Collaborative Research: IMAGiNE: Quantifying Diatom Resilience in an Acidified Ocean

这项研究旨在调查海洋酸化等长期环境变化将如何影响硅藻，硅藻是形成许多海洋食物网基础的关键微观浮游植物。硅藻占我们海洋初级产品的约40%，它们的组成和丰度的变化可能导致沿海生态系统的巨大变化。将开发一种压力测试来量化硅藻的“弹性”，即它们能够承受环境压力（如饱和光、紫外线辐射或温度升高）的程度。通过对生活在不同海洋环境中的三种模式硅藻（海洋海藻、三角褐藻和假海藻）进行压力测试，本研究将揭示海洋酸化是否会对这些重要生物的未来命运产生类似或不同的后果。此外，本研究还将描述硅藻恢复力变化的分子机制。对海洋酸化如何改变硅藻恢复力的机制理解，将为更好的环境管理提供可预测和可操作的策略。此外，这个项目将产生新的高中课程，关于我们日常生活中遇到的复杂系统的弹性和崩溃的概念。课程将通过教师培训广泛传播。硅藻已经进化出表型可塑性，以在波动的环境中生存，并有能力忍受不同类型的压力。提出的研究解决了量化硅藻如何在维持表型可塑性和投入资源减轻压力之间进行权衡的挑战，这对于预测它们在复杂环境中的恢复能力至关重要。压力测试框架将能够量化硅藻的生态弹性，即硅藻种群能够容忍干扰并在不改变生理状态的情况下持续存在的程度。通过对代表不同生态位的三种模式硅藻进行压力测试，并在当前和未来海洋的相关条件下（即温度、CO2、NO3、Fe和光照条件），本研究将能够预测特定因素之间的相互作用何时会对硅藻的恢复力产生协同或拮抗作用。系统水平的转录（RNA-seq）和生理变化分析，结合基于crispr -cas9的基因组编辑的假设检验，将为动态环境中硅藻恢复力的变化提供预测性和机制性的理解。由此产生的知识、框架和工具将作为预测指标，预测不断变化的海洋中物种的划分和生态系统功能的变化。此外，压力测试框架和系统方法将被推广到研究具有环境重要性的微生物群落的弹性和其他复杂特征。该奖项由综合生物系统部和分子与细胞生物科学部共同资助。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。

This research seeks to investigate how long-term environmental changes like ocean acidification will affect diatoms, a key microscopic phytoplankton forming the basis of many marine food webs. Diatoms account for ~40 percent of the primary production in our oceans, and a shift in their composition and abundance may result in dramatic changes in coastal ecosystems. A stress test will be developed to quantify the “resilience” of diatoms, i.e., the degree to which they can withstand environmental stress such as saturating light, ultraviolet radiation, or increased temperature. By applying this stress test to three model diatoms that inhabit different oceanic environments, Thalassiosira oceanica, Phaeodactylum tricornutum, and Thalassiosira pseudonana, this study will uncover whether ocean acidification will have similar or distinct consequences on the future fate of these important organisms. Furthermore, this study will also characterize molecular mechanisms responsible for the observed shifts in the resilience of diatoms. Mechanistic understanding of how ocean acidification might alter the resilience of diatoms will enable predictive and actionable strategies for better environmental stewardship. Additionally, this project will generate new high school curriculum on the concepts of resilience and collapse of complex systems encountered in our everyday life. The curricula will be disseminated widely through teacher training.Diatoms have evolved phenotypic plasticity to survive in fluctuating environments, and the capability to tolerate diverse types of stress. The proposed research addresses the challenge of quantifying how diatoms manage trade-offs between maintaining phenotypic plasticity and devoting resources to mitigating stress, which is central to predicting their resilience in complex environments. The stress test framework will enable the quantification of ecological resilience of a diatom, i.e., the degree to which a diatom population can tolerate a disturbance and persist without changing physiological state. By performing the stress test on three model diatoms representing different ecological niches, and in relevant conditions of current and future oceans (i.e., temperature, CO2, NO3, Fe, and light conditions), this study will allow the prediction of when interactions among specific factors will have synergistic or antagonistic effects on the resilience of diatoms. Systems level analysis of transcriptional (RNA-seq) and physiological changes coupled to hypothesis testing using CRISPR-cas9-based genome editing will provide predictive and mechanistic understanding of changes in diatom resilience in dynamic environments. The resulting knowledge, framework, and tools will serve as predictive indicators to forecast species partitioning and shifts in ecosystem function in changing oceans. Furthermore, the stress test framework and systems approaches will be generalizable to investigate resilience and other complex traits across microbial communities of environmental importance. This award is cofunded by the Division of Integrative Organismal Systems and the Division of Molecular and Cellular Biosciences.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.