With annual precipitation less than 20 mm and extreme UV intensity, the Atacama Desert in northern Chile has long been utilized as an analogue for recent Mars. In these hyperarid environments, water and biomass are extremely limited, and thus, it becomes difficult to generate a full picture of biogeochemical phosphate‐water dynamics. To address this problem, we sampled soils from five Atacama study sites and conducted three main analyses—stable oxygen isotopes in phosphate, enzyme pathway predictions, and cell culture experiments. We found that high sedimentation rates decrease the relative size of the organic phosphorus pool, which appears to hinder extremophiles. Phosphoenzyme and pathway prediction analyses imply that inorganic pyrophosphatase is the most likely catalytic agent to cycle P in these environments, and this process will rapidly overtake other P utilization strategies. In these soils, the biogenic δ¹⁸O signatures of the soil phosphate (δ¹⁸O_PO4) can slowly overprint lithogenic δ¹⁸O_PO4 values over a timescale of tens to hundreds of millions of years when annual precipitation is more than 10 mm. The δ¹⁸O_PO4 of calcium‐bound phosphate minerals seems to preserve the δ¹⁸O signature of the water used for biogeochemical P cycling, pointing toward sporadic rainfall and gypsum hydration water as key moisture sources. Where precipitation is less than 2 mm, biological cycling is restricted and bedrock δ¹⁸O_PO4 values are preserved. This study demonstrates the utility of δ¹⁸O_PO4 values as indicative of biogeochemical cycling and hydrodynamics in an extremely dry Mars‐analogue environment.

中文翻译：

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使用磷酸盐中的稳定氧同位素揭示高干旱火星-类似土壤中的生物地球化学磷动力学。

智利北部的阿塔卡马沙漠年降水量不足20毫米，且紫外线强度极高，长期以来一直被用作近期火星的类似物。在这些高干旱的环境中，水和生物量极为有限，因此，难以生成生物地球化学磷酸盐-水动力学的全貌。为了解决这个问题，我们从五个阿塔卡马研究地点采样了土壤，并进行了三项主要分析：磷酸盐中的稳定氧同位素，酶途径预测和细胞培养实验。我们发现高沉积速率降低了有机磷库的相对大小，这似乎阻碍了极端微生物的生长。磷酸酶和途径预测分析表明，在这些环境中，无机焦磷酸酶是最有可能使P循环的催化剂，这个过程将迅速取代其他磷的利用策略。在这些土壤中，生物成因δ^18个土壤中磷的O-签名（δ ¹⁸ Ø _PO4）可以慢慢套印尿石症δ ¹⁸ Ø _PO4值超过几十的时间内，要亿万年的时候年降水量超过10毫米。的δ ¹⁸ ö _PO4钙结合的磷酸盐矿物似乎保留δ ¹⁸用于生物地球化学磷循环水的O-签名，朝向零星降雨和石膏水合水作为键湿气源指向。其中沉淀小于2毫米，生物循环受到限制，基岩δ ^18个ö _PO4值被保留。这项研究表明的δ效用¹⁸ Ø_PO4值在极端干燥的Mars类似环境中指示生物地球化学循环和流体动力学。