ESPCI web site
PMMH’s weekly seminar is held every Friday at 11 am (map)
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH - François Peaudecerf, ETH Zürich
Wall entrapment enhances bacterial chemotactic response to deposited aerosols in the microlayer
The sea surface microlayer is the thin layer of water separating the atmosphere from marine waters below. This typically half-millimeter-deep laminar layer mediates all gas exchange and receives all material deposited from the atmosphere, such as aerosol particles, before any transfer to deeper water can occur. The microlayer is a harsh environment characterized by large temperature and salinity fluctuations and strong ultraviolet radiation. Yet field sampling suggests a microlayer bacterial community does indeed exist, distinct from that in deeper waters. We hypothesize that motile microlayer and near-surface bacteria can successfully exploit the transient nutrient patches produced by surface-deposited aerosols using chemotaxis-driven foraging strategies, thus obtaining privileged access to rare resources. We developed a novel millifluidic device to image a static air-water interface with falling aerosol particles and swimming bacteria, enabling tracking of individual particles and cells. We observed that marine bacteria swam to and accumulated at the surface when exposed to environmentally relevant fluxes of deposited chemoattractant aerosols. These accumulations formed within seconds to minutes in extraordinarily thin films (< 0.1 mm) and were approximately an order of magnitude higher than expected from previously established chemotactic accumulations observed in bulk. Using a novel theoretical model of bacterial behavior, we demonstrated that this strong accumulation can indeed be explained by the coupling of chemotaxis to dissolved aerosol-borne attractants and ‘wall entrapment' at the air-water interface – a physical mechanism by which motile bacteria reside near boundaries for longer times. Our results highlight how interfaces in the environment modify the behavior of microorganisms, and in particular demonstrate that the microlayer is an environment where motile bacteria, through both active and passive mechanisms, quickly respond to aerosol deposition and accumulate in high-nutrient regions, thus resulting in a competitive advantage for motile cells.
- Seminar archive
- Recent seminars
- Seminars
Seminars (4)
-
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
The audience is composed of people with rather heterogeneous backgrounds including specialists in solids, fluids, granular flows, statistical physics... so the idea is to keep your talk understandable by people not necessarily working in your field... The seminar time slot runs from 11am to noon so the best is to make the talk last around 45 minutes to leave some time for discussion.
- Séminaires ESPCI-ENS de biophysique
- Séminaires du Département de Physique de l’ENS
- Séminaires du Laboratoire d’Hydrodynamique de l’X
- Séminaire de Mécanique d’Orsay (page web FAST)
- Séminaire de Mécanique d’Orsay (page web LIMSI)
- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
- Séminaires Gulliver
Link to cofee seminar (internal, every Thursday)
