TY - JOUR
T1 - Decomposition of amino acids in water with application to in-situ measurements of Enceladus, Europa and other hydrothermally active icy ocean worlds
AU - Truong, Ngoc
AU - Monroe, Adam A.
AU - Glein, Christopher R.
AU - Anbar, Ariel
AU - Lunine, Jonathan I.
N1 - Funding Information:
The authors acknowledge the contribution of E. Shock and helpful discussions regarding residence times in reservoirs of different sizes with E. Kite and S. Desch in the original calculations reported in Monroe et al. (2017) , which inspired the present work. Support from the Cassini Project and a JPL Distinguished Visiting Scientist position (JIL) are gratefully acknowledged.
Publisher Copyright:
© 2019 Elsevier Inc.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - To test the potential of using amino acid abundances as a biosignature at icy ocean worlds, we investigate whether primordial amino acids (accreted or formed by early aqueous processes) could persist until the present time. By examining the decomposition kinetics of amino acids in aqueous solution based on existing laboratory rate data, we find that all fourteen proteinogenic amino acids considered in this study decompose to a very large extent (>99.9%) over relatively short lengths of time in hydrothermally active oceans. Therefore, as a rule of thumb, we suggest that if amino acids are detected at Enceladus, Europa, or other hydrothermally active ocean worlds above a concentration of 1 nM, they should have been formed recently and not be relicts of early processes. In particular, the detection of aspartic acid (Asp) and threonine (Thr) would strongly suggest active production within the ocean, as these amino acids cannot persist beyond 1 billion years even at the freezing point temperature of 273 K. Identifying amino acids from the oceans of icy worlds can provide key insight into their history of organic chemistry.
AB - To test the potential of using amino acid abundances as a biosignature at icy ocean worlds, we investigate whether primordial amino acids (accreted or formed by early aqueous processes) could persist until the present time. By examining the decomposition kinetics of amino acids in aqueous solution based on existing laboratory rate data, we find that all fourteen proteinogenic amino acids considered in this study decompose to a very large extent (>99.9%) over relatively short lengths of time in hydrothermally active oceans. Therefore, as a rule of thumb, we suggest that if amino acids are detected at Enceladus, Europa, or other hydrothermally active ocean worlds above a concentration of 1 nM, they should have been formed recently and not be relicts of early processes. In particular, the detection of aspartic acid (Asp) and threonine (Thr) would strongly suggest active production within the ocean, as these amino acids cannot persist beyond 1 billion years even at the freezing point temperature of 273 K. Identifying amino acids from the oceans of icy worlds can provide key insight into their history of organic chemistry.
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U2 - 10.1016/j.icarus.2019.04.009
DO - 10.1016/j.icarus.2019.04.009
M3 - Article
AN - SCOPUS:85064151784
VL - 329
SP - 140
EP - 147
JO - Icarus
JF - Icarus
SN - 0019-1035
ER -