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Black Carbon: Linking the chemical structure of black carbon to its biological degradation and transport dynamics in a northern temperate forest soil

Project Abstract: 
<p>We test the effects of charring temperature on Black Carbon (BC) chemical structure and subsequent degradation rates. While plant species effects on BC structure and dynamics in the environment are not well studied, species effects have been shown as minor compared with the temperature of biomass combustion. We chose <em>Pinus banksiana</em> as it is a dominant tree species in fire-prone northern temperate&ndash;boreal forests in the Great Lakes Region and eastern North America. As species effects on BC structure seem plausible, we compare the effect of plant species (<em>P. banksiana vs Acer rubrum</em>, expanding in both abundance and range in eastern North America) on BC physicochemical structure and degradation rates over increasing combustion temperature. BC made from dissimilar gymnosperm (<em>P. banksiana</em>) and angiosperm (A<em>. rubrum</em>) wood sources will provide a useful indicator for predicting BC residence times. To better match the climate and soil environment of a recently burned forest, we located the Field study to a recently burned plot at the on-going Fire study at UMBS. Our results will be scalable to forests of the temperate-boreal ecotones, that contain typical to high BC content on similar soils. Our analysis showed that ~7% of soil C is BC in UMBS surface soils on sites burned in 1911. While the estimates of natural fire frequency for jack pine forests are ~80 yr, current and future fire frequency may be higher because of several interacting factors, including the susceptibility of welldrained Spodosols/Inceptisols to drought under predicted warmer and drier climate; and forestry management including the greater use of prescribed burns.</p>
<p>Mesocosm/lysimeter with 13C/15N wood and black carbon substrates added to soil Soil temperature and moisture monitored in Burn Plots in situ 13CO2 soil respiration and dissolved organic 13C and 15N measured in soil leachates Total 13C and 15N recoveries in soil in years 1,2, and 4 after substrate application Soil microbial community characterization 13C and 15N quantified in soil fauna 13C and 15N soil organic matter characterization with density fractionation, Copper Oxide, benzene polycarboxylic acid, hydrodrolyzasble sugars, and oxidative/hydrolytic enzymes Lab-based soil incubations</p>
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