Palaeometabolomes yield biological and ecological profiles at early human sites - Nature

"The metabolic rate of an organism is the sum of the energy necessary to acquire, convert and allocate energy to growth, reproduction and maintenance, which sets energetic limits on biological activities and establishes the pace and pattern of life. The temperature- and mass-dependence of metabolic rate, from the smallest unicellular organisms to the largest plants and animals9, enables one to reconstruct the metabolic rates of extinct organisms and retrodict fundamental large-scale features of their palaeoenvironments11."

"Otherwise, efforts to obtain knowledge of internal and external influences on fossil vertebrate metabolism have been limited to bone microanatomical correlates of thermophysiology12 and palaeoenvironmental reconstructions, which typically depend on studies of stable isotopes, faunal composition and community ecology, dental wear analyses, and/or palynology or palaeovegetation in geological context. Here we explore molecular ecological strategies for obtaining ultrafine-scale details of an ancient organism's metabolism that: (1) reflect its internal physiological responses to environmental conditions; and (2) reflect the diet that fuelled its metabolic rate."

Metabolic rate integrates energy acquisition, conversion, and allocation to growth, reproduction, and maintenance, thereby constraining biological activity and shaping life history. Temperature and body mass determine metabolic rate across taxa, allowing reconstruction of extinct organisms' metabolic rates and inference of palaeoenvironmental features. Traditional approaches to fossil vertebrate metabolism rely on bone microanatomy and palaeoenvironmental proxies such as stable isotopes, faunal composition, dental wear, and palaeovegetation. Metabolomic profiling of blood, plasma, urine, and saliva provides molecular ecological strategies to obtain ultrafine-scale metabolic and dietary details. Metabolites can persist within small compartments of interstitial water in mineralized tissue niches or in crystalline palaeosol matrices, representing entombed serum transudates from mineralizing extracellular matrix.

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