Statistical Mechanics Modeling of Critical Phenomena in Phytoplankton Living in a Cold Environment

浮游植物是地球碳循环的重要组成部分，因此在气候系统中发挥着重要作用。最近的观察表明，气候变化可能是影响生态系统行为的一个主要因素。环境条件可能与浮游生物生态系统的动态有关的一个具体例子是在北冰洋的冰层下观察到的不寻常的大规模浮游植物水华。在北极融化季节，海冰表面经历了一个显着的转变，融化的池塘，雪和冰的复杂马赛克。池塘分形几何的转变围绕着面积约为100平方米的临界长度尺度，因为孤立的池塘生长并合并成具有复杂自相似边界的更大的连接结构。此外，从与单个池塘相关的孤立阳光渗透到与大型连接池塘配置相关的连续光矩阵的过渡可能有助于引发冰下水华，并影响生物生产力和生物地球化学过程。这项工作将阐明一些关键问题，如太阳辐射变化条件下的生态系统变化;生物物质的融化过程和动态;北极气候系统的能量平衡;北极浮游植物对气候反馈的贡献。PI将探索如何在统计力学中产生的概念物理模型可以用来有效地描述和量化北极浮游植物在非线性动力学。在外联工作中，PI将向公众传达严格和基本方法对气候和生态系统研究的重要性。PI将准备有关这项研究的说明性材料（科学信息图），解释解决这一问题的强有力的跨学科方法。公众和教育工作者可以从项目网页上免费下载科学信息图表。生态系统建模的基本概念将用于计算和统计物理课程的教学环境中。一个基于这些原则的棋盘游戏将在当地的K-12学校进行开发和测试。这项研究还将为本科生和博士生提供资金，在跨学科研究的广泛框架内提供理论应用方面的宝贵经验。PI将涉及正在参加代顿大学为少数民族服务机构举办的夏季研究项目的本科生参与该项目，这将使他们能够获得建模和团队合作的技能。该项目将提供统计力学模型的普遍性，对浮游植物种群关键转变的定量预测，其中局部动态的全部复杂性永远无法明确建模。该项目将揭示最近的环境变化和浮游植物群落的复杂行为之间的一些普遍联系，并增加我们对浮游植物生态系统的了解，包括水华的发展。在这项研究中发现的生物物质-气候相互作用的方法和物理解释也将适用于未来对地球极地地区和冰面下“地外海洋”可能存在的生物的研究。该项目综合了现有的遥感和实地工作数据，在一个创新的定量框架，以改善浮游植物dynamics.This奖项的描述反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Phytoplankton are a critical component of Earth's carbon cycle and thus play an important role in the climate system. Recent observations have shown that climate change can be a leading factor influencing ecosystem behavior. One specific example where environmental conditions may be related to the dynamics of the plankton ecosystem is an unusual massive phytoplankton bloom that was observed underneath the ice pack in the Arctic Ocean. During the Arctic melt season, the sea ice surface undergoes a remarkable transformation to a complex mosaic of melt ponds, snow and ice. The transition in pond fractal geometry revolves around a critical length scale of about 100 square meters in area, as isolated ponds grow and coalesce into larger connected structures with complex, self-similar boundaries. Moreover, the transition from isolated sunlight penetration associated with individual ponds to a continuous matrix of light associated with large connected pond configurations could help trigger the under-ice blooms and influence biological productivity and bio-geochemical processes. This work will shed light on key concerns such as ecosystem transformations under changing conditions of solar radiation; the melting process and the dynamics of living matter; energy balance in the Arctic climate system; and, the contribution of phytoplankton in the Arctic to climate feedbacks. The PI will explore how conceptual physical models arising in statistical mechanics can be used to efficiently characterize and quantify Arctic phytoplankton under nonlinear dynamics. In outreach efforts, the PI will convey to the general public the importance of rigorous and fundamental approaches to climate and ecosystem research. The PI will prepare illustrative material (scientific infographics) about this research that will explain a strong interdisciplinary approach to this problem. The scientific infographics will be made freely downloadable by the general public and educators from a project webpage. The fundamental concepts of ecosystem modeling will be used in a teaching context in computational and statistical physics classes. A board game based on these principles will be created and tested in local K-12 schools. This research will also provide funding for an undergraduate and PhD student, providing valuable experience in theoretical applications within the broad framework of interdisciplinary research. The PI will involve undergraduate students who are participating in the summer research program of the University of Dayton for minority-serving institutions to participate in this project, which will enable them to gain skills in modeling and teamwork.This project will offer the universality of statistical mechanics models for making robust, quantitative predictions about critical transitions in phytoplankton populations where the full complexity of local dynamics could never be modeled explicitly. The project will reveal some universal links between recent environmental changes and complex behavior of phytoplankton communities and increase our knowledge of phytoplankton ecosystems, including bloom development. The methods and physical interpretation of living matter-climate interaction discovered in this research will also be applicable to future studies of possible organisms in polar regions of the Earth and "extraterrestrial oceans" beneath icy surfaces. This project synthesizes available remote sensing and fieldwork data in an innovative quantitative framework to improve description of phytoplankton dynamics.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.