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.
