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

热带珊瑚礁是初级生产力总值最高的海洋生态系统之一，尽管它们周围是贫营养的沃茨。这种珊瑚礁悖论尚未完全理解，但是，很明显，机制必须到位，允许提取的基本元素，特别是N，对这个浓度梯度沿着与他们的快速循环和保护。几个关键的珊瑚礁固碳初级生产者（如珊瑚，大型和草坪藻类）和基板（如珊瑚礁砂，死珊瑚和岩石表面），表现出内部或外部与固氮微生物，如蓝藻。这种联系可能促进初级生产和生长，但没有研究说明珊瑚及其珊瑚礁中的碳和氮固定与控制环境因素之间的联系。因此，本研究项目将同时量化主要珊瑚礁初级生产者的C-和N-固定，以及这如何有助于整体珊瑚礁C-和N-固定。此外，还将研究关键环境因素（如光和无机养分供应、温度、酸度）对生物体和生态系统水平上这些过程的影响。这一全面的数据集将有助于在环境变化时期获得有关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.