The Effects of Landscape and Soil Development on the Terrestrial Phosphorus Cycle

以前的研究还没有定量地记录过去的气候，特别是冰期-间冰期循环，是如何影响大陆物质中磷的释放和/或陆地和海洋生态系统中磷的可用性的。作为一种生物限制养分，磷有效性在生物循环和全球碳平衡的重建中起着关键作用。本研究项目的主要重点将是全面检查湖泊沉积物中的磷地球化学，作为冰川消融以来周围景观土壤发育的记录。从湖泊沉积物记录的研究中获得的新观点有望为理解气候和景观发展对陆地磷循环的影响增加坚实的地质成分。本研究将对来自北美各种源头湖的沉积物岩心进行研究，涵盖一系列古气候、基岩岩性、坡向特征和生态系统类型。该项目还将包括对湖泊样带磷转化的评估。这将有助于描述磷可用性的变化特征，并评估外部输入（周围流域风化的土壤和凋落物）和内部生产（湖河系统中溶解磷酸盐的有机物生产和沉积以及沉积物成岩作用的影响）对磷地球化学记录的影响。该项目还将包括使用最新开发的技术检查这些湖泊中其他几个潜在的古风化指标，包括粘土矿物学、有机质和湖泊硅藻的碳氮磷比、磷铝比和锗硅比。该项目的结果将为重建全球磷质量平衡增加一个关键的陆地维度。它将为长期进入海洋环境的磷通量的生物地球化学提供新的线索，并将提供有关大陆上作为气候函数的营养动态状态的定量信息。

Previous research has yet to quantitatively document how past climates, especially glacial-interglacial cycles, have affected the release of phosphorus from continental material and/or the availability of phosphorus to terrestrial and marine ecosystems. As a biolimiting nutrient, phosphorus availability plays a key role in reconstructions of the biological cycle and the global carbon balance. The major focus of this research project will be a comprehensive examination of phosphorus geochemistry in lake sediments as a record of soil development in surrounding landscapes since deglaciation. New perspectives gained from studies of lake-sediment records promise to add a solid geologic component to understandings of the effects of climate and landscape development on the terrestrial phosphorus cycle. This research will be performed on sediment cores from a variety of headwater lakes in North America, spanning a range of paleoclimates, bedrock lithologies, slope-aspect characteristics, and ecosystem types. The project also will include an assessment of phosphorus transformations along a transect of lakes. This will allow characterization of changes in phosphorus availability and assessment of the impacts on the phosphorus geochemical record from external input (soil and litter weathered from surrounding watersheds) and internal production (organic matter production and deposition from dissolved phosphate in the lake-river systems and the effects of sediment diagenesis). The project also will include examination of several other potential paleoweathering indicators in these lakes, including clay mineralogy, organic matter and carbon-nitrogen-phosphorus ratios, phosphorus-aluminum ratios, and germanium-silicon ratios of lake diatoms using a recently developed technique. Results from this project will add a critical terrestrial dimension to reconstructions of the global phosphorus mass balance. It will shed new light on the biogeochemistry of phosphorus fluxes into oceanic environments over time, and it will provide quantitative information about the state of nutrient dynamics on the continents as a function of climate.