Study of the bioaerosols atmospheric variability in the île de France region.

Les bioaérosols atmosphériques sont des particules d’aérosols biologiques primaires en suspension dans l’air et référencés dans la littérature comme étant des: Primary Biological Aerosol Particles (PBAPs). Les PBAPs sont de tailles et de natures très différentes. Ils ont la capacité à agir comme noyaux de condensation nuageux ou de glace et participent ainsi au cycle de l’eau sur terre. Ils peuvent être transportés loin de leur zone d’émission et coloniser de nouveaux écosystèmes. Leur caractère allergisant ou pathogène a un impact sur la santé humaine et animale. Ce travail de thèse qui porte sur l’étude de la variabilité des bioaérosols atmosphériques en région île de France concerne les pollens, les moisissures et les bactéries. Les observations ont été réalisées dans la couche limite à l’observatoire du SIRTA/LSCE. Ce travail pionnier dans la région Francilienne a permis: (1) de documenter la variabilité interannuelle, saisonnière et journalière propre à chacun des PBAPs, (2) de déterminer leurs origines géographiques respective, (3) d’étudier les paramètres météorologiques qui gouvernent leur cycle de vie dans l’atmosphère. Mon dernier objectif (4) a été de developper un instrument de mesure en temps reel des PBAPs et plus specifiquement des pollens.Atmospheric bioaerosols are particles of primary biological aerosols suspended in the air and referred in the literature as: Primary Biological Aerosol Particles (PBAPs). PBAPs have very different sizes and coposition. They have the ability to act as cloud condensation nuclei or ice nuclei and thus participate in the water cycle on earth. They can be transported far from their sources and they can in this way colonize new ecosystems. Their allergenic or pathogenic propoeries have an impact on human and animal health. This work on the variability of atmospheric bioaerosols in the Ile de France region concerns pollens, molds and bacteria. The observations were made in the boundary layer at the SIRTA/LSCE observatory. This pioneering work in the Ile-de-France region had the objective to: (1) document the interannual, seasonal and daily variability specific to each of the PBAPs, (2) determine their respective geographical origins, (3) study the meteorological parameters that control their life cycle in the atmosphere. My last objective (4) has been to develop an on line instrumenst to measure in real time BPAPs concentrations with a focus on pollen

Isoprene concentrations in the surface Arctic waters during POLARSTERN cruise PS92 (ARK-XXIX/1 TRANSSIZ) in May 2015

Isoprene concentrations in the surface Arctic waters, measured during the TRANSSIZ cruise from May 20th to May 27th, 2015, on board the R/V Polarstern. Measurements were made on-line with water extracted from the "ship's membrane pump" (~6m under the surface)

Surface transect data of trace gases, biomass and phytoplankton group composition during RV POLARSTERN cruise PS92

This data set includes the concentration of surface water volatile organic compounds and carbon monoxide, biomass concentrations and temperature from the ferry box system of RV POLARSTERN on the cruise track from Bremerhaven to the ice covered region north of Svalbard during RV POLARSTERN cruise PS92. Temperature and salinity were used to classify the sampled water masses based on the criteria applied in Tran et al., 2013

Depth profiles of trace gases, biomass and phytoplankton group composition during RV POLARSTERN cruise PS92

This data set contains the concentrations of chlorohyll a (chla) and the phytoplankton fuctional types from the CTD stations during PS 92, which were calculated from marker pigment ratios using the CHEMTAX program (Mackey et al, 1996).Pigment ratios were constrained as suggested by Higgins et al. (2011) based on microscopic examination of representative samples during the cruise, and the input matrix published by Fragoso et al. (2016) was applied. The resulting phytoplankotn group composition is represented in chl a concentrations. From the same bottles various trace gases were measured as carbon monoxide (CO) and the Volatile Organic Compounds (VOCs) as Dimethyl sulphide (DMS), methanethiol (MeSH) and isoprene

Vers une surveillance automatique normalisée des pollens et des spores par imagerie

International audienc

Concentrations of dissolved dimethyl sulfide (DMS), methanethiol and other trace gases in context of microbial communities from the temperate Atlantic to the Arctic Ocean

Abstract. Dimethyl sulfide (DMS) plays an important role in the atmosphere by influencing the formation of aerosols and cloud condensation nuclei. In contrast, the role of methanethiol (MeSH) for the budget and flux of reduced sulfur remains poorly understood. In the present study, we quantified DMS and MeSH together with the trace gases carbon monoxide (CO), isoprene, acetone, acetaldehyde and acetonitrile in North Atlantic and Arctic Ocean surface waters, covering a transect from 57.2 to 80.9∘ N in high spatial resolution in May–June 2015. Whereas isoprene, acetone, acetaldehyde and acetonitrile concentrations decreased northwards, CO, DMS and MeSH retained substantial concentrations at high latitudes, indicating specific sources in polar waters. DMS was the only compound with a higher average concentration in polar (31.2 ± 9.3 nM) than in Atlantic waters (13.5 ± 2 nM), presumably due to DMS originating from sea ice. At eight sea-ice stations north of 80∘ N, in the diatom-dominated marginal ice zone, DMS and chlorophyll a markedly correlated (R2 = 0.93) between 0–50 m depth. In contrast to previous studies, MeSH and DMS did not co-vary, indicating decoupled processes of production and conversion. The contribution of MeSH to the sulfur budget (represented by DMS + MeSH) was on average 20 % (and up to 50 %) higher than previously observed in the Atlantic and Pacific oceans, suggesting MeSH as an important source of sulfur possibly emitted to the atmosphere. The potential importance of MeSH was underlined by several correlations with bacterial taxa, including typical phytoplankton associates from the Rhodobacteraceae and Flavobacteriaceae families. Furthermore, the correlation of isoprene and chlorophyll a with Alcanivorax indicated a specific relationship with isoprene-producing phytoplankton. Overall, the demonstrated latitudinal and vertical patterns contribute to understanding how concentrations of central marine trace gases are linked with chemical and biological dynamics across oceanic waters

A reassessment of the budget of formic and acetic acids in the boundary layer at Dumont d'Urville (coastal Antarctica): The role of penguin emissions on the budget of several oxygenated volatile organic compounds

International audienceInitiated in 1997, the year-round study of formic and acetic acids was maintained until 2011 at the coastal Antarctic site of Dumont d'Urville. The records show that formic and acetic acids are rather abundant in summer with typical mixing ratios of 200 pptv and 700 pptv, respectively. With the aim to constrain their budget, investigations of their potential marine precursors like short-chain alkenes and acetaldehyde were initiated in 2011. Acetic acid levels in December 2010 were four times higher than those observed over summers back to 1997. These unusually high levels were accompanied by unusually high levels of ammonia, and by an enrichment of oxalate in aerosols. These observations suggest that the guano decomposition in the large penguin colonies present at the site was particularly strong under weather conditions encountered in spring 2010 (important snow storms followed by sunny days with mild temperatures). Although being dependent on environmental conditions, this process greatly impacts the local atmospheric budget of acetic acid, acetaldehyde, and acetone during the entire summer season. Present at levels as high as 500 pptv, acetaldehyde may represent the major precursor of acetic acid, alkene-ozone reactions remaining insignificant sources. Far less influenced by penguin emissions, the budget of formic acid remains not fully understood even if alkene-ozone reactions contribute significantly