Cold-water coral mound development underneath an eastern boundary upwelling system - the great wall of(f) Mauritania

冷水珊瑚(CWC)代表着全球重要的碳酸盐工厂，它们可以沿着大陆边缘形成大型三维结构，称为CWC丘陵。CWC土丘的形成主要取决于(I)在环境条件下珊瑚的持续生长，这种环境条件促进了具有高阻隔能力的珊瑚骨架的形成，以及(Ii)沉积物的输入稳定了珊瑚骨架，通过快速埋葬限制了珊瑚骨架的生物侵蚀，并有利于CWC土丘的快速沉积。该项目将集中在毛里塔尼亚附近的化学武器组织丘陵，那里有许多丘陵分布在一条壮观的190公里长的样带(17-19°N)上，因此是迄今为止已知的最大的化学武器组织丘陵省份之一。毛里塔尼亚的丘陵高达100米，由两个平行的丘状斜坡组成，水深在360米到550米之间。毛里塔尼亚的化学武器公约丘陵省不同于所有其他研究的丘陵省份，因为它位于热带东部边界上升流系统的下方，并直接受到发达的氧气最小区(OMZ)的影响，后者的值低于主要建造框架的珊瑚Lophelia pertusa的首选氧浓度。先前的研究表明，尽管活着的Lophelia殖民地在今天很少出现，但自上一次冰川结束以来，CWC丘陵的形成似乎停滞不前。该项目将调查：(I)毛里塔尼亚近海化学武器公约丘陵形成的环境控制，特别注重食物输送的相互作用、周围底层水团的氧气浓度以及不同的泥沙输入对化学武器公约框架的影响，作为潜在的关键控制因素。(2)两条平行的化学武器公约丘链的发展的海洋强迫作用。以及(Iii)潜在的纬向历时海洋变化对毛里塔尼亚大陆斜坡上CWC丘陵形成阶段的影响。除了旨在了解毛里塔尼亚化学武器公约丘陵省份应对环境变化的长期发展外，该项目还将有助于我们了解控制化学武器公约活力和一般丘陵形成的过程。这里最明显的特征将是CWC对相当低的氧气条件的弹性，以及斜面平行CWC丘链的发展。

Cold-water corals (CWC) represent globally significant carbonate factories that can form large 3-dimensional structures along the continental margins, called CWC mounds. CWC mound formation primarily depends on (i) sustained coral growth under environmental conditions that promote the formation of coral frameworks with a high baffling capacity and (ii) sediment input that stabilises the coral framework, limits bioerosion of the coral skeletons by fast burial and favours fast CWC mound aggradation. The project will focus on CWC mounds off Mauritania, where numerous mounds occur along a spectacular 190-km-long transect (17-19° N), hence being one of the largest CWC mound provinces known so far. The Mauritanian mounds exhibit heights of up to 100 m and are organised in two slope-parallel mound chains in water depths between 360 and 550 m. The Mauritanian CWC mound province differs from all other studied mound provinces by being positioned underneath a tropical eastern boundary upwelling system and being directly influenced by a well-developed oxygen minimum zone (OMZ), which exhibits values below the preferred oxygen concentrations of the dominant framework-building coral Lophelia pertusa. Prior studies showed that even though living Lophelia-colonies occur rarely today, CWC mound formation seems to stagnate since the termination of the last glacial. The project will investigate: (i) The environmental controls of CWC mound formation off Mauritania with a special focus on the interplay of food delivery, the oxygen concentration of the surrounding bottom water mass, and the influence of variable sediment input on the CWC framework as potential key controlling factors. (ii) The oceanographic forcing of the development of two slope-parallel CWC mound chains. And (iii) the influence of potential latitudinal diachronous oceanographic changes on CWC mound formation phases along the Mauritanian continental slope. Beyond the aim to understand the long-term development of the Mauritanian CWC mound province in response to changing environmental settings, this project will contribute to our understanding of the processes controlling CWC vitality and mound formation in general. Most obvious features here will be the resilience of CWC to rather low oxygen conditions and the development of slope-parallel CWC mound chains.