Sciences and Exploration Directorate

Research Interests


Life detection strategies for ancient Earth rocks and on Mars and Ocean Worlds; Raman spectroscopy for planetary science and the characterization of terrestrial environments; the interactions between microbes and minerals and how these interactions shape the geologic landscape; the evolution of carbon in the solar system; Low-temperature microscopy and spectroscopy; development of hybrid spectroscopic instruments for field work and in situ planetary surface exploration; lunar mineralogy

Solar System: Astrobiology

Dr. Dina M. Bower is an astrobiologist - biomineralogist interested in the intersection and evolution of microbes and minerals. She uses geochemical techniques like Raman spectroscopy and elemental analysis to characterize a variety of geologic materials from modern and ancient terrestrial environments, meteorites, and laboratory synthesized analogs. She has expertise in biosignature detection in ancient Earth rocks that contain microfossils or carbonaceous materials, experimentally induced biominerals, and modern terrestrial rocks and mineral deposits. In particular, her research focuses on mineral deposits in lava tube environments and how they record environmental conditions and biogeochemical processes. Dr. Bower also develops different types of Raman spectroscopy technologies and instrumentation for in situ planetary body exploration and tests the utility of portable instruments in analog field sites around the world.

Brief Bio


Dr. Dina Bower is an interdisciplinary scientist with a background in marine chemistry and mineralogy. She has focused much of her career on geochemistry and life detection in the context of reconstructing early life on Earth. Dr. Bower has several years of experience utilizing Raman spectroscopy and spectroscopic imaging for in situ field measurements and high-resolution laboratory applications. Her expertise is complemented with the use of other analytic approaches to characterize a wide variety of bio-geologic materials, including microscopy-optical petrography, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), electron probe microanalysis, cathodoluminescence, and reflectance spectroscopy. Dr. Bower applies her knowledge of biogeochemical science requirements and hands on expedition experience to the development of spectroscopic instruments and hybridized systems for field work and planetary missions.

Current Projects


Spectroscopic studies of nitrogen cycling in basaltic environments

Astrobiology

The complex nitrogen cycle on Earth has had profound effects on the evolution of the atmosphere and surface environments through a cascade of biological and geochemical feedbacks. Nitrogen (N) is one of the essential elements for life on Earth (among the “CHNOPS”) elements, and its importance for the organic molecules that define life as we know it likely drove the development of many of the pathways for fixing and recycling nitrogen on early Earth and potentially on other planetary bodies. However, there are still major gaps in our understanding of how the nitrogen cycle and its related metabolisms evolved over the course of Earth’s history. Nitrogen compounds such as cyanates play a central role in N-cycling in the marine environment, and their signatures have been detected on land where water and microbial activity interact with with basalts. This research focuses on understanding what nitrogen compounds are involved in these processes, their formation mechanisms, and their preservation potential, with the goal of establishing spectroscopic signatures for life detection.


Instrument Development for in situ Spectroscopy Techniques

Technology & Missions

Dr. Bower is working on projects that facilitate the use of Raman spectroscopy for in situ planetary missions, for landers, rovers, or future human-led endeavors. She works on hybrid instrumentation to merge spectroscopic techniques for geochemical measurements as well as spectrometry-spectroscopy instrumentation for combined biochemical-geochemical measurements. Her projects focus on the development of spectrometer components and subsystems using novel technologies to improve the capabilities of UV-VIS Raman spectroscopy for Ocean Worlds exploration.


Field comparisons of Microbe-Mineral Interactions in Basaltic Environments

Astrobiology

Basaltic environments on Earth offer a wide variety of habitable environments. Subsurface environments, such as lava tubes, can provide protection from harsh surface conditions while providing unique hydrogeological environments for life to proliferate. Mineralogical variations in lava tubes are the result of geological and biogeochemical processes, depending on factors such as exposure to fracture waters, volcanic gases, and microbial activity. In contrast, surface environments such as geothermal streams, offer similar features as warm, vigorous waters and local microbial communities interact with basalt rocks. The mineralogies may differ between lava tube and geothermal stream environments, but the biogeochemical processes are often very similar. Understanding these differences and similarities helps in deciphering signatures in rocks and how they record environmental conditions and habitability on other planetary bodies


The Identification of Biosignatures and Evidence of Habitability in Ocean Worlds Analogues using Raman and Reflectance Spectroscopy

Astrobiology

The ability to identify biosignatures in icy environments is essential for upcoming life detection missions on Europa, Enceladus or other Ocean Worlds. Raman spectroscopy can be used to quickly and efficiently identify minerals, salts, and organics with in situ measurements, and reflectance spectroscopy provides large-sale characterizations of icy environments. Dr. Bower's work couples the two techniques to bridge the gap between remote sensing and in situ measurements. The applications of her work stretch beyond planetary science into oceanography, where Raman facilitates the measurements of salinity, temperature, gas composition, and organics characterization of seawater and sea ice. 


Geochemical characterization of ancient terrestrial hydrothermal deposits to establish biosignatures for exoplanetary life detection

Astrobiology

Raman spectroscopy is a non-destructive technique that can identify several different chemical species in one scan, and Raman imaging facilitates the visualization of spatial relationships and an understanding of context. Many ancient cherts on Earth contain different types of biosignatures indicative of the earliest forms of life as far back as ~3.5 Ga. Signatures useful for life detection, such as organics, biominerals, and carbon isotopes, are detectable using Raman spectroscopy. With Raman spectroscopy we can reconstruct the geologic history of deposits by characterizing the the chemical composition and structural attributes of mineral phases and fluid inclusions. The data collected from Earth rocks guides mission protocols for upcoming planetary missions.

