RedoxPhos: How do physical and biogeochemical conditions in pelagic boundaries control vertical transport and generation of phosphorus species?

RedoxPhos：远洋边界的物理和生物地球化学条件如何控制磷物质的垂直运输和生成？

• 批准号: 173814031
• 负责人: Professor Dr. Michael Hupfer
• 金额: --
• 依托单位: Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/173814031?language=en
• 关键词: RedoxPhos; How; do; physical; biogeochemical

Scenarios of climate change emanate, that the duration and stability of thermal stratification will increase. Previous studies on the consequences for the productivity of lakes reported contradicting results. It is often assumed that anaerobic processes will lead to an enhanced release of phosphorus (P) from the sediments. New results from marine research show that pelagic redoxclines act as P traps due to the formation of mineral phases. Our project aims at the observation of transformation of organic and inorganic P species and their transport towards the sediment using geochemically quite different lakes with distinct pelagic redoxclines. Thereby the temporal and spatial changes of biogenic phosphorus are considered in close connection with the iron-sulfurand manganese cycle. The hypothesis will be verified whether a prolonged stratification can additionally remove phosphorus from the water body via the formation of solid phases. For this purpose, using cylindrical sedimentation traps above and below of natural redoxclines, settling matter will be sampled and structurally analyzed. In a long-term in situ experiment, exposing ’meromixis columns’, the complete mixing will be suppressed and strong gradients will be induced in the water body above the sediment. By means of chemical analyses, modern physical structure determination and thermodynamic calculations the influence of pelagic boundaries onto the sink function of sediments for phosphorus will be quantified.

气候变化的情景表明，热分层的持续时间和稳定性将会增加。以前关于湖泊生产力影响的研究报告了相互矛盾的结果。人们通常认为厌氧过程将导致沉积物中磷(P)的释放增强。海洋研究的新结果表明，由于矿物相的形成，远洋氧化还原斜起到了P圈闭的作用。我们的项目旨在利用地球化学上完全不同的湖泊，观察有机和无机磷的转化及其向沉积物的输送，这些湖泊具有不同的远洋氧化斜。因此，生物源磷的时空变化与铁硫锰循环密切相关。这一假设将验证长期分层是否可以通过形成固相来额外去除水体中的磷。为此，在天然氧化还原斜的上方和下方使用圆柱形沉淀池，对沉淀物质进行取样和结构分析。在长期的原位试验中，暴露“混合柱”，完全混合将被抑制，并在沉积物上方的水体中引起强烈的梯度。通过化学分析、现代物理结构测定和热力学计算，量化了远洋边界对沉积物磷汇函数的影响。