch wood & branch bark, stem wood & stem bark, leaves (high canopy and low canopy), and monthly litterfall samples. In addition, will be collected monthly composite samples of : 1/throughfall (using a funnel system connected to reservoirs), 2/stemflow (using PVC pipes spiraling down a section of the trunk to reservoirs), 3/soil solutions (using gravitational flow to lysimetric plates at the litterfall-soil surface interface and at 15 cm, with collections planned for further analyses at 40 cm and 100 cm post-harvest), 3/atmospheric deposition (with a receptor above the tree canopies at the top of the flux tower), 4/groundwater samples (collected via the piezometers using a weighted tube receptor). In addition, samples will be collected from water points and micro-watersheds in Itatinga close to the EucFlux site during the second phase of the project. In parallel, experiments will be run at the Ecotron (Ile de Paris) that will allow various levels boron application, as well as drought simulation to be applied to these eucalyptus (of the same clone, AEC144). Running these experiments in parallel will be of great value, between the precisely contrived conditions of the Ecotron to the in-situ field measurements at Itatinga. The Ecotron experiments are not part of the postdoctoral work and will be made by a French PhD student. Combining data from Eucalyptus stands and experimentations in Ecotron will allow boron fractionation between different soil, tree and water reservoir compartments to be determined, as well as the relationship between boron and other macro- and micronutrients will be evaluated. These findings have the potential to improve knowledge on the nature of nutritional dynamics in these Eucalyptus plantations in typically nutrient-deficient soils and subject to the increasing intensity and frequency of droughts. Boron isotopic measurements, major elements and complementary analyses will be conducted in Brazil as much as possible. These measurements will open perspectives of of collaboration with a modelling team at Cirad.  Job application: The Global Critical Zone Science Chair at the Mohammed VI Polytechnic University (UM6P) invites applications for a two years postdoc fellowship (candidates from Moroccan or African universities). The successful applicant will conduct research on the boron and potassium biogeochemistry in the critical zone of instrumented sites in Brazil. He.She will be mostly based in Brazil. The different compartments of the system will be investigated (soil, vegetation, soil pore water, river water) in the framework of the in-situ research experiment described above. The work will be done in collaboration with international teams and teams in Brazil. Boron isotopic measurements will be made in Brazil at least in a routine phase. Collaboration will also associate the private sector in charge of the forest exploitations. High precision isotopic measurements will be conducted. The candidate must have a background in either isotope geochemistry and if possible, an experience working with MCICPMS. The candidate is expected to adopt a system approach in its way to understand the behavior of boron and other nutrients in the studied agrosystems (/planted forestry systems). Modeling skills will be appreciated even if the main part of the postdoctoral work in field and lab-related. Writing skills are necessary as the results of the postdoctoral work will be published in high standard scientific journals. Criteria of the candidate: PhD in environmental science, soil science, surface geochemistry, or related fields from a recognized Moroccan or African university. At least one or two high publications record in international well-ranked journals Significant knowledge in environmental science studies, including experienced in soil field work and abilities in isotopic geochemistry techniques and/or modeling capabilities. Excellent verbal and written communication skills in English. Skilled in both field and lab work Proactive, ethic, and respectful person Tentative Schedule: Year 1 1 Collection of flux data B isotopic analysis, macro- and micronutrient analysis Monitoring and analysis of flux data 2 Collection of flux data B isotopic analysis, macro- and micronutrient analysis Monitoring and analysis of flux data 3 Monitoring and analysis of flux data Relationship between B and other macro- and micronutrients 4  Monitoring and analysis of flux data Relationship between B and other macro- and micronutrients Modelling boron and potassium fluxes Year 2 1 Monitoring and analysis of flux data Establishment of boron and potassium budgets Relationship between B and other macro- and micronutrients Paper 1: Boron budget in tropical soil-tree planted systems. Modelling boron and potassium fluxes  Paper 2: Boron and potassium dynamics in a planted tropical forestry system 2. 