To corroberate the Raman results, Dr. Bower also analyzes the same samples using electronprobe microanalysis (EPMA) and microscopy. This provides a better understanding of the sources of some of the more ambiguous mineral assemblages and organics that appear to be indicative of life but are actually abiotic. The combination of EPMA and Raman provides a way to calibrate changes in the Raman spectra with changes in elemental composition, increasing the robustness of Raman spectrscopy.


Discerning the Origins and Geologic Evolution of Lunar Deposits Using Raman Spectroscopy

Planetary Geology

Lunar rocks are composed of a limited suite of minerals, and being able to detect the subtle differences between mineral phases is essential in understanding their origins and evolution. The lunar surface is constantly bombarded by micrometeorites and solar wind, resulting in a dynamic sedimentary environment. Raman spectroscopy provides specific compositional and structural information of mineral phases in lunar regolith and has the potential to identify trapped gases implanted by the solar wind. Dr. Bower has characterized Apollo 16 samples and other lunar simulants, and she is developing methods to detect implanted species using Raman spectroscopy in combination with more traditional methods. This work supports science questions regarding the origins and evolution of lunar regolith, as well as ISRU efforts.

Publications


Refereed

Bower, D., A. McAdam, C. Yang, et al. M. Millan, R. Arevalo, C. Achilles, C. Knudson, T. Hewagama, C. Nixon, C. Fishman, S. Johnson, J. Bleacher, and P. Whelley. 2023. Spectroscopic comparisons of two different terrestrial basaltic environments: Exploring the correlation between nitrogen compounds and biomolecular signatures Icarus 402 115626 [10.1016/j.icarus.2023.115626]

Schuster, J., A. V. Sampath, J. L. Smith, et al. S. B. Kelley, G. A. Garrett, D. B. Habersat, M. A. Derenge, M. Wraback, D. M. Bower, S. Aslam, and T. Hewagama. 2023. Design and optimization of NUV-enhanced 4H-SiC separate-absorption-charge-multiplication avalanche photodiodes Physics and Simulation of Optoelectronic Devices XXXI 12415 [10.1117/12.2649236]

Fishman, C. B., J. G. Bevilacqua, A. S. Hahn, et al. C. Morgan‐Lang, N. Wagner, O. Gadson, A. C. McAdam, J. Bleacher, C. Achilles, C. Knudson, M. M. Millan, D. M. Bower, M. Musilova, and S. S. Johnson. 2023. Extreme Niche Partitioning and Microbial Dark Matter in a Mauna Loa Lava Tube Journal of Geophysical Research: Planets 128 (6): [10.1029/2022je007283]

Bower, D., G. Chin, T. Livengood, et al. T. Hewagama, C. Anderson, M. Ugelow, C. I. Honniball, P. Racette, and S. Aslam. 2022. The CORGIE Instrument Suite: Understanding Hydrogeologic Cycles on Planetary Bodies Through In Situ Characterization of Surface-Atmosphere Interactions Optimizing Planetary In Situ Surface-Atmosphere Interaction Investigations Workshop, Boise, Idaho, LPI Contribution No. 2685 id. 7008

Bower, D. M., S. X. Li, S. Aslam, T. Hewagama, and N. Gorius. 2022. Planetary exploration enabled by a compact adaptable time-resolved spatial-heterodyne Raman spectrometer Proc. SPIE 12121, Sensors and Systems for Space Applications XV [10.1117/12.2618777]

Yang, C. S., D. M. Bower, F. Jin, et al. T. Hewagama, S. Aslam, C. A. Nixon, J. Kolasinski, and A. C. Samuels. 2022. Raman and UVN+LWIR LIBS detection system for in-situ surface chemical identification MethodsX 9 101647 [10.1016/j.mex.2022.101647]

Bower, D. M., C. Yang, T. Hewagama, et al. C. A. Nixon, S. Aslam, P. L. Whelley, J. L. Eigenbrode, F. Jin, J. Rullifson, J. Kolasinski, and A. Samuels. 2021. Spectroscopic Characterization of Samples from Different Environments in a Volcano-Glacial Region in Iceland: Implications for in situ Planetary Exploration Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 263 [10.1016/j.saa.2021.120205]

Aslam, S., D. Bower, N. Gorius, et al. T. Hewagama, P. Lucey, T. Acosta-Maeda, and S. Sharma. 2021. In situ Chemistry Experiment - µscope, Photoluminescence and Raman Observations on Icy Satellites (ICE-µPROBIS) EPSC Abstracts 15 (EPSC2021-432): [10.5194/epsc2021-432]

Bower, D., S. Aslam, T. Hewagama, et al. N. Gorius, A. Sampath, J. Schuster, J. Smith, Q. Trieu, S. Kelley, and G. Nehmetallah. 2021. Enabling in situ Raman Spectroscopic Exploration of Icy Worlds: Ultra-Violet Detector Innovation for Raman Exploration and CharacTerization (UV-DIRECT) of Ocean Worlds EPSC2021 [10.5194/epsc2021-330]

