Low molecular weight carboxylate anions such as formate (HCOO⁻), acetate (CH₃COO⁻) and oxalate (C₂O${}_4^{2-}$) have been shown to play an important role in supporting deep subsurface microbial ecosystems. Their origin whether biological or abiotic is currently highly debated, but surprisingly radiolytic production has rarely been considered, as it is the case for H₂. Here, we address this question through dedicated irradiation experiments. Aqueous solutions containing carbonate, formate, acetate or oxalate have been irradiated using both the 60.7 MeV α-beam of the ARRONAX cyclotron (Nantes, France) and 661.7 keV γ-Ray in order to reveal the mechanism and chemical yield of radiation-induced dissolved carbonate degradation.

The yields (G-values) of carboxylate anions production/degradation in low-concentration carbonate solution (0.01 to 1 mmol L⁻¹) are measured. Carbonate degradation occurs through three consecutive steps (Carbonate $\stackrel{I}{\to }$ Formate $\stackrel{\mathit{II}}{\to }$ Acetate $\stackrel{\mathit{III}}{\to }$ Oxalate) involving formate radical (CO₂^−•), dihydrogen (H₂), and carbon dioxide (CO₂) generation. Dissolved carbonate radiolysis provides a consistent pathway for both enhancing two-fold the radiolytic H₂ production compared to pure water and generating carboxylic species, chiefly oxalate, readily available for microbes. Radiation-induced carbonate degradation may produce substantial amount (millimolar concentration) of carboxylate anions in ancient groundwaters from deep crystalline bedrocks. Subsurface lithoautotrophic microbial ecosystems may not only be supported by radiolytic H₂ but also by carboxylate species from carbonate radiolysis. Carbonate radiolysis can be also an endogenous source of carboxylate species on Mars and other planetary bodies.

低分子量的羧酸盐阴离子，如甲（HCOO ^- ），乙酸盐（CH ₃ COO ^- ）和草酸（C ₂ Ò${}_4^{\mathrm{2个}-}$已被证明在支持深层地下微生物生态系统中起着重要作用。目前，对于它们的起源，无论是生物学的还是非生物的，一直备受争议，但是令人惊讶的是，几乎没有考虑过放射分解的产生，因为H ₂就是这种情况。在这里，我们通过专门的辐射实验解决了这个问题。含碳酸盐，甲酸盐，乙酸盐或草酸盐的水溶液经过照射同时使用60.7兆电子伏α -beam的ARRONAX回旋加速器（南特，法国）和661.7千电子伏γ仪射线以揭示辐射诱发的溶解的机制和化学收率碳酸盐降解。

测量在低浓度碳酸盐溶液（0.01至1mmol  L ^-1）中羧酸根阴离子产生/降解的产率（G值）。碳酸盐的降解通过三个连续的步骤发生（碳酸盐$\stackrel{\mathrm{一世}}{\to }$ 格式化 $\stackrel{\mathit{II}}{\to }$ 醋酸盐 $\stackrel{\mathit{三级}}{\to }$草酸盐）涉及甲酸根（CO _2- ^•），二氢（H ₂）和二氧化碳（CO ₂）的产生。与纯水相比，溶解的碳酸盐辐射分解提供了一个恒定的途径，既可以使辐射分解的H ₂产量提高两倍，又可以生成可用于微生物的羧酸类物质，主要是草酸盐。辐射引起的碳酸盐降解可能会在深层结晶基岩中的古代地下水中产生大量（毫摩尔浓度）的羧酸根阴离子。地下岩石自养微生物生态系统可能不仅受到辐射分解H _2的支持而且还可以通过碳酸盐辐射分解产生的羧酸盐类物质。碳酸盐辐射分解也是火星和其他行星体上羧酸盐物种的内源性来源。