Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 117, Issue 2, Pages 883-888Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1916109117
Keywords
phosphate; origin of life; early Earth; carbonate-rich lakes
Categories
Funding
- Simons Collaboration on the Origin of Life grant [511570]
Ask authors/readers for more resources
Phosphate is central to the origin of life because it is a key component of nucleotides in genetic molecules, phospholipid cell membranes, and energy transfer molecules such as adenosine triphosphate. To incorporate phosphate into biomolecules, pre-biotic experiments commonly use molar phosphate concentrations to overcome phosphate's poor reactivity with organics in water. However, phosphate is generally limited to micromolar levels in the environment because it precipitates with calcium as low-solubility apatite minerals. This disparity between laboratory conditions and environmental constraints is an enigma known as the phosphate problem. Here we show that carbonate-rich lakes are a marked exception to phosphate-poor natural waters. In principle, modern carbonate-rich lakes could accumulate up to similar to 0.1 molal phosphate under steady-state conditions of evaporation and stream inflow because calcium is sequestered into carbonate minerals. This prevents the loss of dissolved phosphate to apatite precipitation. Even higher phosphate concentrations (>1 molal) can form during evaporation in the absence of inflows. On the prebiotic Earth, carbonate-rich lakes were likely abundant and phosphate-rich relative to the present day because of the lack of microbial phosphate sinks and enhanced chemical weathering of phosphate minerals under relatively CO2-rich atmospheres. Furthermore, the prevailing CO2 conditions would have buffered phosphate-rich brines to moderate pH (pH 6.5 to 9). The accumulation of phosphate and other prebiotic reagents at concentration and pH levels relevant to experimental prebiotic syntheses of key biomolecules is a compelling reason to consider carbonate-rich lakes as plausible settings for the origin of life.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available