Hudson, R., B. Theiling, D. Bower, et al. H. Graham, M. Trainer, C. Nixon, and S. Milam. 2021. Laboratory Studies in Support of the Exploration of Ocean Worlds and NASA Missions Vol. 53, Issue 4 (Planetary/Astrobiology Decadal Survey Whitepapers) 53 (4): [10.3847/25c2cfeb.935e24ec]

Bower, D., P. Misra, M. Peterson, et al. M. Howard, T. Hewagama, N. Gorius, S. Li, S. Aslam, T. Livengood, A. McAdam, and J. Kolasinski. 2020. Comparative VIS and NIR Raman and FTIR Spectroscopy of Lunar Analog Samples Europlanet Science Congress 2020, online [10.5194/epsc2020-427]

Bower, D. M., T. Hewagama, N. J. Gorius, et al. F. Jin, S. Trivedi, S. Li, S. Aslam, P. Misra, T. A. Livengood, and J. R. Kolasinski. 2020. Correlated Raman and Reflectance Spectroscopy for In Situ Lunar Resource Exploration Lunar Surface Science Workshop (LPI Contrib No. 2241) id. 5113

Livengood, T. A., M. K. Barker, D. M. Bower, T. Hewagama, and J. Ward. 2020. Moonba, a Micro-Rover for a Targeted Investigation of Lunar Surface Dust Lunar Surface Science Workshop (LPI Contrib No. 2241) id. 5092

Aslam, S., D. M. Bower, F. Cepollina, et al. T. Flatley, T. Hewagama, M. Jhabvala, and T. A. Livengood. 2020. Compact Lunar Mineralogy Imager (CLuMI) Lunar Surface Science Workshop 2020 (LPI Contrib. No. 2241)

Chin, G., S. Aslam, C. Anderson, et al. M. K. Barker, D. M. Bower, T. Hewagama, and T. Livengood. 2020. The CORGIE (Confirming Orbital Remote-Sensing with Ground Information Experiments) Consortium Lunar Surface Science Workshop 2020 (LPI Contrib. no 2241)

Nguyen, T. C., S. Aslam, D. Bower, et al. J. Eigenbrode, N. J. Gorius, T. Hewagama, L. R. Miko, and G. Nehmetallah. 2020. Portable flow device using Fourier ptychography microscopy and deep learning for detection in biosignatures Real-Time Image Processing and Deep Learning 2020 11401 1-6 [10.1117/12.2557316]

Chan, M. A., N. W. Hinman, S. L. Potter-McIntyre, et al. K. E. Schubert, R. J. Gillams, S. M. Awramik, P. J. Boston, D. M. Bower, D. J. Des Marais, J. D. Farmer, T. Z. Jia, P. L. King, R. M. Hazen, R. J. Leveille, D. Papineau, K. R. Rempfert, M. Sanchez-Roman, J. R. Spear, G. Southam, J. C. Stern, and H. J. Cleaves. 2019. Deciphering Biosignatures in Planetary Contexts Astrobiology 19 (9): 1075-1102 [10.1089/ast.2018.1903]

Callefo, F., F. Ricardi-Branco, G. Hartmann, et al. D. Galante, F. Rodrigues, L. Maldanis, E. Yokoyama, V. Teixeira, N. Noffke, D. Bower, E. Bullock, A. Braga, J. Coaquira, and M. Fernandes. 2019. Evaluating iron as a biomarker of rhythmites — An example from the last Paleozoic ice age of Gondwana Sedimentary Geology 383 1-15 [10.1016/j.sedgeo.2019.02.002]

Bower, D. M., D. R. Hummer, and A. Steele. 2017. AN EXPERIMENTAL LOOK AT THE TAPHONOMY OF CYANOBACTERIAL MATS IN SILICICLASTIC SEDIMENTS PALAIOS 32 (12): 725-738 [10.2110/palo.2017.016]

Bower, D. M., A. Steele, M. D. Fries, O. R. Green, and J. F. Lindsay. 2016. Raman imaging spectroscopy of a putative microfossil from the ~3.46 Ga Apex Chert: insights from quartz crystal orientation Astrobiology 16 (2): [10.1089/ast.2014.1207]

Bower, D. M., D. R. Hummer, A. Kyono, and A. Steele. 2015. The co-evolution of Fe-,Ti-oxides and other microbially induced mineral precipitates in sandy sediments: understanding the role of cyanobacteria in weathering and early diagenesis Journal of Sedimentary Research 85 1213-1227 [10.2110/jsr.2015.76]

Bower, D. M., A. Steele, M. D. Fries, and L. Kater. 2013. Micro Raman spectroscopic investigations of carbonaceous material in microfossils and meteorites: improving the use of G- and D-band parameters for life detection Astrobiology 13 (1): 103-113 [10.1089/ast.2012.0865]

Szponar, N., W. J. Brazelton, M. O. Schrenk, et al. D. M. Bower, A. Steele, and P. L. Morrill. 2013. Geochemistry of a continental site of serpentinization in the Tablelands Ophiolite, Gros Morne National Park: a Mars analogue Icarus 224 286-296 [10.1016/j.icarus.2012.07.004]

