Untersuchung der Fraktionierung von Stickstoffisotopen in marinen Sedimenten, abhängig von unterschiedlichen Sedimentcharakteristika

根据不同沉积物特征研究海洋沉积物中氮同位素的分馏

• 批准号: 123863710
• 负责人: Dr. Kirstin Dähnke
• 金额: --
• 依托单位: Institut für Biologie
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/123863710?language=en
• 关键词: Untersuchung; der; Fraktionierung; von; Stickstoffisotopen

Reactive nitrogen is entrained to the ocean at large scales, leading to eutrophication of coastal oceans. As this enhances primary production, it also affects global carbon cycling. In the light of these increased inputs and an ongoing revision of the marine nitrogen budget, the outlined research project shall provide tools for a better estimation of nitrogen sinks in the ocean. Specifically, we aim to measure stable nitrogen isotope fractionation during sedimentary denitrification and anammox (anaerobic ammonia oxidation), which we expect to be more variable than previously assumed. The focus is set on the influence of bioirrigation and the influence of varying sediment redox conditions on the isotope fractionation of both nitrogen removal processes. During sediment incubations, the porewater shall be analysed for concentrations and isotopic composition of different nitrogen species that are sequestered or produced by the respective micro-organisms. Because of the high natural variability regarding redox state, anthropogenic nitrogen or carbon loads and oxygen saturation in bottom waters, the Baltic/North Sea transition provides an excellent study area for the variances in isotope effects. This can later be used as a basis for modelling approaches to improve the estimation of nitrogen removal by shelf sediments.

活性氮大规模夹带至海洋，导致沿海海洋富营养化。由于这提高了初级生产，它也影响了全球碳循环。鉴于投入的增加和海洋氮预算的不断修订，概述的研究项目将为更好地估计海洋氮汇提供工具。具体来说，我们的目标是测量沉积反硝化和厌氧氨氧化（anammox）过程中的稳定氮同位素分馏，我们预计这比之前假设的变化更大。重点是生物灌溉的影响以及不同沉积物氧化还原条件对两种脱氮过程同位素分馏的影响。在沉积物培育过程中，应对孔隙水进行分析，了解由相应微生物隔离或产生的不同氮物种的浓度和同位素组成。由于氧化还原态、人为氮或碳负荷以及底层水域氧饱和度等方面的自然变异性较高，波罗的海/北海过渡区为同位素效应的变化提供了一个极好的研究区域。这以后可以用作建模方法的基础，以改进陆架沉积物去除氮的估计。