Research

Deep Carbon Observatory

Over the five years support from the Deep Carbon Observatory has been utilized towards contributing to a Census of Deep Life and to the development of metatranscriptomics and metaproteomics in our research group.

DOE: Arctic Permafrost

Permafrost, or perennially frozen ground, underlies ~24% of the Earth’s surface and contains ~1/3 of the global soil organic C.   It is, therefore, a possible source of extremely potent greenhouse gases, such as CH4, N2O and CO2.   Temperatures in the Arctic may increase 4-8°C over the next 100 years, thereby increasing the depth of the active-layer and thawing the underlying permafrost.   Field observations and ice core records suggest that with thawing, the relatively undegraded permafrost organic C will be rapidly metabolized, creating a positive feedback to global warming through increased CH4, N2O and CO2 emissions.  

NSF: Emerging Topics in Biogeochemical Cycles

Recent studies of the continental subsurface microbial ecosystem present in the Witwatersrand Basin, South Africa have shown that with increasing depth and fracture water age and salinity, biogenic methane diminishes and abiogenic hydrocarbons and H2 increase (7, 10) and the concentration of planktonic cells slowly declines (6) .

NSF: Geobiology

NSF Geobiology and Low Temperature Chemistry - Racemization dating of subsurface microorganisms

Part 1 - How quickly do subsurface microbial communities metabolize and grow? Microbial communities are responsible for the transformation of organic matter that is deeply buried in marine and terrestrial sediments and of organic matter generated at depth by hydrothermal processes and rock/water interactions, such as serpentinization.

NSF: Go Life

Current interpretations of Archean carbonaceous sediments suggest the emergence of first forms of life, presumably ancestors of modern bacteria and archaea, by 3.5 billion years ago, providing ample time for genetic diversification. About 1030 of these predominantly unicellular organisms currently occupy every known suitable environment and metabolic niche on Earth. The great majority of bacterial and archaeal phylogenetic groups have not yet been obtained in pure culture and we have only recently become aware of their presence, mainly through cultivation-independent surveys of 16S rRNA genes. However, 16S rRNA gene sequences alone have limited capacity to reveal biological features of this so-called "Microbial Dark Matter" or MDM.

NSF: Siberia

This project will provide additional knowledge to formulate answer for a major unresolved question in microbial ecology of permanently frozen sediments  - whether microbes recovered from deep permafrost sediments are living fossils, representing an ancient surface community preserved through time, or an active extant community that has been interacting and evolving continuously since becoming buried.