Iron manganese co-limitation – a potential driver of Southern Ocean phytoplankton ecology

铁锰共同限制——南大洋浮游植物生态的潜在驱动力

• 批准号: 404421353
• 负责人: Dr. Scarlett Trimborn
• 金额: --
• 依托单位: Sektion Ökologische Chemie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/404421353?language=en
• 关键词: Iron; manganese; co; limitation; potential

The Southern Ocean (SO) exerts a disproportional control on the global carbon cycle, thus affecting climate at a global scale. Southern Ocean phytoplankton are major drivers of global carbon cycling accounting for 20% of the global annual primary production. In the SO, the biological uptake of carbon dioxide is mainly controlled by the availability of the trace metal iron (Fe) and light, both being essential for photosynthesis. Whereas most studies so far focused on disentangling how Fe and light influence SO phytoplankton growth and productivity, almost nothing is known whether other trace metals such as manganese (Mn) also act as limiting or co-limiting nutrient in the SO. Mn is required for various cellular processes in phytoplankton cells and has been suggested to be (co-)limiting with Fe in some parts of the SO such as the Drake Passage. Currently, we lack information on growth, photosynthesis, oxidative stress and Mn and Fe requirements under Fe-Mn limitation for SO phytoplankton species. This research project aims to improve our understanding about the potential effects of Fe-Mn co-limitation on SO phytoplankton physiology and their implications for the ecology and biogeochemistry in the present and future SO. To this end, the responses of SO phytoplankton will be studied in response to altered Fe and Mn availabilities under different light conditions, simulating different climate change scenarios. A multidisciplinary approach will be followed that integrates biology and marine chemistry and combines laboratory and field work. Laboratory experiments with ecologically and biogeochemically important phytoplankton species of the SO will provide a mechanistic understanding on physiological processes such as photosynthesis and trace metal requirements. Shipboard manipulation experiments with natural SO phytoplankton assemblages of different regions of the SO will further reveal the occurrence of Fe-Mn co-limitation and will help to identify phytoplankton species in the field, which are particularly sensitive, but also tolerant towards altered trace metal and light availabilities. All together this research project will help to assess an ecophysiological explanation for the spatial distribution of SO key phytoplankton species in the present and the future SO. Improved knowledge on the functioning and the sensitivity of the SO ecosystem is pivotal to improve our existing predictive tools (e.g. modelling) and increase our understanding on the mechanisms, by which the SO affects climatic processes at global scale. Therefore, this research project will significantly contribute to the key research topic 2.2.4 Response to Environmental Change within the DFG Schwerpunktprogramm 1158 Antarktis-Forschung.

南大洋对全球碳循环施加了不成比例的控制，从而影响了全球范围内的气候。南大洋浮游植物是全球碳循环的主要驱动力，占全球年初级生产量的20%。在SO中，生物对二氧化碳的吸收主要受微量金属铁(Fe)和光的有效性控制，这两种元素都是光合作用所必需的。虽然到目前为止，大多数研究都集中在了解铁和光如何影响SO浮游植物的生长和生产力，但几乎没有人知道其他痕量金属，如锰(Mn)是否也是SO中的限制或共同限制营养物质。在浮游植物细胞的各种细胞过程中，锰是必需的，并被认为在SO的某些部分(如德雷克海峡)与铁(共同)限制。目前，我们缺乏关于浮游植物生长、光合作用、氧化胁迫以及在铁-锰限制下对锰和铁的需求的信息。本研究旨在加深我们对Fe-Mn共限制对SO浮游植物生理的潜在影响及其对当前和未来SO的生态学和生物地球化学的影响的认识。为此，将研究SO浮游植物对不同光照条件下铁和锰有效性变化的响应，模拟不同的气候变化情景。将采用多学科方法，将生物学和海洋化学结合起来，并将实验室和实地工作结合起来。对具有生态和生物地球化学意义的重要浮游植物物种进行的实验室实验将提供对光合作用和痕量金属需求等生理过程的机械理解。利用SO不同区域的天然SO浮游植物组合进行的船上操纵实验将进一步揭示Fe-Mn共限制的发生，并将有助于识别现场浮游植物物种，这些物种对改变的痕量金属和光的有效性特别敏感，但也耐受。综上所述，这一研究项目将有助于评估对当前和未来SO关键浮游植物物种空间分布的生态生理解释。提高对SO生态系统的功能和敏感性的认识，对于改进我们现有的预测工具(如模型)和增加我们对SO影响全球范围气候过程的机制的理解至关重要。因此，这一研究项目将对DFG Schwerpenkt方案1158南极-福尔松的关键研究课题2.2.4“应对环境变化”作出重大贡献。