International Research Fellowship Program: The Effect of Ecto-Mycorrhiza and Organic Acids on Weathering and CO2 Production in Forest Soils

国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。 该计划的奖项提供了联合研究的机会，以及使用独特或互补的设施，专业知识和国外的实验条件。该奖项将支持博士24个月的研究奖学金。H. Spears将与瑞典松兹瓦尔的瑞典中部大学的Ulla Lundstrom博士合作，该项目的目标是更好地了解外生菌根真菌（EM）通过低分子量有机酸（LMWOAs）风化的控制和生态系统效应。 它将解决两个主要问题：（1）高生产率和分解率的低分子量有机酸解释高演变的二氧化碳有时从森林土壤中观察到？(2)树木能在多大程度上直接从矿物质中获取营养？ PI将研究EM感染（渐开线变形杆菌和乳牛肝菌属）的影响。在无菌/非无菌条件下，以樟子松和欧洲云杉为寄主植物，对土壤和纯矿物风化速率（Si、Al、Ca、Mg和K释放）的影响。 将构建土壤的风化预算，包括幼苗中的累积。 将在溶液中测定LMWOA和铁载体。 她还将评估CO2的生产，由于在现场和实验室条件下的森林土壤中的LMWOAs的生物降解。 将使用基于机械的数学扩散模型估计微孔中的LMWOA浓度。 EM真菌分泌物的贡献将被计算/估计。Lundstrom博士的实验室是研究土壤真菌对森林土壤化学影响的领导者之一。

The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Julie D. H. Spears to work with Dr. Ulla Lundstrom at Mid Sweden University in Sundsvall, Sweden.The goal of this project is to gain greater understanding of the controls on and ecosystem effects of ectomycorrhizal fungi (EM) weathering via low molecular weight organic acids (LMWOAs). It will address two major questions: (1) do high production and decomposition rates of LMWOAs explain the high evolution of CO2 sometimes observed from forest soils? (2) To what extent could trees get their supply of nutrients directly from mineral grains? The PI will study the impact of EM infection (P. involutus and Suillus sp.) on weathering rates (Si, Al, Ca, Mg and K release) of soils and pure minerals with Pinus sylvestris and Picea abies as host plants under sterile/non-sterile conditions. Weathering budgets for the soil including accumulation in seedlings will be constructed. LMWOAs and siderophores will be determined in solution. She will also evaluate CO2 production due to biodegradation of LMWOAs in forest soils under field and laboratory conditions. LMWOA concentrations in micropores will be estimated using a mechanistically based mathematical diffusion model. The contribution of EM fungi exudates will be calculated/estimated.Dr. Lundstrom's lab is one of the leaders in researching the impacts of soil mycorrhizae on forest soil chemistry.