Rachel L. Harris

Rachel L. Harris
Harvard University | Harvard · Department of Organismic and Evolutionary Biology

Doctor of Philosophy

About

42
Publications
5,119
Reads
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372
Citations
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
September 2017 - present
Princeton University
Position
  • Assistant in Instruction
August 2014 - February 2017
Princeton University
Position
  • PhD Student
September 2012 - May 2014
Wellesley College
Position
  • Research Assistant
Description
  • Assistant in instruction to ASTR 101 and 102 labs under Dr. Stephen Slivan.
Education
September 2014 - May 2020
Princeton University
Field of study
  • Geosciences
September 2014 - May 2016
Princeton University
Field of study
  • Geosciences
August 2010 - May 2014
Wellesley College
Field of study
  • Biological Sciences

Publications

Publications (42)
Preprint
Full-text available
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...
Preprint
Full-text available
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...
Article
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...
Article
Full-text available
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...
Article
Full-text available
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...
Preprint
Full-text available
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...
Article
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...
Preprint
Full-text available
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...
Article
Full-text available
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...
Conference Paper
Full-text available
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...
Poster
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
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...
Conference Paper
Full-text available
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...
Preprint
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...
Presentation
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.
Article
Full-text available
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...
Presentation
Full-text available
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

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