Show simple item record Alexandre M. en_US W. en_US George R. en_US David J. en_US Kenneth en_US 2009-09-23T14:09:24Z 2009-09-23T14:09:24Z 2005 en_US
dc.identifier en_US
dc.identifier.citation Anesio , A M , Graneli , W , Aiken , G R , Kieber , D J & Mopper , K 2005 , ' Effect of humic substance photodegradation on bacterial growth and respiration in lake water ' Applied and Environmental Microbiology , pp. 6267-6275 . , 10.1128/AEM.71.10.6267-6275.2005 en_US
dc.identifier.other PURE: 118421 en_US
dc.identifier.other dspace: 2160/3057 en_US
dc.description.abstract This study addresses how humic substance (HS) chemical composition and photoreactivity affect bacterial growth, respiration, and growth efficiency (BGE) in lake water. Aqueous solutions of HSs from diverse aquatic environments representing different dissolved organic matter sources (autochthonous and allochthonous) were exposed to artificial solar UV radiation. These solutions were added to lake water passed through a 0.7-µm-pore-size filter (containing grazer-free lake bacteria) followed by dark incubation for 5, 43, and 65 h. For the 5-h incubation, several irradiated HSs inhibited bacterial carbon production (BCP) and this inhibition was highly correlated with H2O2 photoproduction. The H2O2 decayed in the dark, and after 43 h, nearly all irradiated HSs enhanced BCP (average 39% increase relative to nonirradiated controls, standard error = 7.5%, n = 16). UV exposure of HSs also increased bacterial respiration (by 18%, standard error = 5%, n = 4), but less than BCP, resulting in an average increase in BGE of 32% (standard error = 10%, n = 4). Photoenhancement of BCP did not correlate to HS bulk properties (i.e., elemental and chemical composition). However, when the photoenhancement of BCP was normalized to absorbance, several trends with HS origin and extraction method emerged. Absorbance-normalized hydrophilic acid and humic acid samples showed greater enhancement of BCP than hydrophobic acid and fulvic acid samples. Furthermore, absorbance-normalized autochthonous samples showed 10-fold greater enhancement of BCP than allochthonous-dominated samples, indicating that the former are more efficient photoproducers of biological substrates. en_US
dc.format.extent 9 en_US
dc.relation.ispartof Applied and Environmental Microbiology en_US
dc.title Effect of humic substance photodegradation on bacterial growth and respiration in lake water en_US
dc.contributor.pbl Aberystwyth University en_US
dc.contributor.pbl Institute of Biological, Environmental and Rural Sciences en_US

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