Bower, D. M. 2011. Micro Raman spectroscopic investigations of laminae associated mineral assemblages in 2.9 Ga sandstones of the Pongola Supergroup, South Africa Journal of Raman Spectroscopy 42 (8): 1626-1633 [10.1002/jrs.2903]

Noffke, N., N. Beukes, D. M. Bower, R. M. Hazen, and D. J. Swift. 2008. An actualistic perspective into Archean worlds – (cyano-)bacterially induced sedimentary structures in the siliciclastic Nhlazatse Section, 2.9 Ga Pongola Supergroup, South Africa Geobiology 6 5-20 [10.1111/j.1472-4669.2007.00118.x]

Non-Refereed

Whelley, P., C. N. Achilles, A. M. Baldridge, et al. M. E. Banks, E. Bell, H. Bernhardt, J. Bishop, J. G. Blank, D. M. Bower, S. Byrne, J. Clark, D. A. Crown, L. S. Crumpler, S. Czarnecki, A. Davies, A. D. Wet, J. W. Dean, S. Dibb, C. Dong, L. A. Edgar, S. Fagents, T. D. Glotch, T. A. Goudge, A. H. Graettinger, T. G. Graff, A. L. Gullikson, C. W. Hamilton, C. I. Honniball, K. Hubbard, L. Kerber, L. Kestay, S. Kobs-Nawotniak, M. D. Lane, G. Lau, E. Law, E. Lev, A. Matiella-Novak, A. McAdam, J. E. Moersch, C. Neish, G. Osinski, R. Parekh, K. Paris, E. L. Patrick, E. Rampe, J. Richardson, R. Romo, M. E. Rumpf, K. Runyon, A. M. Rutledge, S. P. Scheidt, N. Schmerr, S. Semken, B. Shiro, E. L. Shock, J. R. Skok, S. S. Sutton, J. Swann, M. T. Thorpe, I. A. Ukstins, P. J. Susante, N. Whelley, D. A. Williams, R. A. Yingst, K. Young, J. Zaloumis, and J. R. Zimbelman. 2021. The Importance of Field Studies for Closing Key Knowledge Gaps in Planetary Science Vol. 53, Issue 4 (Planetary/Astrobiology Decadal Survey Whitepapers) 53 (4): [10.3847/25c2cfeb.0a087f9f]

Curran, N., D. Bower, and B. Cohen. 2017. Near-Surface Age Distribution of Lunar Impact-Melt Rocks 2017 Annual Meeting of the Lunar Exploration Analysis Group 2041

Bower, D., N. Curran, and B. Cohen. 2017. Determining the Mineralogy of Lunar Samples Using Micro Raman Spectroscopy: Comparisons Between Polished and Unpolished Samples 2017 Annual Meeting of the Lunar Exploration Analysis Group 2041

Lewis, J. M., J. L. Eigenbrode, A. C. Mcadam, et al. S. Andrejkovicova, C. Knudson, G. Wong, M. Millan, C. Freissinet, C. Szopa, X. Li, and D. M. Bower. 2017. The Preservation and Detection of Organic Matter within Jarosite AGU Fall Meeting

Positions/Employment


NAI Postdoctoral Program Fellow

Geophysical Laboratory, Carnegie Institution of Washington - Washington, DC

January 2009 - January 2012

Experimental and observational approaches to using minerals as biosignatures in ancient
rocks: perfecting analytical techniques to identify life on early Earth and on other planets
 


Adjunct Professor

Tidewater Community College - Norfolk, VA

January 2012 - June 2012

Oceanography, Natural Sciences Department

Education


PhD Ocean, Earth, and Atmospheric Science 2003-2008
Old Dominion University, Norfolk, Virginia
Dissertation: Microtextures of cyanobacterial mats in siliciclastic sedimentary environments (modern & ancient): applications to the search for life on Mars

B.Sc. Oceanography / B.A. Geology 1998-2003
Richard Stockton College of New Jersey, Pomona, New Jersey
 

Talks, Presentations and Posters


Invited

Detecting Microbial Life with Raman Spectroscopy: Applications to Ocean Ecology

5, 2019

Raman spectroscopy is a non-destructive vibrational spectroscopy technique that provides real-time characterization of the chemical and physical structure of materials for Earth and planetary science, forensics, the medical and dental field, archaeology, and oceanographic research. Raman data include spectra that record specific molecular configurations and spectral maps that provide insights to spatial relationships and small-scale variations that are not easily distinguished using other methods. Terrestrial microbial ecosystems are typically intertwined with geochemical processes. In the ancient rock record, geochemical signatures such as biominerals or chemical gradients are often the main indicator of a relict biome, and spatial relationships are crucial to reconstructing the original ecosystem. In many modern sedimentary environments, microbial populations and geochemical processes are constantly changing on short time scales. Fast, compound-specific techniques like Raman spectroscopy are necessary to characterize the nature and diversity of these dynamic environments. For oceanographic research, Raman spectroscopy is used to determine salinity, temperature, gas composition, organic matter composition, and pigment distribution in the ocean or glacial ice. Raman spectroscopy can be deployed for in situ or measurements, as well as for remote sensing. The portability and utility of Raman systems make the technique a valuable asset for field research, providing an “all in one” method for determining multiple seawater characteristics for both deep sea and surface ocean measurements.
 