2 Monitoring and analysis of flux data Establishment of boron and potassium budgets Relationship between B and other macro- and micronutrients Paper 1: Boron budget in tropical soil-tree planted systems Modelling boron and potassium fluxes Paper 2: Boron and potassium dynamics in a planted tropical forestry system 2. 3 Relationship between B and other macro- and micronutrients Paper 1: Boron budget in tropical soil-tree planted systems. Modelling boron and potassium fluxes Paper 2: Boron and potassium dynamics in a planted tropical forestry system 2. Executive summary for policy makers 4  Paper 2: Boron and potassium dynamics in a planted tropical forestry system 2. Executive summary for policy makers Final report References: Chetelat, B., Gaillardet, J., Chen, J.Bin, 2021. Dynamic of boron in forest ecosystems traced by its isotopes: a modeling approach. Chem. Geol. 560, 119994. https://doi.org/10.1016/j.chemgeo.2020.119994. Christina, M., Nouvellon, Y., Laclau, J. P., Stape, J. L., Bouillet, J. P., Lambais, G. R., & Le Maire, G. (2017). Importance of deep water uptake in tropical eucalypt forest. Functional Ecology, 31(2), 509-519. Cividini D., D. Lemarchand, F. Chabaux, R. Boutin, M.-C. Pierret (2010) From biological to lithological control of the B geochemical cycle in a forest watershed (Strengbach, Vosges) Geochimica et Cosmochimica Acta 74 3143– 3163  Cornut, I., Le Maire, G., Laclau, J. P., Guillemot, J., Mareschal, L., Nouvellon, Y., & Delpierre, N. (2021). Potassium limitation of wood productivity: A review of elementary processes and ways forward to modelling illustrated by Eucalyptus plantations. Forest Ecology and Management, 494, 119275. Cornut I. et al. (2022a) Potassium-limitation of forest productivity, part 1: A mechanistic model simulating the effects of potassium availability on canopy carbon and water fluxes in tropical eucalyptus stands. EGUsphere, 1-37. Cornut I. et al. (2022b). Potassium-limitation of forest productivity, part 2: CASTANEA-MAESPA-K shows a reduction in photosynthesis rather than a stoichiometric limitation of tissue formation. EGUsphere, 1-27 Dessert et al. (2025), Geochim. et Cosmochim. Acta 171, 216–237 Du, E., Terrer, C., Pellegrini, A. F. A., Ahlström, A., van Lissa, C. J., Zhao, X., Xia, N., Wu, X., and Jackson, R. B. (2020). Global patterns of terrestrial nitrogen and phosphorus limitation. Nature Geoscience, 13(3):221–226. Gaillardet J. and Lemarchand D. (2018) Boron the weathering environments. In Boron isotopes, the fifth element. Springer ISBN 978-3-319-64664-0 Hou  et al. (2020), Nature communications 11, 637. José, J. F. B. D. S., Silva, I. R. D., Barros, N. F. D., Novais, R. F., Silva, E. F., Smyth, T. J., ... & Gebrim, F. O. (2009). Boron mobility in eucalyptus clones. Revista Brasileira de Ciência do Solo, 33, 1733-1744.Lemarchand, D., Cividini, D., Turpault, M. P., & Chabaux, F. (2012). Boron isotopes in different grain size fractions: Exploring past and present water–rock interactions from two soil profiles (Strengbach, Vosges Mountains). Geochimica et Cosmochimica Acta, 98, 78-93.  Pena-Vergara, G., Castro, L. R., Gasparetto, C. A., & Bizzo, W. A. (2022). Energy from planted forest and its residues characterization in Brazil. Energy, 239, 122243. Penuelas et al. (2020), Communications Biology 3, 125. Sakya, A. T., Dell, B., & Huang, L. (2002). Boron requirements for Eucalyptus globulus seedlings. Plant and soil, 246, 87-95. Sgarbi, F., Silveira, R. L. V. A., Takahashi, E. N., & Camargo, M. D. (1999). Crescimento e produção de biomassa de clone de Eucalyptus grandis x Eucalyptus urophylla em condições de deficiência de macronutrientes, B e Zn. Scientia Forestalis, 56(1), 69-82. da Silva Damasceno, A. S., Boechat, C. L., de Souza, H. A., Capristo-Silva, G. F., de Sousa Mendes, W., Teodoro, P. E., ... & da Silva Junior, C. A. (2023). Nutritional monitoring of boron in Eucalyptus spp. in the Brazilian cerrado by multispectral bands of the MSI sensor (Sentinel-2). Remote Sensing Applications: Society and Environment, 29, 100913. Roux, P., Lemarchand, D., Redon, P. O., & Turpault, M. P. (2022). B and δ11B biogeochemical cycle in a beech forest developed on a calcareous soil: Pools, fluxes, and forcing parameters. Science of the Total Environment, 806, 150396. Seymour et al. (2022), Not just carbon, https://doi.org/10.46830/wrirpt.19.00004 Wurzburger et al. (2012), PLOS ONE 7, e33710

