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

这项研究旨在研究海洋酸化等长期环境变化将如何影响硅藻，硅藻是一种关键的微观浮游植物，构成许多海洋食物网的基础。硅藻占我们海洋初级生产的约40%，其组成和丰度的变化可能导致沿海生态系统发生巨大变化。将开发压力测试来量化硅藻的“弹性”，即，它们能够承受环境应力的程度，例如饱和光、紫外线辐射或升高的温度。通过对三种生活在不同海洋环境中的模式硅藻（Thalassiosira oceanica，Phaeodactylum tricornutum和Thalassiosira dangerana）进行这种压力测试，这项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，这项研究还将表征负责观察到的硅藻弹性变化的分子机制。对海洋酸化可能如何改变硅藻弹性的机制性理解将使预测和可操作的战略能够更好地管理环境。此外，该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。这些课程将通过教师培训广泛传播。硅藻已经进化出在波动环境中生存的表型可塑性，并具有耐受各种压力的能力。拟议的研究解决了量化硅藻如何管理维持表型可塑性和投入资源缓解压力之间的权衡的挑战，这对于预测它们在复杂环境中的弹性至关重要。压力测试框架将能够量化硅藻的生态恢复力，即，硅藻种群能够忍受干扰并持续存在而不改变生理状态的程度。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），这项研究将允许预测特定因素之间的相互作用何时对硅藻的弹性产生协同或拮抗作用。对转录（RNA-seq）和生理变化的系统水平分析与使用基于CRISPR-cas9的基因组编辑的假设检验相结合，将提供对动态环境中硅藻弹性变化的预测性和机制性理解。由此产生的知识、框架和工具将作为预测性指标，用于预测物种划分和生态系统功能在不断变化的海洋中的变化。此外，压力测试框架和系统方法将可推广到调查环境重要性微生物群落的恢复力和其他复杂性状。 该奖项由整合有机系统部和分子与细胞生物科学部共同资助。该奖项反映了NSF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.