<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Allison, S. D.</style></author><author><style face="normal" font="default" size="100%">Czimczik, C. I.</style></author><author><style face="normal" font="default" size="100%">Treseder, K. K.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial activity and soil respiration under nitrogen addition in Alaskan boreal forest</style></title><secondary-title><style face="normal" font="default" size="100%">Global Change Biology</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Glob. Change Biol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">240</style></keyword><keyword><style  face="normal" font="default" size="100%">Alaska</style></keyword><keyword><style  face="normal" font="default" size="100%">bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">boreal forest</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon cycle</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon storage</style></keyword><keyword><style  face="normal" font="default" size="100%">community structure</style></keyword><keyword><style  face="normal" font="default" size="100%">Content Type: Biblio</style></keyword><keyword><style  face="normal" font="default" size="100%">deposition gradient</style></keyword><keyword><style  face="normal" font="default" size="100%">ectomycorrhizal fungi</style></keyword><keyword><style  face="normal" font="default" size="100%">environmental-samples</style></keyword><keyword><style  face="normal" font="default" size="100%">enzymatic-activity</style></keyword><keyword><style  face="normal" font="default" size="100%">extracellular enzyme</style></keyword><keyword><style  face="normal" font="default" size="100%">extracellular enzymes</style></keyword><keyword><style  face="normal" font="default" size="100%">extraction method</style></keyword><keyword><style  face="normal" font="default" size="100%">litter decomposition</style></keyword><keyword><style  face="normal" font="default" size="100%">microbial biomass</style></keyword><keyword><style  face="normal" font="default" size="100%">mycorrhizal responses</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen fertilization</style></keyword><keyword><style  face="normal" font="default" size="100%">nucleotide analog</style></keyword><keyword><style  face="normal" font="default" size="100%">soil respiration</style></keyword><keyword><style  face="normal" font="default" size="100%">Trumbore / Czimczik Research Group</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">May</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">&lt;Go to ISI&gt;://000255463600017</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">5</style></number><volume><style face="normal" font="default" size="100%">14</style></volume><pages><style face="normal" font="default" size="100%">1156-1168</style></pages><isbn><style face="normal" font="default" size="100%">1354-1013</style></isbn><language><style face="normal" font="default" size="100%">English</style></language><abstract><style face="normal" font="default" size="100%">Climate warming could increase rates of soil organic matter turnover and nutrient mineralization, particularly in northern high-latitude ecosystems. However, the effects of increasing nutrient availability on microbial processes in these ecosystems are poorly understood. To determine how soil microbes respond to nutrient enrichment, we measured microbial biomass, extracellular enzyme activities, soil respiration, and the community composition of active fungi in nitrogen (N) fertilized soils of a boreal forest in central Alaska. We predicted that N addition would suppress fungal activity relative to bacteria, but stimulate carbon (C)-degrading enzyme activities and soil respiration. Instead, we found no evidence for a suppression of fungal activity, although fungal sporocarp production declined significantly, and the relative abundance of two fungal taxa changed dramatically with N fertilization. Microbial biomass as measured by chloroform fumigation did not respond to fertilization, nor did the ratio of fungi : bacteria as measured by quantitative polymerase chain reaction. However, microbial biomass C : N ratios narrowed significantly from 16.0 +/- 1.4 to 5.2 +/- 0.3 with fertilization. N fertilization significantly increased the activity of a cellulose-degrading enzyme and suppressed the activities of protein- and chitin-degrading enzymes but had no effect on soil respiration rates or C-14 signatures. These results indicate that N fertilization alters microbial community composition and allocation to extracellular enzyme production without affecting soil respiration. Thus, our results do not provide evidence for strong microbial feedbacks to the boreal C cycle under climate warming or N addition. However, organic N cycling may decline due to a reduction in the activity of enzymes that target nitrogenous compounds.</style></abstract><work-type><style face="normal" font="default" size="100%">Article</style></work-type><accession-num><style face="normal" font="default" size="100%">ISI:000255463600017</style></accession-num><notes><style face="normal" font="default" size="100%">ISI Document Delivery No.: 295GSTimes Cited: 24Cited Reference Count: 72Allison, Steven D. Czimczik, Claudia I. Treseder, Kathleen K.Blackwell publishingOxford</style></notes><auth-address><style face="normal" font="default" size="100%">[Allison, Steven D.; Treseder, Kathleen K.] Univ Calif Irvine, Dept Ecol &amp; Evolut Biol, Irvine, CA 92697 USA. [Allison, Steven D.; Czimczik, Claudia I.; Treseder, Kathleen K.] Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA.Allison, SD, Univ Calif Irvine, Dept Ecol &amp; Evolut Biol, Irvine, CA 92697 USA.allisons@uci.edu</style></auth-address></record></records></xml>