Description
Organisation/Company: Ecole Centrale de Lyon
Research Field: Environmental science › Ecology
Researcher Profile: Recognised Researcher (R2)
Application Deadline: 19/08/2022 18:00 - Europe/Brussels
Location: France › Ecully
Type Of Contract: Temporary
Job Status: Full-time
Hours Per Week: 40
Offer Starting Date: 03/10/2022
Mission
The main objective of this post doc is to determine links between some
sugars/sugar alocohols (S/SA) and specific bacteria and fungi in the
atmosphere. It will further identify possible microbial sources of S/SA in the
atmosphere. One focus will be on the possibility that glucose (one of the
major S/SA in PM, of current unknown source) arises in situ from
decomposition of cellulose directly in the PM. The co-occurrence of S/SA
species and microorganisms will be studied, for various environments and
seasons. For this purpose, a series of PM samples previously collected and
analyzed will be sequenced.
Context: Tropospheric particulate matter (PM) is involved in many aspects of
Human environments, including large impacts on climate change, health,
dispersion of pollutants, or damages to all compartments of the critical zone.
Some impacts can be positive (the fertilization of Oceans), but most are
negative, particularly when it comes to anthropogenic emissions. Assessing
these impacts requires a proper understanding of some properties of PM (mass,
size distribution, chemistry, physical and optical properties, ..), and also
a good parametrization of the fluxes in and out of the atmosphere, in order to
develop Chemical Transport Models (CTM). Primary Biogenic Organic Aerosols
(PBOA) are not included in CTMs, despite their large contribution to the
organic matter fraction of PM. As opposed to Secondary Biogenic Organic
Aerosol (SBOA) that is formed in the atmosphere from the biogenic VOC's
emitted by biota, PBOA is a subset of organic PM that comprises all
particulate material of biogenic origin directly entering the atmosphere, and
is indeed including components like plant debris, fungi, pollen, and viruses
(Elbert et al., 2007; Hummel et al., 2015; Amato et al., 2017). The current
estimate of the global flux to the atmosphere is between 10 and 310 Tg.year-1
(Hummel et al., 2015), to be compared to values of 21,3 (MACCCity) or 29,6
(CMIP6) Tg.year-1 for particulate organic components from anthropogenic
origins (Rémy et al., 2019).
A large part of this PBOA fraction is related to the fungi emission sources
(Hummel et al., 2015; Marynowski et al., 2020; Wang et al., 2021). It
follows that seasonal cycles of some sugars / sugar alcohols (S/SA)
concentrations in atmospheric PM can probably be directly related to the
microbiology of large biomes. However, this link has only been characterized
for a limited number of cases and S/SA (Samake et al., 2020, 2021; Marynowski
et al., 2020), and the main sources and drivers of many other S/SA in PM have
not been identified yet. Currently, the mechanisms of S/SA emissions (along
with their full organic cortege) to the atmosphere, and their fate and
transfer to other ecosystem compartments remain poorly understood. Within the
framework of the ANR call for proposals, a one-year post-doctoral and
financial support was granted to ABS (atmospheric biogenic sugars), which
sets up a collaboration between three laboratories, the Institute of
Environmental Geosciences, the Ampere laboratory and EDYTEM in Chambéry. The
majority of the experimental work will be carried out at the Ampere Lab in
Lyon and IGE in Grenoble.
The main objective of this post-doc is to determine The DNA of a total of
600 aerosol samples will be extracted at IGE using in-house protocols
developed specifically for aerobiology. Subsequent molecular analysis will be
carried out at AMPERE (C Larose in collaboration with IGE). Quantitative PCR
analyses of 16S rRNA and 18S rRNA genes will be performed to estimate the
abundance of bacterial and fungal cells per sample, respectively. Microbial
community structure will be obtained by MiSeq Illumina amplicon sequencing of
the V3-V4 region of bacterial/archaeal 16S rRNA genes and fungal ITS2 regions.
The selection of the samples will be based on sequences with high vs low
concentrations of S/SA from the different series / environments. A total of
600 filters will be selected and sequenced. The chemical composition of the
field samples will be correlated to the microbiological data using a range of
statistical approaches such as PCA, PCοA and NMDS to identify the possible
sources and grouping of the S/SA. Different modelling approaches such as
network analysis and gradient-boost machine learning will be used to link
specific taxa to the wide range of S/SA and other tracers in the PM.
Skills We are looking for a highly motivated candidate with a PhD degree in
atmospheric chemistry related to the molecular characterisation of complex
organic aerosols or microbially ecology, and a background in environmental
science. The candidate must be able to integrate into teams of different
cultures, have a strong taste for data analysis, be autonomous and know how to
take initiatives. Experience in atmospheric/analytical chemistry and data
mining in R language and a strong early-career track record in science
communication would be a plus.
General information
Duration: 12 months
Expected starting date : fall 2022
Eligibility criteria
We will consider applications from any candidate with the relevent skill sets
required that has a PhD.
Selection process
The eligible candidates will undergo online interviews.
Offer Requirements
Skills/Qualifications
We are looking for a highly motivated candidate with a PhD degree in
atmospheric chemistry related to the molecular characterisation of complex
organic aerosols or microbially ecology, and a background in environmental
science. The candidate must be able to integrate into teams of different
cultures, have a strong taste for data analysis, be autonomous and know how to
take initiatives. Experience in atmospheric/analytical chemistry and data
mining in R language and a strong early-career track record in science
communication would be a plus.
Contact Information
Organisation/Company: Ecole Centrale de Lyon
Organisation Type: Higher Education Institute
Website: https:// www. ec-lyon.fr
E-Mail: benedicte.martin@ec-lyon.fr
Country: France
City: Ecully
State/Province: France
Postal Code: 69130
Street: 36, av Guy de Collongue
