MoccAMeBo - Climate-driven initiation and development of cold-water coral mounds along the Moroccan Atlantic margin revealed by MeBo-cores

硬核系冷水珊瑚（CWC）能够形成实质性的三维海底结构，即所谓的珊瑚丘。这些土丘由CWC碎片和半深海沉积物组成，这些沉积物沉积了数千到数百万年。在摩洛哥大西洋沿岸，数百个小型珊瑚丘存在于500至1000米的水深中，这些珊瑚丘的海拔高度很少高于海底10-20米。今天，在摩洛哥大西洋珊瑚省（MACP）几乎完全没有活的CWC，而化石珊瑚堆积广泛存在。此外，研究表明，沿摩洛哥大西洋边缘的CWC生长（以及土丘增生）在末次冰期最为明显，这可能是由生产力提高引发的，并在全新世开始时终止。然而，这些发现只涉及珊瑚丘的上部6米，因为到目前为止已经没有材料可用。2014年春季，在与RV MARIA S. MERIAN一起进行的MSM36考察中，MARUM海底钻井平台MeBo在摩洛哥大西洋边缘收集了数十米长的恢复记录。因此，MACP的两个珊瑚丘可以完全穿透到它们的底部。两人都获得了“上场”MeBo记录（达到最大值）。钻探深度约47-52米)将使我们对摩洛哥珊瑚丘的形成和早期发展有一些实质性和详细的了解，这是迄今为止基本上未知的。此外，在摩洛哥珊瑚丘之间的一个区域获得了“离丘”MeBo记录（包括两次平行钻探），最大钻探深度为45米。这一记录将提供关于气候驱动的环境变化的独特的古海洋学信息，涵盖几个冰期-间冰期旋回，因此，将允许测试在最后一个冰期确定的地表水生产力与CWC增长之间的联系是否是MACP的长期特征。此外，离丘记录被放置在一个以许多埋藏的土丘为标志的区域，这些土丘包括扎根于不同反射体上的不同世代的珊瑚丘，从而可以评估这些反射体的性质，这些反射体要么形成土丘的基础，要么形成土丘停止生长后的第一个覆盖物。总的来说，为该项目选择的四个MeBo岩心提供了高质量的记录，这将大大提高我们对MACP中控制CWC发生和发展的强迫因子的最终气候联系的理解。特别是有了现有的完整的珊瑚丘记录，可以解决生物化学和珊瑚丘研究的一些基本问题。

Scleractinian cold-water corals (CWC) are capable of forming substantial 3-dimensional seafloor structures, so-called coral mounds. These mounds are composed of CWC fragments and hemipelagic sediments, which deposited over thousands to millions of years. Along the Moroccan Atlantic margin, hundreds of small-sized coral mounds exist in water depths between 500 and 1000 m, which rarely reach elevations higher than 10-20 m above the seafloor. Today, living CWC are almost completely absent in this Moroccan Atlantic Coral Province (MACP) while fossil coral accumulations are widespread. Moreover, it has been shown that along the Moroccan Atlantic margin CWC growth (and thus mound accretion) was most pronounced during the last glacial, presumably triggered by enhanced productivity, and terminated with the onset of the Holocene. However, these findings just refer to the upper 6 meters of the coral mounds, as up to date no longer material was available. During expedition MSM36 with RV MARIA S. MERIAN in spring 2014, records with remarkable long recoveries of several tens of meters were collected along the Moroccan Atlantic margin with the MARUM sea floor drill rig MeBo. Thereby, two coral mounds of the MACP could be completely penetrated down to their bases. The two obtained "on-mound" MeBo records (reaching max. drilling depths of ~47-52 m) will allow to gain some substantial and detailed insight into the initiation and early development of the Moroccan coral mounds, which is essentially unknown so far. In addition, an "off-mound" MeBo record (comprising two parallel drillings) was retrieved from an area in between the Moroccan coral mounds reaching maximum drilling depths of 45 m. This record will provide unique palaeoceanographic information about climate-driven environmental changes covering several glacial-interglacial cycles, and thus, will allow to test if the link between surface water productivity and CWC growth as identified for the last glacial is a long-lasting feature in the MACP. Moreover, the off-mound record was placed in an area marked by numerous buried mounds which comprise different generations of coral mounds rooted on different reflectors, thus allowing for an assessment of the nature of those reflectors forming either the base of the mounds or the first coverage once the mounds stopped growing. Overall, the four MeBo cores selected for the proposed project offer high-quality records, which will significantly improve our understanding of the ultimate climatic link driving the forcing factors that control the occurrence and development of CWC in the MACP. In particular with the now available complete mound records some fundamental topics in CWC and coral mound research can be addressed.