Postdoctoral Fellowship: OCE-PRF: Diving into the chemical signatures and spatial variability of Caribbean coral reef health

珊瑚礁是地球上最多样化、最多产、最受威胁的生态系统之一。珊瑚礁所承载的丰富生物多样性促进了沿海国家的经济发展和世界各地人民的生计。不幸的是，在过去的50年里，由于自然和人为造成的压力，包括疾病发病率的上升，珊瑚种群数量下降了50%。新的疾病正在迅速蔓延，影响到许多珊瑚物种，并造成下游生态后果。为了帮助保护这些重要的生态系统，有必要开发更好的方法，在疾病过程的早期发现和干预。该项目旨在确定一种被称为代谢物的小生物分子，这种生物分子与一种被称为石珊瑚组织丧失病（SCTLD）的特定类型的珊瑚疾病有关，这种疾病正在整个加勒比地区迅速蔓延。通过表征这些代谢物，研究人员可以更好地了解SCTLD发病和进展过程中发生的代谢变化，并有可能在明显症状出现之前识别疾病的早期预警信号。目前检测代谢物变化的方法效率低下，缺乏空间分辨率。该项目旨在对与SCTLD相关的化学变化进行更彻底的调查，并提高我们对代谢物如何作为珊瑚疾病可追溯标志的理解。这将使早期干预和预防工作成为可能，以保护这些重要的生态系统。该项目的更广泛影响包括支持来自代表性不足群体的第一代女性PI。PI将通过当地（马萨诸塞州伍兹霍尔）和全球（美属维尔京群岛）的活动与STEM中代表性不足的团体合作。其他更广泛的影响包括参与：(1)旨在改善科学传播的努力，(2)公众外展活动，以及(3)本科生指导。目前的SCTLD研究依赖于珊瑚组织的散装匀浆或浆液，使用非靶向代谢组学调查和/或使用RNA测序的微生物测量。该研究的主要目的是利用靶向和非靶向代谢组学、超高分辨率质谱和溶解代谢物分析的最新进展来表征SCTLD在空间梯度上的代谢谱。这项工作将使我们能够量化三个单独的珊瑚微栖息地（即组织，粘液和骨架）以及周围海水的化学成分，并将这些动态剖面与疾病进展联系起来。珊瑚全息剂释放或吸收的代谢物作为一种无形的信号，可以提高我们对疾病进展的理解，提供诊断性生物标志物，并允许早期干预和预防工作。利用新的代谢组学方法和化学衍生化，该项目将使我们能够捕获和量化生态相关的、不稳定的极性代谢物，使用传统的溶相分析提取效率低于1%。该项目将通过研究六种不同珊瑚物种在SCTLD易感性方面的珊瑚微生境的物种内和物种间变异，建立代谢组变化与疾病易感性之间的联系。鉴定SCTLD的化学生物标志物和了解不同珊瑚生态位在疾病进展中的作用将为珊瑚礁保护主义者提供快速检测方法，并为研究人员提供阐明病原体和疾病发生机制所必需的新信息。这项研究的成果将引起不同科学家群体的广泛兴趣，包括化学家、生态学家和珊瑚礁疾病专家，以及广大公众，特别是受SCTLD或其他珊瑚疾病影响的生态和社会经济影响的沿海地区的公众。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Coral reefs are one of the most diverse, productive, and threatened ecosystems on the planet. The rich biodiversity hosted by coral reefs has enhanced the economies of coastal countries and the livelihoods of people around the world. Unfortunately, coral populations have declined by 50% in the last 50 years due to both natural and human-caused stressors, including increasing rates of disease. New diseases are spreading quickly, affecting many coral species and causing downstream ecological consequences. To help protect these important ecosystems, it is necessary to develop better methods to detect and intervene early in the disease process. This project aims to identify small biomolecules called metabolites that are associated with a specific type of coral disease called Stony Coral Tissue Loss Disease (SCTLD), which is spreading rapidly throughout the Caribbean. By characterizing these metabolites, researchers can better understand the metabolic changes that occur during the onset and progression of SCTLD, and potentially identify early warning signs of the disease before visible symptoms appear. Current methods for detecting changes in metabolites are inefficient and lack spatial resolution. This project seeks to provide a more thorough investigation of the chemical changes associated with SCTLD and improve our understanding of how metabolites can serve as traceable signatures of coral disease. This will allow for earlier intervention and prevention efforts to protect these essential ecosystems. The Broader Impacts for this project include support for a first-generation female PI from an underrepresented group. The PI will work with groups that have been underrepresented in STEM through local (Woods Hole, MA) and global (United States Virgin Islands) activities. Additional broader impacts include participation in: (1) efforts aimed at improving science communication, (2) public outreach activities, and (3) undergraduate mentoring.Current studies of SCTLD have relied on bulk homogenates or slurries of coral tissue using untargeted metabolomic surveys and/or microbial measurements using RNA sequencing. The primary objective of the proposed research is to leverage targeted and untargeted metabolomics, ultrahigh-resolution mass spectrometry, and recent advances in the analysis of dissolved metabolites to characterize the metabolic profiles of SCTLD across a spatial gradient. The work will allow us to quantify the chemical composition of three individual coral microhabitats (i.e., tissue, mucus, and skeleton) in addition to the surrounding seawater and correlate these dynamic profiles with disease progression. Metabolites released or taken up by the coral holobiont serve as invisible signals that can improve our understanding of disease progression, provide diagnostic biomarkers, and allow for earlier intervention and prevention efforts. Using novel metabolomics methods and chemical derivatization, this project will allow us to capture and quantify ecologically relevant, labile polar metabolites with extraction efficiencies of less than 1% using traditional dissolved phase analyses. This project will establish a link between metabolome changes and disease susceptibility by studying the intra- and inter-species variability of coral microhabitats across six different coral species ranging in SCTLD susceptibility. The identification of chemical biomarkers of SCTLD and understanding the role different coral niches play in disease progression will supply coral reef conservationists with rapid detection methods, in addition to providing researchers with new information essential for elucidating pathogens and mechanisms of disease inception. Products of this research will be of broad interest to a diverse group of scientists, including chemists, ecologists, and coral reef disease experts, in addition to the broader public, especially those in coastal regions affected by the ecological and socio-economic impacts of SCTLD or other coral diseases.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.