Rachel L. HarrisHarvard University | Harvard · Department of Organismic and Evolutionary Biology
Rachel L. Harris
Doctor of Philosophy
About
42
Publications
5,119
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Introduction
I am a postdoctoral fellow under Dr. Peter Girguis in the Department of Organismic and Evolutionary Biology at Harvard University. My research interests include investigating the functional diversity of active but rare microbial players implicated in oligotrophic deep biosphere carbon cycling. Applications include early evolution and habitability on early Earth, Mars Special Regions, and Ocean Worlds.
Additional affiliations
Education
September 2014 - May 2020
September 2014 - May 2016
Princeton University
Field of study
- Geosciences
August 2010 - May 2014
Publications
Publications (42)
It is widely accepted that ancient Mars hosted long-lived habitable environments, and that habitable refugia may persist in the subsurface today. The presence and behavior of methane gas in the Martian atmosphere makes a compelling case to study methanogenesis as a potential biosignature under simulated Mars surface or shallow subsurface conditions...
Mars, with its ancient history of long-lived habitable environments, continues to captivate researchers exploring the potential for extant life. This study investigates the viability of hydrogenotrophic methanogenesis, a potential biosignature, in Methanosarcina barkeri MS under simulated Martian surface conditions. We expose M. barkeri to sustaine...
The Mars 2020/Mars Sample Return (MSR) Sample Depot Science Community Workshop was held on September 28 and 30, 2022, to assess the Scientifically‐Return Worthy (SRW) value of the full collection of samples acquired by the rover Perseverance at Jezero Crater, and of a proposed subset of samples to be left as a First Depot at a location within Jezer...
Keystone species or ecological engineers are vital to the health of an ecosystem; however, often, their low abundance or biomass present challenges for their discovery, identification, visualization and selection. We report the development of fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB), a fixation-free pr...
Observations of trace methane (CH 4 ) in the Martian atmosphere are significant to the astrobiology community given the overwhelming contribution of biological methanogenesis to atmospheric CH 4 on Earth. Previous studies have shown that methanogenic Archaea can generate CH 4 when incubated with perchlorates, highly oxidizing chaotropic salts which...
Observations of trace methane (CH4) in the Martian atmosphere are significant to the astrobiology community given the overwhelming contribution of biological methanogenesis to atmospheric CH4 on Earth. Previous studies have shown that methanogenic Archaea can generate CH4 when incubated with perchlorates, highly oxidizing chaotropic salts which ha...
Ca-Na-Cl fluids with high concentrations of dissolved reduced gases reside within fractures in crystalline Precambrian rocks around the world, and have been most intensively studied within South Africa, Fennoscandia and the Canadian Shield. In contrast to surface waters, shallow groundwaters, sedimentary basin brines and metamorphic fluids, the δ¹⁸...
Keystone species or ecological engineers are vital to the health of an ecosystem, however, often their low abundance or biomass present challenges for their discovery, identification, visualization and selection. We report the development of fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB), a fixation-free pro...
On November 5-8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The conference gathered a community of actively publishing experts in disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset of conference attendees concluded that there is a realistic...
Numerous reports observing trace methane (CH4) in the Martian atmosphere 1-5 including the recently published 5-year record of CH4 seasonality in Gale Crater 6,7 have generated much consternation in our attempts to explain the temporal and spatial variability of this astrobio-logically relevant greenhouse gas 8-13. Several mechanisms have been sugg...
Anaerobic oxidation of methane (AOM) is a significant but poorly constrained biological sink in the global carbon cycle. While several studies estimate AOM is responsible for consuming ~80-90% produced in marine sediments, its role in curbing the CH4 atmospheric flux in terrestrial freshwater systems, particularly the deep continental biosphere, is...
Metagenomic sequencing of fracture fluid from South Africa recovered a nearly complete “ Candidatus Bathyarchaeota” archaeon genome. The metagenome-assembled genome of BE326-BA-RLH contains genes involved in methane metabolism and dissimilatory nitrate reduction. This study presents the first genomic evidence for potential anaerobic methane oxidati...
Chloride-bearing deposits and phyllosilicates-bearing units are widely distributed in the southern highlands of Mars, but these phases are rarely found together in fluviolacustrine environments. The study of the coexistence of these minerals can provide important insights into geochemistry, water activity, and ultimately the climate and habitabilit...
Metatranscriptomics has recently been applied to investigate the active biogeochemical processes and elemental cycles, and in situ responses of microbiomes to environmental stimuli and stress factors. De novo assembly of RNA-Sequencing (RNA-Seq) data can reveal a more detailed description of the metabolic interactions amongst the active microbial c...
The anaerobic oxidation of methane (AOM) is an important sink in the global methane (CH4) budget. ANMEs are known to oxidize CH4 either independently or in consortia with bacteria, coupling the reduction of electron acceptors such as, SO42-, NO2-, NO3-, Mn4+, or Fe3+. To further constrain the contribution of AOM to the global CH4 budget, it is impo...
High-throughput sequencing and cellular imaging have expanded our knowledge of microbial diversity and expression of cellular activity. However, it remains challenging to characterize low-abundance, slow-growing microorganisms that play key roles in biogeochemical cycling. With the goal of isolating transcriptionally active cells of these microorga...
A plan to drill into seismogenic zones of M2.0 - M5.5 earthquake in deep South African gold mines (DSeis) was introduced, which International Continental Scientific Drilling Program accepted in August 2016.
Significance
Microorganisms are known to live in the deep subsurface, kilometers below the photic zone, but the community-wide metabolic networks and trophic structures (the organization of their energy and nutritional hierarchy) remain poorly understood. We show that an active subsurface lithoautotrophic microbial ecosystem (SLiME) under oligotrop...
Oral presentation presented by Rachel Harris regarding the development of fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB) in the session ”Cutting-edge methods in Microbial Ecology” at ISME-16