Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds

Bedrossian, Manuel; Lindensmith, C. A.; Nadeau, Jay L.

doi:10.1089/ast.2016.1616

Cited by 27 publications

(30 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Expected microorganism sample sizes for a single 50 km transect increase from 1 up to 10 3 organisms. This is within range of current microimaging capabilities (Bedrossian et al, 2017 , in this issue).…”

Section: Sample Collection and Expectationssupporting

confidence: 69%

“…Over 100 Enceladus days (or 138 Earth days), the sample size collected by a lander would be ∼10 5 cells in a water volume of ∼40 mL. These estimates are now well within the range of current microimaging capabilities (Bedrossian et al, 2017 , in this issue). If bubble-scrubbing enhancement is at work, these estimates are hundreds to thousands of times higher.…”

Section: Sample Collection and Expectationsmentioning

confidence: 78%

“…For a reconnaissance survey seeking to detect microbes, a microimager with a reasonable field of view would be required. Currently, such imagers have spatial resolutions of ∼0.5 μ (Bedrossian et al, 2017 , in this issue). Consequently, the smallest organisms we could expect to see, assuming they are there at all, would be the size of the smallest terrestrial prokaryotes but not as small as viruses (tens to hundreds of nanometers, i.e., < 1 μ).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Could It Be Snowing Microbes on Enceladus? Assessing Conditions in Its Plume and Implications for Future Missions

2017

View full text Add to dashboard Cite

We analyzed Cassini Imaging Science Subsystem (ISS) images of the plume of Enceladus to derive particle number densities for the purpose of comparing our results with those obtained from other Cassini instrument investigations. Initial discrepancies in the results from different instruments, as large as factors of 10–20, can be reduced to ∼2 to 3 by accounting for the different times and geometries at which measurements were taken. We estimate the average daily ice production rate, between 2006 and 2010, to be 29 ± 7 kg/s, and a solid-to-vapor ratio, S/V > 0.06. At 50 km altitude, the plume's peak optical depth during the same time period was τ ∼ 10−3; by 2015, it was ∼10−4. Our inferred differential size distribution at 50 km altitude has an exponent q = 3. We estimate the average geothermal flux into the sea beneath Enceladus' south polar terrain to be comparable to that of the average Atlantic, of order 0.1 W/m2. Should microbes be present on Enceladus, concentrations at hydrothermal vents on Enceladus could be comparable to those on Earth, ∼105 cells/mL. We suggest the well-known process of bubble scrubbing as a means by which oceanic organic matter and microbes may be found in the plume in significantly enhanced concentrations: for the latter, as high as 107 cells/mL, yielding as many as 103 cells on a 0.04 m2 collector in a single 50 km altitude transect of the plume. Mission design can increase these numbers considerably. A lander mission, for example, catching falling plume particles on the same collector, could net, over 100 Enceladus days without bubble scrubbing, at least 105 cells; and, if bubble scrubbing is at work, up to 108 cells. Key Words: Enceladus—Microbe—Organic matter—Life detection. Astrobiology 17, 876–901.

show abstract

Section: Sample Collection and Expectationssupporting

confidence: 69%

Section: Sample Collection and Expectationsmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Could It Be Snowing Microbes on Enceladus? Assessing Conditions in Its Plume and Implications for Future Missions

2017

View full text Add to dashboard Cite

show abstract

“…q Parro et al (2011). rZubkov et al (1999).s Cornett et al (2007).t Guenther et al (2010).u Riedler et al (2007).v Bentley et al (2016).w Hecht et al (2008).x Bedrossian et al (2017).y Branson et al (2016). z Jin and Bose (2019).aa Brockwell et al (2016)…”

mentioning

confidence: 99%

Returning Samples From Enceladus for Life Detection

Neveu

Anbar

Dávila

et al. 2020

Front. Astron. Space Sci.

View full text Add to dashboard Cite

Evidence suggests that Saturn's icy moon Enceladus has a subsurface ocean that sources plumes of water vapor and ice vented to space from its south pole. In situ analyses of this material by the Cassini spacecraft have shown that the ocean contains key ingredients for life (elements H, C, N, O and possibly S; simple and complex organic compounds; chemical disequilibria at water-rock interfaces; clement temperature, pressure, and pH). The Cassini discoveries make Enceladus' interior a prime locale for life detection beyond Earth. Scant material exchange with the inner Solar System makes it likely that such life would have emerged independently of life on Earth. Thus, its discovery would illuminate life's universal characteristics. The alternative result of an upper bound on a detectable biosphere in an otherwise habitable environment would likewise considerably advance our understanding of the prevalence of life beyond Earth. Here we outline the rationale for returning vented ocean samples, accessible from Enceladus' surface or low altitudes, to Earth for life detection. Returning samples allows analyses using laboratory instruments that cannot be flown, with decades or more to adapt and repeat analyses. We describe an example set of measurements to estimate the amount of sample to be returned and discuss possible mission architectures and collection approaches. We then turn to the challenges of preserving sample integrity and implementing planetary protection policy. We conclude by placing such a mission in the broader context of Solar System exploration.

show abstract

“…Bedrossian et al ( 2017 ) expand on their previous work (Wallace et al, 2015 ; Lindensmith et al, 2016 ) in designing and field testing an extraordinary microscopic system being developed at JPL and Caltech: the digital holographic microscope (DHM). True to its name, the DHM is a microscope capable of taking holographic images of a (comparatively) wide field of view, which is necessary for exploratory “survey” work, that capture phase as well as spatial information.…”

mentioning

confidence: 99%

A Community Grows around the Geysering World of Enceladus

Porco

2017

Astrobiology

View full text Add to dashboard Cite

The discovery by NASA's Cassini mission at Saturn in 2005 of a large plume of material erupting from the south polar terrain of Enceladus, sourced within a subsurface ocean of salty liquid water laced with organic compounds, has brought together scientists from a diverse range of disciplines over the last decade to evaluate this small moon's potential for extraterrestrial life. The collection of papers published today in Astrobiology, as the mission draws to a close, is the outcome of our most recent meeting at UC Berkeley in June 2016. Key Words: Enceladus—Enceladus Focus Group—Ocean world—Search for biosignatures. Astrobiology 17, 815–819.

show abstract

Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds

Cited by 27 publications

References 57 publications

Could It Be Snowing Microbes on Enceladus? Assessing Conditions in Its Plume and Implications for Future Missions

Could It Be Snowing Microbes on Enceladus? Assessing Conditions in Its Plume and Implications for Future Missions

Returning Samples From Enceladus for Life Detection

A Community Grows around the Geysering World of Enceladus

Contact Info

Product

Resources

About