||Schönheit P, Buckel W, Martin WF. On the Origin of Heterotrophy. Trends Microbiol. 2016 Jan24(1):12-25. doi: 10.1016/j.tim.2015.10.003. p.14 top paragraphPubMed ID26578093
|| Fisher, A.T. (2005) Marine hydrogeology: recent accomplishments and future opportunities. Hydrogeol. J. 13, 69–97 link
||P.14 top paragraph:"A common theme of meteorite organics is ‘complete structural diversity’, meaning that a plethora of isomers for a given chemical formula are present [ref 36], with meteoritic carboxylic acids outweighing the corresponding amino acids by about 50-fold [BNID 112449]. One can argue that low local concentrations of these compounds could have been overcome somehow, perhaps by circulation through hydrothermal vents and sequestration there. Indeed the volume of today's oceans is circulated
through hydrothermal vents about once every 100,000 years [primary source]."