<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Burke-Scholl, Medora J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nitrogen and sulphur input and accumulation in continental ombrotrophic peatland ecosystems in Alberta, Canada</style></title></titles><keywords><keyword><style  face="normal" font="default" size="100%">nutrient cycles</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://search.proquest.com/docview/193991476</style></url></web-urls></urls><pub-location><style face="normal" font="default" size="100%">Villanova University</style></pub-location><pages><style face="normal" font="default" size="100%">100</style></pages><language><style face="normal" font="default" size="100%">en</style></language><abstract><style face="normal" font="default" size="100%">Models predict increases in N and S deposition in the Athabasca Oil Sands Region of Alberta that often exceed critical load values for sensitive ecosystems. I used 10 bog sites within a modeled deposition gradient to assess current SO42- , NO3- , and NH 4+ deposition rates compared to historical N and S accumulations. There were no spatial patterns in NO3- , NH 4+ , total inorganic N, and SO42- deposition rates, and deposition from all sites were low and not above predicted background levels. There were also no spatial patterns in C, N, and S accumulation data. An interesting pattern persisted across all sites: data showed substantially more peat N accumulation than can be accounted for through atmospheric deposition alone. I examined whether biological N2 fixation could be an additional source and found evidence of nitrogenase activity in all bryophyte communities sampled. This phenomenon may represent a previously underestimated source of N to boreal bogs.</style></abstract><issue><style face="normal" font="default" size="100%">M. S. </style></issue><custom1><style face="normal" font="default" size="100%">Biology</style></custom1><custom2><style face="normal" font="default" size="100%">Athabasca Oil Sands</style></custom2><custom4><style face="normal" font="default" size="100%">Science</style></custom4></record></records></xml>