Coupling shell growth and geochemistry in giant clams to explore biomineralization pathways

这位博士希望通过研究沙巴州不同珊瑚礁环境中的几个贝壳标本，使用跨学科的方法来探索Tridacna贝壳生长和生物矿化的根本控制。沙巴州的珊瑚礁是珊瑚三角的一部分，该地区拥有地球上最高的海洋生物多样性。在目前的全球变化情景下，人们假设浑浊的珊瑚礁可能对白化事件更具弹性，因此它们可能充当避难所，从长期来看可能支持对清水礁的保护。除了珊瑚生物多样性研究外，重要的是纳入其他关键的珊瑚礁分类群，如巨蛤，以更好地了解生物群对温度和光照控制的环境反应。这种方法将使用先进的成像和矿物学技术，如扫描电子显微镜(SEM)、激光共聚焦扫描显微镜(CLSM)和电子背向散射衍射(EBSD)，来研究婆罗洲浑浊和清澈水环境中的巨蛤的壳生长、微结构和矿化途径。此外，学生将使用同位素比值质谱仪和激光烧蚀电感耦合等离子体质谱(LA-ICP-MS)对最近存活的Tridacna贝壳进行分析，以生成地球化学替代记录(d18O、锶/钙、巴/钙)，以重建浑浊和清水环境中的环境变化。这些重建将有助于破译环境应激源如何影响海洋固着生物及其钙化能力。除了探索现代贝壳收藏，学生还将利用化石收藏来确定类似的生物矿化特征是否在不同的环境条件下持续存在。

This PhD looks to use an interdisciplinary approach to explore the fundamental controls of Tridacna shell growth and biomineralization by examining several shell specimens from diverse reef environments in Sabah. Reefs from Sabah are part of the Coral Triangle, the region with the highest marine biodiversity on Earth. Under the current global change scenario, it has been hypothesized that turbid reefs maybe more resilient to bleaching events, therefore they may act as refugia habitats that could potentially support the conservation of clear-water reefs in the long term. Besides coral biodiversity studies, it is fundamental to incorporate other key reefal taxa, such as giant clams, to better understand environmental responses of biota to temperature and light controls. This approach will use advancing imaging and mineralogical techniques such as Scanning Electron Microscopy (SEM), Confocal Laser Scanning Microscopy (CLSM), and Electron Backscatter Diffraction (EBSD) to examine shell growth, microstructure and mineralization pathways of giant clams from turbid and clear water environments in Borneo. Alongside this, the student will use isotope ratio mass spectrometry and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis on recently living Tridacna shells to generate geochemical proxy records (d18O, Sr/Ca, , Ba/Ca) to reconstruct environmental changes in both turbid and clear-water environments. These reconstructions will aid in deciphering how environmental stressors impact marine sessile organism and their ability to calcify. In addition to exploring the modern shell collection, the student will also utilize the fossil collection to determine if similar biomineralization features persisted under different environmental conditions.