Accretion patterns of Belize barrier and atoll reefs: an archive of environmental change during the Holocene

由于气候变暖、海洋酸化、污染和疾病，热带珊瑚礁的地位一直在下降(Pandolfi等人。2003年，2011年；休斯等人。2017年；Eyre等人。2018年)。这一点在加勒比海地区的珊瑚礁中也很明显，因为活珊瑚覆盖率已经减少(Gardner等人)。2003年)，许多珊瑚礁不再以珊瑚为主，而是肉质藻类(Hughes 1994)，造礁的顶孔珊瑚和大型浮游珊瑚的数量减少，取而代之的是杂草、一般的分类群(Perry等人)。2015年；库夫纳和托斯2016年)，珊瑚礁增长潜力下降(Perry等人。2018年)。由于数以百万计的人生活在热带海岸和岛礁上，而且这些人在社会经济上依赖珊瑚礁，这个问题不是纯粹的科学问题。对从现代珊瑚礁中提取的钻芯材料的研究，可以根据沉积学、古生态和地质年代学分析，详细重建全新世期间的环境条件。基于这些数据，可以重建以前的生态和环境变化，这可能允许决定当前的下降是否是史无前例的，并作为未来预测的基础。建议重新考察伯利兹堡礁和环礁--Atantic中最大的珊瑚礁系统--的现有核心材料，并进行更多的年龄测定，以限制珊瑚礁的堆积模式，确定动物群的变化时间，并确定可能的珊瑚礁缺口。这将通过定量分析生物礁成分，从22个钻芯(全新世总长度213.4米)的珊瑚中获得约50个新的U/Th年龄，并将这些年龄与58个现有年龄相加来实现。作为一个有价值的副作用，伯利兹地区全新世海平面曲线可以根据新的年龄数据进行修正。

The status of tropical coral reefs has been declining due to warming, ocean acidification, pollution, and disease (Pandolfi et al. 2003, 2011; Hughes et al. 2017; Eyre et al. 2018). This is also visible in reefs of the Caribbean realm in that live coral cover has diminished (Gardner et al. 2003), many reefs are no longer dominated by corals but fleshy algae (Hughes 1994), reef-building acroporid and massive faviid corals are reduced in abundance and replaced by weedy, generalistic taxa (Perry et al. 2015; Kuffner and Toth 2016), and reef accretion potential has decreased (Perry et al. 2018). As millions of people are living along tropical coasts and on reef islands and because these people are dependent on coral reefs socio-economically, this issue is not purely scientific. The study of drill core material extracted from modern coral reefs allows detailed reconstructions of environmental conditions during the Holocene based on sedimentological, paleoecological, and geochronological analyses. Based on these data, previous ecological and environmental changes can be reconstructed that may allow to decide whether or not current declines are unprecedented and serve also as basis for future predictions. It is proposed to revisit existing core material from Belize barrier and atoll reefs, the largest reef system in the Atantic, and to perform additional age dating to constrain patterns of reef accretion, date faunal changes, and identify possible reef gaps. This will be achieved by quantitatively analyzing reef composition and by obtaining some 50 new U/Th-dates from corals in 22 drill cores (total Holocene length 213.4 m) and to add these to 58 existing age dates. As a valuable side-effect, the regional Holocene sea-level curve of Belize can be refined based on the new age data.