Co-Transport of Polycyclic Aromatic Hydrocarbons by Motile Microorganisms Leads to Enhanced Mass Transfer under Diffusive Conditions

Gilbert, DorotheaGothenburg University,Göteborgs universitet,Institutionen för biologi och miljövetenskap,Department of Biological and Environmental Sciences (författare)

The environmental chemodynamics of hydrophobic organic chemicals (HOCs) are often rate-limited by diffusion in stagnant boundary layers. This study investigated whether motile microorganisms can act as microbial carriers that enhance mass transfer of HOCs through diffusive boundary layers. A new experimental system was developed that allows (1) generation of concentration gradients of HOCs under the microscope, (2) exposure and direct observation of microorganisms in such gradients, and (3) quantification of HOC mass transfer. Silicone O-rings were integrated into a Dunn chemotaxis chamber to serve as sink and source for polycyclic aromatic hydrocarbons (PAHs). This resulted in stable concentration gradients in water (>24 h). Adding the model organism Tetrahymena pyriformis to the experimental system enhanced PAH mass transfer up to hundredfold (benzo[a]pyrene). Increasing mass transfer enhancement with hydrophobicity indicated PAH co-transport with the motile organisms. Fluorescence microscopy confirmed such transport. The effective diffusivity of T. pyriformis, determined by video imaging microscopy, was found to exceed molecular diffusivities of the PAHs up to four-fold. Cell-bound PAH fractions were determined to range from 28% (naphthalene) to 92% (pyrene). Motile microorganisms can therefore function as effective carriers for HOCs under diffusive conditions and might significantly enhance mobility and availability of HOCs.

NATURVETENSKAP Geovetenskap och miljövetenskap Miljövetenskap hsv//swe
NATURAL SCIENCES Earth and Related Environmental Sciences Environmental Sciences hsv//eng
HYDROPHOBIC ORGANIC-CHEMICALS
SOLID-PHASE MICROEXTRACTION
FACILITATED
TRANSPORT
POROUS-MEDIA
CONTAMINANT TRANSPORT
AQUIFER MATERIAL
MOBILE
BACTERIA
MATTER
COLUMNS
SPECIATION

Jakobsen, H. H. (författare)
Winding, A. (författare)
Mayer, P. (författare)
Göteborgs universitetInstitutionen för biologi och miljövetenskap (creator_code:org_t)

Ingår i:Environmental Science & Technology: American Chemical Society (ACS)48:8, s. 4368-43750013-936X1520-5851

Av författaren/redakt...: Gilbert, Dorothe ...; Jakobsen, H. H.; Winding, A.; Mayer, P.

Om ämnet

NATURVETENSKAP: NATURVETENSKAP; och Geovetenskap och ...; och Miljövetenskap

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