Research

Microorganisms have dominated the history of Earth, playing an intimate role in shaping its chemical and physical properties. Microbes continue their role as agents of biogeochemistry today as they drive a wide range of processes, including the cycling of carbon, oxygen, nitrogen, sulfur, and metals. Our research interests are focused on this interplay between the biosphere and the geosphere, examining how microbes drive geochemistry and how geochemistry in turn shapes microbial diversity, metabolism, and evolution. Many biogeochemical cycles are actively driven by genetically encoded molecules that are often carefully regulated to be produced only under certain environmental or physiological conditions. Thus an understanding of biogeochemical cycles that take place on global scales demands knowledge of dynamics that take place on molecular scales. As such, our research relies heavily on molecular-biological approaches that are closely coupled with geochemical approaches to achieve an integrated view of geomicrobiology.


Cyanobacterial harmful algal blooms

Harmful algal blooms (HABs) are a global threat to freshwater ecosystems, water resources, and human health. The interplay of microbial, ecological, and chemical processes causes toxin production and formation of lake “dead zones”. This project will better understand this problem by integrating new approaches, including community ‘omics, to a local natural laboratory, Lake Erie, which experienced the largest HAB in recorded history in 2011 and then again in 2015.  We are particularly interested in the potential controls on toxicity and the dynamics of hydrogen peroxide within the blooms.


Geomicrobiology of Laurentian sinkholes

High-throughput DNA sequencing is being applied to understand novel microbial mats inhabiting sediments of Lake Huron, where saline, sulfur-rich groundwater emerges from submerged sinkholes. This system is a fantastic analog of ancient microbial mats, and a model system for understanding the role of cyanobacteria in Earth’s oxygenation.



Field Sites:

  • Lake Huron near Alpena, MI

Collaborators:

Funding:

  • Collaborative Research: Revealing the interplay between light, sulfur cycling, and oxygen production in cyanobacterial mats.  National Science Foundation Geobiology & Low-Temperature Geochemistry EAR 1637066.
  • Collaborative Research: EAGER: Genomic insights into microbial mat diversity and Proterozoic geobiology. National Science Foundation Geobiology & Low-Temperature Geochemistry EAR 1035955
  • Will Climate, Invasives and Toxicants Imperil Unique Biodiversity in the Great Lakes? University of Michigan Mcubed.

Diversity and function of microbial communities in deep-sea hydrothermal plumes

This project addresses questions of how deep-sea microbial communities respond to and transform potential energy sources emanating from deep-sea hydrothermal vents, such as methane, ammonium, sulfur, iron, and manganese. We work with a large team of collaborators to develop new methods to sample, analyze, and model plume microbial ecology and geochemistry.

Field Sites: 

  • Lau Basin (southwestern Pacific)
  • Guaymas Basin (Gulf of California)
  • Cayman Rise (Caribbean)

Collaborators:

Funding:

  • Unveiling the microbiology that underpins deep-sea biogeochemistry. Gordon and Better Moore Foundation Marine Microbiology Initiative #2609.
  • Linking biogeochemistry and microbial community dynamics in deep-sea hydrothermal plumes. National Science Foundation Biological Oceanography OCE 1029242.
  • Collaborative Research: Integrating geochemistry, microbiology, and hydrodynamics: A model for trace element transport and fate in hydrothermal plumes. National Science Foundation Ridge2000 (Marine Geology and Geophysics) OCE 1038006.