Searching for fossilized life on other planets: Insights from the geochemical characterization of terrestrial sedimentary rocks

October 21, 2019

Different types of ancient terrestrial sedimentary deposits contain compelling microtextures and chemical components that may be biosignatures indicative of early life on Earth. These biosignatures are useful for the search for life on other planets, like Mars, with similar lithologies. Unfortunately on Earth, multiple processes over geologic time result in the alteration of the rocks which can obscure otherwise syngenetic biosignatures and likewise create false signatures in the form of secondary carbon emplacement or mineral phase changes making it difficult to accurately ascertain their origins. Here I will present some of the ways in which I try to understand the differences between true biosignatures and abiotic signatures using experimental and observational methods. This includes some discussion on the experimental simulation of cyanobacterial biomineralization and fossilization in sandy sediments with a larger focus on the characterization of fossil bio-relevant features and their host materials in ancient sedimentary rocks using micro Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPM). Upcoming Mars astrobiology missions will focus on siliceous lithologies similar to hydrothermal deposits on Earth. Some of these possible mars analogs include the ~400 Ma Rhynie chert (Scotland), 1.88 Ga Gunflint Formation (Ontario, Canada), and three chert units from the Pilbara (Australia), the ~3.42 Ga Strelley Pool Formation, ~3.46 Ga Apex basalt, and ~3.49 Ga Dresser Formation. The collective results show that at least two main factors may hinder direct comparisons between the younger, unambiguously biotic chert samples with the older chert ambiguous samples: 1) the macromolecular carbon (MMC) in the younger cherts was originally more complex with a diversity of multicellular and unicellular organisms, whereas the MMC in the older cherts had much simpler structural origins, 2) the degree of geologic processing experienced by the older cherts resulted in alteration and recrystallization of the host quartz, MMC, and associated mineral assemblages, which is not seen in the younger cherts. Despite these factors, the possibility remains that we can establish biosignatures that are specific to each individual hydrothermally-influenced paleoenvironment and ultimately use these signatures in upcoming life detection missions.

Ocean, Earth, and Atmospheric Science Department Seminar, Old Dominion University, Norfolk, VA


The Variability of Biosignatures Through Geologic Time

October 12, 2017

The identification of biosignatures in ancient rocks is hampered by the effects of geologic time. Micro Raman spectroscopy can be used to characterize morpholgical and chemical features in terrestrial cherts. Some of the oldest cherts are useful as analogs for siliceous lithologies on Mars. The older the cherts on Earth, however, the more ambiguous the signatures indicative of life become. The implications of these difficulties and the recent advances in understaning are discussed with an emphasis on applications to upcoming Mars rover missions.

EON Workshop, Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan


The geochemical characterization of ancient terrestrial rocks using micro Raman spectroscopy: applications to the search for life beyond Earth

October 26, 2017

Ancient terrestrial rocks contain some of the most compelling microtextures and geochemical signatures indicative of early life on Earth. Some of these rocks are good analogs for other planetary environments where similar deposits have been identified. Unfortunately the geologic events that occurred over billions of years on Earth have obscured otherwise syngenetic biosignatures and likewise created false signatures in the form of secondary carbon emplacement or diagenetic phase changes. Typically the younger rocks ≤ 2 Ga, contain unambiguous evidence for life, but the origins of fossil features in much older rocks are more difficult to clearly ascertain. Here confocal micro Raman spectroscopy and imaging are used to characterize the chemical composition and spatial relationships of mineral phases and carbonaceous materials in ancient fossil-bearing chert deposits from the ~400 Ma Rhynie, 1.88 Ga Gunflint, ~3.42 Ga Strelley Pool, ~3.46 Ga Apex, and ~3.49 Ga Dresser Formations. Our results show some similarities between the younger and older samples, but the mineral and carbon signatures in the older samples are more indicative of abiotic processes. The exploration of these types of deposits with Raman spectroscopy is of particular relevance to upcoming life detection missions on Mars, and the unambiguous detection of biosignatures in these rocks will be important for the success of these missions.

WITec 14th Confocal Raman Imaging Symposium, Ulm, Germany


From MARS Major to Mars Scientist: My Journey from the Ocean to Space

November 21, 2016

Biology Seminar, Stockton University, Pomon, NJ


Applications of Micro Raman Spectroscopy: Microfossils and Astrobiology

May 5, 2016

Micro Raman imaging is essential in the study of microfossils in the context of astrobiology, because the technique is non-destructive, spectral signatures are useful in identifying compounds that are relevant to biologic processes, and the imaging capabilities establish spatial relationships and make it easy to put the identified features in context.

 

WITec Micro Raman Imaging Workshop, Rutgers University, Newark, NJ  April 5-6, 2016


Understanding the origins of possible cyanobacterial biosignatures in ancient siliciclastic rocks

 

Geological Society of Washington

October 30, 2015

Cyanobacteria are well-known architects of modern microbial mats and likely thrived on Earth as far back as the Archean. Siliciclastic sediments in particular are home to a wide variety of microbial mat communities, yet traces of their ancestors in ancient siliciclastic rocks are difficult to detect.The results suggest that over time, the collection of morphological, mineralogical, and carbonaceous features that formed at the end of incubation experiments could ultimately create the laminations characteristic of microbial mats found in ancient sandstones.


