COLLABORATIVE RESEARCH: Ecological Controls on Biogenic Silica in Grasslands - The Role of Long-term Fire and Grazing History on Two Continents

合作研究：草原生物二氧化硅的生态控制——两大洲长期火灾和放牧历史的作用

• 批准号: 0743786
• 负责人: Eugene Kelly
• 金额: $ 25万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-15 至 2011-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0743786&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Ecological; Controls; Biogenic

This research will investigate the quantities and chemistry of biogenic Si (plant-derived silica) along climatic and geologic gradients in grassland ecosystems of the central Great Plains of North America and the savannas of the South Africa. Factors that affect the production, storage, and chemical behavior of biogenic Si in geographically diverse grassland ecosystems will be identified. Furthermore, the influence of grazing and fire in grasslands on biogenic Si will be assessed. The terrestrial production, movement and cycling of silica is closely linked to the global carbon cycle. In the oceans, certain minute marine algae (diatoms) are a major control on the distribution of silica and also play a major role in controlling atmospheric CO2 concentration due to their photosynthetic activity. The importance of biological controls on silica cycling in the terrestrial environment is much less well known, but likely results from the formation and storage of biogenic silica in plants and soils, particularly in grasslands. Recent estimates suggest that the global uptake of biogenic silica by terrestrial vegetation rivals quantities stored in the biologically active portions of the ocean systems. More importantly, the largest reservoir of biogenic Si in terrestrial systems resides not in living biomass but in soils and, in particular, grassland soils. Biogenic silica accumulates belowground upon death and decomposition of plant materials. This large reservoir of biogenic Si in grasslands may be greatly influenced by global change factors, with unknown consequences for global biogeochemical cycles.

这项研究将研究北美中部大平原和南非萨凡纳斯的草原生态系统中的气候和地质梯度沿气候和地质梯度沿气候和地质梯度的数量和化学。将确定影响生物SI在地理上多样化的草地生态系统中的生产，储存和化学行为的因素。 此外，将评估草原放牧和火对生物源​​的影响。 二氧化硅的陆地生产，运动和循环与全球碳循环密切相关。 在海洋中，某些分钟海藻（硅藻）是对二氧化硅分布的主要控制，并且由于其光合活性而在控制大气二氧化碳浓度方面也起着重要作用。 生物控制对陆地环境中二氧化硅循环的重要性知之甚少，但可能是由于生物二氧化硅在植物和土壤中，尤其是在草原中的形成和储存而产生的。最近的估计表明，陆生植被对生物二氧化硅的全球摄取匹配匹配的量，存储在海洋系统的生物活性部分中。更重要的是，陆地系统中最大的生物SI水库不在生物量中，而是在土壤中，尤其是草原土壤中。 生物二氧化硅在死亡和植物材料的分解后累积在地下。 草原生物SI的大量储层可能受到全球变化因素的极大影响，对全球生物地球化学周期造成了未知的影响。