Ecological Stoichiometry and the Relevance of Prokaryotic Heterotroph Biodiversity

就碳储存而言，湖泊和海洋是地球表面的重要区域。水生系统储存碳的能力的重要调节因素之一是植物和分解者(细菌)生长之间的平衡。这种平衡受到水中营养物质可获得性的强烈影响。众所周知，植物多样性在生态系统产生生物量的能力中发挥着重要作用，但对细菌多样性在分解植物产生的物质方面的重要性知之甚少。这项研究将考察细菌多样性对美国中北部湖泊营养循环和有机质生产的重要性。最近的研究表明，湖泊中的细菌群落可能不是特别“物种丰富”，但不同湖泊之间存在相当大的差异性。物种丰富的湖泊被假设为非常有效地循环营养物质，也许储存碳的效率非常低，而物种丰富的湖泊应该低效地循环营养物质，同时非常有效地储存碳。这些假说将通过研究实验室中从湖泊中分离出来的单个细菌菌株和完整的细菌群落的行为来检验。菌株和完整的群落将以其循环养分的能力为特征，群落多样性对养分循环的重要性将进行数学评估和建模。这项研究将促进教学和培训目标，包括：与中学数学教师、高中科学博览会学生、研究生培训和博士后研究员合作。PI将参加以少数族裔学生为重点的暑期本科生研究项目。

Lakes and oceans are important regions on the Earth's surface in terms of carbon storage. One of the important regulators of the ability of aquatic systems to store carbon is the balance between plant and decomposer (bacterial) growth. This balance is strongly affected by the availability of nutrients in the water. Plant diversity is known to play an important role in the ability of ecosystems to produce biomass in ecosystems but little is known of the importance of bacterial diversity in decomposing the material produced by plants. This study will examine the importance of bacterial diversity to nutrient cycling and organic matter production in lakes in the north-central United States. Recent studies suggest that bacterial communities in lakes may not be particularly "species rich" but there is considerable variability among different lakes. Lakes that are species-rich are hypothesized to recycle nutrients very efficiently, and perhaps store carbon very inefficiently, whereas, species-poor lakes should recycle nutrient inefficiently while storing carbon very efficiently. These hypotheses will be examined by studying the behavior of both individual strains of bacteria isolated from lakes in the laboratory and intact communities of bacteria. Strains and intact communities will be characterized with respect to their ability to recycle nutrients and the importance of community diversity to nutrient recycling will be evaluated and modeled mathematically.This study will promote teaching and training goals including: working with a middle school math teacher, high school science fair students, training of graduate students, and a post-doctoral fellow. The PIs will participate in summer undergraduate research programs focused on minority students.