Article by: Harper Mason, on 06 July 2023, at 01:45 am PDT

In a quest to unlock the secrets behind the preservation of peculiar fossils from the Ediacaran biota, scientists have achieved a significant breakthrough. By recreating the conditions that led to the exceptional preservation of these ancient soft-bodied organisms, researchers have gained valuable chemical insights into the mysterious world of the Ediacaran period.

The Ediacaran period, spanning from 635 to 538.8 million years ago, represents a fascinating era of evolutionary experimentation before the emergence of major branches in the Tree of life. The enigmatic Ediacaran biota, comprising bizarre organisms like Dickinsonia and Charnia, has intrigued scientists for years due to their unique soft-bodied nature. These fossils, found across the globe, have long presented a puzzle regarding their remarkable preservation.

Among the proposed theories, the leading hypothesis is the pyritic "death mask" model, suggesting that microbial mats played a crucial role. These mats coated the ancient seafloors and, in the absence of burrowing organisms, facilitated the preservation process. Now, a team of scientists led by geobiologist Brandt Gibson from Vanderbilt University has undertaken an ambitious experiment to recreate these "death masks" in the lab.

The researchers meticulously sealed sea anemones and sea slugs in containers filled with sand, varying iron concentrations, and sulfate-reducing microbial mats. Over a span of 28 days, they closely observed the decay process, aiming to replicate the conditions that led to the preservation of the Ediacaran fossils.

The outcomes of the experiment were intriguing. The anemone specimens exhibited iron sulfide veneers reminiscent of potential pyrite precursors, offering insight into the formation of Ediacaran-like features. However, the sea slugs and anemone tentacles did not display similar veneers, highlighting the role of tissue composition in the preservation process.

These findings challenge previous assumptions and demonstrate the flexibility of the taphonomic pathway. The study indicates that specific iron sulfide minerals, such as pyrite, may not be necessary for the formation of the "death masks." The availability of iron alone was not sufficient for this style of preservation; seawater sulfate, sulfate-reducing microbes, and suitable tissue nucleation sites for iron sulfide minerals all played critical roles.

The research marks a significant step forward in understanding the complex preservation process of the Ediacaran fossils. While the laboratory experiment did not precisely replicate the natural conditions of the Ediacaran period, it provided valuable insights into the underlying chemical mechanisms. As scientists continue to explore the mysteries of the Ediacaran biota, these new findings contribute to unraveling the enigma and shed light on the early chapters of complex life on our planet.

The research was published here.