Incubation studies of cyanobacteria and natural ilmenites (FeTiO3): understanding the co-evolution of microbes and minerals during diagenesis

 

Geochemistry Seminar Series, Geology Department, University of Maryland, College Park

October 2011

The contribution of benthic mat-building cyanobacteria to weathering and compositional changes to minerals in sandy sediments is not typically considered. To understand the influence of cyanobacterial mats on mineral weathering, incubation exepriments using abiotic controls for comparison were done using ilmenite sands and ilmenite enriched beach sands over 5 months at 3 temperature steps. A large variety of mineral phases formed only in the samples incubated with cyanobacteria, suggesting that cyanobacteria do indeed play an important role in sediment weathering.


Investigations of the nature and provenance of mineral and carbonaceous material in fossiliferous cherts: revisiting the 1.9 Ga Gunflint Formation

 

Geological Society of Washington

March 17, 2010

The Gunflint cherts represent an ancient microbial ecosystem as evidenced by the ample microfossils and carbon signatures. Using micro Raman spectroscopy, the composition and spatial relationships of microfossils and other features can be readily attained. In the Gunflint samples, carbon is not limited to the microfossils, but is also found within the quartz grain interstices. The results suggest a post-depositional emplacement of some of the carbon in theses samples, possibly by hydrothermal overprint.


Other

In Situ Raman and Reflectance Spectroscopy for Planetary Science

December 22, 2019


Wide Field Time-Resolved Raman Spectrometer for Planetary Science

December 7, 2019

Planetary and small body missions continue to seek instrumentation that comprehensively characterize the composition of the planetary surface and/or near-subsurface materials. raman spectroscopy is uniquely suited for planetary exploration because of its ability to identify minerals, organic compounds, and biomarkers with both in situ and at distance (1-100m) measurements. We developed a compact spatial heterodyne spectrometer (SHS) with high efficiency YB:YAG fiber lasers for time-resolved, high-resolution dual-wavelength (VIS-NIR) Raman spectroscopy.


Correlated Raman and Reflectance Spectroscopy for in situ Lunar Resource Exploration

August 16, 2019

A composite instrument combining Raman spectros-copy and reflectance spectroscopy will enable rapid, nondestructive, passive characterization of planetary surface materials to identify trace compounds without sample preparation. The Rapid Optical Characteriza-tion Suite for in situ Target Analysis of Lunar Rocks (ROCSTAR) is designed to search for minerals and volatiles in lunar materials using a combined package of time-resolved visible (VIS) 532 nm and near-infrared (NIR) 785 nm Raman, supported by near-Infrared/mid-Infrared (NIR-MIR) reflectance spectros-copy. ROCSTAR implements mature vibrational spectroscopy techniques to probe for chemical species of significance in lunar prospecting. Resource identifica-tion is critical to develop a viable long-term lunar ex-ploration program enabling a continued human presence. ROCSTAR capabilities will enable rapid quanti-tative measurements on lunar surface materials while reducing the need for mechanical or thermal processing to evaluate water and metal contents. Water is a priority resource essential to life support, facility opera-tions, and synthesizing fuels. Mineral-bound metals are important resource targets in regolith and mare basalts [1]. Lunar minerals ilmenite and pyroxene are known hosts of metals like Cr, Ni, Co, and Mn, and ilmenite in particular has been considered for Fe and O2 extraction [2][3].
Raman spectroscopy provides structural infor-mation to identify trace compounds, including minerals, in a matter of seconds. Raman spectroscopy has been used for decades to measure the composition of returned lunar samples and analog materials ([4][5][6] and references therein). Reflectance spectroscopy has a strong lunar mission heritage to build on, having been used for decades to evaluate the mineralogy of the lunar surface via remote measurements from orbital plat-forms like Galileo, Clementine, Lunar Prospector, and the Moon Mineralogy Mapper (M3) on Chandrayaan 1, as well as multiple Earth-based telescope measure-ments [7][8][9] The two complimentary techniques, used together, ensure near-comprehensive identification and accurate characterization of lunar materials suitable for resource extraction. Our main goal is to provide the means for in situ standalone identification of priority resource materials on the lunar surface with minimal power needs in an compact package. The architecture of ROCSTAR ensures adaptability to any mission platform, whether that be inside a lander/rover or extended on a robotic arm, or as a handheld device carried by astronauts. ROCSTAR can determine the composition, variety, and distribution of minerals, metals, and water with correlated spectroscopic meas-urements. These measurements are achieved by point-ing ROCSTAR’s probe at a target at a distance of a few mm with sequential activation of MIR-NIR reflec-tance acquisitions followed by NIR-VIS Raman acqui-sitions, each for ~0.5 – 40s integration time (depending on the target material).


