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Environmental Sciences
Hydrogen
Education (3)
University of Washington: Ph.D. 2005
University of Washington: M.Sc 2001
University of Wisconsin-Madison: B.Sc. 1998
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Rural water crisis vital to health of the planet | Opinion
Detroit Free Press online
2024-04-22
As we celebrate Earth Day 2024 and think about the health of the blue planet, there is no other crisis more important than where land meets water in rural America.
Life may have originated miles underground
USA Today online
2013-12-14
The samples were more than 97% identical, or practically the same species, according to researcher Matt Schrenk, who notes that some may "live as deep as (6 miles) into the Earth."
Journal Articles (5)
Determining the biogeochemical transformations of organic matter composition in rivers using molecular signatures
Frontiers in Water2023 nland waters are hotspots for biogeochemical activity, but the environmental and biological factors that govern the transformation of organic matter (OM) flowing through them are still poorly constrained. Here we evaluate data from a crowdsourced sampling campaign led by the Worldwide Hydrobiogeochemistry Observation Network for Dynamic River Systems (WHONDRS) consortium to investigate broad continental-scale trends in OM composition compared to localized events that influence biogeochemical transformations. Samples from two different OM compartments, sediments and surface water, were collected from 97 streams throughout the Northern Hemisphere and analyzed to identify differences in biogeochemical processes involved in OM transformations.
An untargeted exometabolomics approach to characterize dissolved organic matter in groundwater of the Samail Ophiolite
Frontiers in Microbiology2023 The process of serpentinization supports life on Earth and gives rise to the habitability of other worlds in our Solar System. While numerous studies have provided clues to the survival strategies of microbial communities in serpentinizing environments on the modern Earth, characterizing microbial activity in such environments remains challenging due to low biomass and extreme conditions. Here, we used an untargeted metabolomics approach to characterize dissolved organic matter in groundwater in the Samail Ophiolite, the largest and best characterized example of actively serpentinizing uplifted ocean crust and mantle.
Chemolithoautotroph distributions across the subsurface of a convergent margin
The ISME Journal2023 Subducting oceanic crusts release fluids rich in biologically relevant compounds into the overriding plate, fueling subsurface chemolithoautotrophic ecosystems. To understand the impact of subsurface geochemistry on microbial communities, we collected fluid and sediments from 14 natural springs across a ~200 km transect across the Costa Rican convergent margin and performed shotgun metagenomics. The resulting 404 metagenome-assembled genomes (MAGs) cluster into geologically distinct regions based on MAG abundance patterns: outer forearc-only (25% of total relative abundance), forearc/arc-only (38% of total relative abundance), and delocalized (37% of total relative abundance) clusters.
Sampling across large-scale geological gradients to study geosphere–biosphere interactions
Frontiers in Microbiology2022 Despite being one of the largest microbial ecosystems on Earth, many basic open questions remain about how life exists and thrives in the deep subsurface biosphere. Much of this ambiguity is due to the fact that it is exceedingly difficult and often prohibitively expensive to directly sample the deep subsurface, requiring elaborate drilling programs or access to deep mines. We propose a sampling approach which involves collection of a large suite of geological, geochemical, and biological data from numerous deeply-sourced seeps—including lower temperature sites—over large spatial scales. This enables research into interactions between the geosphere and the biosphere, expanding the classical local approach to regional or even planetary scales.
Expansion of the global RNA virome reveals diverse clades of bacteriophages
Cell2022 High-throughput RNA sequencing offers broad opportunities to explore the Earth RNA virome. Mining 5,150 diverse metatranscriptomes uncovered >2.5 million RNA virus contigs. Analysis of >330,000 RNA-dependent RNA polymerases (RdRPs) shows that this expansion corresponds to a 5-fold increase of the known RNA virus diversity. Gene content analysis revealed multiple protein domains previously not found in RNA viruses and implicated in virus-host interactions. Extended RdRP phylogeny supports the monophyly of the five established phyla and reveals two putative additional bacteriophage phyla and numerous putative additional classes and orders.