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Nonphotosynthetic Pigments as Potential Biosignatures

Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, facilitated by pigments evolved to capture phot...

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Detalles Bibliográficos
Autores principales: Schwieterman, Edward W., Cockell, Charles S., Meadows, Victoria S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Mary Ann Liebert, Inc. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4442567/
https://www.ncbi.nlm.nih.gov/pubmed/25941875
http://dx.doi.org/10.1089/ast.2014.1178
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author Schwieterman, Edward W.
Cockell, Charles S.
Meadows, Victoria S.
author_facet Schwieterman, Edward W.
Cockell, Charles S.
Meadows, Victoria S.
author_sort Schwieterman, Edward W.
collection PubMed
description Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, facilitated by pigments evolved to capture photons, is the dominant metabolism on our planet, pigmentation has evolved for multiple purposes to adapt organisms to their environment. We present an interdisciplinary study of the diversity and detectability of nonphotosynthetic pigments as biosignatures, which includes a description of environments that host nonphotosynthetic biologically pigmented surfaces, and a lab-based experimental analysis of the spectral and broadband color diversity of pigmented organisms on Earth. We test the utility of broadband color to distinguish between Earth-like planets with significant coverage of nonphotosynthetic pigments and those with photosynthetic or nonbiological surfaces, using both 1-D and 3-D spectral models. We demonstrate that, given sufficient surface coverage, nonphotosynthetic pigments could significantly impact the disk-averaged spectrum of a planet. However, we find that due to the possible diversity of organisms and environments, and the confounding effects of the atmosphere and clouds, determination of substantial coverage by biologically produced pigments would be difficult with broadband colors alone and would likely require spectrally resolved data. Key Words: Biosignatures—Exoplanets—Halophiles—Pigmentation—Reflectance spectroscopy—Spectral models. Astrobiology 15, 341–361.
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spelling pubmed-44425672015-07-10 Nonphotosynthetic Pigments as Potential Biosignatures Schwieterman, Edward W. Cockell, Charles S. Meadows, Victoria S. Astrobiology Research Articles Previous work on possible surface reflectance biosignatures for Earth-like planets has typically focused on analogues to spectral features produced by photosynthetic organisms on Earth, such as the vegetation red edge. Although oxygenic photosynthesis, facilitated by pigments evolved to capture photons, is the dominant metabolism on our planet, pigmentation has evolved for multiple purposes to adapt organisms to their environment. We present an interdisciplinary study of the diversity and detectability of nonphotosynthetic pigments as biosignatures, which includes a description of environments that host nonphotosynthetic biologically pigmented surfaces, and a lab-based experimental analysis of the spectral and broadband color diversity of pigmented organisms on Earth. We test the utility of broadband color to distinguish between Earth-like planets with significant coverage of nonphotosynthetic pigments and those with photosynthetic or nonbiological surfaces, using both 1-D and 3-D spectral models. We demonstrate that, given sufficient surface coverage, nonphotosynthetic pigments could significantly impact the disk-averaged spectrum of a planet. However, we find that due to the possible diversity of organisms and environments, and the confounding effects of the atmosphere and clouds, determination of substantial coverage by biologically produced pigments would be difficult with broadband colors alone and would likely require spectrally resolved data. Key Words: Biosignatures—Exoplanets—Halophiles—Pigmentation—Reflectance spectroscopy—Spectral models. Astrobiology 15, 341–361. Mary Ann Liebert, Inc. 2015-05-01 /pmc/articles/PMC4442567/ /pubmed/25941875 http://dx.doi.org/10.1089/ast.2014.1178 Text en © The Author(s) 2015; Published by Mary Ann Liebert, Inc. This Open Access article is distributed under the terms of the Creative Commons Attribution Noncommercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.
spellingShingle Research Articles
Schwieterman, Edward W.
Cockell, Charles S.
Meadows, Victoria S.
Nonphotosynthetic Pigments as Potential Biosignatures
title Nonphotosynthetic Pigments as Potential Biosignatures
title_full Nonphotosynthetic Pigments as Potential Biosignatures
title_fullStr Nonphotosynthetic Pigments as Potential Biosignatures
title_full_unstemmed Nonphotosynthetic Pigments as Potential Biosignatures
title_short Nonphotosynthetic Pigments as Potential Biosignatures
title_sort nonphotosynthetic pigments as potential biosignatures
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4442567/
https://www.ncbi.nlm.nih.gov/pubmed/25941875
http://dx.doi.org/10.1089/ast.2014.1178
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