Context and chronology are fundamental in archaeological studies, and without rigorous standards in both fieldwork and analysis, researchers risk drawing faulty conclusions. The role of submerged aquatic plants in radiocarbon dating is a case in point. For example, research at White Sands National Park, New Mexico, has dated fossil human and megafauna trackways using Ruppia cirrhosa (Ruppia) seeds. Some studies, such as Pigati et al. (2024), argue that there are no site formation issues with the Ruppia seed layers used to date the ancient footprints at White Sands Locality-2 (WHSA-2) and that the hard water effect has not impacted their radiocarbon dating. These assertions have significant implications for understanding broader issues like the peopling of the Americas. However, we disagree with these claims, emphasizing the importance of understanding the physical context of the Ruppia seed layers at WHSA-2—whether the plants grew in situ or were transported—and the ecological requirements of Ruppia. These issues remain unresolved. Additionally, the potential impacts of physical mixing and the hard water effect on radiocarbon dates have been largely overlooked. In this paper, we examine both the ecology and depositional context of Ruppia and discuss why the Ruppia seeds at Paleolake Otero still present challenges for radiocarbon dating.

中文翻译：

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争议的种子：白沙步道上 Ruppia cirrhosa 的生态学、沉积背景和放射性碳测年


背景和年代学是考古研究的基础，如果没有实地考察和分析的严格标准，研究人员就有可能得出错误的结论。沉水植物在放射性碳测年中的作用就是一个很好的例子。例如，新墨西哥州白沙国家公园的研究使用 Ruppia cirrhosa （Ruppia） 种子确定了人类和大型动物化石足迹的年代。一些研究，如 Pigati 等人（2024 年）认为，用于测定白沙 2 号（WHSA-2）古代足迹年代的 Ruppia 种子层不存在位点形成问题，而且硬水效应没有影响它们的放射性碳测年。这些断言对于理解更广泛的问题（如美洲的人口）具有重要意义。然而，我们不同意这些说法，强调了解 WHSA-2 的 Ruppia 种子层的物理环境的重要性——植物是原地生长还是运输——以及 Ruppia 的生态要求。这些问题仍未解决。此外，物理混合和硬水对放射性碳测年的潜在影响在很大程度上被忽视了。在本文中，我们研究了 Ruppia 的生态学和沉积背景，并讨论了为什么 Paleolake Otero 的 Ruppia 种子仍然对放射性碳测年构成挑战。