Detecting Biosignatures in Ocean Worlds Brines with Raman and Reflectance Spectroscopy

July 26, 2019

Ocean Worlds (OW) like Europa and Enceladus are covered in icy shells that surround a watery interior. Remote observations indicate that plumes and cracks are possible vehicles for the deposition of subsurface materials like salts and organics. Exposure to the harsh environmental conditions on the surfaces of these moons, however, creates an additional barrier to the interpretation of surface sample measurements; e.g., ionizing irradiation causes the breaking of molecular bonds and disintegration of macro-molecules resulting in a completely different molecular structure from what was originally present beneath the icy surface (Ferrini et al., 2004). Pristine subsurface material deposited near a vent or plume will likely evolve in time by cosmic ray gardening and vacuum exposure. Thus, an understanding of the change in spectroscopic properties of representative compounds as a function of weathering is important.
UV/Vis/IR spectrometers (Galileo/NIMS, Cassini/VIMS+CIRS) have a long heritage of remote measurements of OW such as Titan, Enceladus, and Europa providing information on the rich chemical inventory of these bodies. However, the km-scale footprints and spectral sensitivity of these spectrometers miss trace species, including possible macromolecules, dispersed on the surface. Robotic in-situ Raman spectroscopy is a versatile and non-destructive tool that is well-established for in situ measurements for the detection of minerals and a wide variety of compounds in host materials like rocks and ice.
The optical properties of water are modified by salts and other impurities resulting in frequency shifts in Raman spectral signatures. For example, salts like NaCl or KCl are either inactive or very weak Raman scatterers, but their presence is revealed in frequency shifts particularly in the water bands ~3200 and ~3400 cm-1 (Wu et al., 2016). Conversely, Raman spectral signatures for sulfosalts and organics are easily resolved along with the host ice (Fig.1). Reflectance spectroscopy provides a way to verify Raman measurements (and visa-versa) using IR fundamental, overtone, and combination vibrational transitions. Data collected using laboratory IR spectrometers and Galileo/NIMS show that chloride salts have distinct peak characteristics (Hanley et al., 2013). With the two techniques combined, a complete characterization of materials in ice can be accomplished. Here we present our initial findings from laboratory experiments using portable and bench top Raman and reflectance spectroscopy along with fluorescence microscopy to characterize salt- and organics-infused water ices. We will also discuss the integration of irradiation experiments to discern the effects of surface exposure on Raman and reflectance spectra of salts and organic materials in icy substrates.


INDICATORS OF SUBSURFACE COMPOSITION ON OCEAN WORLDS DETECTED BY RAMAN AND REFLECTANCE SPECTROSCOPY

June 21, 2019

Ocean Worlds (OW) like Europa and Enceladus are covered in icy shells that obscure much of the process-es and chemical composition within the moons’ watery interior. Remote observations indicate that plumes and cracks are possible vehicles for subsurface materials like salts and organics to reach the icy surface. These surface materials may provide clues to the subsurface chemical environment. Exposure to the harsh radiation environment on the surfaces of these moons, however, creates an additional barrier to the interpretation of surface sample measurements.. Ionizing irradiation causes the breaking of molecular bonds and disintegra-tion of macro-molecules resulting in a completely dif-ferent molecular structure from what was originally present [1]. Pristine subsurface material deposited near a vent or plume will likely evolve in time by cosmic ray gardening. Thus, an understanding of the change in spectroscopic properties of representative compounds as a function of weathering is important..
UV/Vis/IR spectrometers (Galileo/NIMS, Cassi-ni/VIMS+CIRS) have a long heritage of remote meas-urements of OW such as Titan, Enceladus, and Europa providing information on the rich chemical inventory of these bodies. However, the km-scale footprints and spectral sensitivity of these spectrometers miss trace species, including possible macromolecules, dispersed on the surface. Robotic in-situ Raman spectroscopy is a versatile and non-destructive tool that is well-established for in situ measurements for the detection of minerals and a wide variety of compounds in host materials like rocks and ice. A Composite Vibrational Spectrometer (CVS) consisting of co-registered Ra-man, fluorescence and reflectance spectrometers will provide valuable information on indicators of subsur-face composition, when used in concert with other in-situ analytical techniques. In conjunction with space-craft remote spectrometers, an in situ CVS will aid characterization of surface materials on different spatial scales providing context for transport processes. The optical properties of water are modified by salts and other impurities resulting in frequency shifts in Raman spectral signatures. For example, salts like NaCl or KCl are either inactive or very weak Raman scatterers, but their identity is revealed in shifts partic-ularly in the water bands ~3200 and ~3400 cm-1 [2] (Wu et al., 2016). Conversely, Raman spectral signatures for sulfosalts and organics are easily resolved along with the host ice (Fig.1). Reflectance spectroscopy provides a way to verify Raman measurements (and visa-versa) using IR fundamental, overtone, and com-bination vibrational transitions. Data collected using laboratory IR spectrometers and NIMS show that chlo-ride salts have distinct peak characteristics [3] (Hanley et al., 2013). With the two techniques combined, a complete characterization of materials in ice can be accomplished.


Understanding Life Signatures Across Geothermal-Ice Gradients in Europa-like environments using Raman spectroscopy

November 10, 2018

Ocean worlds like Europa exhibit geophysical and geochemical characteristics that are similar to terrestrial icy environments. The interface of geothermal activity with icy terrestrial environments is a dynamic setting where microbes thrive and the composition of surface sediments is ephemeral. Icy materials that interface with geothermal activity can entrain microbes, rocks and minerals, as well as gases, and in the absence of readily identifiable biosignatures, geochemical gradients derived from biological processes can offer clues to the presence of life. Some of these geochemical gradients are distinguished by subtle variations in mineral assemblages. Deviations in mineral structure can be attributed to the incorporation of cations used in metabolic processes or from the influence of decaying organic matter on local chemistry. Raman spectroscopy is a powerful, versatile, and non-destructive tool that is well-established for in situ measurements and the detection of minerals and compounds in a wide variety of host materials like rocks and ice. To test the utility of Raman spectroscopy for supporting life detection investigations on Europa-like materials, Raman measurements were made on laboratory-synthesized Europa analogs along with rocks and ice collected near the Kverkfjöll volcano-Vatnajokull glacier in Iceland. Here we present our initial findings and discuss future directions in developing Raman spectroscopy instrumentation for life detection on Europa-like worlds.


