Collaborative Research: RUI: Development and application of a method using coralline algae to reconstruct past changes in pH and impacts on calcification

最近和未来人类造成的大气二氧化碳增加对浅水冷水海洋环境的酸度(PH)(称为“海洋酸化”的过程)以及对居住在其中的生物体的影响知之甚少。这在一定程度上是由于在这些偏远环境中重建过去海洋化学变化的困难。这项研究试图开发和应用一种技术，根据广泛存在于浅水冷水海洋环境中的长寿命壳状珊瑚藻类中的硼同位素特征，重建过去的海水pH值。此外，研究还将评估海水pH值变化对这些具有生态重要性的生物生长速度的影响，这些生物被认为特别容易受到海洋酸化的影响，因为它们骨骼的镁含量很高。总体而言，该项目将增进对浅水冷水环境中海洋酸化的了解，并为评估海洋pH值变化对生活在这些环境中的生物造成的影响提供关键信息。这项工作的结果将为寻求减轻大气二氧化碳上升对这些脆弱的高纬度海洋生态系统的负面影响的政策制定者和立法者提供重要信息。资金支持一名研究生、众多本科生研究人员，以及两名早期职业教师之间的新合作。外联活动包括通过斯克里普斯学院指导科学界代表性不足群体的高中生，以及制作一部关于海洋酸化的生物影响的教育电影。研究团队将通过与加拿大和英国科学家的合作来加强国际联系，同时帮助美国科学家保持在这一重要的海洋酸化研究子领域的前沿。工作计划包括三个主要部分：(1)开发第一个实验室得出的和现场验证的珊瑚藻类古海水pH的delta11B替代物校准，(2)生成第一个高分辨率的、多个百年来的高纬度海水pH数据集，在(约公元1365至1760年；即“基线”)之前和之后(约公元1760年至今；即“人为信号”)工业革命，以及(3)评估人为海洋酸化对生态上重要的、形成栖息地的珊瑚红藻产生的骨骼的线性延伸、密度和超微结构的影响。相关的目标是：(1)提供一个恢复古海水pH值的新工具；(2)产生海洋酸化的历史记录，以阐明可用于验证预测模型的高纬度海洋酸化的速度和程度；(3)建立海洋酸化与珊瑚藻类钙化之间的经验关系，从而为预测海洋酸化对高纬度海洋钙化的未来影响提供信息。

The impacts of recent and future human-caused increases in atmospheric CO2 on the acidity (pH) of shallow cold-water marine environments (a process known as "ocean acidification"), and on the organisms that inhabit them, are poorly understood. This is due, in part, to the difficulty in reconstructing past changes in ocean chemistry in these remote environments. This research seeks to develop and apply a technique to reconstruct past seawater pH from boron isotope signatures in long-lived crustose coralline alga that are widespread throughout shallow, cold-water marine environments. In addition, the research will evaluate the impact of changing seawater pH on the growth rate of these ecologically important organisms, which are thought to be particularly vulnerable to ocean acidification because of the high magnesium content of their skeleton. Overall, this project will advance understanding of ocean acidification in shallow, cold-water environments, and provide key information to evaluate the impact that changes in ocean pH have had on organisms inhabiting these environments. The outcomes of this work will provide important information to policy makers and legislators seeking to mitigate the negative effects of rising atmospheric CO2 on these fragile, high-latitude marine ecosystems. Funding supports a graduate student, numerous undergraduate researchers, and a new collaboration between two early career faculty members. Outreach includes mentoring high school students from groups underrepresented in the sciences through the Scripps College Academy and production of an educational film on the biological impacts of ocean acidification. The research team will strengthen international ties through collaboration with Canadian and UK scientists, while helping maintain US-based scientists at the forefront of this important sub-field of ocean acidification research. The work plan includes three main parts: (1) developing the first laboratory-derived and field-verified calibration of the delta11B-proxy of paleoseawater pH for coralline algae, (2) generating the first high-resolution, multi-centennial dataset of high-latitude seawater pH before (ca. 1365 to 1760 AD; i.e., "baseline") and after (ca. 1760 AD to present; i.e., "anthropogenic signal") the Industrial Revolution, and (3) evaluating the impact of anthropogenic ocean acidification on the linear extension, density, and ultrastructure of skeletons produced by an ecologically important, habitat-forming coralline red alga. The associated objectives are: (1) to provide a new tool for reconstructing paleo-seawater pH, (2) to generate historical records of ocean acidification that would elucidate the rate and magnitude of high-latitude ocean acidification that could be used to verify predictive models, and (3) to establish empirical relationships between ocean acidification and coralline algal calcification that would inform predictions of future impacts of ocean acidification on high-latitude marine calcifiers.