Oxalate Biogeochemistry of Forest Soil Ectomycorrhizal Mat Communities

格里菲思、考德威尔、巴哈姆和克罗马克博士已经证明， 高蒂氏菌属和海鞘属的特化外生菌根种 形成广泛的菌丝或根索垫结构， 温带针叶林的重要特征。 在 与无明显席垫发育的土壤相比， 的垫具有升高的孔隙水浓度的溶解 有机碳、氟化物、草酸盐和硫酸盐，以及主要的 和痕量金属阳离子，包括Al和Fe，其可以是 负责控制有机物和 无机磷 在囊垫中，大多数草酸盐 存在于固相中，可能是草酸钙， 而在Gautieria垫中，草酸盐的相对较大部分 在溶液中的浓度接近于 土壤有机质提取物。 虽然长期以来与矿物溶解有关， 草酸盐在森林土壤中的其他重要作用 流程. 格里菲思、考德威尔、巴汉姆和克罗马克博士 这些垫社区调查草酸盐物种的作用， 和其他主要的有机配体在矿物风化，溶液和 固相土壤化学、Al和Fe活性以及处理 不同土壤酶对有机氮和磷的影响 森林生态类型 现场研究和实验室结果 实验将被用作准稳态模型的输入， 土壤溶液和固相土壤地球化学。 这种模式的 深入了解控制养分循环的实际机制 在森林生态系统中。 这些研究人员是该领域的专家 森林土壤生物地球化学 为此提供的设施 研究是杰出的。

Drs. Griffiths, Caldwell, Baham and Cromack have shown that certain specialized ectomycorrhizal species of Gautieria and Hysterangium form extensive hyphal or rhizomorph mat structures that are significant features of temperate coniferous forests. In comparison with soils without obvious mat development, both types of mats have elevated pore-water concentrations of dissolved organic carbon, fluoride, oxalate, and sulfate, as well as major and trace metal cations, including Al and Fe which can be responsible for controlling the solubility of both organic and inorganic phosphorus. In Hysterangium mats, most of the oxalate was present in the solid phase, presumably as calcium oxalate, while in Gautieria mats, a relatively larger fraction of oxalate was in solution at concentrations that approached those used in organic matter extractions of soils. While long implicated in mineral dissolution, the ligand properties of oxalate also suggest other significant roles in forest soil processes. Drs. Griffiths, Caldwell, Baham and Cromack will use these mat communities to investigate the role of oxalate species and other major organic ligands in mineral weathering, solution and solid phase soil chemistry, Al and Fe activity, and the processing of organic nitrogen and phosphorus by soil enzymes in diverse forest ecotypes. Results from field studies and laboratory experiments will be used as input to a quasi-steady-state model of soil solution and solid phase biogeochemistry. This model will provide insight into actual mechanisms controlling nutrient cycling in forest ecosystems. These researchers are experts in the area of forest soil biogeochemistry. The facilities available for this research are outstanding.