C- and N-fixation of coral reefs in response to environmental factors (CANCOR)

热带珊瑚礁是总初级生产力最高的海洋生态系统之一，尽管它们被非常少营养的水域所包围。这种暗礁悖论尚未被完全理解；然而，很明显，必须有适当的机制，允许提取基本元素，特别是氮，反对这种浓度梯度，以及它们的快速回收和保存。几个关键的珊瑚礁c固定初级生产者（如珊瑚、巨藻和草皮藻类）和底物（如礁砂、死珊瑚和岩石表面）与蓝藻等固定n微生物表现出内部或外部的联系。这种联系可能促进初级生产和生长，但没有研究解决珊瑚及其珊瑚礁中C和n固定的联系以及控制环境因素。因此，本研究项目将同时量化关键珊瑚礁初级生物的固碳和固氮，以及这对整体珊瑚礁固碳和固氮的贡献。此外，关键的环境因素（如光和无机营养的可用性，温度，酸度）对这些过程的影响，在生物和生态系统的水平，将进行检查。这个全面的数据集将有助于在环境变化时期获得珊瑚礁生态系统功能和恢复力的新的重要见解。

Tropical coral reefs are among the marine ecosystems with the highest gross primary productivity, although they are surrounded by very oligotrophic waters. This reef paradoxon is not yet completely understood; however, it is evident that mechanisms must be in place allowing extraction of essential elements, particularly N, against this concentration gradient along together with their fast recycling and conservation. Several key reef C-fixing primary producers (e.g. corals, macro and turf algae) and substrates (e.g. reef sands, dead coral and rocky surfaces), exhibit internal or external association with N-fixing microbes like cyanobacteria. Such association potentially facilitates primary production and growth, but there are no studies that address linkage of C- and N-fixation in corals and their reefs and the controlling environmental factors. Therefore, this research project will simultaneously quantify both C- and N-fixation of key reef primary producers, and how this contributes to overall reef C- and N-fixation. Additionally, the influence of key environmental factors (e.g. light and inorganic nutrient availability, temperature, acidity) on these processes, both on the organism and ecosystem level, will be examined. This comprehensive dataset will help to gain new important insights in coral reef ecosystem functioning and resilience in a time of environmental change.