Years of Experience: 0 to 4 years Education Level: Doctoral degree  Type of Contract: 1 year contract (renewable) Number of Positions: 2 Expected Start Date: February 1st, 2026 About the University: Located at the heart of the future Green City of Benguerir, Mohammed VI Polytechnic University (UM6P), a higher education institution with an international standard, is established to serve Morocco and the African continent. Its vision is honed around research and innovation at the service of education and development. This unique nascent university, with its state-of-the-art campus and infrastructure, has woven a sound academic and research network, and its recruitment process is seeking high quality academics and professionals in order to boost its quality-oriented research environment in the metropolitan area of Marrakech. About the School The College of Computing (UM6P-CC) is located in the future Green City of Benguerir. It provides world-class university education in computer science promoting discovery and innovation. The College currently offers an engineering degree in computer engineering, and a doctoral program in computer science. About the Group The Data Intelligence Group at UM6P-CC is a growing and supportive team with internationally recognized expertise in data management and machine learning. The group has a strong network of national and international collaborators in both academia and industry. Job Title Postdoctoral Fellow – College of Computing Job Description The Data Intelligence Group at UM6P-CC is seeking two postdoctoral fellows in machine learning who will support the group’s projects in the rapidly growing field of multimodal representation learning and retrieval. The specific responsibilities of the postdoctoral fellow will include: conduct scientific research in the field of machine learning. develop novel machine learning algorithms primarily for representation learning, dimensionality reduction, clustering and search. conduct theoretical and experimental performance analyses of the proposed algorithms. publish research results in high-quality venues (conferences and journals) and present them in national and international scientific events and conferences. contribute to the supervision of undergraduate and graduate students. assist in writing research proposals. contribute to training and teaching activities, including the development of new courses. assist in the organization of workshops, seminars and other national and international events related to machine learning. work effectively with the DMG team and help nurture internal and external collaborations with academic and industrial partners. Qualifications Ph.D. in Computer Science, Applied Mathematics, or a related field. Strong publication record in machine learning, with preference for expertise in representation learning, deep embeddings, contrastive learning, or foundation models. Solid background in linear algebra, probability, and statistics. Strong programming skills with deep learning frameworks (e.g., PyTorch) and standard data analysis tools. Familiarity with data structures, algorithms, and—ideally—search or indexing techniques. Excellent communication skills and strong analytical, teamwork, and organizational abilities. Application: Applications should be submitted online and emailed to karima.echihabi@um6p.ma with the subject "[Postdoctoral Fellow Position]". Ph.D students in their final year of study are also encouraged as long as they expect to obtain their degree by September 2026.  Emailed application materials should contain an up-to-date CV and a zipped archive which includes a cover letter and full transcripts. The CV should clearly indicate the following information: type of high-school degree obtained (e.g., Sciences Mathematiques A), overall high-school average, Mathematics grade in the national exam, and overall average/ranking in university studies. Job Location Benguerir, Morocco