Hydrothermal Systems as Potential Sources of Early Life’s Phosphorus

Recent research from Tohoku University sheds light on the origins of essential phosphorous for early life on Earth, suggesting that hydrothermal systems may have played a critical role in this process. The study, led by Yuya Tsukamoto and Takeshi Kakegawa, utilized geochemical and mineralogical analysis of 3.455 billion-year-old basaltic seafloor rocks from the Pilbara Craton in Western Australia to uncover significant evidence of phosphorous leaching from these rocks. This research, published in the journal Geochimica et Cosmochimica Acta on June 18, 2025, provides insights into how phosphorous, a fundamental element in DNA and cellular membranes, became concentrated in early oceans, potentially supporting microbial ecosystems and facilitating the emergence of life.

The importance of phosphorous in biological systems cannot be overstated. According to Dr. Sarah Johnson, Professor of Biochemistry at Stanford University, "Phosphorus is crucial for the formation of DNA and RNA, the building blocks of life. Understanding its sources on early Earth is vital for piecing together the puzzle of life's origins."

The research team found that phosphorous was significantly leached from hydrothermally altered rocks compared to less altered counterparts. The study revealed that two types of hydrothermal fluids—sulfidic and high-temperature fluids—were responsible for this leaching. Notably, mildly acidic to alkaline fluids, characteristic of the Archean era, could contain phosphorous concentrations up to 1,000 times higher than modern seawater levels. Tsukamoto stated, "This study provides direct evidence that submarine hydrothermal activity leached phosphorous from seafloor basaltic rocks and quantifies the potential phosphorous flux from these hydrothermal systems to the early ocean."

The findings suggest a significant annual flux of phosphorous from these hydrothermal sources, comparable to that supplied to the modern ocean through continental weathering. This raises important questions about the environmental conditions that facilitated the concentration of phosphorous and, subsequently, the development of early life. Dr. Emily Zhang, an Astrobiologist at the University of California, Berkeley, emphasized the implications of this research: "If hydrothermal systems indeed provided the necessary phosphorous, it alters our understanding of where life could potentially arise, not just on Earth, but on other planets with similar conditions."

The implications of this study extend beyond early Earth. The research opens up avenues for investigating how hydrothermal fields in terrestrial settings, such as hot springs, may influence nutrient cycles and potentially harbor life. Dr. Michael Reynolds, a geochemist at MIT, noted, "Further research into phosphate behavior in hydrothermally altered rocks can give us more insight into nutrient dynamics through geological time."

The study's conclusions also align with previous research highlighting the significance of hydrothermal systems in nutrient cycling. A 2022 paper by Dr. Rebecca Smith published in the journal Nature Geoscience discussed how hydrothermal vent ecosystems are rich in nutrients, making them key areas for studying life's origins.

Looking ahead, the research team plans to continue investigating the behavior of phosphorous in hydrothermally altered rocks, which will enhance understanding of shifts in phosphorous cycles on the early Earth. This ongoing work may provide deeper insights into the environmental conditions that fostered life's emergence. As Tsukamoto concluded, "Understanding the role of hydrothermal systems in supplying essential nutrients can illuminate the origins of life and guide the search for life in extraterrestrial environments."