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的三维结构，称为CWC丘。化武丘的形成主要取决于(i)在促进具有高阻流能力的珊瑚框架形成的环境条件下珊瑚的持续生长，以及（ii）稳定珊瑚框架的沉积物输入，通过快速埋藏限制珊瑚骨骼的生物侵蚀，并有利于快速化武丘的沉积。该项目将重点关注毛里塔尼亚附近的化武公约土丘，那里沿着一条壮观的190公里长的样带（17-19°N）分布着许多土丘，因此是迄今为止已知的最大的化武公约土丘省之一。毛里塔尼亚土丘的高度高达100米，在水深360至550米之间的两个斜坡平行的土丘链中组织。毛里塔尼亚CWC丘区与所有其他研究过的丘区不同，它位于热带东部边界上升流系统的下方，并直接受到发育良好的氧气最低带（OMZ）的影响，该带的氧浓度低于主要框架构建珊瑚Lophelia pertusa的首选氧浓度。先前的研究表明，尽管活的罗菲利亚群落今天很少出现，但自末次冰期结束以来，CWC丘的形成似乎停滞不前。该项目将调查：(i)毛里塔尼亚近海化武堆形成的环境控制，特别侧重于食物输送、周围底水体的氧浓度以及作为潜在关键控制因素的可变沉积物输入对化武框架的影响。（ii）两个斜坡平行的CWC丘链形成的海洋强迫。（iii）沿毛里塔尼亚大陆斜坡的潜在纬向历时海洋变化对CWC丘形成阶段的影响。除了了解毛里塔尼亚禁化武丘省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禁化武活力和丘形成的总体过程。这里最明显的特征将是CWC对相当低氧条件的恢复能力和斜坡-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.