title: Miniaturized test system for soil respiration induced by volatile pollutants.
abstract: A miniaturized method based on 96-well microtitre plates was developed and used to study respiration in pristine and contaminated soils following addition of volatile substrates. Small soil samples were exposed to fuel components, which were volatilized from spatially separate reservoirs of 2,2,4,4,6,8,8-heptamethylnonane (HMN) as an organic carrier. Respiration was determined as CO(2) production by means of a pH-indicator and bicarbonate-containing agar, or as (14)CO(2) evolution from (14)C-labelled substrates. Substrate concentrations inducing maximum microbial activity or inhibition were determined and CO(2) production profiles examined by multivariate analysis. When high concentrations of fuel components were applied, distinction of hydrocarbon exposed soils from unexposed soil was achieved within 6 h of incubation. With low concentrations, adequate distinction was achieved after 24 h, probably as a result of community adaptation. Nutrient limitation was identified with the (14)C method for toluene, and the optimal N and P amendment determined. Further potential applications of this rapid and inexpensive method are outlined.
authors.affiliation: Swiss Federal Institute of Technology, EPFL, ENAC-ISTE-LPE, CH-1015 Lausanne, Switzerland.
authors.forename: Karin
authors.initials: K
authors.lastname: Kaufmann
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Chapman
authors.forename: Colin D
authors.initials: CD
authors.lastname: Campbell
authors.forename: Hauke
authors.initials: H
authors.lastname: Harms
authors.forename: Patrick
authors.initials: P
authors.lastname: Höhener
mesh_terms: D018407:Bacterial Physiological Phenomena; D002245:Carbon Dioxide / Q000502:physiology*; D017753:Ecosystem; D015386:Hazardous Substances / Q000633:toxicity; D007648:Kerosene / Q000633:toxicity*; D008828:Microbiological Techniques; D009584:Nitrogen / Q000502:physiology; D010758:Phosphorus / Q000502:physiology; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*; D014050:Toluene / Q000633:toxicity
chemical_list: D015386:Hazardous Substances; D007648:Kerosene; D012989:Soil Pollutants; D002245:Carbon Dioxide; D010758:Phosphorus; D014050:Toluene; D009584:Nitrogen