Acidic pit lakes: Novel biogeochemical reactors evaluated via multi-omics approaches

酸性矿山废水是全球分布最广、成本最高的污染形式之一。本项目将研究如何利用阳光和自然微生物群落对采矿(酸性矿山废水)造成的污染进行低成本有效的补救，从而改善人类和支持人类的生态系统获得清洁水的机会。此外，该项目还将更广泛地促进制定方法和对微生物种群如何与环境中的矿物、有机化合物和其他微生物种群相互作用的新理解。这一认识对于利用微生物系统的巨大生物技术潜力至关重要，这些微生物系统可以被设计成为人类社会提供必要的服务。拟议的工作将改善环境健康，增加STEM管道的多样性，并加强国际科学合作。将招募女性和代表性不足的研究生和本科生参与这一项目。这个项目将通过建立西班牙地质调查局(IGME)和宾夕法尼亚州立大学之间的长期关系来促进美国和国际研究人员之间的合作，这样参与者将从国际科学和工程培训中受益。这个项目的目标是确定刺激酸性矿坑湖硫化物产生的策略。作为一个模型系统，我们选择了位于西班牙西南部的一个永久分层的酸性矿坑湖Cueva de la Mora(CM)的缺氧深层，它是世界上研究最深入的湖之一。我们之前的研究产生了两个相互竞争的假设：1)硫化物的生产受到有机碳的限制，或者2)硫化物的生产受到零价硫的限制。该项目的目标是：A)在接种CM缺氧层微生物群落的实验室培养中刺激自养和异养硫化物的产生；B)分解模拟群落中活性种群的代谢潜力和活性；C)确定在硫化物产生条件下循环C、S、Fe、N和P的微生物种群之间的相互作用。解决这些目标的任务包括：1)开展实地活动，从CM的缺氧层收集大量生物质；2)进行实验室培养，以评估不同条件下的硫化物产生；3)对基因组和转录组进行测序，以确定最丰富和最活跃的微生物种群；以及4)建立概念性的物种和社区水平的代谢模型，以产生关于如何增加硫化物产生及其生物修复潜力的新假设。该项目将有助于从根本上和机制上理解微生物如何在酸性环境中相互作用来产生和消耗硫化物，这对于减轻酸性矿山废水的有毒影响至关重要。这些结果将促进对以前未描述的和新的微生物物种的知识，包括它们的代谢潜力、酶机制和进化关系的细节。目前只有1-2株硫化物产生菌能够在pH值为4的条件下生长，尽管这一组的多样性可能更高，仍未被描述。自然界中的微生物群落是由相互依赖、交换代谢物的种群组成的，但科学研究很少明确考虑这种复杂性。这一建议的一个重要优点是，它侧重于具有中等复杂性的自然环境，适合为自然生态系统的实验室培养开发的建模工具的扩展和调整。记录社区中的微生物相互作用是理解社区组装和利用能够为人类社会提供基本服务的工程微生物系统的巨大生物技术潜力的关键。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Acid mine drainage is globally among the most widespread and expensive forms of pollution.This project will investigate how to use sunlight and natural microbial communities to providecost-effective remediation of pollution caused by mining (acid mine drainage), thus improvingaccess to clean water for humans and the ecosystems that support them. In addition, theproject will contribute more broadly to the development of methods and new understanding ofhow microbial populations interact with minerals, organic compounds, and other microbialpopulations in the environment. This understanding is crucial in order to harness the enormousbiotechnological potential of microbial systems that can be engineered to provide essentialservices to human societies. The proposed work will improve environmental health, increasediversity in the STEM pipeline, and strengthen international scientific collaborations. Womenand underrepresented graduate and undergraduate students will be recruited to work on thisproject. This project will promote collaboration between U.S. and international researchers bybuilding on long-term relationships between the Spanish Geological Survey (IGME) and PennState, such that participants will benefit from international science and engineering training.The goal of this project is to identify strategies to stimulate sulfide production in acidic pit lakes.As a model system, we selected the anoxic deep layer of Cueva de la Mora (CM), a permanentlystratified acidic pit lake in SW Spain that is among the most intensively studied in the world.Two competing hypotheses emerged from our previous research: 1) Sulfide production islimited by organic carbon, or 2) Sulfide production is limited by zero-valent sulfur. The projectobjectives are to: A) Stimulate autotrophic and heterotrophic sulfide production in laboratoryincubations inoculated with the CM anoxic layer microbial community; B) Resolve the metabolicpotentials and activities of the active populations in the stimulated communities; and C)Identify interactions between microbial populations cycling C, S, Fe, N, and P under sulfide producingconditions. Tasks to address these aims include: 1) Conduct a field campaign tocollect large quantities of biomass from the anoxic layer of CM; 2) Conduct laboratoryincubations to evaluate sulfide production under different conditions; 3) Sequencemetagenomes and metatranscriptomes to identify the most abundant and active microbialpopulations; and 4) Construct conceptual species-level and community-level metabolic modelsto generate new hypotheses about how to increase sulfide production and thereforebioremediation potential. This project will contribute to a fundamental and mechanistic understanding of howmicroorganisms interact to produce and consume sulfide in acidic environments, which iscrucial to mitigating the toxic effects of acid mine drainage. The results will advance knowledgeof previously undescribed and novel microbial species, including details of their metabolicpotentials, enzymatic machinery, and evolutionary relationships. There are currently only 1-2sulfide-producing isolates able to grow at pH4, although the diversity of this group is probablyhigher and remains undescribed. Microbial communities in nature are made up of mutuallydependent populations that exchange metabolites, yet scientific studies rarely consider thiscomplexity explicitly. A significant merit of this proposal is that it focuses on a naturalenvironment with intermediate complexity, appropriate for expanding and adapting modelingtools developed for laboratory cultures for natural ecosystems. Documenting microbialinteractions in communities is key to understanding community assembly and to harnessing theenormous biotechnological potential of engineered microbial systems that can provideessential services to human societies.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.