Teaching Experience


Adjunct Instructor:

Tidewater Community College, Norfolk, VA (2012) Introduction to Oceanography

Old Dominion University, Norfolk, VA (2008) Introduction to Oceanography, Physical Geology

 

Teaching Assistant:

Old Dominion University, Norfolk, VA (2007) Paleontology

Richard Stockton University, Pomona, NJ (2001-2003) Physical Geology, Chemical Oceanography

Professional Societies


Geochemical Society

2010 - Present


Geological Society of America

2000 - Present


American Geophysical Union

1999 - Present


American Chemical Society

2019 - Present

Grants


Ultra-Violet Detector Innovation for Raman Exploration and CharacTerization (UV-DIRECT) of Ocean Worlds

PICASSO - NASA (NNH19ZDA001N-PICASSO) - Awarded: 2020-03-13


Dates: 2020-08-01  - 2023-07-31

Coverage: 0.2


RAMS: RAman-Mass Spectrometer for planetary exploration

PICASSO - NASA (NNH19ZDA001N-PICASSO) - Awarded: 2020-03-13


Dates: 2020-08-01  - 2023-07-31

Coverage: 0.20


Habitability of basaltic subsurface environments

ISFM/FLaRe - NASA (ISFM) - Awarded: 2019-04-01


Dates: 2019-04-01  - 2020-04-01

Coverage: 0.1


Wide field, time-resolved Raman spectrometer for planetary science

IRAD - NASA (IRAD) - Awarded: 2019-01-01


Dates: 2019-01-01  - 2020-01-01

Coverage: 0.1


Biogeochemical characterization of returned samples from a potential ocean worlds analog site using Raman and reflectance spectroscopy

ISFM/FLaRe - NASA (ISFM) - Awarded: 2019-01-01


Dates: 2019-01-01  - 2020-01-01

Coverage: 0.2


Exploring radiolytic production of chlorinated and sulfurized organic molecules on Mars and Europa

ISFM/FLaRe - NASA (ISFM) - Awarded: 2018-05-01


Dates: 2018-05-01  - 2020-05-31

Coverage: 0.25

Awards


NASA Astrobiology Institute Postdoctoral Fellowship 2009-2012
National Prominence Award, Old Dominion University, Norfolk, Virginia 2003-2004
NSF Research Experience for Undergraduates, Shannon Point Marine Center, WA 2002
Distinguished Student Fellowship Award, Richard Stockton College of New Jersey
 

Selected Public Outreach


Chair, Gordon Research Seminar on Geobiology

February 2013 - February 2013

The Future of Geobiology: Perspectives from Graduate and Postdoctoral Research

The focus of this meeting is to explore the diverse and dynamic field of geobiology . The discussions and presentations will address these main themes:

  • microbial structures in ancient and modern settings
  • taphonomy and micropaleontology
  • biomineralization and the co-evolution of minerals and microbes
  • life detection for applications to early life on Earth and other planets
  • integrating geobiobiology into interdisciplinary research and academic programs

Special Experience


Dr. Bower has many years of field experience in a wide variety of environments:

Recent (2016-present):

Lava tubes at Lava Beds National Monument, CA (2022): Team Biogeochemistry Lead): In situ Raman spectroscopy, LIBS, and XRF measurements and sample collection of mineral precipitates, rock rinds, host basalts, microbial mats, and percolating water within the lava tube.

Lava tubes on Mauna Loa, Hawaii (2019): (Team Geochem) In situ Raman measurements and sample collection of mineral precipitates, rock rinds, host basalts, microbial mats, and percolating water within the lava tube.

Yellowstone National Park (2019): In situ Raman measurements and sample collection of silicified microbial mats in snow-covered hot springs.

Vatnajokul Glacier, Iceland (2018): (Team Ice) In situ Raman measurements and sample collection of volcanic rocks, sediments, and ice.

Dinosaur Provincial Park, Alberta, Canada (2016): sample collection for Ar-Ar dating and scouting for future instrument testing

Fieldwork Pre-2015:

Pongola Supergroup, South Africa (2005) : mapping, sketching, videography, and sample collection of sandstones. 

Fisherman's Island, Virginia (2005-2007): transects of tidal flats, collection of microbial mat samples.

Biosignatures in Ancient Rocks Workshop, Ontario, Canada (2007): collection of Gunflint cherts and samples from rock successions related to the Sudbury impact event

Gros Morne National Park, Newfoundland, Canada (2009,2010): "clean" field methods to asses life in serpentinzed ophiolite sequence; CHEMin portable XRD field analysis of carbonates.

White Sands, New Mexico (2009): collection of microbial mats and sulfates in gypsum dunes; Delta Nu portable Raman (785 nm) field analysis of sulfates.

Saskatchewan, Canada (2009): sample collection of halophilic microbial mats.

Mono Lake, California (2010): videographer for rover drill prototype