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Harvard Forest REU Symposium Abstract 2011

  • Title: Studying the Hydrogen Soil Sink at the Harvard Forest through Isolation of Streptomyces and Flux Chamber Work
  • Author: Deepa Rao (Massachusetts Institute of Technology)
  • Abstract:

    Atmospheric H2 is a secondary greenhouse gas (GHG) and is vital to the removal of methane (CH4) from the atmosphere. Natural and anthropogenic outputs are nearly equally responsible as sources of H2 and human output is expected to increase in the future. Soil microorganisms are responsible for about 80% of the Earth’s atmospheric H2 sink and are the least understood term in the overall H2 budget. It is speculated that Streptomyces, a ubiquitous genus of soil microbe, is a large contributor to H2 deposition through its enzyme: hydrogenase. Specifically, Streptomyces has a unique high-affinity, low-threshold hydrogenase. How Streptomyces and other hydrogenase-containing microbes respond to changes in the climate can help us predict if and how the H2 cycle can potentially change. We will examine soil uptake of H2 by isolating and varying the environment of Streptomyces from the Harvard Forest (HF) and by measuring soil’s H2 flux in a set of plots that cover a wide range of environmental conditions (soil moisture, temperature, increased and decreased levels of H2, etc.). So far, we have optimized a protocol for Streptomyces isolation from forest soil, extraction of DNA, and amplification of the hydrogenase DNA sequence through polymerase chain reaction (PCR). We plan on testing our isolated strains to see if their H2 uptake drastically alters under different environmental conditions. The second part of our project deals with measuring H2 uptake by using flux chambers in various long-term plots around the HF (e.g., nitrogen amendment, heated, litter removal plots) With these two methods combined, we will gain a better understanding about the variability of the Earth’s largest H2 sink and how it may respond to climate change.

  • Research Category: Soil Carbon and Nitrogen Dynamics